Pattern Alopecia during Hormonal Anticancer Therapy in Patients with Breast Cancer

We report five cases of pattern alopecia in female patients who are undergoing hormonal anticancer therapy for the prevention of recurrence of breast cancer after surgery. Three patients demonstrated male pattern alopecia with receding frontal hairlines, and two patients demonstrated female pattern alopecia without receding hairlines. The detailed clinical history showed that the pattern alopecia of the patients developed after the full recovery of global hair loss of the entire scalp due to previous cytotoxic chemotherapy. All of the adjuvant hormonal anticancer drugs that were used in the patients are antiestrogenic agents, either aromatase inhibitors or selective estrogen receptor modulators. Considering androgen effect on the hair follicles of the fronto-parietal scalp, the androgen-estrogen imbalance caused by the drugs was thought to be the reason for the onset of pattern alopecia in the patients. In general, alopecia that develops during cytotoxic chemotherapy is well known to both physicians and patients; however, the diagnosis of pattern alopecia during hormonal anticancer therapy in breast cancer patients seems to be overlooked.