Recurrence-free and overall survival among elderly stage III colon cancer patients treated with CAPOX or capecitabine monotherapy

The aim of this study is to investigate the effects of CAPOX and capecitabine on recurrence-free survival (RFS) and overall survival (OS) among elderly stage III colon cancer patients and to evaluate the effect of (non-)completion. Patients aged 70 years who underwent resection only or who were subsequently treated with CAPOX or capecitabine in 10 large non-academic hospitals were included. RFS and OS were analyzed with Kaplan-Meier curves and multivariable Cox regression adjusted for patient and tumor characteristics. 982 patients were included: 630 underwent surgery only, 191 received CAPOX and 161 received capecitabine. Five-year RFS and OS did not differ between capecitabine and CAPOX (RFS: 63% vs. 60% (p=0.91), adjusted HR=0.99 (95%CI 0.68-1.44); OS: 66% vs. 66% (p=0.76), adjusted HR=0.93 (95%CI 0.64-1.34)). After resection only, RFS was 38% and OS 37%. Completion rates were 48% for CAPOX and 68% for capecitabine. Three-year RFS and OS did not differ between patients who discontinued CAPOX early and patients who completed treatment with CAPOX (RFS: 61% vs. 69% (p=0.21), adjusted HR=1.42 (95%CI 0.85-2.37); OS: 68% vs. 78% (p=0.41), adjusted HR=1.17 (95%CI 0.70-1.97)). Three-year RFS and OS differed between patients who discontinued capecitabine early and patients who completed treatment with capecitabine (RFS: 54% vs. 72% (p=0.01), adjusted HR=2.07 (95%CI 1.11-3.84); OS: 65% vs. 80% (p=0.01), adjusted HR=2.00 (95%CI 1.12-3.59)). Receipt of CAPOX or capecitabine is associated with improved RFS and OS. The advantage does not differ by regimen. The addition of oxaliplatin might not be justified in elderly stage III colon cancer patients.

What's new? With adjuvant chemotherapy the standard treatment option for stage III colon cancer patients, great effort has been made to identify combinations of drugs that effectively reduce the risk of cancer recurrence in this setting. Here, for elderly stage III colon cancer patients treated in everyday clinical practice, receipt of adjuvant chemotherapy consisting of capecitabine with oxaliplatin or capecitabine alone was associated with improved recurrence-free and overall survival. Improved outcome depended more on completion of treatment cycles than regimen, suggesting that the addition of oxaliplatin may not be necessary.