Vitamin D—The Nutritional Status of Post-Gastrectomy Gastric Cancer Patients—Systematic Review

Gastric cancer is a malignant neoplasm of the gastrointestinal tract, with one of the standard treatment methods remaining gastrectomy. The authors conducted a systemic review of the Medline and Embase databases concerning the serum vitamin D level in post-gastrectomy gastric cancer patients, regarding all articles published until 22 May 2022 according to the PRISMA guidelines. 18 studies with a total number of 908 gastric cancer survivors were included in the analysis. The initial rate of vitamin D deficiency in gastric cancer patients undergoing gastrectomy appears to be similar to the global population deficiency. In post-gastrectomy survivors, the level of 25(OH)D may remain stable or decrease, while the level of 1, 25(OH)(2)D remains normal. Supplementation with vitamin D results in an improvement in its serum concentration and positively affects bone mineral density, which is gradually reduced in post-gastrectomy survivors. Combining vitamin D supplementation with calcium and bisphosphonates enables us to obtain better results than vitamin D and calcium only. The type of surgery influences the level of serum vitamin D and its metabolites, with total or partial gastrectomy and maintenance of the duodenal food passage remaining the most important factors. There is a strong need for randomized, controlled trials that would investigate this matter in the future.