Dialysis Patient Undergoing Chemotherapy for Synchronous Double Cancer Involving Breast Cancer and Small Bowel Adenocarcinoma: A Case Report

The prevalence of malignant tumors is increasing in patients undergoing dialysis. This report elucidates the case of a female patient in her 70s undergoing dialysis with synchronous double cancer involving breast cancer (pStageⅡA) and small bowel adenocarcinoma (pStageⅣ). The patient was diagnosed with hormone receptor-positive breast cancer and treated with letrozole. For small bowel adenocarcinoma, the patient received sLV5FU2 regimen as the first-line treatment and mFOLFOX6 therapy as the second-line treatment. After consultation with the doctor and pharmacist, letrozole was administered at the standard dose, whereas 5-fluorouracil (5-FU) and oxaliplatin were reduced to 80％ and 70％ of the dose, respectively. Dialysis was performed on the day before administration and on Days 2 and 4 for sLV5FU2 and mFOLFOX6 therapies. During the treatment period, the treatment was not interrupted because of myelosuppression, and adverse events were controlled at Grade 2 or lower for 20 months.