Age and comorbidity association with survival outcomes in metastatic colorectal cancer: CALGB 80405 analysis

Abstract

Background: Little is known about the interaction of comorbidities and age on survival outcomes in colorectal cancer (mCRC), nor how comorbidities impact treatment tolerance.

Methods: We utilized a cohort of 1345 mCRC patients enrolled in CALGB/SWOG 80405, a multicenter phase III trial of fluorouracil/leucovorin + oxaliplatin (FOLFOX) or irinotecan (FOLFIRI) plus bevacizumab, cetuximab or both. Endpoints were overall survival (OS), progression-free survival (PFS), and grade ≥ 3 toxicities assessed using NCI CTCAE v.3.0. Participants completed a questionnaire, including a modified Charlson Comorbidity Index. Adjusted Cox and logistic regression models tested associations of comorbidities and age on the endpoints.

Results: In CALGB/SWOG 80405, 1095 (81%) subjects were < 70 years and >70 250 (19%). Presence of ≥1 comorbidity was not significantly associated with either OS (HR 1.10, 95% CI 0.96-1.25) or PFS (HR 1.03, 95% CI 0.91-1.16). Compared to subjects <70 with no comorbidities, OS was non-significantly inferior for ≥70 with no comorbidities (HR 1.21, 95% CI 0.98-1.49) and significantly inferior for ≥70 with at least one comorbidity (HR 1.51, 95% CI 1.22-1.86). There were no significant associations or interactions between age or comorbidity with PFS. Comorbidities were not associated with treatment-related toxicities. Age ≥ 70 was associated with greater risk of grade ≥ 3 toxicities (OR 2.15, 95% CI 1.50-3.09, p < 0.001).

Conclusions: Among participants in a clinical trial of combination chemotherapy for mCRC, presence of older age with comorbidities was associated with worse OS but not PFS. The association of age with toxicity suggests additional factors of care should be measured in clinical trials.