Worse oncological impact of preoperative anemia in patients with locally advanced gastric cancer after curative gastrectomy: A retrospective cohort study

Background: The impact of preoperative anemia on long-term survival outcomes after gastrectomy remains unclear. This study determined the effect of preoperative anemia on long-term survival outcomes in patients undergoing gastrectomy for gastric cancer. Methods: This retrospective cohort study included consecutive patients who underwent radical gastrectomy for primary pStages I-III gastric cancer between May 2006 and March 2017. According to the World Health Organization hemoglobin classification, >= 13.0 g/dL for men and >= 12.0 g/dL for women are considered normal, 11.0-12.9 g/dL for men and 11.0-11.9 g/dL for women as mild anemia, 8.0-10.9 g/dL moderate anemia, and <8.0 g/dL as severe anemia. The primary outcome was overall survival (OS). Comparisons were made using the log-rank test, and prognostic factors were identified using Cox proportional hazards regression analysis. Results: The median follow-up duration was 60 months. Of 4730 patients, 3066 (64.8 %) were classified as normal, 1093 (23.1 %) as mild, 540 (11.4 %) as moderate, and 31 (0.7 %) as severe anemia. Patients with anemia had poorer survival outcomes than those without anemia (P < 0.001). No differences were found among survival outcomes in OS based on severity. When stratified by pStage, patients with anemia had a poorer survival outcome than those without anemia in each pStage. Multivariate analysis showed that preoperative anemia was an independent poor prognostic factor for OS regardless of blood transfusion (hazard ratios: 1.650, 95 % confidence interval: 1.432-1.902, P < 0.001). Conclusions: Preoperative anemia, independent of perioperative blood transfusions, may worsen OS in patients with gastric cancer after curative gastrectomy.