Role of Vitamin D in Patients with Rectum Cancer Receiving Neoadjuvant Treatment

Background: Relationship between vitamin D level and pathological response and survival in rectal cancer patients receiving neoadjuvant therapy, is an unstudied issue.Aim: We planned to investigate the relationship between vitamin D level and pathological response in this population.Materials and Methods: Patients diagnosed with rectal cancer and followed up at Ankara University Faculty of Medicine, Medical Oncology Clinic between January 2012 and May 2023 were included. Patients' demographic data, vitamin D level, stages, chemotherapy and radiotherapy protocols, type of surgery and postoperative pathological responses were recorded and compared statistically.Results: Eighty-three patients were included in the study. Median vitamin D level at the time of diagnosis was 15.89 ng/mL. Each 1-year increase in age was associated with a 0.22 ng/mL decrease in vitamin D levels. No significant relationship between vitamin D level and pathological response was found. Vitamin D levels were 13 ng/mL lower in stage 4 compared to stage 1 disease, but the difference was not significant. Relapse and survival rates were not significantly related with Vitamin D levels. When patients over 60 years of age were evaluated, vitamin D levels were significantly lower in patients with ypT4 against ypT0 disease. Conclusion: No significant relationship could be demonstrated between vitamin D levels and pathological response. More studies are needed to investigate the effect of vitamin D levels on prognosis and pathological response in older age and more advanced disease.