Impact of age and comorbidities on treatment effect, tolerance, and toxicity in metastatic colorectal cancer (mCRC) patients treated on CALGB 80203

Abstract

4038 Background: Little is known regarding the interaction of comorbid conditions (CC) and age when treating pts for mCRC. We sought to determine the impact of CC and age (<70 and ≥70 yrs) on survival and toxicity in these pts. Methods: We utilized a cohort of 238 pts with mCRC enrolled in CALGB 80203, a curtailed, multicenter 2x2 phase III trial of fluorouracil/leucovorin + oxaliplatin (FOLFOX) or irinotecan (FOLFIRI) ± cetuximab. Endpoints were overall survival (OS; time to death), progression-free survival (PFS; time to recurrence or death), and grade 3/4 toxicity. Pts completed a self-administered questionnaire on diet and lifestyle that included a modified Charlson's comorbidity survey. Cox models were adjusted for treatment (rx) arm, gender, and prior rx. Results: In CALGB 80203, 77% were < 70 and 23% ≥70. Thirty-five percent of pts had at least one CC (34% < 70 yrs; 41% ≥ 70 yrs). At least one grade 3/4 toxicity was experienced by 87% of pts ≥70 v 66% <70 (p=0.002), primarily hematologic (56% v 31%, p=0.003). Amongst 238 pts, 94% and 84% experienced a PFS event and OS event, respectively. No pts are censored prior to 3 yrs. Median follow-up was 23 mos. The adjusted hazard ratio (HR) for ≥70 v <70 of PFS was 1.0 (0.7–1.4) and of OS was 1.1 (0.8–1.6). Similarly, there were no significant differences in HR for PFS and OS by # CC. The table demonstrates no evidence of interaction between CC and age. Conclusions: While the early closure of CALGB 80203 presents sample size limitations for subset analyses, we did not observe an impact on PFS or OS by age and/or CC. Older pts did experience more toxicity from rx. Further studies with larger datasets are warranted. [Table: see text] [Table: see text]