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.