Circulating Tumor DNA in Identifying Resistant Sub-Clones Post EGFR Blockade: Implications for EGFR Rechallenge.

For patients with metastatic RAS/RAF wild-type refractory colorectal cancer, the question of anti-EGFR therapy rechallenge often comes up after initial use. However, not all patients derive benefit. It is now well known that these tumors acquire mechanisms of resistance in the mitogen-activated protein kinase (MAPK) pathway, which can be detected on circulating tumor DNA (ctDNA)-based testing. We present a series of patients who had serial testing post-EGFR blockade showing its feasibility and value. This would have implications for EGFR rechallenge. We reviewed records for patients who were initially noted to be RAS/RAF wild-type on tissue, who received prior anti-EGFR therapy and then subsequently had at least one circulating tumor DNA-based testing. These patients also had tissue-based genomic testing obtained earlier as part of their standard of care, alongside serial ctDNA-based testing that was done later when subsequent lines of therapy were being decided. The median duration of initial prior anti-EGFR therapy was around 10 months. Known acquired mechanisms of resistance were noted in 100% of the cases. These included KRAS, NRAS, extracellular domain mutations in EGFR, and BRAF mutations. Interestingly, the levels of the sub-clones expressed in variant allele fraction percentage varied and decreased over time in relation to timing of the prior EGFR exposure. Additionally, these were noted to be polyclonal, and the number of clones also varied including some disappearing over time during non-EGFR-based therapy (EGFR holiday). Patients' post-EGFR blockade may have multiple mechanisms of acquired resistance that can be easily detected on non-invasive liquid biopsies. These patients do not benefit from EGFR rechallenge based on the results of the recently reported CRICKET (NCT02296203) and CAVE (NCT04561336) clinical trials. Furthermore, excluding these patients from EGFR rechallenge is already being adopted in prospectively done clinical trials, e.g., the CHRONOS study (NCT03227926). Rechecking the liquid biopsy plasma RAS/RAF status is one thing that may be incorporated into practice with EGFR rechallenge only a consideration if acquired mechanisms of resistance are absent.

Risk Factors and Biomarkers for Immune-Related Adverse Events: A Practical Guide to Identifying High-Risk Patients and Rechallenging Immune Checkpoint Inhibitors.

Immune-related adverse events (irAEs) are a range of complications associated with the use of immune-checkpoint inhibitors (ICIs). Two major classes of ICIs widely used are Cytotoxic T-Lymphocyte Antigen 4 (CTLA4) and Programmed Cell death-1 (PD-1)/Programmed death-ligand 1 (PD-L1) inhibitors. High-grade irAEs are life-threatening and often cause a severe decline in performance status in such that patients do not qualify for any further anticancer treatments. It is difficult to generalize the evidence in the current literature on risk factors or biomarkers for the entire class of ICIs as the studies so far are either disease-specific (e.g., lung cancer or melanoma) or ICI agent-specific (e.g., pembrolizumab, ipilimumab) or irAE-specific (e.g., pneumonitis or gastritis). In this review, risk factors and biomarkers to consider before initiating or monitoring ICI are listed with a practical purpose in day-to-day practice. Risk factors are grouped into demographics and social history, medical history, and medication history, tumor-specific and agent-specific risk factors. A higher risk of irAE is associated with age <60 years, high body mass index, women on CTLA4 and men on PD-1/PD-L1 agents, and chronic smokers. Patients with significant kidney (Stage IV-V), cardiac (heart failure, coronary artery disease, myocardial infarction, hypertension), and lung (asthma, pulmonary fibrosis, and chronic obstructive pulmonary disease) are at a higher risk of respective organ-specific irAEs. Pre-existing autoimmune disease and chronic use of certain drugs (proton pump inhibitors, diuretics, anti-inflammatory drugs) also increase the irAE-risk. Biomarkers are categorized into circulating blood counts, cytokines, autoantibodies, HLA genotypes, microRNA, gene expression profiling, and serum proteins. The blood counts and certain protein markers (albumin and thyroid-stimulating hormone) are readily accessible in current practice. High neutrophil-lymphocyte ratio, eosinophil/monocyte/lymphocyte counts; TSH and troponins at diagnosis and drop in the white count and lymphocyte count can predict irAE. Other biomarkers with limited evidence are cytokines, autoantibodies, HLA genotypes, microRNA, and gene expression profiling. With fast-expanding approvals for ICIs in various cancer types, knowledge on risk factors and biomarkers can help providers assess the irAE-risk of their patients. Prospective disease and agent-specific studies are needed to provide further insight on this essential aspect of ICI therapy.

