Differences in patient- and tumor characteristics, treatment and survival between patients with screen-detected versus clinically detected colorectal peritoneal metastases.

Introduction: Screening for colorectal cancer has been implemented to improve cancer-specific survival. This study aims to compare patient- and tumor characteristics, treatment, and survival between patients with screen-detected and clinically detected synchronous colorectal peritoneal metastases (CPM) in a Dutch population-based cohort.

Methods: Data from the Netherlands Cancer Registry (NCR) were used. Screening was performed nationwide with biennial FIT and subsequent colonoscopy if positive. Patients within the screening age (55-75 years) and diagnosed with synchronous CPM between 2014 and 2020 were included. Data from the NCR was linked to the Dutch Nationwide Pathology Databank (Palga) to identify mode of detection. Baseline characteristics and treatment were compared between screen-detected CPM patients and clinically detected CPM patients using χ-tests. Overall survival (OS) was compared between both groups with the log-rank test and a multivariable Cox regression analysis.

Results: Of 2,773 included patients with synchronous CPM, 197 (7 %) were detected by screening. In the screen-detected group, 56 (28 %) patients underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) versus 363 (14 %) in the clinically detected group (p < 0.001). Median OS was 20.0 months (IQR 9.7-51.7) in the screen-detected group versus 10.8 months (IQR 3.4-25.5) in the clinically detected group (p < 0.001). In the multivariable analysis, CPM detected through screening was associated with improved OS compared to clinically detected CPM (adjusted HR 0.68, 95%CI [0.57-0.81]).

Conclusions: Screen-detected patients with colorectal peritoneal metastases more often received treatment with curative intent and had better OS compared to clinically detected patients.