Incidence of chemotherapy-induced amenorrhea in hormone-sensitive breast cancer patients: the impact of addition of taxanes to anthracycline-based regimens

Adjuvant chemotherapy prolongs survival in patients with breast cancer, but it also causes side effects such as ovarian-function suppression. The incidence of chemotherapy-induced amenorrhea (CIA) varies depending on the patients' age, dose and the type of chemotherapy that they receive. CIA produced by anthracycline-based regimens has been widely studied, but less is known about the incidence of CIA caused by the combined use of taxanes and anthracyclines. It has been suggested that tamoxifen might influence the maintenance of amenorrhea. However, most studies of CIA have explored series of patients with hormone-sensitive and hormone-resistant tumors, so data about CIA could be strongly influenced by endocrine adjuvant therapy. The aims of our study were to assess the incidence of CIA with the addition of taxanes to anthracyclines regimens in pre- or perimenopausal patients diagnosed with hormone-sensitive breast cancer and to determine predictive factors for CIA. A retrospective non-randomized study was conducted in the Hospital Clinico Universitario of Valencia, Spain. Three hundred and five premenopausal and perimenopausal patients were recruited between January 1998 and May 2005, 212 of whom had been treated with anthracycline-based regimens and 93 with a combination of anthracyclines and taxanes. Amenorrhea was permanent in 222 patients (93.7%) and menses returned in 6.3%. CIA was present in 75.5% of patients treated with anthracyclines and in 82.7% of patients treated with anthracyclines and taxanes. This difference did not reach statistical significance (p = 0.16). CIA appeared in 95% of patients older than 45 years, while the proportion of CIA decreased to 52% in patients younger than 40 years. This suggests age as an important predictive factor for CIA (p < 0.001). Although a slightly superior incidence of CIA in patients with hormone-sensitive tumors treated with combination regimens was observed, no statistically significant difference in incidence was found. Age was found to be the main predictive factor for CIA in both groups.