Poly Adenosine Diphosphate-Ribose Polymerase (PARP) Inhibitors in Pancreatic Cancer.

Pancreatic cancer is the third most common cause of cancer death in the United States and eleventh worldwide. The majority of patients present with advanced disease with five-year overall survival of less than 10%. Traditional chemotherapy has been the mainstay treatment for years, with limited improvement in survival. Relative success has been achieved with agents targeting the DNA damage repair (DDR) mechanisms with poly adenosine diphosphate-ribose polymerase (PARP) inhibitors. The initial benefit was observed in patients with germline breast cancer-associated (BRCA) mutations. Multiple trials are now underway exploring PARP inhibitors in other DDR mutations such as the ataxia-telangiectasia mutated (ATM) gene and the cyclin-dependent kinase inhibitor 2A (CDKN2A) gene (familial atypical multiple mole and melanoma syndrome), mismatch repair genes (Lynch syndrome), and others. PARP inhibitors are being evaluated as a single agent or combination chemotherapy, immunotherapy, and maintenance after chemotherapy. Here, we review current clinical trials targeting various DDR mutations and treatment strategies.

Outcomes of patients with stage III non-small cell lung cancer (NSCLC) that harbor a STK11 mutation.

BACKGROUND: STK11 mutation (STK11m ) in patients (pts) with stage IV non-small cell lung cancer (NSCLC) is associated with inferior survival and poor response to immune checkpoint inhibitors (ICI). The significance of STK11m in stage III NSCLC pts treated with concurrent chemoradiation (CCRT) with or without consolidation ICI is unknown. METHODS: Stage III NSCLC patients who received CCRT and had known STK11 mutational status were included in this retrospective study. The data on the STK11m pts were collected from 4 cancer institutions. A cohort of pts with wild type STK11 (STK11w ) from the University of Iowa served as a comparison group. Patient demographics and clinical characteristics were collected. Cox regression models were used to explore the effect of STK11 mutation on survival. RESULTS: 75 pts with stage III NSCLC who had known STK11 mutational status were identified. 16/75 (21%) had STK11m . 5/16 with STK11 m did not receive CCRT so they were excluded from the analysis. The clinical and demographic characteristics for the 11 STK11m and 59 STK11w pts were not statistically different (STK11m vs. STK11w ): mean age: 57 vs. 64 yrs, non-squamous histology: 8/11 (73%) vs. 37/59 (63%), KRAS mutation: 3/11 (27%) vs. 11/59 (19%), TP53 mutation: 6/11 (55%) vs. 15/59 (25%), PD-L1 ≥50%: 1/8 (13%) vs. 10/32 (31%), and consolidation ICI 6/11 (55%) vs. 17/59 (29%). Regarding the 6 STK11m pts who received ICI (4 pembrolizumab, 2 durvalumab), the median number of ICI infusions was 8 (range, 3-17) vs. 6 (range, 1-25) in the 17 pts with STK11w who received ICI (durvalumab). After adjusting for performance status and cancer stage, multivariable analysis showed that progression free survival (PFS) for the STK11m pts was significantly worse than STK11 w pts (HR =2.25; 95% CI, 1.03-4.88, P=0.04), whereas overall survival (OS) showed no significant difference for STK11m vs. STK11w patients (HR 1.47, 95% CI, 0.49-4.38, P=0.49). CONCLUSIONS: In stage III NSCLC patients who received CCRT, STK11m was associated with worse PFS compared to STK11w . Larger studies are needed to further explore the prognostic implications of STK11m in stage III NSCLC and whether ICI impacts survival for this subgroup.

Twenty-year Experience with Genitourinary Lymphoma at a Community Hospital.

