More than 20 years after treatment, breast cancer patients who received adjuvant chemotherapy exhibited cognitive deficits compared with women who were never diagnosed with cancer. The results, which appears in the Journal of Clinical Oncology, suggest that the phenomenon known as chemobrain can persist for decades after cancer treatment ends and may become more common as the number of cancer survivors grows.

To investigate chemotherapy’s long-term effects on cognition, Dr. Vincent Koppelmans of Erasmus MC University Medical Center in Rotterdam, the Netherlands, and his colleagues identified 196 eligible breast cancer patients from two Dutch hospital registries and invited them to participate in tests that measured learning, memory, information processing, and psychomotor abilities.

All of the patients had received six cycles of adjuvant chemotherapy with cyclophosphamide, methotrexate, and fluorouracil (CMF) on average 21 years earlier and were between 50 and 80 years old when recruited to the trial. Women who had experienced a relapse, second primary tumour, or distant metastases, and those who used adjuvant endocrine therapy were excluded from the study.

The 1,509 women in the reference group were selected from the Rotterdam Study, a population-based study also being conducted in the Netherlands. These women had no history of cancer and were also between 50 and 80 years old when they were tested.

Although the researchers observed no difference between the two groups in a dementia screening test, the breast cancer survivors performed worse on some tests of delayed verbal memory, processing speed, and psychomotor speed. The survivors also had more memory complaints but fewer symptoms of depression.

This pattern of deficits is similar to those from other trials conducted closer to the time patients finished chemotherapy. But it is unclear whether the results of this study are representative of the long-term effects of other chemotherapy regimens.

Although newer regimens are now available for women with early-stage breast cancer, the authors noted, “[CMF] was the standard regimen up to the 1990s... [and] cyclophosphamide and fluorouracil continue to be incorporated into currently used regimens.”

“This work is an important reminder that it is not enough to focus on the cure and control of cancer,” commented Dr. Julia Rowland, director of NCI’s Office of Cancer Survivorship. “We must also attend to the impact of therapy on the long-term health and function of our growing population of survivors.”

Source: NCI