Most older breast cancer survivors maintain cognitive function

The majority of breast cancer survivors aged 65 years or older maintained good long-term self-reported cognitive function, according to the results of a trajectory group analysis.

Only a small subgroup of patients who were exposed to chemotherapy experienced accelerated cognitive decline.

“There is a growing body of evidence that cancer and its systemic treatments can have adverse effects on cognition in some, but not all, survivors of breast cancer,” Jeanne S. Mandelblatt, MD, MPH, associate director for population sciences at Lombardi Comprehensive Cancer Center and professor of oncology at Georgetown University School of Medicine, and colleagues wrote. “Cognitive issues can go unrecognized in clinical encounters, but can limit the ability of older survivors to conduct daily activities, ... lead to social isolation due to difficulty driving or organizing social activities, or attempts to conceal these deficits.”

Mandelblatt and colleagues evaluated cognitive data from a prospective cohort of 1,280 breast cancer survivors aged 65 to 91 years to assess long-term self-reported cognitive function, and to examine the effects of chemotherapy on cognitive function.

Study participants completed baseline surveys. They provided follow-up data at 6 months, and then annually for 7 years.

Participants used the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ–C30) — which tabulates scores on a scale from 0 to 100 — to provide cognitive data. Higher scores indicated better function.

After a median follow-up of 4.1 years, researchers categorized survivors into three categories based on EORTC QLQ–C30 cognitive function scores.

The “maintained high” group (42.3%) consisted of survivors who had near-perfect baseline scores (mean, 99.4; standard deviation, 3.8) and maintained that level.

The “phase shift” group (50.1%) consisted of survivors who had baseline scores slightly below the high group (mean, 89.9; standard deviation, 13.2), and their scores declined at a similar rate to the high group.

The “accelerated decline” group (7.6%) reported the lowest baseline scores (mean, 71.7; standard deviation, 19.8) and also demonstrated the steepest rate of decline by the end of follow-up (mean, 58.3; standard deviation, 21.9).

Overall, 40.5% of participants received chemotherapy, and nearly two-thirds (60.4%) of chemotherapy regimens were anthracycline-based.

Survivors who received chemotherapy were more than twice as likely to be in the “accelerated decline” group than the “maintained high” group (OR = 2.1; 95% CI, 1.3-3.5).

Survivors who had two or more comorbid illnesses were three times more likely to be in the “accelerated decline” group than the “maintain high” group (OR = 3; 95% CI, 1.74-5.4). Patients classified as frail were significantly more likely to be in the “accelerated decline” group (OR = 19.9; 95% CI, 7.8-50.8) or the “phase shift” group (OR = 4.5; 95% CI, 2.1-9.8) than the “maintained high” group.

In a secondary analysis, researchers used EORTC QLQ–C30 scores for physical function to evaluate the association between physical status and cognitive status. Survivors in the “accelerated cognitive decline” group were nearly 10 times more likely than those in the “maintained high” cognitive group to be in the “accelerated physical decline” group (OR = 9.5; 95% CI, 3.6-25.5).

Researchers acknowledged limitations, such as the reliance on self-reported data, the lack of data regarding neuropsychological testing, as well as the lack of longitudinal measures of fatigue, pain, activities of daily living and instrumental activities of daily living.

“The results of the current study suggest that the majority of older survivors of breast cancer maintain high self-reported cognitive function, but that chemotherapy — with or without hormonal treatment, which was received by the healthiest older survivors — can have adverse long-term effects in a small number of survivors,” Mandelblatt and colleagues wrote. “These findings suggest further research is needed to determine risk factors for cognitive decline to identify those individuals most likely to benefit from cognitive monitoring during survivorship care.” – by Nick Andrews

Disclosure: Mandelblatt reports no relevant financial disclosures. Please see the full study for a list of all other researchers’ relevant financial disclosures.