Introduction: Non-Hodgkin lymphoma is the seventh most common cancer in the United States. It may involve any extranodal organ, although involvement of the genitourinary (GU) tract accounts for <5% of all primary extranodal lymphomas. Published GU lymphoma literature is currently limited to small case series and case reports. The last substantial American series was published in 2009. Our objective was to characterize cases of GU lymphoma from our institution based on organ involved and to review relevant literature.Patients and Methods: After institutional review board approval, we retrospectively reviewed medical records of patients diagnosed with lymphoma involving the GU organs from 1995 through 2015. Patients with obstructive uropathy from retroperitoneal adenopathy without parenchymal involvement of a GU organ were excluded. We classified extranodal GU lymphomas as primary or secondary, based on involvement of other organs and distant lymphadenopathy.Results: Thirty-six patients had lymphoid neoplasms involving the kidney, ureters, bladder, testis, penile skin, or prostate in our health system during the study period. Of these, 15 (41.6%) were primary. Most patients initially sought consultation for GU-related symptoms, such as bladder obstruction, hematuria, testicular mass, or abdominal pain. Histological subtypes and flow cytometry findings varied broadly.Conclusion: Our series reports site-specific outcomes data and adds detail to findings from other published series. Although GU lymphomas are rare, our series confirms prior studies demonstrating presentation in urologic organs. They should be considered in the differential diagnosis in all patients, especially those with unusual findings on examination, cystoscopy, or computed tomography scan.

Patient Characteristics and Survival Outcomes of Non-Metastatic, Non-Clear Cell Renal Cell Carcinoma.

BACKGROUND: Non-clear cell renal cell carcinoma (ccRCC) includes histologically and molecularly distinct subtypes such as papillary, chromophobe, collecting duct, and sarcomatoid RCC, with an incidence ranging from 20% to 25%. Oncologic outcomes and the role of adjuvant systemic therapy [vascular endothelial growth factor inhibitor (VEGFi) or immunotherapy] for non-ccRCC are not well-described. OBJECTIVE: To assess the incidence and survival outcomes of non-ccRCC subtypes in comparison to ccRCC. METHODS: The National Cancer Database was utilized to identify patients with non-metastatic RCC (T1-T4, N0-N1) between 2004 and 2015. The non-ccRCC cohort was further stratified by histologic subtype: papillary, chromophobe, sarcomatoid, and collecting duct RCC. Multivariable Cox regression models were used to compare overall survival (OS). RESULTS: The 5-year OS for chromophobe, papillary, clear cell, collecting duct, and sarcomatoid RCC was 91%, 82%, 81%, 44%, and 40%, respectively. After adjusting for clinicopathologic and treatment characteristics, there was no significant difference in OS between papillary RCC and ccRCC (p = 0.17). Patients with collecting duct and sarcomatoid subtypes were at over two times increased risk of death compared to patients with clear cell (p < 0.01 and p < 0.01, respectively). Conversely, patients with chromophobe RCC were at 36% decreased risk of death compared to ccRCC (p < 0.01). CONCLUSIONS: This hospital-based analysis confirms that collecting duct and sarcomatoid histologic subtypes are uncommon and associated with poor survival after surgery when compared to the other RCC subtypes. Further studies are needed to evaluate the role of neoadjuvant and adjuvant systemic therapies in these subtypes to improve oncologic outcomes.

Multivariable Analysis of 169 Cases of Advanced Cutaneous Melanoma to Evaluate Antibiotic Exposure as Predictor of Survival to Anti-PD-1 Based Immunotherapies.

Recently antibiotic exposure has been associated with worse outcomes in patients undergoing treatment with antibodies directed against programmed cell death protein-1 (PD-1). We reviewed data of 1264 patients enrolled at Melanoma Skin and Ocular Tissue Repositories at University of Iowa Hospitals and Clinic. Reviewed data included patient demographics, prior medical history, baseline hematologic and disease parameters and outcomes including progression-free survival (PFS) and overall survival (OS). Cox regression models were used to determine predictive markers. Overall, 169 patients with advanced cutaneous melanoma received anti-PD-1 based therapies. Median follow up was 18.46 (range 0.89 to 62.52) months. On multivariable analysis brain metastasis, higher absolute neutrophil count (ANC) and lower absolute lymphocyte count were associated with poorer PFS while brain and liver metastasis and lower albumin were associated with poorer OS. Prior antibiotics, radiation as well as age, gender, basal metabolic index (BMI), smoking status, BRAF mutation, line of therapy (first or latter), prior treatments (ipilimumab or BRAF inhibitors), hemoglobin, neutrophil-to-lymphocyte ratio, white blood cell, platelet and eosinophil counts were not associated with PFS or OS in multivariable analysis. Contrary to some prior studies BMI, radiation, and antibiotics were not associated with PFS or OS.

