The Effect of Primary Tumour Resection on Patients with Synchronous Metastatic Colorectal Cancer Treated with Cetuximab‐containing Regimens

BACKGROUND:This study aims to assess the effect of primary tumour resection (PTR) on patients with metastatic colorectal cancer (mCRC) treated with cetuximab.METHODS:This retrospective cohort study was conducted in a tertiary cancer center in Turkey. Patients with mCRC between January 2009 and December 2020 were extracted from the electronic hospital management system. Patients with RAS wild-type synchronous metastatic left-sided colon or rectum cancer who had cetuximab-containing treatment protocol were included in the study. The primary outcomes were overall survival (OS) and progression-free survival (PFS). The secondary outcome was response rates.RESULTS:A total of 111 patients with mCRC were included in this study. PTR was performed in 57.7% of all patients. Fifty-nine (53.2%) and 52 (46.8%) patients had rectal and left colon tumours, respectively. The combination treatment with cetuximab was FOLFIRI in 62.2% and FOLFOX in 29.7% of all patients. In subgroup analysis, the median PFS was 7.9 and 9 months in PTR (+) and PTR (-) patients, respectively. The difference between the groups was not statistically significant (P = 0.3). The median OS was 33 months in all patients. In subgroup analysis, the median OS was 39 and 27.9 months in PTR (+) and PTR (-) patients, respectively. The difference between the groups was statistically significant (P = 0.002). After adjusting for confounding factors, PTR and ECOG performance score were the independent prognostic factors for OS.CONCLUSION:PTR improved the OS in patients with RAS wild-type synchronous left-sided colon or rectum cancer treated with cetuximab-containing chemotherapy regimens.