SAN FRANCISCO – Patients with breast cancer who received hormone therapy were over seven times more likely to show cognitive decline as were untreated patients after controlling for other factors, based on a prospective study of 81 patients.
Further, objective results on neuropsychological testing tended to back up patients’ complaints of cognitive difficulties.
Hormone therapy may be a risk factor for cognitive deficits, and interventional studies should be designed to focus on this group of patients, Dr. Hope S. Rugo and her associates recommended in a poster presentation at a breast cancer symposium sponsored by the American Society of Clinical Oncology.
The study collected neuropsychological test results and patient reports before treatment and at several points after starting hormone therapy (22 patients), chemotherapy (14), or chemotherapy followed by hormone therapy (33), and in a control group of 12 untreated patients.
Compared with baseline results, nearly 25% of patients had cognitive decline on neuropsychological testing after 5 months. (Among treated patients, this occurred 1 month after ending chemotherapy or 5 months after starting hormone therapy.) Nearly 35% had cognitive declines at 9 months of follow-up, and 30% had cognitive declines after 18 months.
"Decline in cognitive function is common in patients receiving adjuvant therapy for early-stage breast cancer," concluded Dr. Rugo, director of the Breast Oncology Clinical Trials Program at the University of California, San Francisco. "Ongoing hormone therapy appears to be a risk factor for worse cognitive function."
Other factors that did not predict cognitive decline in the multivariate analysis included age, education level, average estradiol level over time, and estimated verbal IQ at baseline.
Separate univariate conditional logistic regression analyses found that hormone therapy predicted cognitive decline with an odds ratio of 5, but chemotherapy, radiation therapy, average fatigue over time, and average depression over time were not predictive of cognitive decline at any point.
The study enrolled women aged 35-80 years with early-stage breast cancer. Those who underwent adjuvant therapy received 3-4 months of chemotherapy alone, 5 years of hormone therapy alone, or both.
A separate analysis in the same study looked at how well subjective patient reports correlated with objective measures on neuropsychological tests. Dr. Lara Heflin and her associates found significant cross-section correlations between patient-reported cognitive problems and psychological distress and fatigue.
After researchers controlled for the influence of depression and fatigue, however, significant relationships remained between patients’ perceived cognitive functioning and measurable cognitive decline from baseline (pretreatment) to the first follow-up. Patients whose scores indicated memory decline were more likely to perceive memory problems, and patients whose scores on letter fluency declined were more likely to perceive problems with verbal fluency.
"Patients who self-report cognitive problems may indeed be experiencing cognitive decline, and their self-report should not simply be attributed to fatigue or to psychological factors such as anxiety and depression," concluded Dr. Heflin, a visiting professor of psychology at New Mexico Highlands University, Las Vegas.
Patients in the study had no prior chemotherapy or central nervous system radiation and no history of major psychiatric illness, serious head injury, neurologic disease, drug or alcohol abuse, or significant medical illness. The median age was 54 years, and 78% of patients were white. Patient characteristics were similar between groups.
The symposium was cosponsored by the American Society of Breast Disease, the American Society of Breast Surgeons, the National Consortium of Breast Centers, the Society of Surgical Oncology, and the American Society for Radiation Oncology.
The National Institutes of Health funded the study. Dr. Rugo reported having financial associations with Merck, Novartis, and Pfizer.
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