Toxicity risk score and clinical decline after adjuvant chemotherapy in older breast cancer survivors.

BACKGROUND

Chemotoxicity risk scores were developed to predict grade 3-5 chemotherapy toxicity in older women with early breast cancer. However, whether these toxicity risk scores are associated with clinically meaningful decline in patient health remains unknown.

METHODS

In a prospective study of women aged 65 years and older with stage I-III breast cancer treated with chemotherapy, we assessed chemotoxicity risk using the Cancer and Aging Research Group-Breast Cancer (CARG-BC) score (categorized as low, intermediate, and high). We measured patient health status before (T1) and after (T2) chemotherapy using a clinical frailty index (Deficit Accumulation Index, categorized as robust, prefrail, and frail). The population of interest was robust women at T1. The primary outcome was decline in health status after chemotherapy, defined as a decline in Deficit Accumulation Index from robust at T1 to prefrail or frail at T2. Multivariable logistic regression was used to examine the association between T1 CARG-BC score and decline in health status, adjusted for sociodemographic and clinical characteristics.

RESULTS

Of the 348 robust women at T1, 83 (24%) experienced declining health status after chemotherapy, of whom 63% had intermediate or high CARG-BC scores. After adjusting for sociodemographic and clinical characteristics, women with intermediate (odds ratio = 3.14, 95% confidence interval = 1.60 to 6.14, P < .001) or high (odds ratio = 3.80, 95% confidence interval = 1.35 to 10.67, P = .01) CARG-BC scores had greater odds of decline in health status compared with women with low scores.

CONCLUSIONS

In this cohort of older women with early breast cancer, higher CARG-BC scores before chemotherapy were associated with decline in health status after chemotherapy independent of sociodemographic and clinical risk factors.