Impact of Tumor Suppressor Gene Co-Mutations on Differential Response to EGFR TKI Therapy in EGFR L858R and Exon 19 Deletion Lung Cancer.

BACKGROUND: In most studies, patients with EGFR L858R mutant non-small cell lung cancer (NSCLC) have a shorter duration of response to EGFR tyrosine kinase inhibitor (TKI) therapy than do patients with EGFR exon 19 deletion NSCLC. The role that co-mutations play in this observation is unknown. METHODS: We performed a single-institution retrospective analysis of patients with EGFR-mutant NSCLC (exon 19 deletion or L858R mutation) who received frontline EGFR TKI for metastatic disease between 2014 and 2019, and who had STAMP next-generation sequencing (NGS), a 130-gene platform. Time to treatment failure (TTF) and overall survival were calculated using Cox models adjusted for age, race, and brain metastases. Co-mutations in key tumor suppressor genes (TP53, RB1, KEAP1, CDKN2A, or CTNNB1) were identified and their effects on outcomes were evaluated. Analyses were stratified according to receipt of osimertinib versus nonosimertinib as frontline EGFR TKI. RESULTS: Of 137 patients, 72 (57%) had EGFR exon 19 deletions and 65 (43%) had EGFR L858R mutations. Median TTF and OS on frontline TKI was shorter for the L858R cohort versus the exon 19 deletion cohort in univariate analysis. In adjusted models, this difference persisted for TTF but was no longer significant for OS. The difference in TTF in L858R mutant tumors was driven by the presence of co-mutations in key tumor suppressor genes. CONCLUSION: Patients with metastatic NSCLC with mutations in EGFR L858R had shorter TTF on frontline TKI compared to patients with EGFR exon 19 deletions. Co-mutations in tumor suppressor genes may play an important role in the differential response to TKI therapy.

Chemotherapy Plus Immunotherapy Versus Chemotherapy Plus Bevacizumab Versus Chemotherapy Alone in EGFR-Mutant NSCLC After Progression on Osimertinib.

INTRODUCTION: Patients with EGFR-mutant lung cancer who have had disease progression on osimertinib commonly receive platinum doublet chemotherapy, but whether adding immunotherapy or bevacizumab provides additional benefit is unknown. MATERIALS AND METHODS: This was a retrospective analysis at 2 university-affiliated institutions. Patients with EGFR-mutant lung cancer who had progression on osimertinib and received next-line therapy with platinum doublet chemotherapy (chemo), platinum doublet chemotherapy plus immunotherapy (chemo-IO), or platinum doublet chemotherapy plus bevacizumab (chemo-bev), were identified; patients who continued osimertinib with these regimens were included. Efficacy outcomes including duration on treatment (DOT) and overall survival (OS) from the start of chemotherapy were assessed. Associations of treatment regimen with outcomes were evaluated using adjusted Cox regression models, using pairwise comparisons between groups. RESULTS: 104 patients were included: 57 received chemo, 12 received chemo-IO, and 35 received chemo-bev. In adjusted models, patients who received chemo-IO had worse OS than did those who received chemo (hazard ratio (HR) 2.66, 95% CI 1.25-5.65; P= .011) or those who received chemo-bev (HR 2.37, 95% CI 1.09-5.65; P= .030). A statistically significant difference in OS could not be detected in patients who received chemo-bev versus those who received chemo (HR 1.50, 95% CI 0.84-2.69; P= .17). CONCLUSION: In this retrospective study, giving immunotherapy with platinum doublet chemotherapy after progression on osimertinib was associated with a worse OS compared with platinum doublet chemotherapy alone. Platinum doublet chemotherapy without immunotherapy (with consideration of continuation of osimertinib, in selected cases) is a reasonable choice in this setting, while we await results of clinical trials examining optimal next-line chemotherapy-based regimens in EGFR-mutant lung cancer.

Combining Osimertinib With Chemotherapy in EGFR-Mutant NSCLC at Progression.

