Phase I trial of single-photon emission computed tomography-guided liver-directed radiotherapy for patients with low functional liver volume.

BACKGROUND: Traditional constraints specify that 700 cc of liver should be spared a hepatotoxic dose when delivering liver-directed radiotherapy to reduce the risk of inducing liver failure. We investigated the role of single-photon emission computed tomography (SPECT) to identify and preferentially avoid functional liver during liver-directed radiation treatment planning in patients with preserved liver function but limited functional liver volume after receiving prior hepatotoxic chemotherapy or surgical resection. METHODS: This phase I trial with a 3 + 3 design evaluated the safety of liver-directed radiotherapy using escalating functional liver radiation dose constraints in patients with liver metastases. Dose-limiting toxicities were assessed 6-8 weeks and 6 months after completing radiotherapy. RESULTS: All 12 patients had colorectal liver metastases and received prior hepatotoxic chemotherapy; 8 patients underwent prior liver resection. Median computed tomography anatomical nontumor liver volume was 1584 cc (range = 764-2699 cc). Median SPECT functional liver volume was 1117 cc (range = 570-1928 cc). Median nontarget computed tomography and SPECT liver volumes below the volumetric dose constraint were 997 cc (range = 544-1576 cc) and 684 cc (range = 429-1244 cc), respectively. The prescription dose was 67.5-75 Gy in 15 fractions or 75-100 Gy in 25 fractions. No dose-limiting toxicities were observed during follow-up. One-year in-field control was 57%. One-year overall survival was 73%. CONCLUSION: Liver-directed radiotherapy can be safely delivered to high doses when incorporating functional SPECT into the radiation treatment planning process, which may enable sparing of lower volumes of liver than traditionally accepted in patients with preserved liver function. TRIAL REGISTRATION: NCT02626312.

Serum Tumor Markers and Outcomes in Patients With Appendiceal Adenocarcinoma.

Importance: Serum tumor markers carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), and cancer antigen 125 (CA125) have been useful in the management of gastrointestinal and gynecological cancers; however, there is limited information regarding their utility in patients with appendiceal adenocarcinoma. Objective: To assess the association of serum tumor markers (CEA, CA19-9, and CA125) with clinical outcomes and pathologic and molecular features in patients with appendiceal adenocarcinoma. Design, Setting, and Participants: This is a retrospective cohort study at a single tertiary care comprehensive cancer center. The median (IQR) follow-up time was 52 (21-101) months. Software was used to query the MD Anderson internal patient database to identify patients with a diagnosis of appendiceal adenocarcinoma and at least 1 tumor marker measured at MD Anderson between March 2016 and May 2023. Data were analyzed from January to December 2023. Main Outcomes and Measures: Association of serum tumor markers with survival in patients with appendiceal adenocarcinoma. Cox proportional hazards regression analyses were also performed to assess associations between clinical factors (serum tumor marker levels, demographics, and patient and disease characteristics) and patient outcomes (overall survival). Results: A total of 1338 patients with appendiceal adenocarcinoma were included, with a median (range) age at diagnosis of 56.5 (22.3-89.6) years. The majority of the patients had metastatic disease (1080 patients [80.7%]). CEA was elevated in 742 of the patients tested (56%), while CA19-9 and CA125 were elevated in 381 patients (34%) and 312 patients (27%), respectively. Individually, elevation of CEA, CA19-9, or CA125 were associated with worse 5-year survival; elevated vs normal was 81% vs 95% for CEA (hazard ratio [HR], 4.0; 95% CI, 2.9-5.6), 84% vs 92% for CA19-9 (HR, 2.2; 95% CI, 1.4-3.4), and 69% vs 93% for CA125 (HR, 4.6; 95% CI, 2.7-7.8) (P < .001 for all). Quantitative evaluation of tumor markers was associated with outcomes. Patients with highly elevated (top 10th percentile) CEA, CA19-9, or CA125 had markedly worse survival, with 5-year survival rates of 59% for CEA (HR, 9.8; 95% CI, 5.3-18.0), 64% for CA19-9 (HR, 6.0; 95% CI, 3.0-11.7), and 57% for CA125 (HR, 7.6; 95% CI, 3.5-16.5) (P < .001 for all). Although metastatic tumors had higher levels of all tumor markers, when restricting survival analysis to 1080 patients with metastatic disease, elevated CEA, CA19-9, or CA125 were all still associated worse survival (HR for CEA, 3.4; 95% CI, 2.5-4.8; P < .001; HR for CA19-9, 1.8; 95% CI, 1.2-2.7; P = .002; and HR for CA125, 3.9; 95% CI, 2.4-6.4; P < .001). Interestingly, tumor grade was not associated with CEA or CA19-9 level, while CA-125 was slightly higher in high-grade tumors relative to low-grade tumors (mean value, 18.3 vs 15.0; difference, 3.3; 95% CI, 0.9-3.7; P < .001). Multivariable analysis identified an incremental increase in the risk of death with an increase in the number of elevated tumor markers, with an 11-fold increased risk of death in patients with all 3 tumor markers elevated relative to those with none elevated. Somatic mutations in KRAS and GNAS were associated with significantly higher levels of CEA and CA19-9. Conclusions and Relevance: In this retrospective study of serum tumor markers in patients with appendiceal adenocarcinoma, CEA, CA19-9, and CA125 were associated with overall survival in appendiceal adenocarcinoma. Given their value, all 3 biomarkers should be included in the initial workup of patients with a diagnosis of appendiceal adenocarcinoma.

