Predicting the surgical benefit of primary tumor resection in patients with stage IV colorectal cancer

Background: There exists continuous controversy regarding the benefit of primary tumor resection (PTR) for stage IV colorectal cancer (CRC) patients. Little is known about how to predict the patients' benefit from PTR. This study aimed to develop a tool for surgical benefit prediction. Methods: Stage IV CRC patients diagnosed between 2010 and 2015 from the Surveillance, Epidemiology and End Results database were included. Patients receiving PTR who survived longer than the median cancer-specific survival (CSS) time of those who did not undergo PTR were considered to benefit from surgery. Logistic regression analysis identified prognostic factors influencing surgical benefit, based on which a nomogram was constructed. The data of patients who underwent PTR from our institution was used for external validation. A user-friendly webserver was then built for convenient clinical use. Results: The median CSS of the PTR group was 23 months, significantly longer than that of the non-PTR group (7 months, P < 0.001). In the PTR group, 23.3% of patients did not benefit from surgery. Logistic regression analysis identified age, marital status, tumor location, CEA level, chemotherapy, metastasectomy, tumor size, tumor deposits, number of examined lymph nodes, N stage, histological grade and number of distant metastases as independently associated with surgical benefit. The established prognostic nomogram demonstrated satisfactory performance in both the internal and external validation. Conclusion: PTR was associated with prolonged CSS in stage IV CRC. The proposed nomogram could be used as an evidenced-based platform for risk-to-benefit assessment to select appropriate patients for undergoing PTR.