Women who receive mastectomy, surgical oophorectomy and Nolvadex® therapy during the luteal phase of menstruation experience significantly better outcomes than women who receive the same treatment during the follicular phase of menstruation, according to the results of a study recently published in the
Journal of the National Cancer Institute.
While some people have speculated that the phase of the menstrual cycle could impact outcomes of primary surgical treatment in premenopausal women with breast cancer, the relationship between menstrual cycle phase during surgery and disease-free survival and overall survival has been unclear. In this study, researchers evaluated this issue in the context of a clinical trial designed to compare mastectomy alone with mastectomy plus adjuvant oophorectomy and Nolvadex® in premenopausal women with operable breast cancer. The study involved 565 women who reported a last menstrual period (LMP) within 42 days before surgery. The researchers used the date of the LMP to determine the phase of the menstrual cycle. The follicular phase was defined as days 1-14 from LMP, while the luteal phase was defined as days 15-42 from LMP.
The women in the study were placed in one of two treatment arms: the mastectomy only treatment arm involved 289 women who were treated with mastectomy only and the adjuvant treatment arm involved 276 women who were treated with mastectomy, oophorectomy and Nolvadex®. Women in the mastectomy only treatment arm experienced no differences in disease-free survival (DFS) or overall survival (OS) related to menstrual cycle phase. However, women in the adjuvant treatment arm experienced better DFS and OS if their treatment occurred during the luteal phase of menstruation rather than the follicular phase.
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The researchers concluded that there was no evidence that the timing of mastectomy influences outcomes in women with operable breast cancer who do not receive adjuvant systemic therapy. However, they concluded that women who undergo adjuvant oophorectomy simultaneously with mastectomy experience better outcomes if the treatment occurs during the luteal phase of menstruation. Women with operable breast cancer may wish to speak with their physician about the results of this study and the timing of their surgery.
Reference: Love RR, Duc NB, Dinh NV, et al. Mastectomy and oophorectomy by menstrual cycle phase in women with operable breast cancer.
Journal of the National Cancer Institute. 2002;94:662-669.