O’Connell, Michael J.

Purpose In February 2000, the criteria for measuring tumor shrinkage as an indicator of antitumor activity were redefined by the Response Evaluation Criteria in Solid Tumors (RECIST). This resulted in simplifying bidimensional to unidimensional measurement of lesions. Under RECIST, all lesions, up to 10, must be measured. Scanning and measuring multiple lesions is costly, time-consuming, and a disincentive to participation in clinical trials. We investigated whether fewer than 10 lesions can be measured without compromising the accuracy of assessing a regimen's activity. Patients and Methods Thirty-two North Central Cancer Treatment Group trials including 2,374 patients were analyzed. Twelve studies were conducted before RECIST; 20 were conducted post-RECIST. Agreement between objective status by cycle, confirmed response, overall response rate, and time to progression (TTP) was evaluated based on all 10 versus the largest one through five lesions. Results The median number of lesions reported on RECIST trials did not differ from pre-RECIST trials (median = 2.0). One lesion at baseline was reported in 49% of patients, two lesions in 28% of patients, three lesions in 12% of patients, four lesions in 6% of patients, and five lesions in 5% of patients in post-RECIST trials. Utilizing the largest two lesions produced excellent concordance with that using all lesions for all end points. In no trial did the overall response rate differ by more than 3% when two versus all lesions were considered. Evaluating more than two lesions did not significantly improve agreement. Conclusion Based on these trials, the assessment of more than two lesions did not alter the conclusions regarding a treatment's efficacy as judged by response rate or TTP.

Purpose Limited data are available on the time course of treatment failures (recurrence and/or death), the nature and duration of adjuvant treatment benefit, and long-term recurrence rates in patients with resected stage II and III colon cancer. Methods The data set assembled by the Adjuvant Colon Cancer Endpoints Group, a collection of individual patient data from 18 trials and more than 20,800 patients testing fluorouracil-based adjuvant therapy in patients with stage II or III colon cancer, was analyzed. Results A significant overall survival (OS) benefit of adjuvant therapy was consistent over the 8-year follow-up period. The risk of recurrence in patients treated with adjuvant chemotherapy never exceeds that of control patients, signifying that adjuvant therapy cures some patients, as opposed to delaying recurrence. After 5 years, recurrence rates were less than 1.5% per year, and after 8 years, they were less than 0.5% per year. Significant disease-free survival (DFS) benefit from adjuvant chemotherapy was observed in the first 2 years. After 2 years, DFS rates in treated and control patients were not significantly different, and after 4 years, no trend toward benefit was demonstrated. This benefit was primarily driven by patients with stage III disease. Conclusion Adjuvant chemotherapy provides significant DFS benefit, primarily by reducing the recurrence rate, within the first 2 years of adjuvant therapy with some benefit in years 3 to 4, translating into long-term OS benefit. This reflects the curative role of chemotherapy in the adjuvant setting. After 5 years, recurrence rates in patients treated on clinical trials are low, and after 8 years, they are minimal; thus, long-term follow-up for recurrence is of little value.

Abstract Purpose: Proapoptotic BH3-only proteins (Bim, Bad, Bid, Puma, and Noxa) initiate apoptosis by binding to regulatory sites on antiapoptotic Bcl-2 proteins, directly neutralizing their cytoprotective function. Expression of these proteins in colon cancer patients may account for differences in recurrence and survival rates. Experimental Design: Archival tumor-node-metastasis stage II and III primary colon carcinomas from patients treated in 5-fluorouracil–based adjuvant therapy trials were studied. Immunohistochemical analysis of Bim, Puma, and Noxa proteins was done using tissue microarrays (n = 431). Immunoscores were determined and correlated with clinicopathologic variables and disease-free survival (DFS) and overall survival (OS) rates. Results: Elevated expression of proapoptotic Bim (hazard ratio, 0.65; 95% confidence interval, 0.44-0.97; P = 0.033) and Puma (hazard ratio, 0.59; 95% confidence interval, 0.37-0.93; P = 0.022), but not Noxa, proteins in the tumor cytoplasm was significantly associated with more favorable OS in a univariate analysis, and elevated Bim expression was also associated with better DFS (P = 0.023). Patient age, tumor stage, and histologic grade were also prognostic. Multivariate Cox analysis showed that Bim (DFS, P = 0.030; OS, P = 0.045) and Puma (OS, P = 0.037) expression were independent predictors of OS after adjustment for histologic grade, tumor stage, age, and treatment. Furthermore, the combined variable of Bim and Puma was highly discriminant for both DFS (P = 0.0034) and OS (P = 0.0011). Conclusions: The proapoptotic BH3-only proteins Bim and Puma can provide prognostic information for stage II and III colon cancer patients receiving 5-fluorouracil–based adjuvant chemotherapy. Furthermore, our results support BH3-only proteins as molecular targets of novel anticancer drugs.

