Effects of circulating 25(OH)D status in advanced colorectal cancer patients undergoing chemotherapy: A systematic review

Abstract

Background/Aim: Colorectal cancer (CRC) is a disease of poor prognosis. An advantageous connection between vitamin D supplementation and prognostic improvement was depicted in CRC patients. However, the effects of circulating vitamin D on cancer outcomes are unclear for advanced CRC patients, especially for those receiving chemotherapy. Materials and Methods: The review was registered on PROSPERO (register number: CRD42021243547). PUBMED, EMBASE, Cochrane Library, and Web of Science were searched for English-language publications using relevant keywords. Two reviewers independently selected articles, assessed quality, and extracted data. We applied RevMan5.4 and Stata14 for meta-analysis. Results: We included an RCT and three prospective cohort studies, which were of high overall quality. Higher circulating 25(OH)D level was related with better disease outcomes in advanced CRC patients undergoing chemotherapy: progression-free survival (HR=0.85, 95% CI=0.71-0.99; I2=34.4%), overall survival (OR=0.56, 95% CI=0.38-0.82; I2=0%). Conclusion: High circulating 25(OH)D content is beneficial for improving prognosis of advanced CRC receiving chemotherapy.