Krishnamurthi, Smitha

Abstract Background Surrogate endpoints are increasingly used as the basis of cancer drug approvals. A strong association between treatment effects on the surrogate and true endpoint is essential for their validation as reliable endpoints. We assess the current evidence of trial-level surrogacy for colorectal cancer (CRC) endpoints through a novel framework. Methods We developed a framework to grade the quality of oncology surrogate endpoints in 7 domains of the surrogate relationship: data source quality (A-B); disease setting homogeneity (0-3); uniformness of surrogate and true endpoint definitions (0-3); number of trials evaluated (0-4); and individual- (0-2) and trial-level associations (0-8). We screened PubMed using keywords and medical subject headings terms for meta-analyses published before July 6, 2024, validating surrogate endpoint associations across CRC trials. Two reviewers blindly assessed each article before reaching a consensus score. The main outcomes were framework-derived evidence scores and reported trial-level associations (R2) with overall survival. Results A total of 18 articles were identified, containing 39 evaluations of 12 unique surrogate endpoints for overall survival. Evidence scores ranged from B6 to A23. Only disease-free survival consistently demonstrated high-quality evidence of trial-level surrogacy (≥A18, median R2 = 0.92). Progression-free survival and objective response rate were low-quality surrogates in metastatic CRC (progression-free survival: B6-A15, median R2 = 0.55; objective response rate: B6-A13, median R2 = 0.33). Other evaluated endpoints were demonstrated to be unreliable surrogates. Conclusion Disease-free survival shows high-quality surrogacy in stage II-III colon cancer. Endpoints identified in the metastatic setting demonstrate inconsistent surrogacy evidence. Reassessment and identification of new endpoints are warranted, particularly with immunotherapy.

Abstract Background Completing adjuvant chemotherapy and reducing toxicities are critical for maximizing survival after a colon cancer diagnosis. Sex, as a biological variable, may affect colon cancer chemotherapy completion, toxicities, and survival differently. Methods From a National Cancer Institute–sponsored trial conducted among patients with stage III colon cancer (Cancer and Leukemia Group B (Alliance)/Southwest Oncology Group 80702), we included 2201 patients receiving the standard adjuvant chemotherapy regimen of fluorouracil, leucovorin, and oxaliplatin. We calculated relative dose intensity to indicate chemotherapy completion and considered reduced relative dose intensity (values <85%) as a clinically significant deviation from standard fluorouracil, leucovorin, and oxaliplatin. Using National Cancer Institute’s Common Terminology Criteria for Adverse Events, we defined severe adverse events (grade ≥3) as the occurrence of any following event, including neutrophil count decrease, nausea, platelet count decrease, hypertension, peripheral neuropathy, diarrhea, fatigue, gastritis, creatinine level increase, gastric ulcer, myocardial ischemia, and cerebral ischemia. The primary survival outcome was disease-free survival (time from enrollment to colon cancer recurrence or death from any cause), and secondary survival outcomes were recurrence-free and overall survival. Results Compared with men, women were at statistically significantly higher risks of experiencing reduced relative dose intensity (adjusted odds ratio = 1.59, 95% CI = 1.29 to 1.96; P < .001) and severe advance events (adjusted odds ratio = 1.72, 95% CI = 1.41 to 2.11; P < .001). Yet, women had statistically significantly better disease-free survival (adjusted hazard ratio = 0.72, 95% CI = 0.59 to 0.87; P < .001) as well as better recurrence-free and overall survival. Conclusions Our findings suggested that women with colon cancer are more likely to have worse chemotherapy completion rates and more severe adverse events, but they have better survival. Sex as a biological variable warrants further consideration in chemotherapy administration and survivorship management after colon cancer diagnosis.

PURPOSE To determine the specific types, durations, and intensities of recreational physical activity associated with the greatest improvements in disease-free survival (DFS) of patients with colon cancer. METHODS We conducted a prospective cohort study nested within a randomized multicenter trial of stage III colon cancer that compared 3 versus 6 months of fluorouracil, leucovorin, and oxaliplatin with or without celecoxib. We measured recreational physical activity in the first 3 months of chemotherapy and again 6 months after completion of chemotherapy. The primary end point was DFS. RESULTS During a median follow-up of 5.9 years, 457 of 1,696 patients experienced disease recurrence or death. For total recreational physical activity volume, the 3-year DFS was 76.5% with < 3.0 metabolic equivalent task hours per week (MET-h/wk) and 87.1% with ≥ 18.0 MET-h/wk (risk difference [RD], 10.6%; 95% CI, 4.7 to 19.4; P < .001). For light-intensity to moderate-intensity activities, the 3-year DFS was 65.7% with 0.0 h/wk and 87.1% with ≥ 1.5 h/wk (RD, 21.4%; 95% CI, 9.2 to 37.1; P < .001). For vigorous-intensity activity, the 3-year DFS was 76.0% with 0.0 h/wk and 86.0% with ≥ 1.0 h/wk (RD, 10.0%; 95% CI, 4.5 to 18.9; P < .001). For brisk walking, the 3-year DFS was 81.7% with < 1.0 h/wk and 88.4% with ≥ 3.0 h/wk (RD, 6.7%; 95% CI, 3.0 to 13.8; P < .001). For muscle strengthening activity, the 3-year DFS was 81.8% with 0.0 h/wk and 88.8% for ≥ 0.5 h/wk (RD, 7.0%; 95% CI, 3.1 to 14.2; P = .003). CONCLUSION Among patients with stage III colon cancer enrolled in a trial of postoperative treatment, larger volumes of recreational physical activity, longer durations of light- to moderate-intensity aerobic physical activity, or any vigorous-intensity aerobic physical activity were associated with the greatest improvements in DFS.