491. VITAMIN B12 DEFICIENCY AFTER ONCOLOGICAL ESOPHAGECTOMY AND GASTRECTOMY

Abstract

Abstract Vitamin B12 deficiency is common in patients with resections of the upper digestive tract and must be expected during follow-up examinations. While esophagectomy with gastric pull-ups preserve the duodenal passage and a large part of the stomach, (sub)total gastrectomies result in significant losses of gastric tissue and the common Y-Roux reconstruction bypasses the duodenal passage. This is a monocentric, retrospective, descriptive analysis of prospectively collected follow-up data. Between January 2015 and December 2019, 232 patients underwent an oncological (sub)total gastrectomy or esophagectomy. After applying the exclusion criteria (patient below 18, primary bone marrow disease, hereditary forms of anemia, postoperative tumor recurrence, R1/R2 situation), 157 patients remained for analysis: 103 patients (=66%) with esophagectomy (ER) and 54 (=34%) with (sub)total gastrectomy (SGE). Vitamin B12 levels were analyzed three, six, twelve, 18, and 24 months after the surgery. Prophylactic intramuscular vitamin B12 substitution (Erycytol 1 mg depot) was routinely prescribed quarterly only in patients with a total gastrectomy. After 3 postoperative months the incidence of vitamin B12 deficiency were 24% in the ER group vs. 5% (p = 0,064) in the SGE group; 17% vs. 10% (p = 0.4) after 6 months; 8% vs. 5% (p = 0.65) after 1 year; 10% vs. 10% (p = 0.83) after 18 months, and 12.5% vs. 39% (p = 0.022) after 2 years. The resulted incidence of hyperchromic macrocytic anemia is furtherly discussed in the abstract entitled ‘Types and incidence of postoperative anemia after oncological esophageal and gastric resections’. Comparing the total gastrectomy versus subtotal gastrectomy subgroups, patients with a subtotal gastrectomy have higher vitamin B12 deficiency incidences throughout the 24-month follow-up period. The human body physiologically provide a sufficient vitamin B12 storage for minimum 6–9 months. The high incidence of vitamin B12 deficiency in the ER group in the first 6 postoperative months might be due to a pre-existing vitamin B12 deficiency. After the 6th postoperative month there is an approximation between the Vitamin B12 deficiency incidences of ER and (S)GE patients. In the final 2-year follow-up, the incidence of vitamin B12 deficiency was significantly higher in the (S)GE group.