Clinicopathological Characteristics of Metastatic Colorectal Cancer Patients with Prolonged Survival

Objective: The median overall survival (OS) of metastatic colorectal cancer (mCRC) has reached 30 months in recent trials; however, data on the the clinicopathological features of long-term survivors remain limited. Material and Methods: This is a single-center retrospective analysis of the clinical, pathological, and genetic characteristics of patients who survived more than 30 months after diagnosis of mCRC. Results: Fifty-eight patients were included; mean age was 59.7±10.0 years. At diagnosis, 63.8% of patients had stage 4 disease and 84.5% had left-sided tumors. All underwent primary tumor surgery; a KRAS mutation was present in 48.3% of patients. Of the patients, 84.5% received local treatment, with metastasectomy being the most common (70.7%). The identified mutations were PIK3A (3 patients), SMAD4 (2), ERBB3 (1), MAP2K and FGFR (1), and germline POL (1) mutations. The most common metastatic sites were the liver (65.5%), the lungs (56.9%), and the peritoneum (15.5%). The Fluoropyrimidine-oxaliplatin combination was the most commonly used first-line treatment (59.6%). The median OS was not reached (range: 31.5-217.03 months). Univariate analysis identified female gender (p=0.019), KRAS mutation (p=0.033), higher number of metastatic lesions (p=0.016), increased number of treatment lines (p=0.001), and liver metastases in segments 6 (p<0.001) and 8 (p=0.007) as poor prognostic factors. Multivariate analysis confirmed that female sex (p=0.036), KRAS mutation (p=0.02), liver metastasis in segment 6 (p=0.018), and an increased number of treatment lines (p=0.007) were associated with poorer survival. Conclusion: Patients with mCRC and above-average survival constituted a heterogeneous group. However, female sex, KRAS mutation, and segment 6 liver metastasis were associated with poor prognosis. Primary tumor surgery may have contributed to prolonged survival, warranting further comparative studies to guide clinical decisions.