Therapeutic Potential of Combining PARP Inhibitor and Immunotherapy in Solid Tumors.

Immunotherapy has revolutionized the treatment of both hematological malignancies and solid tumors. The use of immunotherapy has improved outcome for patients with cancer across multiple tumor types, including lung, melanoma, ovarian, genitourinary, and more recently breast cancer with durable responses seen even in patients with widespread metastatic disease. Despite the promising results, immunotherapy still helps only a subset of patients due to overall low response rates. Moreover, the response to immunotherapy is highly cancer specific and results have not been as promising in cancers that are considered less immunogenic. The strategies to improve immunotherapy responses have focused on biomarker selection, like PD-L1 status, and usage of combinatorial agents, such as chemotherapy, targeted therapy, and radiotherapy. Of particular interest, DNA-damaging agents have the potential to enhance the response to immunotherapy by promoting neoantigen release, increasing tumor mutational burden, and enhancing PD-L1 expression. Poly-ADP-ribose polymerase (PARP) inhibitors are one such class of drugs that has shown synergy with immunotherapy in preclinical and early clinical studies. PARP-based therapies work through the inhibition of single-strand DNA repair leading to DNA damage, increased tumor mutational burden, making the tumor a more attractive target for immunotherapy. Of the solid tumors reviewed, breast, ovarian, and prostate cancers have demonstrated efficacy in the combination of PARP inhibition and immunotherapy, predominately in BRCA-mutated tumors. However, initial investigations into wildtype BRCA and gastrointestinal tumors have shown moderate overall response or disease control rates, dependent on the tumor type. In contrast, although a number of clinical trials underway, there is a paucity of published results for the use of the combination in lung or urothelial cancers. Overall this article focuses on the promise of combinatorial PARP inhibition and immunotherapy to improve patient outcomes in solid tumors, summarizing both early results and looking toward ongoing trials.

Utilization and Outcomes of Surgical Castration in Comparison to Medical Castration in Metastatic Prostate Cancer.

BACKGROUND: Androgen deprivation therapy (ADT) is the gold standard for metastatic prostate cancer, which can be achieved either by surgical or medical castration. In this study, we evaluated the trends of utilization of surgical castration and also assess the survival differences of patients who underwent surgical castration when compared with those who underwent medical castration. MATERIALS AND METHODS: The National Cancer Database was used to identify patients with metastatic prostate cancer from 2004 to 2014. Cochran-Armitage tests were used to assess temporal trends in the proportion of patients receiving surgical castration relative to medical castration. Logistic and Cox regression models were utilized to estimate the odds of utilization of surgical castration and the effect of castration on overall survival (OS). RESULTS: A total of 33,585 patients with metastatic prostate cancer were identified; 31,600 (94.1%) had medical castration, and 1985 (5.9%) underwent surgical castration. There was significant decline in the trend of utilization of surgical castration from 8.6% in 2004 to 3.1% in 2014. On multivariable analysis, being of a non-Caucasian race, having lower median income levels, having non-private insurance, and earlier years of diagnosis were found to be associated with increased odds of choosing surgical castration over medical castration. Notably, the odds of surgical castration were lower at academic centers. On univariable analysis, a survival difference between castration modality was evidenced (P < .01); 5-year OS for medical castration and surgical castration were 24.3% and 18.2%, respectively. However, on multivariable analysis, there was no OS difference between surgical castration and medical castration (P = .13). CONCLUSIONS: In this large contemporary analysis, the utilization of surgical castration has declined over time, with no OS difference when compared with medical castration. Increasing the utilization of surgical castration could help reduce health care expenditures. With rising health care costs, patients and physicians need to be aware of treatment options and their financial implications.

