Impact of primary tumour resection on survival of patients with colorectal cancer and synchronous metastases treated by chemotherapy: results from the multicenter, randomised trial Fédération Francophone de Cancérologie Digestive 9601

Objective: To assess the impact of primary tumour resection on overall survival (OS) of patients diagnosed with stage IV colorectal cancer (CRC).

Design: Among the 294 patients with non-resectable colorectal metastases enrolled in the Fédération Francophone de Cancérologie Digestive (FFCD) 9601 phase III trial, which compared different first-line single-agent chemotherapy regimens, 216 patients (73%) presented with synchronous metastases at study entry and constituted the present study population. Potential baseline prognostic variables including prior primary tumour resection were assessed by univariate and multivariate Cox analyses. Progression-free survival (PFS) and OS curves were compared with the logrank test.

Results: Among the 216 patients with stage IV CRC (median follow-up, 33 months), 156 patients (72%) had undergone resection of their primary tumour prior to study entry. The resection and non-resection groups did not differ for baseline characteristics except for primary tumour location (rectum, 14% versus 35%; p=0.0006). In multivariate analysis, resection of the primary was the strongest independent prognostic factor for PFS (hazard ratio (HR), 0.5; 95% confidence interval [CI], 0.4-0.8; p=0.0002) and OS (HR, 0.4; CI, 0.3-0.6; p<0.0001). Both median PFS (5.1 [4.6-5.6] versus 2.9 [2.2-4.1] months; p=0.001) and OS (16.3 [13.7-19.2] versus 9.6 [7.4-12.5]; p<0.0001) were significantly higher in the resection group. These differences in patient survival were maintained after exclusion of patients with rectal primary (n=43).

Conclusion: Resection of the primary tumour may be associated with longer PFS and OS in patients with stage IV CRC starting first-line, single-agent chemotherapy.