O’Callaghan, Chris J.

LBA7005 Background: In meta-analyses, platinum-based adjuvant (adj) chemotherapy (CT) in completely resected NSCLC increased cure rate by ∼5%. At BR.19 initiation, adj study results with third-generation agents were unavailable. Gefitinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, showed activity in monotherapy trials. We report a trial of adj gefitinib versus placebo after complete resection of NSCLC. Methods: Patients (pts) with stage IB-IIIA NSCLC were stratified by sex, stage, histology, post-op radiation, and after Jan 2003, adj CT. Pts were randomized to gefitinib 250 mg or placebo daily x 2 years. Study endpoints included overall survival (OS), disease free survival (DFS), toxicity, preplanned correlative studies. Study closed prematurely in Apr. 2005. Trial committee and NCIC CTG staff remained blinded to study drug. Results: 503 pts randomized (Sep 2002-Apr 2005); median age 67, males 54%, PS 0 54%; stage IB 49%, II 38%, III 13%; adenocarcinoma 59%, squamous 28%; ever smokers 89%; adj CT 17%; lobectomy 82%. Commonest grade 3/4 toxicities = fatigue 5%, rash 4% and diarrhea 5%. grade 3+ pneumonitis in 7 (1.4%) pts and led to death in 1. Median follow-up is 4.7 yrs; median treatment time is 4.8 mos. For gefitinib versus placebo, median DFS is 4.2 yrs versus not yet reached (NYR) HR1.22 (95% C.I. 0.93-1.61), p=0.15 and median OS 5.1 yrs versus NYR HR 1.24 (95% C.I. 0.94-1.64), p=0.14. In multivariate analysis, tumor size >4cm was predictive of poor DFS (p<0.0001) and never smoking for better OS with gefitinib (p=0.02). Results for KRAS and EGFR copy are available on 350 and 348 pts respectively. KRAS mutations were neither prognostic HR 1.12 (95% C.I. 0.67-1.86), p=0.66 nor predictive of gefitinib benefit (p = 0.16) on OS. EGFRcopy whether low/high polysomy or amplification was neither prognostic (p=0.77) nor predictive of OS benefit from gefitinib. Conclusions: Adjuvant gefitinib after complete resection of early stage NSCLC did not confer DFS or OS advantage in overall population. KRAS and EGFR copy were neither prognostic nor predictive of benefit from gefitinib. EGFR mutational analysis will be presented. [Table: see text]

Purpose Factors associated with early mortality after surgery and treatment with adjuvant chemotherapy in colon cancer are poorly understood. We aimed to characterize the determinants of early mortality in a large cohort of colon cancer trial participants. Methods A pooled analysis of 37,568 patients in 25 randomized trials of adjuvant systemic therapy was conducted. Multivariable logistic regression models with several definitions of early mortality (30, 60, and 90 days, and 6 months) were constructed, adjusting for clinically and statistically significant variables. A nomogram for 6-month mortality was developed and validated. Results Median age among patients was 61 years, patient demographics included 54% men and 90% White, 29% and 71% had stage II and III disease, respectively, and 79%, 20%, and 1% had an Eastern Cooperative Oncology Group performance status (PS) of 0, 1, and ≥ 2, respectively. Early mortality was low: 0.3% at 30 days, 0.6% at 60 days, 0.8% at 90 days, and 1.4% at 6 months. Of those patients who died by 6 months post–random assignment, 40% had documented disease recurrence prior to death. Early disease recurrence was associated with a markedly increased risk of death during the first 6 months post-treatment (hazard ratio, 82.6; 95%CI, 66.9 to 102.1). In prognostic analyses, advanced age, male sex, poorer PS, increasing ratio of positive to examined lymph nodes, earlier decade of enrollment, and higher tumor stage and grade predicted a greater likelihood of early mortality, whereas treatment received was not strongly predictive. A multivariable model for 6-month mortality showed strong optimism-adjusted discrimination (concordance index, 0.73) and calibration. Conclusion Early mortality was infrequent but more prevalent in patients with advanced age and a PS of ≥ 2, underscoring the need to carefully consider the risk-to-benefit ratio when making treatment decisions in these subgroups.

Purpose We previously validated disease-free survival (DFS) as a surrogate for overall survival (OS) in fluorouracil-based adjuvant colon cancer clinical trials. New therapies have extended survival after recurrence from 1 to approximately 2 years. We examined the possible impact of this improvement on the DFS/OS association. Methods The Adjuvant Colon Cancer Endpoints (ACCENT) data set of 20,898 patients was analyzed. In an exploratory fashion, time from recurrence to death in patients experiencing recurrence was extended using several algorithms, and the association of DFS after 3 years of median follow-up and OS after varying lengths of follow-up (median of 5, 6, and 7 years) was assessed. Results Seven thousand four hundred two patients (35%) experienced recurrence. Median time from recurrence to death was 24 months in the hypothetical data sets. When times from recurrence to death were doubled, the association between treatment effects on DFS and 5-year OS was modest (R2 = 0.51 for both 2- and 3-year DFS) but remained strong for DFS and 6-year OS (R2 = 0.67 for both 2- and 3-year DFS) and 7-year OS (R2 = 0.70 for both 2- and 3-year DFS). The reduced DFS/OS association with extended survival after recurrence was greater in stage II than stage III patients. Multiple simulations provided consistent findings. Conclusion Extended survival after recurrence reduces the association between treatment effects on 3-year DFS and 5-year OS, particularly in stage II patients; longer follow-up strengthens the association. In modern adjuvant trials, 6 or 7 years may be required to demonstrate OS improvements, further supporting DFS as the preferred primary end point for future adjuvant colon cancer clinical trials.

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.