Although smaller prospective studies have found that surgical menopause is associated with specific deficits in the memory (visual and verbal) and verbal fluency domains, larger randomized, controlled trials have generally found no effect of surgical menopause on cognitive functioning. The effects of chemical menopause are harder to assess as only three prospective trials have explicitly investigated the effect of induced menopause in the context of breast cancer treatment, and the results remain inconclusive. However, as surgical and chemical menopause both comprise the abrupt withdrawal of estrogen, there is the potential that this process may exert neurobiological effects that are different from those occurring with natural menopause and further prospective investigations comprising pre- and postsurgical/chemotherapy neuropsychological assessments are warranted.

This study examined whether chemotherapy-induced menopause affects cognitive functioning in women with early breast cancer. The neuropsychological performance of 121 breast cancer patients (age M=49.62, SD=8.11, range=25.25-67.92) treated with chemotherapy was assessed pre-chemotherapy, as well as 1, 6, and 18 months post-chemotherapy completion. Linear mixed modeling was used to evaluate the data. Type of menopause (pre, chemotherapy-induced, and post menopause) was found to significantly interact with cognitive performance on two cognitive variables. Specifically, chemotherapy-induced menopausal women did not show any significant changes in performance on an abstract reasoning task, while the pre-menopausal and post-menopausal groups significantly improved over time. A significant interaction on a test of finger dexterity and coordination was also found, although inspection of the results indicated that this was due to a significant improvement in the pre-menopausal groups at 6 months post chemotherapy. After chemotherapy most cognitive variables showed improvements over time, although two indicators of verbal memory showed significant declines immediately after chemotherapy, with improvement by 18 months post completion. The current study found little evidence to suggest that chemotherapy-induced menopause broadly affects cognitive functioning after treatment administration. However, longer follow-up assessments are warranted to assess the long-term effects of combined chemotherapy and endocrine treatment.