Clinical Outcomes of Upfront Primary Tumor Resection in Synchronous Unresectable Metastatic Colorectal Cancer

SIMPLE SUMMARY: The role of upfront primary tumor resection (PTR) in patients with unresectable synchronous metastatic colorectal cancer without severe symptoms remains controversial. This study aimed to report the clinical outcomes of synchronous unresectable stage IV colorectal cancer patients with or without upfront PTR. A subgroup analysis was performed to determine clinical characteristics associated with better PTR outcomes. In this retrospective study, upfront PTR was not associated with overall survival (OS) after adjusting for other variables. Subgroup analysis revealed that the male sex, good performance, the T3 stage, the M1a stage, <2 organ metastases, and the administration of targeted agents, especially bevacizumab, seemed to be related to survival benefits after PTR. Upfront PTR could be considered in some subgroups, but these findings require larger studies to verify. ABSTRACT: The role of upfront primary tumor resection (PTR) in patients with unresectable metastatic colorectal cancer without severe symptoms remains controversial. We retrospectively analyzed the role of PTR in overall survival (OS) in this population. Among the 205 patients who enrolled, the PTR group (n = 42) showed better performance (p = 0.061), had higher frequencies of right-sided origin (p = 0.058), the T4 stage (p = 0.003), the M1a stage (p = 0.012), and <2 organ metastases (p = 0.002), and received fewer targeted agents (p = 0.011) than the chemotherapy group (n = 163). The PTR group showed a trend for longer OS (20.5 versus 16.0 months, p = 0.064) but was not related to OS in Cox regression multivariate analysis (p = 0.220). The male sex (p = 0.061), a good performance status (p = 0.078), the T3 stage (p = 0.060), the M1a stage (p = 0.042), <2 organ metastases (p = 0.035), an RAS wild tumor (p = 0.054), and the administration of targeted agents (p = 0.037), especially bevacizumab (p = 0.067), seemed to be related to PTR benefits. Upfront PTR could be considered beneficial in some subgroups, but these findings require larger studies to verify.