Care Management and Survival of Patients Diagnosed with Synchronous Metastatic Colorectal Cancer: A High-Resolution Population-Based Study in Two French Areas

SIMPLE SUMMARY: The management of colorectal cancer with synchronous metastasis is complex and heterogenous depending on numerous factors related to patients and health care organisation. The description of real-word medical practices is challenging. While hospital series are mainly promoted by highly specialised hospitals and are not in position to accurately measure the heterogeneity of patients and practices, cancer registries are essential to describe such practices in the area covered with no regards to hospital status nor degree of specialisation. The goals of our study were to describe the colorectal cancer with synchronous metastasis population and to evaluate the impact of the different treatments on survival. Our results indicate that a combined treatment, chemotherapy and primary tumor resection, is the cornerstone of oncological management, with survival being negatively impacted by other treatment strategies. ABSTRACT: Population-based studies provide the opportunity to assess the real-world applicability of current clinical practices. The present research evaluated the survival outcomes of different therapeutic strategies for colorectal cancer (CRC) with synchronous metastasis (SM). The differential impact of treatment sequence, viz. whether chemotherapy (CT) or primary tumor resection (PTR) was performed first, was also evaluated. Methods: All CRC cases with SM diagnosed between 2006 and 2016 (N = 3062) were selected from two specialized digestive cancer registries from northwest France. Cox regression analysis was used to assess survival. Multivariable logistic regression was used to examine factors related to the combination of PTR and CT. Results: The longest survival was observed in patients treated by PTR combined with CT (Group 4; N = 1159). Overall survival was 51.80% at one year (95% Confidence Interval (CI) 50.00–53.60%) and 9.40% at five years (95% CI, 8.30–10.60%). Survival did not differ with respect to the order of treatment in multivariable analysis (hazard ratio, 1.05; 95% CI, 0.88–1.24; p = 0.55). Conclusion: Regardless of the sequence of treatment, a PTR + CT offered the best survival in patients with CRC and SM, even though few were eligible for combination therapy (38%).