Adjuvant AI Breast Cancer Therapy May Cause Long-Term Cognitive Decline

The cognitive function of postmenopausal women who take hormonal maintenance therapy after surgery for breast cancer remains compromised after the regimen’s 5-year course, according to study results presented at the ONS 44^th Annual Congress in Anaheim, California, April 12.

Catherine M. Bender, Ph.D., RN, FAAN, and colleagues embarked on the study because they and others had previously established that postmenopausal women with breast cancer who take aromatase inhibitor (AI) therapy experience deteriorations in concentration and working memory in the first 24 months of treatment. In addition, the researchers knew that this population experiences poor executive function before adjuvant therapy compared with women who don’t have breast cancer, said Bender, professor and endowed oncology chair in the university’s School of Nursing.

However, the trajectory of cognitive function through the five-year AI therapy course had not been documented, nor was it clear whether cognitive function recovers post-therapy. Thus, the researchers sought to determine the long-term effect of AI therapy on objectively measured cognitive function in postmenopausal women with early-stage breast cancer. Their study, which was supported by the National Cancer Institute, compared results at 1 year post-therapy to baseline findings before AI therapy and to a final assessment taken near the end of the course of drugs.

Forty-seven study participants had stage I to IIIa breast cancer. One group was taking AIs alone (n = 33) and another took chemotherapy followed by an AI (n = 14). A third group (n = 36) included healthy controls matched to the other groups by age and education.

Cognitive function was assessed before adjuvant therapy, twice annually in years 1 and 2 of therapy, annually in years 3 through 5, and once post-therapy. In assessing cognitive function, the researchers considered attention; concentration; verbal, visual and working memory; executive function; mental flexibility; and psychomotor speed. That information, plus data including age, education, IQ, and levels of depression, anxiety, fatigue, and pain, was assessed using linear mixed modeling.

Women who received AIs alone had poorer concentration and psychomotor speed 1 year after therapy compared with their scores before therapy. At the same time point, they also had poorer concentration relative to their last assessment during therapy. Healthy controls also experienced a decline in concentration at 1 year compared with their year 5 assessment.

Other than that, women taking chemotherapy followed by an AI and healthy controls had improved executive function, attention, working memory, and verbal memory at therapy completion relative to before therapy, and also at 1 year post-therapy compared with before therapy.

“Deficits in concentration and psychomotor speed may persist after completion of AI therapy in women with breast cancer,” the researchers concluded. “While these results need to be verified in a larger sample, they point to a need for interventions to help women compensate for persistent cognitive changes they may experience after AI therapy.”

The results also suggest that the disease itself, and not just its treatments, may be affecting cognitive function in women with breast cancer, Bender said. In addition, they indicate that concentration may be “the seminal domain” affected by breast cancer treatment, as without it, patients are unable to plan or organize.

Finally, Bender said that the findings “add to evidence suggesting that aging is accelerated in people with cancer…through multiple biological mechanisms.”

Reference:

Bender C, Zhu Y, Nilsen M, Sereika S. Long-term trajectory of objectively measured cognitive function with aromatase inhibitor therapy in women with early-stage breast cancer. Presented at: Oncology Nursing Society 44^th Annual Congress; Anaheim, California; April 11-14, 2019. Abstract No. 5787.