Sustained Disease Control in Immune Checkpoint Blockade Responders with Microsatellite Instability-high Colorectal Cancer after Treatment Termination.

Immune checkpoint inhibitors improve survival in patients with mismatch repair deficiency/microsatellite instability-high (MSI-H) colorectal cancer. The recurrence outcomes following discontinuation of immunotherapy after prolonged disease control have not been definitively reported in large series. Records from patients with advanced MSI-H colorectal cancer from The University of Texas - MD Anderson Cancer Center who received immunotherapy between 2014 and 2022 and stopped after prolonged clinical benefit were reviewed. Median progression-free and overall survival were estimated. Associations between the event of recurrence and coexisting mutations (KRAS/NRAS, BRAFV600E), metastatic organ involvement (lung, liver, lymph node, or peritoneum), metastatic timing (synchronous vs. metachronous), prior immunotherapy [anti-PD-(L)1 alone or in combination with anti-CTLA antibodies], etiology of MSI status (sporadic vs. hereditary non-polyposis colorectal cancer), and duration of immunotherapy were assessed. Sixty-four patients with MSI-H colorectal cancer without progression on immunotherapy were reviewed. Of these 48 and 16 received anti-PD(L)1 antibody alone or in combination with anti-CTLA-4 antibody, respectively. Median exposure to immunotherapy was 17.6 months (range, 1.3-51.9). After a median follow-up of 22.6 months (range, 0.3-71.7) after stopping immunotherapy, 56 of 64 patients (88%) remained without disease progression. Lung metastases were associated with recurrence/progression (OR, 6.1; P = 0.04), but coexisting mutation, primary tumor sidedness, and immunotherapy were not. These data provide a retrospective, single-institution analysis that showed that most patients with advanced MSI-H colorectal cancer do not recur after treatment cessation, regardless of the reason for stopping treatment or a variety of patient and disease features, supporting an optimistic prognosis of sustained disease control. SIGNIFICANCE: Outcomes for patients with MSI-H colorectal cancer stopping immunotherapy after disease control remain unknown. Sixty-four patients with MSI-H colorectal cancer from our institution stopping treatment for sustained benefit or toxicity were retrospectively assessed. After median follow up of 22 months and median immunotherapy exposure of 18 months, 88% patients remained without progression. All patients who recurred or progressed and were rechallenged with immunotherapy have continued to experience disease control.

Novel Clinical Tool to Estimate Risk of False-Negative KRAS Mutations in Circulating Tumor DNA Testing.

PURPOSE: In metastatic colorectal cancer, the detection of RAS mutations by circulating tumor DNA (ctDNA) has emerged as a valid and noninvasive alternative approach to determining RAS status. However, some RAS mutations may be missed, that is, false negatives can occur, possibly compromising important treatment decisions. We propose a statistical model to assess the probability of false negatives when performing ctDNA testing for RAS. METHODS: Cohorts of 172 subjects with tissue and multipanel ctDNA testing from MD Anderson Cancer Center and 146 subjects from Massachusetts General Hospital were collected. We developed a Bayesian model that uses observed frequencies of reference mutations (the maximum of APC and TP53) to provide information about the probability of KRAS false negatives. The model was alternatively trained on one cohort and tested on the other. All data were collected on Guardant assays. RESULTS: The model suggests that negative KRAS findings are believable when the maximum of APC and TP53 frequencies is at least 8% (corresponding posterior probability of false negative <5%). Validation studies demonstrated the ability of our tool to discriminate between false-negative and true-negative subjects. Simulations further confirmed the utility of the proposed approach. CONCLUSION: We suggest clinicians use the tool to more precisely quantify KRAS false-negative ctDNA results when at least one of the reference mutations (APC, TP53) is observed; usage may be especially important for subjects with a maximum reference frequency of <8%. Extension of the methodology to predict false negatives of other genes is possible. Additional reference genes can also be considered. Use of personal training data sets is supported. An open-source R Shiny application is available for public use.

The Clinical Significance of CEA, CA19-9, and CA125 in Management of Appendiceal Adenocarcinoma.