Purpose This study was undertaken to examine five possible prognostic factors in patients with recurrent stage II and III colon cancer: time from randomization on an adjuvant therapy clinical trial to tumor recurrence (< 1 year, 1 to 2 years, 2 to 3 years, 3 to 4 years, > 4 years), initial stage (II v III), initial adjuvant treatment (fluorouracil [FU]-based v surgery alone), the era in which the patient entered an adjuvant therapy clinical trial (1978 to 1985, 1986 to 1992, 1993 to 1999), and patient age at recurrence. Methods The Adjuvant Colon Cancer End Points (ACCENT) data set was analyzed using univariate and multivariate Cox proportional hazards models, stratified by study. Results 5,722 (32.9%) of 17,381 patients experienced recurrence. Median survival following recurrence was 13.3 months. Time from randomization to recurrence was highly prognostic of survival following recurrence (P < .0001). Longer survival following recurrence was seen in patients with initial stage II versus III disease (P < .0001; 14.3% 6-year overall survival after recurrence in initial stage II patients), patients entered more recently onto trials (P < .0001), and patients initially treated with surgery alone versus FU adjuvant treatment (P = .0005). All relationships were maintained in multivariate models. Conclusion Time from initial treatment to recurrence and initial stage are important prognostic factors in patients with recurrent colon cancer. Survival following recurrence increased modestly from 1978 to 1999. Patients who had a recurrence following adjuvant therapy had poorer prognosis than those who progressed after surgery alone. These prognostic factors may be useful for clinical trial design and treatment decisions in patients with recurrent colon cancer.

Purpose The traditional end point for colon adjuvant clinical trials is overall survival (OS). We previously validated disease-free survival (DFS) after 3-year follow-up as an excellent predictor of 5-year OS results. Here we explore shorter term DFS and OS end points, as well as stage dependency. Methods Individual patient data from 18 phase III trials including 43 arms and 20,898 patients were pooled. Association measures included correlation of event rates within arms, correlation of hazard ratios (HRs) between arms, trial level significance comparisons (via log-rank testing), and a formal surrogacy model. Results DFS at earlier times was less accurate in predicting OS than 3-year DFS, but 2-year DFS remained a strong predictor. DFS with 1-year minimum follow-up demonstrated perfect negative predicted value; all trials negative at 1 year for DFS were negative for 5-year OS. OS with 3-year minimum follow-up was also an excellent predictor for 5-year OS; OS at earlier time points provided inaccurate prediction. The association between 3-year DFS and 5-year OS was greater for stage III patients; correlation of HR within trials was 0.92 (95% CI, 0.85 to 0.95) for stage III patients and 0.70 (95% CI, 0.44 to 0.80) for stage II patients. Conclusion DFS outcomes after 2- or 3-year median follow-up are excellent predictors of 5-year OS. DFS outcomes are appropriate for trials in which the majority of patients are stage III. DFS after 2- or 3-year median follow-up should be considered as the primary end point in future colon adjuvant trials.

Emerging technologies have greatly expanded our ability to detect, characterize, and treat colorectal cancer. The Coalition of Cancer Cooperative Groups convened a multidisciplinary panel, the Scientific Leadership Council in GI cancer, to discuss and advise on the priorities and opportunities to advance current and future approaches into the clinical arena to impact most rapidly the morbidity and mortality from this disease. The Council's recommendations for research priorities are the result of engagement of community and academic oncologists, patient advocacy groups, and other stakeholders including the pharmaceutical industry and governmental agencies. We detail some key prospects for investigation in the areas of colon cancer detection, prevention, and surgical and medical management. Many are in early or definitive clinical trials, and a focus on rapid accrual is urged. The implementation of biology-directed laboratory investigations, both in association with ongoing clinical trials and as a separate developmental strategy for targeted therapies, is supported as the route to individualized therapy.