Survival Benefit of Palliative Primary Tumor Resection Based on Tumor Location in Patients with Metastatic Colorectal Cancer: A Single-center Retrospective Study.

Backgrounds/Aims: The molecular underpinnings of colorectal cancer (CRC) vary according to the tumor location. The advantages of a palliative primary tumor resection in patients with metastatic CRC are controversial. This study examined the survival outcomes of a palliative primary tumor resection based on the tumor location in patients with metastatic CRC. Methods: The medical records of 600 patients diagnosed with metastatic CRC between January 2000 and June 2018 were reviewed retrospectively. Patients undergoing surgery for both the primary tumor and metastatic lesions were excluded. The clinical factors affecting the long-term outcomes were evaluated according to the primary tumor location, and the long-term survival was compared between patients with and without a palliative primary tumor resection. The data were analyzed using the Kaplan-Meier estimator and multivariate Cox regression models. Results: The median follow-up duration was 18 months (interquartile range, 10-28). Patients with right-sided CRC had a poor overall- and progression-free survival compared to those with left-sided CRC. In multivariate Cox regression analysis, the palliative primary tumor resection was an independent prognostic factor predicting better overall survival in patients with metastatic CRC, regardless of the primary tumor location. Conclusions: The primary tumor location influences the prognosis, and that a primary tumor resection can improve the overall survival in patients with metastatic CRC, regardless of the primary tumor location.