Importance: Serum tumor markers CEA, CA19-9, & CA125 have been useful in the management of gastrointestinal and gynecological cancers, however there is limited information regarding their utility in patients with appendiceal adenocarcinoma. Objective: Assessing the association of serum tumor markers (CEA, CA19-9, and CA125) with clinical outcomes, pathologic, and molecular features in patients with appendiceal adenocarcinoma. Design: This is a retrospective study with results reported in 2023. The median follow-up time was 43 months. Setting: Single tertiary care comprehensive cancer center. Participants: Under an approved Institutional Review Board protocol, the Palantir Foundry software system was used to query the MD Anderson internal patient database to identify patients with a diagnosis of appendiceal adenocarcinoma and at least one tumor marker measured at MD Anderson between 2016 and 2023. Results: A total of 1,338 patients with appendiceal adenocarcinoma were included, with a median age of 56.5 years. The majority of the patients had metastatic disease (80.7%). CEA was elevated in more than half of the patients tested (56%), while CA19-9 and CA125 were elevated in 34% and 27%, respectively. Individually, elevation of CEA, CA19-9, or CA125 were associated with worse 5-year survival; 82% vs 95%, 84% vs 92%, and 69% vs 93% elevated vs normal for CEA, CA19-9, and CA125 respectively (all p<0.0001). Quantitative evaluation of tumor markers increased prognostic ability. Patients with highly elevated (top 10th percentile) CEA, CA19-9 or CA125 had markedly worse survival with 5-year survival rates of 59%, 64%, and 57%, respectively (HR vs. normal : 9.8, 6.0, 7.6, all p<0.0001). Although metastatic tumors had higher levels of all tumor markers, when restricting survival analysis to 1080 patients with metastatic disease elevated CEA, CA19-9 or CA125 were all still associated worse survival (HR vs. normal : 3.4, 1.8, 3.9, p<0.0001 for CEA and CA125, p=0.0019 for CA19-9). Interestingly tumor grade was not associated with CEA or CA19-9 level, while CA-125 was slightly higher in high relative to low-grade tumors (18.3 vs. 15.0, p=0.0009). Multivariable analysis identified an incremental increase in the risk of death with an increase in the number of elevated tumor markers, with a 11-fold increased risk of death in patients with all three tumor markers elevated relative to those with none elevated. Mutation in KRAS and GNAS were associated with significantly higher levels of CEA and CA19-9. Conclusions: These findings demonstrate the utility of measuring CEA, CA19-9, and CA125 in the management of appendiceal adenocarcinoma. Given their prognostic value, all three biomarkers should be included in the initial workup of patients diagnosed with appendiceal adenocarcinoma.

A phase I trial of the pan-ERBB inhibitor neratinib combined with the MEK inhibitor trametinib in patients with advanced cancer with EGFR mutation/amplification, HER2 mutation/amplification, HER3/4 mutation or KRAS mutation.

PURPOSE: Aberrant alterations of ERBB receptor tyrosine kinases lead to tumorigenesis. Single agent therapy targeting EGFR or HER2 has shown clinical successes, but drug resistance often develops due to aberrant or compensatory mechanisms. Herein, we sought to determine the feasibility and safety of neratinib and trametinib in patients with EGFR mutation/amplification, HER2 mutation/amplification, HER3/4 mutation and KRAS mutation. METHODS: Patients with actionable somatic mutations or amplifications in ERBB genes or actionable KRAS mutations were enrolled to receive neratinib and trametinib in this phase I dose escalation trial. The primary endpoint was determination of the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT). Secondary endpoints included pharmacokinetic analysis and preliminary anti-tumor efficacy. RESULTS: Twenty patients were enrolled with a median age of 50.5 years and a median of 3 lines of prior therapy. Grade 3 treatment-related toxicities included: diarrhea (25%), vomiting (10%), nausea (5%), fatigue (5%) and malaise (5%). The MTD was dose level (DL) minus 1 (neratinib 160 mg daily with trametinib 1 mg, 5 days on and 2 days off) given 2 DLTs of grade 3 diarrhea in DL1 (neratinib 160 mg daily with trametinib 1 mg daily). The treatment-related toxicities of DL1 included: diarrhea (100%), nausea (55.6%) and rash (55.6%). Pharmacokinetic data showed trametinib clearance was significantly reduced leading to high drug exposures of trametinib. Two patients achieved stable disease (SD) ≥ 4 months. CONCLUSION: Neratinib and trametinib combination was toxic and had limited clinical efficacy. This may be due to suboptimal drug dosing given drug-drug interactions. TRIAL REGISTRATION ID: NCT03065387.

Feasibility and Safety of Personalized, Multi-Target, Adoptive Cell Therapy (IMA101): First-in-Human Clinical Trial in Patients with Advanced Metastatic Cancer.

IMA101 is an actively personalized, multi-targeted adoptive cell therapy (ACT), whereby autologous T cells are directed against multiple novel defined peptide-HLA (pHLA) cancer targets. HLA-A*02:01-positive patients with relapsed/refractory solid tumors expressing ≥1 of 8 predefined targets underwent leukapheresis. Endogenous T cells specific for up to 4 targets were primed and expanded in vitro. Patients received lymphodepletion (fludarabine, cyclophosphamide), followed by T-cell infusion and low-dose IL2 (Cohort 1). Patients in Cohort 2 received atezolizumab for up to 1 year (NCT02876510). Overall, 214 patients were screened, 15 received lymphodepletion (13 women, 2 men; median age, 44 years), and 14 were treated with T-cell products. IMA101 treatment was feasible and well tolerated. The most common adverse events were cytokine release syndrome (Grade 1, n = 6; Grade 2, n = 4) and expected cytopenias. No patient died during the first 100 days after T-cell therapy. No neurotoxicity was observed. No objective responses were noted. Prolonged disease stabilization was noted in three patients lasting for 13.7, 12.9, and 7.3 months. High frequencies of target-specific T cells (up to 78.7% of CD8+ cells) were detected in the blood of treated patients, persisted for >1 year, and were detectable in posttreatment tumor tissue. Individual T-cell receptors (TCR) contained in T-cell products exhibited broad variation in TCR avidity, with the majority being low avidity. High-avidity TCRs were identified in some patients' products. This study demonstrates the feasibility and tolerability of an actively personalized ACT directed to multiple defined pHLA cancer targets. Results warrant further evaluation of multi-target ACT approaches using potent high-avidity TCRs. See related Spotlight by Uslu and June, p. 865.

