A recent study shows that women who received a combination breast cancer chemotherapy regimen referred to as CMF between 1976 and 1995 performed worse on cognitive tests compared with women who never had cancer. The subtle differences in performance were statistically significant and occurred primarily in word learning and memory and information processing speed.
The findings, published February 27 in the Journal of Clinical Oncology, indicate that cognitive problems may be observed 20 years following chemotherapy treatment.
“To our knowledge, this is the first study to suggest that subtle cognitive deficits may be among the long-term effects of chemotherapy, especially of the earlier regimens,” said Sanne B. Schagen, PhD, one of the senior authors and a group leader at the Department of Psychosocial Research and Epidemiology at the Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital in Amsterdam.
CMF chemotherapy was the standard of care for breast cancer worldwide from the 1970s through the 1990s and included the drugs cyclophosphamide, methotrexate, and 5-fluorouracil. Although it has now been replaced by anthracycline-based adjuvant regimens, cyclophosphamide and 5-fluorouracil are still frequently incorporated into current chemotherapeutic regimens for breast cancer.
Between November 2009 and June 2010, Dr Schagen and colleagues administered neuropsychological tests to 196 women who had received CMF chemotherapy (6 cycles following surgery) between 1976 and 1995. A control group of 1509 women enrolled in the Rotterdam Study was also given the neuropsychological tests. All participants were between the ages of 50 and 80 years. Beyond the neuropsychological tests, the women were also assessed for depression and self-perceived memory problems.
Adjusting for such factors such as age, education, and depression score, researchers discovered that women who had CMF chemotherapy were more likely than the women in the control group to have inferior scores on tests of immediate and delayed verbal memory (the ability to recall words), information processing speed, and psychomotor speed (coordination of thinking and hand movement, such as putting pegs in a board). These effects were comparable to approximately 6 years of age-related decline in cognitive function.
“Our findings do not suggest that breast cancer survivors treated with CMF chemotherapy need to be monitored more closely for cognitive difficulties. But if breast cancer patients experience cognitive problems, information about the possible long-term effects of their breast cancer treatment may help to guide referral to appropriate support services,” said Dr Schagen.
Source: ASCO.