BACKGROUND: Osimertinib is a third-generation EGFR tyrosine kinase inhibitor that has improved survival and central nervous system (CNS) outcomes in patients with non-small cell lung cancer (NSCLC) with activating EGFR mutations. However, little is known about the efficacy and safety of combining osimertinib with chemotherapy. METHODS: This was a retrospective study performed at 3 institutions. Patients with advanced EGFR-mutated NSCLC who received concurrent osimertinib with chemotherapy in the third-line or beyond were identified by chart review. Efficacy outcomes including duration on treatment (DOT), overall survival (OS), and CNS outcomes were assessed. Safety outcomes were also evaluated. RESULTS: A total of 44 patients met inclusion criteria. Median DOT with osimertinib plus platinum doublet (n = 28) was 6.1 months (95% CI 4.1 months-not reached), and with osimertinib plus single-agent chemotherapy (n = 29) was 2.6 months (95% CI 1.8-4.8 months). Median OS from the start of osimertinib plus chemotherapy was 10.4 months (95% CI 7.0-13.2 months). At initiation of osimertinib plus chemotherapy, 37 patients (84%) had CNS metastases; 9 of these (24%) had CNS disease progression on osimertinib plus chemotherapy. Chemotherapy was delayed or dose reduced due to toxicity in 8 patients (18%); osimertinib was discontinued in 1 patient (2%) for reduced cardiac ejection fraction, and dose reduced in 2 patients (5%). CONCLUSIONS: The combination of osimertinib plus chemotherapy appeared safe and showed favorable control of CNS disease in this cohort of patients who had progressed systemically with multiple prior lines of therapy, with DOT and survival outcomes similar to historical chemotherapy controls.

Outcomes and Tolerability of Definitive and Preoperative Chemoradiation in Elderly Patients With Esophageal Cancer: A Retrospective Institutional Review.

PURPOSE: Our purpose was to report outcomes of elderly patients who underwent definitive treatment involving radiation therapy for esophageal cancer at our institution. METHODS AND MATERIALS: We performed a retrospective review of patients aged ≥75 years with esophageal cancer treated with definitive radiation therapy (≥45 Gy) at our institution from 1997 to 2019. Acute and late Radiation Therapy Oncology Group grade 3+ toxicities were recorded. Survival was estimated using the Kaplan-Meier method. RESULTS: Of the 89 patients included, median age was 80 and 78% were male. Median adjusted Charlson Comorbidity Index and Karnofsky Performance Status were 5 (3-12) and 80 (50-100), respectively. The majority of cancers were adenocarcinoma (58%), distal (67%), and stage III (62%). Fifty-eight percent underwent definitive chemoradiotherapy, and one-third underwent preoperative intent chemoradiotherapy. Median prescribed dose was 50 Gy (45-66 Gy), and intensity modulated radiation therapy was used in 76%. Eighty-five percent completed the radiation therapy course. Among these, 20% had radiation therapy breaks. For those receiving concurrent chemotherapy, 37% had a dose reduction and 39.5% had a break/cycle reduction. Acute grade 3+ toxicity was 22%, with 2% grade 5 toxicity. Twenty-one of the 29 patients (72%) treated with preoperative intent underwent surgery. There were no deaths 90 days postoperatively. For patients who underwent surgery, 1- and 2-year overall survival were 95% and 84%. For those who did not undergo surgery, 1- and 2-year overall survival were 70% and 52%. CONCLUSIONS: There is a role for aggressive radiation therapy in well-selected elderly patients with esophageal cancer. However, optimization of supportive care, chemotherapy regimens, radiation therapy dose/fractionation, and surgical indications are needed to reduce toxicity.

Effects of fish oil supplementation on eicosanoid production in patients at higher risk for colorectal cancer.