Survival improvement for patients with metastatic colorectal cancer over twenty years.

Over the past two decades of successive clinical trials in metastatic colorectal cancer (CRC), the median overall survival of both control and experimental arms has steadily improved. However, the incremental change in survival for metastatic CRC patients not treated on trial has not yet been quantified. We performed a retrospective review of 1420 patients with de novo metastatic CRC who received their primary treatment at the University of Texas M.D. Anderson Cancer Center (UTMDACC) from 2004 through 2019. Median OS was roughly stable for patients diagnosed between 2004 and 2012 (22.6 months) but since has steadily improved for those diagnosed in 2013 to 2015 (28.8 months), and 2016 to 2019 (32.4 months). Likewise, 5-year survival rate has increased from 15.7% for patients diagnosed from 2004 to 2006 to 26% for those diagnosed from 2013 to 2015. Notably, survival improved for patients with BRAFV600E mutant as well as microsatellite unstable (MSI-H) tumors. Multivariate regression analysis identified surgical resection of liver metastasis (HR = 0.26, 95% CI, 0.19-0.37), use of immunotherapy (HR = 0.44, 95% CI, 0.29-0.67) and use of third line chemotherapy (regorafenib or trifluridine/tipiracil, HR = 0.74, 95% CI, 0.58-0.95), but not year of diagnosis (HR = 0.99, 95% CI, 0.98-1), as associated with better survival, suggesting that increased use of these therapies are the drivers of the observed improvement in survival.

Bintrafusp alfa, an anti-PD-L1:TGF-ß trap fusion protein, in patients with ctDNA-positive, liver-limited metastatic colorectal cancer.

Background: Identification of circulating tumor DNA (ctDNA) following curative intent therapies is a surrogate for microscopic residual disease for patients with metastatic colorectal cancer (mCRC). Preclinically, in micrometastatic microsatellite stable (MSS) CRC, increased TGF-ß signaling results in exclusion of anti-tumor cytotoxic T cells from the tumor microenvironment. Bintrafusp alfa (BA) is a bifunctional fusion protein composed of the extracellular domain of the TGF-ßRII receptor ("TGF-ß trap") and anti-PD-L1 antibody. Methods: Patients with liver-limited, MSS mCRC and with detected ctDNA after complete resection of all known tumors and standard-of-care therapy were treated with 1200 mg of BA intravenously every 14 days for six doses. The primary endpoint was ctDNA clearance. Radiographic characteristics at recurrence were compared using independent t-tests to historical data from a similar cohort of patients with liver-limited mCRC who underwent observation. Results: Only 4 of 15 planned patients received BA before the study was stopped early for loss of equipoise. There was no grade ≥3 AE. None of the patients cleared ctDNA. All patients developed radiographic recurrence by the first planned restaging. Although not detectable at prior to treatment, TGFß3 was found in circulation in all patients at cycle 2 day 1. Compared to a historical cohort, patients administered BA developed more metastases (15 versus 2, p=0.005) and greater tumor volumes (9 cm vs 2 cm, p=0.05). Conclusions: Treatment with BA in patients with ctDNA-detected, liver-limited mCRC did not clear ctDNA and was associated with large-volume recurrence, highlighting the potential context-specific complexity of dual TGF-ß and PD-L1 inhibition.

Association of Prediagnosis Obesity and Postdiagnosis Aspirin With Survival From Stage IV Colorectal Cancer.

Importance: The potential relationship between obesity and colorectal cancer (CRC) outcome is poorly understood in patients with late-stage disease. Increased body mass index may negate aspirin use for cancer prevention, but its role as a factor on the effectiveness of postdiagnosis aspirin use is unclear. Objective: To evaluate how prediagnosis obesity and postdiagnosis aspirin use may be associated with overall survival in patients with late-stage colorectal cancer. Design, Setting, and Participants: This cross-sectional study used self-reported data from patients with metastatic or treatment-refractory disease who consented to a clinical protocol at MD Anderson Cancer Center, a large US cancer treatment center. Patients were enrolled between 2010 and 2018 and followed up for mortality through July 2020. Analyses were conducted through March 2022. Exposures: Body mass index in the decade prior to initial diagnosis and regular aspirin use at survey completion. Main Outcomes and Measures: Overall survival was measured from stage IV diagnosis until death or last follow-up. Cox proportional hazards models were constructed to estimate associations of prediagnosis obesity and postdiagnosis aspirin use with overall survival. Results: Of 656 patients included in this analysis, 280 (42.7%) were women, 135 (20.6%) were diagnosed with CRC before age 45 years, 414 (63.1%) were diagnosed between ages 45 and 65 years, and 107 (16.3%) were diagnosed at 65 years or older; 105 patients (16.0%) were Black or Hispanic, and 501 (76.4%) were non-Hispanic White. Controlling for age, sex, race, stage at initial diagnosis, and weight change between prediagnosis and survey date, patients with obesity in the decade prior to CRC diagnosis had significantly higher likelihood of death (hazard ratio, 1.45; 95% CI, 1.11-1.91) compared with those with normal prediagnosis body mass index. Furthermore, only patients with normal prediagnosis body mass index experienced significant survival benefit with postdiagnosis aspirin use (hazard ratio, 0.59; 95% CI, 0.39-0.90). Conclusions and Relevance: In this cross-sectional study, our findings suggest potentially differential tumor development in the long-term physiologic host environment of obesity. Confirmation and further evaluation are needed to determine whether prediagnosis body mass index may be used to estimate the benefit from postdiagnosis aspirin use.

