We have preoperatively and postoperatively investigated the characteristics of anemia in patients with gastric cancer in order to provide optimal medical care for the patients.

Preoperative hemoglobin, serum iron, serum ferritin, serum vitamin B₁₂, and serum folic acid were measured for 321 patients with gastric cancer. These were measured again for 287 patients 6 months postoperatively.

Ninety-four patients (29.3%) had preoperative anemia. Preoperative hemoglobin, serum iron, and serum vitamin B₁₂ levels were higher in the patients with early gastric cancer than in patients with advanced gastric cancer. Preoperative hemoglobin, serum iron, and serum ferritin levels were higher in male patients than in female patients. The patients who had preoperative anemia showed a high probability of having postoperative anemia (P<0.001), and the patients who had low serum ferritin levels preoperatively showed a high probability of having low serum ferritin levels and iron deficiency anemia postoperatively (P<0.001).

Preoperative ferritin deficiency should be improved by iron supplement, even though the patient may not be anemic at that time. Periodic postoperative measurements of the hemoglobin, serum iron, serum ferritin, serum vitamin B₁₂, and serum folic acid levels are highly recommended because postgastrectomy anemia is not rare. Finally, if any low hemoglobin, serum iron, serum ferritin, serum vitamin B₁₂, or serum folic acid levels are found, they should be treated in an appropriate way.