Severe thrombocytopenia induced by chemotherapy after total gastrectomy: A report of three cases.

Pancytopenia associated with vitamin B12 and folic acid deficiency has been reported in patients who have undergone total gastrectomy. Therefore, myelosuppression due to chemotherapy following total gastrectomy is considered to be more serious. We encountered three cases of severe thrombocytopenia in patients who received chemotherapy after total gastrectomy. The lowest platelet levels in these patients were 1.7 × 104/mm3, 2.3 × 104/mm3, and 0.9 × 104/mm3, respectively. None of the patients presented with vitamin B12 deficiency, and one patient presented with folic acid deficiency. The association between serum vitamin levels and chemotherapy-related adverse events is controversial. Since folic acid has a shorter half-life (6 hours) and cannot accumulate in the body, unlike vitamin B12 that is stored for a long time in the liver, folic acid deficiency is suspected to be associated with thrombocytopenia induced by post-total gastrectomy chemotherapy. However, serum folic acid levels fluctuate depending on the timing of evaluation and require a few days to evaluate. In conclusion, patients who undergo chemotherapy after total gastrectomy should be monitored for severe thrombocytopenia but serum vitamin B12 levels are not necessarily clinically important. By measuring serum folic acid levels at appropriate times, folic acid deficiency may prove to be a reference for predicting severe thrombocytopenia.