Phase II study of durvalumab (anti-PD-L1) and trametinib (MEKi) in microsatellite stable (MSS) metastatic colorectal cancer (mCRC).

BACKGROUND: Monotherapy with immune checkpoint blockade is ineffective for patients (pts) with microsatellite stable (MSS) metastatic colorectal cancer (mCRC). This study investigates whether the combination of trametinib (T) with durvalumab (D) can alter the immune tumor microenvironment (TME) by successfully priming and activating T-cells. METHODS: Open-label, single-center, phase II trial with primary endpoint of immune-related response rate for combination of T+D in refractory MSS mCRC pts (NCT03428126). T is 2 mg/day orally starting 1 week prior to D, which is given 1500 mg intravenously every 4 weeks. Simon 2-stage design used to enroll 29 pts into first stage, requiring a response in two or more pts to proceed to stage 2. Tumor biopsies were collected at baseline (BL) and early on-treatment (OT) at week 4. RESULTS: Twenty nine treated pts include 48% females, median age 48 years (range 28-75), and median prior therapies 2 (range 1-5). No grade (G) 4 or 5 treatment-related adverse events (TRAE). The most common TRAE of any grade was acneiform rash, 17% being G3. One of 29 pts had confirmed partial response (PR) lasting 9.3 months (mo) for an overall response rate of 3.4%. Seven pts had stable disease (SD) and five pts (1 PR, 4 SD) demonstrated decrease in total carcinoembryonic antigen ng/mL (best percentage reduction: 94%, 95%, 42%, 34%, and 22%, respectively). Median progression-free survival was 3.2 mo (range 1.1-9.3 months). Three pts with both liver and lung metastases demonstrated discrepant responses in which clinical benefit was present in the lung metastases but not liver metastases. Comparison of BL and 4-week OT tumor tissue flow cytometry demonstrated no changes in T-cell infiltration but upregulation expression of PD-1 and Tim3 on CD8 T cells. However, expression of PD-1 and Tim3 as single markers and as coexpressed markers was observed to increase OT relative to BL (p=0.03, p=0.06 and p=0.06, respectively). CONCLUSIONS: T+D demonstrated acceptable tolerability in pts with refractory MSS mCRC. The response rate in the first stage of the study did not meet efficacy criteria to proceed to the second stage. Specific site of metastatic disease may impact outcomes in novel immunotherapy combination trials. TRIAL REGISTRATION NUMBER: NCT03428126.

Colorectal cancer during pregnancy or postpartum: Case series and literature review.

Background: Colorectal cancer in young adults is on the rise. This rise combined with delayed childbearing increases the likelihood of colorectal cancer diagnosed during pregnancy or in the postpartum period. Methods: Electronic health records were used to identify individuals with colorectal cancer in pregnancy or the postpartum period from 1 August 2007 to 1 August 2019. Results: Forty-two cases were identified. Median age at diagnosis was 33 years. Most (93%) were diagnosed in an advanced stage (III or IV) and had left-sided colorectal cancer tumors (81%). Molecular analysis was completed in 18 (43%) women with microsatellite status available in 40 (95%). The findings were similar to historical controls. Sixty percent were diagnosed in the postpartum period. Common presenting symptoms were rectal bleeding and abdominal pain. Conclusion: Currently there is no consensus recommendation regarding how to manage colorectal cancer during pregnancy. Given the overlapping symptoms with pregnancy, patients often present with advanced disease. We encourage all health care professionals caring for pregnant women to fully evaluate women with persistent gastrointestinal symptoms to rule out colorectal cancer.

Clinical and pathologic features correlated with rare favorable survival in patients with BRAFV600E mutated colorectal cancer.

