Prognostic score for synchronous metastatic rectal cancer: A real-world study.

Background: Prognostic factors of metastatic rectal cancer are not well known.

Aim: The objective of this study was to identify prognostic factors of overall survival (OS) in a cohort of patients with non-resectable synchronous metastatic rectal cancer.

Methods: Patients were retrospectively enrolled from 18 French centres. Univariate and multivariate analyses were performed to identify prognostic factors for OS. A simple score was derived from this a development cohort RESULTS: A total of 243 patients with metastatic rectal cancer were included in the study. Median OS was 24.4 months, 95% CI [19.4-27.2]. Among patients with non-resected metastases (n=141), six independent prognostic factors associated with better OS were identified in multivariate analysis: primary tumour surgery, WHO score 0-1, middle or upper rectal tumour, lung metastases only, systemic chemotherapy and targeted agent in first line. A prognostic score individualized three groups, each factor counting for one point in the score (<3, = 3 et > 3). Their median OS were respectively 27.9 months, 95% CI [21.7-35.1], 17.1 months [11.9-19.7] (HR=2.08, 95%, CI [1.31-3.30], p=0.002) and 9.1 months [4.9-11.7] (HR=2.32, 95% CI [1.38-3.92], p=0.001).

Conclusion: A prognostic score for non-resectable synchronous metastatic rectal cancer can be proposed to classify patients in three prognostic groups.