Association between diabetes mellitus and poor patient outcomes after out-of-hospital cardiac arrest: A systematic review and meta-analysis.

Diabetes mellitus (DM) serves as an important prognostic indicator in patients with cardiac-related illness. Our objective is to compare survival and neurological outcomes among diabetic and non-diabetic patients who were admitted to the hospital after an out-of-hospital cardiac arrest (OHCA). We searched MEDLINE and EMBASE for relevant articles from database inception to July 2018 without any language restriction. Studies were included if they evaluated patients who presented with OHCA, included mortality and neurological outcome data separately for DM patients and Non-DM patients and reported crude data, odds ratio (OR), relative risk (RR) or hazard ratio (HR). Two investigators independently reviewed the retrieved citations and assessed eligibility. The quality of included studies was evaluated using Newcastle-Ottawa quality assessment scale for cohort studies. Random-effect models using the generic variance method were used to create pooled odds ratios (OR) and 95% confidence intervals (CI). Heterogeneity was assessed using the I2 value. Survival and neurological outcomes (using modified rankin scale and cerebral performance category scale) after OHCA in hospitalized patients with DM compared with patients without DM. Out of 57 studies identified, six cohort studies met the inclusion criteria. In an analysis of unadjusted data, patients with DM had lower odds of survival, pooled OR 0.64; 95% CI, 0.52-0.78, [I2 = 90%]. When adjusted ORs were pooled, the association between DM and survival after OHCA was still significantly reduced, pooled OR 0.78, 95% CI, 0.68-0.89 [I2 = 55%]. Unadjusted pooled OR revealed poor neurological outcomes in patients with DM, pooled OR 0.55, 95% CI, 0.38-0.80 [I2 = 90%]. The result demonstrates significant poor outcomes of in-hospital survival and neurological outcomes among DM patients after OHCA.

Survival trends among patients with metastatic melanoma in the pretargeted and the post-targeted era: a US population-based study.

In 2011, ipilimumab was approved by the US Food and Drug Administration (FDA) for metastatic melanoma. Since its approval, numerous targeted therapies have been approved by the FDA. Population-based studies assessing the survival benefit from these agents are lacking. We therefore carried out this study to compare the 1-year, 2-year, and median overall survival (OS) among metastatic melanoma patients in pretargeted and post-targeted eras. This is a retrospective study that utilized the Surveillance, Epidemiology, and End Results (SEER-18) database, version 8.3.4 (22 March 2017). The patient groups were defined as the pretargeted era (2004-2010) and the post-targeted era (2011-2014) as ipilimumab was approved by the FDA in 2011. The database comprised of 5471 patients (3314 in the pretargeted era and 2157 in the post-targeted era). OS in the post-targeted era was found to be significantly better compared with the pretargeted era by Kaplan-Meier curve (1-year OS: 38.9 vs. 36.8%, 2-year OS: 28.3 vs. 23.5%, and median survival: 8 vs. 7 months, P=0.001 by the log-rank test). The survival was significantly better in the post-targeted era compared with the pretargeted era on multivariate analysis using a Cox proportional hazard model after adjusting for age, sex, race, and metasectomy status (adjusted hazard ratio of 0.889, 95% CI: of 0.832-0.951, P=0.001). There is significant survival benefit in metastatic melanoma patients since the introduction of immune checkpoint-blocking agents.

Atrioesophageal Fistula: A Rare Complication of Radiofrequency Ablation.

75-year-old woman was admitted with fever, chills, altered mentation, and right-sided weakness. A month earlier, she had undergone catheter radiofrequency ablation for treatment of chronic atrial fibrillation. A magnetic resonance imaging scan of her brain revealed septic emboli with multiple bilateral cerebral and cerebellar infarcts, as well as extensive bilateral leptomeningeal enhancement. Blood cultures were positive for Streptococcus mitis, Rothia mucilaginosa, Streptococcus pneumonia, and Candida albicans, which suggested a connection between gastrointestinal and cardiovascular systems. A chest computed tomography scan with contrast showed a curvilinear low attenuation structure communicating between the esophagus and the left pulmonary vein-an atrioesophageal fistula. Ten days after admission, the patient died from multiple cerebral septic emboli secondary to atrioesophageal fistula following radiofrequency ablation.