Background: BRAFV600E mutations occur in fewer than 10% of all patients with metastatic colorectal cancer (CRC) and arise from sessile serrated adenomas. Despite efficacy with targeted therapies against MAPK signaling and with immunotherapies in this population, survival outcomes for patients with BRAFV600E mutated metastatic CRC in general are poor. Characteristics distinguishing patients with BRAFV600E mutated metastatic CRC with favorable versus unfavorable outcomes have not been well annotated. Methods: Records of 187 patients with BRAFV600E mutated metastatic CRC evaluated at MD Anderson Cancer Center between 2005-2020 were reviewed. Patients with the shortest and longest metastatic survival (N=25 for each group) were compared. Associations between prognostic group and clinical/pathologic features were measured by odds ratio and for median survival by log-rank testing. Results: Median metastatic survival differed between the 2 BRAFV600E mutated metastatic CRC populations (8.6 vs. 83.9 months, hazard ratio 32; P<0.0001). Patients with poor survival more commonly had hepatic involvement [75% vs. 28%, odds ratio (OR) 8.1, 95% confidence interval (CI): 2.3-29; P=0.001]. Patients with favorable survival were more likely to develop metachronous metastases (52% vs. 16%, OR 5.7, 95% CI: 1.5-21; P=0.01) and undergo definitive locoregional therapy to metastatic disease (40% vs. 0%, OR 34.5, 95% CI: 1.9-630; P=0.01). Microsatellite instability (36% vs. 4%, OR 19.8, 95% CI: 2.2-180; P=0.008) and prior tobacco exposure (44% vs. 16%, OR 4.1, 95% CI: 1.1-15.6, P=0.04) were associated with a favorable prognosis. Durable responses to MAPK-targeted therapies and immunotherapy were noted in the favorable group. Conclusions: A small fraction of patients with BRAFV600E mutated metastatic CRC can achieve excellent long-term survival which belies conventional context and is driven by either surgical metastectomy or by systemic treatment options. While poor overall prognosis remains the recognized outcome for most patients with BRAFV600E mutated metastatic CRC, it is possible that few may achieve exceptionally favorable survival.

Comprehensive Clinical and Molecular Characterization of KRAS G12C-Mutant Colorectal Cancer.

PURPOSE: KRAS p.G12C mutations occur in approximately 3% of metastatic colorectal cancers (mCRC). Recently, two allosteric inhibitors of KRAS p.G12C have demonstrated activity in early phase clinical trials. There are no robust studies examining the behavior of this newly targetable population. METHODS: We queried the MD Anderson Cancer Center data set for patients with colorectal cancer who harbored KRAS p.G12C mutations between January 2003 and September 2019. Patients were analyzed for clinical characteristics, overall survival (OS), and progression-free survival (PFS) and compared against KRAS nonG12C. Next, we analyzed several internal and external data sets to assess immune signatures, gene expression profiles, hypermethylation, co-occurring mutations, and proteomics. RESULTS: Among the 4,632 patients with comprehensive molecular profiling, 134 (2.9%) were found to have KRAS p.G12C mutations. An additional 53 patients with single gene sequencing were included in clinical data but excluded from prevalence analysis allowing for 187 total patients. Sixty-five patients had de novo metastatic disease and received a median of two lines of chemotherapy without surgical intervention. For the first three lines of chemotherapy, the median PFS was 6.4 months (n = 65; 95% CI, 5.0 to 7.4 months), 3.9 months (n = 47; 95% CI, 2.9 to 5.9 months), and 3.0 months (n = 21; 95% CI, 2.0 to 3.4 months), respectively. KRAS p.G12C demonstrated higher rates of basal EGFR activation compared with KRAS nonG12C. When compared with an internal cohort of KRAS nonG12C, KRAS p.G12C patients had worse OS. CONCLUSION: PFS is poor for patients with KRAS p.G12C metastatic colorectal cancer. OS was worse in KRAS p.G12C compared with KRAS nonG12C patients. Our data highlight the innate resistance to chemotherapy for KRAS p.G12C patients and serve as a historical comparator for future clinical trials.

Fertility discussions in young adult stage III colorectal cancer population: a single-center institution experience.

PURPOSE: Colorectal cancer (CRC) is a malignancy that usually occurs in older age individuals. However, CRC cases in young adults are on the rise, and this increase is expected to continue. Young adult CRC requires the healthcare team to familiarize themselves with the unique needs of this population, including concerns about treatment-related infertility. We performed a retrospective review to determine how often our patients, 18-39 years old (yo), had discussions regarding fertility preservation prior to starting stage III CRC treatment. METHODS: Our electronic health record was utilized to identify adult patients < 40 yo with a stage III CRC diagnosis during 1/1/2015-9/1/2019. Fertility preservation discussions were determined by searching the patient's EHR chart. Progress notes from the medical oncology, surgery, and/or radiation oncology teams were reviewed. Additionally, notes from our fertility specialist's team were reviewed when consulted. RESULTS: One hundred and three patients met criteria. Patients were 21-39 yo at diagnosis (median age of 34 yo). Fifty-two percent were male while the remaining 48% were female. Forty-six percent had stage III colon cancer while 54% had stage III rectal cancer. Search terms and progress notes were utilized to determine if discussions were documented. Fertility discussions were documented in 73% of cases while 27% of patients lacked documentation regarding fertility. CONCLUSION: Our results show that most of our young adult stage III CRC population participate in fertility preservation discussions. However, in order to capture all patients, we recognize that a more formal approach is warranted. We additionally recommend these discussions occur with all patients of child-bearing age.

Pilot Clinical Trial of Perioperative Durvalumab and Tremelimumab in the Treatment of Resectable Colorectal Cancer Liver Metastases.

