Chemotherapy-induced amenorrhea temporary in most premenopausal women with breast cancer

Premenopausal women treated with chemotherapy for breast cancer may experience periods of chemotherapy-induced amenorrhea; however, most women will resume bleeding within three years, according to findings from the Menstrual Cycle Maintenance and Quality of Life after Breast Cancer Treatment study.

Ramifications of chemotherapy-induced amenorrhea may include infertility, vasomotor symptoms and premature bone loss. Therefore, researchers, led by Paniti Sukumvanich, MD, of Magee-Women’s Hospital of the University of Pittsburgh Medical Center, assessed the incidence for chemotherapy-induced amenorrhea and the time to subsequent menstrual bleeding at six, 12 and 24 months in 460 women with premenopausal breast cancer treated with standard chemotherapy regimens.

The results were published in Cancer.

The majority of patients were assigned doxorubicin and cyclophosphamide (AC); doxorubicin, cyclophosphamide and paclitaxel (ACT); or cyclophosphamide, methotrexate and 5-FU (CMF).

Women were aged 20 to 45 years at the time of a stage I to III breast cancer diagnosis and were recruited between January 1998 and July 2002. Monthly bleeding calendars were completed by the patients beginning at study recruitment; updated medical history data were collected every six-months.

A significant association was found among women who had six months of chemotherapy-induced amenorrhea and older age (P<.001), BMI (P=.042), treatment regimen type (P=.011), tamoxifen use (P<.001) and a longer duration of chemotherapy (P=.035).

The odds for a six-month chemotherapy-induced amenorrhea period was 0.04 among women aged 20 to 34 years (95% CI, 0.02-0.09) and 0.17 for women aged 35 to 39 years (95% CI, 0.10-0.30) when compared with women aged 40 years or older. The odds for a six-month chemotherapy-induced amenorrhea period was 2.17 for those who were overweight (95% CI, 1.19-3.97) and 1.17 for those who were obese (95% CI, 0.57-2.41).

About 41% of women experienced an initial six months of chemotherapy-induced amenorrhea; 29% had at least one year. In addition, about 50% of women with six months chemotherapy-induced amenorrhea and 29% of women with one year of chemotherapy-induced amenorrhea resumed bleeding during the subsequent three years.

Chemotherapy-induced amenorrhea significantly differed depending on type of chemotherapy after six months of bleeding (P=.002; 68% with AC; 57% with ACT; and 23% with CMF). However, this was not true after one year of CIA (P=.5).

Having chemotherapy-induced amenorrhea for more than one year resulted in less favorable outcomes. “The results of our menstrual data indicate that only 10% of women had resumption of bleeding if they were amenorrheic for 24 months after completing chemotherapy,” the researchers wrote. “None of the patients who received CMF resumed bleeding. In more commonly used regimens such as AC and ACT, approximately 15% to 26% of patients resumed menstrual bleeding despite being amenorrheic for 24 months.” None of these women reported regular menses.

Sukumvanich P. Cancer. 2010;doi:10.1002/cncr.25106.