Unanticipated toxicity to capecitabine.

A 63-year-old African American woman, L.L., was diagnosed with hormone-negative, HER2-negative, stage IIIa breast cancer 18 months ago. Following a left modified radical mastectomy with immediate reconstruction, L.L. was treated with dose-dense adriamycincyclophosphamide followed by paclitaxel. Follow-up visits were uneventful until a month ago, when she reported persistent right-upper quadrant abdominal pain. Review of systems was negative except for fatigue that L.L. rated as 7 of 10 on a 10-point fatigue scale. Computed tomography scan showed three hepatic lesions, the largest measuring 1.7 cm. The remainder of the staging workup was negative for signs of metastatic disease. A needle biopsy of one of the liver lesions was positive for carcinoma consistent with the primary breast cancer. Capecitabine monotherapy at a dose of 1,000 mg BID for 14 days, followed by seven days of rest, was discussed with L.L. and her husband. Verbal and printed instructions were given on dosing, drug administration, and side effects, including symptoms that would require prompt contact with L.L.’s team. The nurse practitioner called L.L. on day 4 and found that, other than mild nausea, L.L. was doing well. At 7 am on day 8, L.L.’s husband called to report that L.L. had been vomiting most of the night and had bloody diarrhea since 4 am. They were instructed to go immediately to emergency triage at the hospital. When L.L. presented to triage, she was hemodynamically unstable and was admitted to the intensive care unit (ICU) for monitoring. On admission, she was found to have grade 3 oral mucositis, grade 4 diarrhea, and grade 4 neutropenia. She remained unstable and in the ICU for 10 days, after which she was transferred to the oncology unit for another 18 days. Early in her fourweek stay in the hospital, L.L. was tested for dihydropyrimidine dehydrogenase (DPD) and had partial deficiency. Capecitabine therapy had been interrupted on admission and was not resumed at discharge. L.L. was switched to gemcitabine, which she tolerated well. Unanticipated Toxicity to Capecitabine