PURPOSE: Despite the prognostic importance of immune infiltrate in colorectal cancer, immunotherapy has demonstrated limited clinical activity in refractory metastatic proficient mismatch-repair (pMMR) colorectal cancer. This study explores combining anti-CTLA-4 and an anti-PD-L1 therapy in the preoperative management of resectable colorectal cancer liver metastases with the intent to improve immune responses in this disease setting. PATIENTS AND METHODS: Patients with resectable colorectal cancer liver-only metastases received one dose of tremelimumab and durvalumab preoperatively followed by single-agent durvalumab postoperatively. Primary objectives were to determine feasibility and safety. RESULTS: A total of 24 patients were enrolled between November 2016 and November 2019. Twenty-three patients received treatment [21 pMMR and 2 deficient mismatch-repair (dMMR)] and subsequently 17 (74%; 95% CI: 53%-88%) underwent surgical resection. Grade 3/4 treatment-related immune toxicity and postoperative grade 3/4 toxicity were seen in 5/23 (22%; 95% CI: 10%-44%) and 2/17 (12%; 95% CI: 2%-38%) patients. The median relapse-free survival (RFS) was 9.7 (95% CI: 8.1-17.8) months, and overall survival was 24.5 (95% CI: 16.5-28.4) months. Four patients demonstrated complete pathologic response, two dMMR patients and two POLE mutation patients. Pre- and post-tumor tissue analysis by flow cytometry, immunofluorescence, and RNA sequencing revealed similar levels of T-cell infiltration, but did demonstrate evidence of CD8+ and CD4+ activation posttreatment. An increase in B-cell transcriptome signature and B-cell density was present in posttreatment samples from patients with prolonged RFS. CONCLUSIONS: This study demonstrates the safety of neoadjuvant combination tremelimumab and durvalumab prior to colorectal cancer liver resection. Evidence for T- and B-cell activation following this therapy was seen in pMMR metastatic colorectal cancer.

Epidemiology and Molecular-Pathologic Characteristics of CpG Island Methylator Phenotype (CIMP) in Colorectal Cancer.

BACKGROUND: CpG island methylator phenotype (CIMP) forms a distinct epigenetic phenotype in colorectal cancer (CRC). Though associated with distinct clinicopathologic characteristics, limited evidence exists of the association of CIMP with patient's reported lifestyle factors and tumor molecular characteristics. We assessed the associations of these characteristics in a pooled analysis of CRC patients. PATIENTS AND METHODS: We pooled data from 3 CRC patient cohorts: Assessment of Targeted Therapies Against Colorectal Cancer (ATTACC), biomarker-based protocol (Integromics), and The Cancer Genome Atlas (TCGA). CIMP was measured using the classical 6-gene methylated-in-tumor (MINT) marker panel (MINT1, MINT2, MINT31, p14, p16, and MLH1) in ATTACC and genome-wide human methylation arrays in Integromics and TCGA, respectively. CIMP-High (CIMP-H) was defined as ≥ 3 of 6 methylated markers in ATTACC. In TCGA and Integromics, CIMP-H group was defined on the basis of clusters of methylation profiles and high levels of methylation in tumor samples. Baseline comparisons of characteristics across CIMP groups (CIMP-H vs. CIMP-0) were performed by Student t test or chi-square test for continuous or categorical variables, respectively. Further logistic regression analyses were performed to compute the odds ratio (OR) of these associations. RESULTS: Pooled prevalence of CIMP-H was 22% across 3 data sets. CIMP-H CRC tumors were associated with older age at diagnosis (OR, 1.02; 95% confidence interval [CI], 1.01, 1.03), microsatellite instability-high (MSI-H) status (OR, 9.15; 95% CI, 4.45, 18.81), BRAF mutation (OR, 7.70; 95% CI, 4.98, 11.87), right-sided tumor location (OR, 2.40; 95% CI, 1.78, 3.22), poor differentiation (OR, 2.94; 95% CI, 1.95, 4.45), and mucinous histology (OR, 2.47; 95% CI, 1.77, 3.47), as reported previously in the literature. CIMP-H tumors were also found to be associated with self-reported history of alcohol consumption (OR, ever vs. never, 1.58; 95% CI, 1.07, 2.34). Pathologically, CIMP-H tumors were associated with the presence of intraepithelial lymphocytes (OR, 3.31; 95% CI, 1.41, 7.80) among patients in the Integromics cohort. CONCLUSION: CIMP-H tumors were associated with history of alcohol consumption and presence of intraepithelial lymphocytes. In addition, we confirmed the previously known association of CIMP with age, MSI-H status, BRAF mutation, sidedness, and mucinous histology. Molecular pathologic epidemiology associations help us explore the underlying association of lifestyle and clinical factors with molecular subsets like CIMP and help guide cancer prevention and treatment strategies.

FOLFOXIRI Versus Doublet Regimens in Right-Sided Metastatic Colorectal Cancer: Focus on Subsequent Therapies and Impact on Overall Survival.