Fish oil supplementation may represent a potential chemopreventive agent for reducing colorectal cancer risk. The mechanism of action of fish oil is unknown but presumed to be related to eicosanoid modification. The purpose of this study was to evaluate the effects of fish oil supplementation on the levels of urinary and rectal eicosanoids. We conducted a randomized, double-blind, controlled trial of 2.5 g of fish oil per day compared with olive oil supplementation over a 6-month period. Study participants had a history of colorectal adenomas. Randomization was stratified based on the gene variant rs174535 in the fatty acid desaturase 1 enzyme (FADS1), which affects tissue levels of arachidonic acid. A total of 141 participants were randomized. Urinary prostaglandin E2 metabolite (PGE-M) was measured at baseline, 3, and 6 months and rectal prostaglandin E2 (PGE2) at baseline and 6 months. Repeated-measures linear regression was used to determine the effect of the intervention on each outcome measure. Overall, fish oil supplementation was found to reduce urinary PGE-M production compared with olive oil (P=0.03). Fish oil did not reduce rectal PGE2 overall; however, it did significantly reduce PGE2 in the subgroup of participants not using aspirin or NSAIDs (P=0.04). FADS1 genotype did not seem to modify effects of fish oil on PGE2 production. We conclude that fish oil supplementation has a modest but beneficial effect on eicosanoids associated with colorectal carcinogenesis, particularly in those not taking aspirin or NSAIDs.

Advanced pancreatic cancer clinical trials: The continued underrepresentation of older patients.

OBJECTIVES: Older patients make up the majority of patients with pancreatic cancer, with a median age of 71 years at diagnosis. However, older patients are underrepresented in clinical trials in pancreatic cancer. This study investigates trends in age distribution of patients enrolled in clinical trials for advanced pancreatic cancer over time, and examines outcomes and toxicity in older patient subgroups from two studies conducted by Eastern Cooperative Oncology Group and American College of Radiology Imaging Network (ECOG-ACRIN) in this disease. MATERIALS AND METHODS: 16,042 patients from 38 phase III clinical trials for locally advanced or metastatic pancreatic adenocarcinoma published between 1997 and 2016 were identified and included in this analysis. Outcomes and toxicity by age were examined in two of the trials, ECOG-ACRIN trials E2297 and E6201, which included a total of 1146 patients. RESULTS: The median age across the trials was 62.7 years; median ages for individual trials ranged from 57 years to 66 years. Weighted linear regression showed no significant change in median age over time. Combined analysis of the two ECOG-ACRIN trials demonstrated higher rates of fatigue, thrombocytopenia, and infection in those ≥75 years compared with those <75 years, but despite this showed no difference in overall survival (OS) or progression-free survival (PFS) (OS: 5.7 vs. 5.6 months and PFS: 2.8 vs 3.5 months). CONCLUSIONS: Enrollment of older adults in phase III pancreatic cancer clinical trials has not increased over time, despite increasing number of older patients seen in clinic. Increased efforts are needed to enhance enrollment of older patients in clinical trials, and to promote trials specifically for older patients, in order to improve the evidence base for treating this patient population.

Caregiving, Transport-Related, and Demographic Correlates of Sedentary Behavior in Older Adults: The Senior Neighborhood Quality of Life Study.

OBJECTIVE: Excess sedentary time predicts negative health outcomes independent of physical activity. The present investigation examined informal caregiving duties and transportation-related factors as potential correlates of sedentary behavior in older adults. METHOD: Average daily sedentary time was measured via accelerometer in adults ages 66 years and older (N = 861). Caregiving variables included dog ownership and informal family caregiving status. Transportation variables included driver status, walking distance to public transit, and reported presence of pedestrians and bicyclists in one's neighborhood. RESULTS: In multivariate models, owning a dog and being a driver were associated with less sedentary time (p ≤ .01). Educational status and geographic region modified the association between dog ownership and sedentary time, and age modified the association between driver status and sedentary time. DISCUSSION: This study identified that older adult dog owners and drivers were less sedentary. Both factors may create opportunities for older adults to get out of their homes.