INTRODUCTION: It has been determined that right-sided metastatic colorectal cancer (mCRC) has a worse prognosis for overall survival (OS). Currently, there is no consensus on the best systemic regimen for treatment-naive right-sided tumors. We compared the impact of subsequent therapies on OS of patients treated with FOLFOXIRI (leucovorin, 5-fluorouracil, oxaliplatin, irinotecan) versus doublet regimens. PATIENTS AND METHODS: Data of patients with treatment-naive right-sided mCRC who received FOLFOXIRI or doublet regimens between January 2001 to December 2018 were retrospectively analyzed. OS was compared between the two groups, and prognostic factors were assessed by multivariate analysis. RESULTS: A total of 196 patients were selected; 33 patients received FOLFOXIRI and 163 patients doublet therapy. Median follow-up was 82.3 months. The FOLFOXIRI cohort received fewer subsequent lines of therapies (61% vs. 78%, P = .043). The greater the number of subsequent lines of therapy, the lower the risk of death (hazard ratio [95% confidence interval] 0.67 [0.46-0.99], 0.62 [0.45-0.86], and 0.56 [0.39-0.81] for > 1, > 2, and > 3 lines, respectively). By multivariate analysis, metastasectomy and bevacizumab with subsequent lines of therapy were the variables with greatest positive impact on OS (respectively, hazard ratio [95% confidence interval] 0.54 [0.38-0.78] and 0.61 [0.44-0.84]). CONCLUSION: Patients with treatment-naive right-sided mCRC who received front-line FOLFOXIRI had a lower number of subsequent therapies than patients who received doublet regimens. Our findings highlight the relevance of the continuum of care in mCRC, regardless of the first-line regimen, and the importance of careful selection of patients for the FOLFOXIRI regimen.

Bevacizumab Does Not Influence the Efficacy of Partial Splenic Embolization in the Management of Chemotherapy-Induced Hypersplenism.

BACKGROUND: Antiangiogenics attenuate chemotherapy-related hepatotoxicity and portal hypertension. The potential impact of bevacizumab on the efficacy and safety of partial splenic embolization (PSE) in the management of chemotherapy-induced hypersplenism (CIH) has never been investigated. PATIENTS AND METHODS: We conducted a retrospective study with gastrointestinal cancer patients who have undergone PSE for the treatment of thrombocytopenia resulting from hypersplenism. Pre- and post-PSE platelet count (PC), the percentage of patients who resumed systemic therapy, and complication rates were compared between patients exposed and not exposed to bevacizumab. RESULTS: A total of 110 patients were eligible. Colorectal cancer was the predominant neoplasm (60%), and 5-fluorouracil, oxaliplatin, and bevacizumab were the most commonly provided drugs (70%, 65%, and 65% of patients, respectively). After PSE, 80% of patients recovered PC ≥ 100 × 109/L (100K). Systemic therapy was resumed in 81% of patients. Seventy-one patients exposed to bevacizumab had a median PC before PSE of 77.5K and after PSE of 167.0K, with a mean difference of 108K (P < .0001). Thirty-nine patients not exposed to bevacizumab had a median PC of pre-PSE of 73.0K and post-PSE of 187.0K, with a mean difference of 117.7K (P < .0001). Both groups had similar values of percentages of patients with PC post-PSE ≥ 100K (83% vs. 74%; P = .463), resumption of systemic therapy (85% vs. 74%; P = .213), and complication rates. A linear association between splenic infarction rate and increment in PC was found (P < .0001). CONCLUSION: PSE is a safe and effective procedure in the management of CIH, regardless of the provision of bevacizumab. Splenic infarction rate should be optimized to enhance patient outcomes.

Patient-reported Symptom Outcomes and Microsatellite Instability in Patients With Metastatic Colorectal Cancer.

BACKGROUND: The survival of patients with metastatic colorectal cancer (mCRC) is influenced by the genetic and epigenetic changes that might influence the patient experience of symptom burden. Understanding the association of molecular changes with the symptom burden could help clinicians gain insight into the molecular basis of symptom burden and improve treatment tolerance. To date, no studies have compared the patient-reported symptom burden with these molecular subsets among patients with mCRC. PATIENTS AND METHODS: We recruited patients with mCRC that was refractory to ≥ 1 line of therapy who had been enrolled in the Assessment of Targeted Therapies Against Colorectal Cancer trial at The University of Texas MD Anderson Cancer Center. All patients completed a baseline gastrointestinal symptom inventory (MD Anderson Symptom Inventory, gastrointestinal). The symptom burden across key demographic variables and molecular changes, including CRC-associated mutations, microsatellite instability (MSI) status, and the CpG island methylator phenotype (CIMP) were compared using χ2 tests. Association of the symptom burden with overall survival was examined using Cox regression models. RESULTS: Patients with an MSI-high (MSI-H) phenotype reported greater pain (odds ratio [OR], 3.06; 95% confidence interval [CI], 1.61-5.84), fatigue (OR, 2.78; 95% CI, 1.41-5.49), sleep (OR, 2.52; 95% CI, 1.32-4.08); and drowsiness (OR, 2.51; 95% CI, 1.32-4.78) compared with microsatellite stable patients. Patients with an MSI-H phenotype also had greater odds of overall symptom burden (OR, 2.48; 95% CI, 1.29-4.74) compared with microsatellite stable patients. The CIMP-high patients experienced greater odds of pain compared with the CIMP-negative patients (OR, 1.72; 95% CI, 1.06-2.80). A greater overall symptom burden was associated with poor overall survival (hazard ratio, 1.42; 95% CI, 0.98-2.06]), although the difference was not significant (P = .06). CONCLUSION: Correlation of MSI-H-associated tumor features with the symptom burden could help provide a better understanding of underlying mechanisms associated with our findings.