Patients With Breast Cancer Over Age 80 Less Likely to Benefit From Chemotherapy Alone Than Younger Patients
Chemotherapy prolongs life for older adults with most types of cancer, but for women with breast cancer over age 80, the chances of survival with chemotherapy alone are significantly lower than in younger patients, according to a study led by researchers from the University of Texas Health Science Center at Houston (UTHealth). The results were published by Du et al in the Journal of the American Geriatrics Society.
“Chemotherapy's reduced effect on the risk of mortality in older breast cancer patients could be due to several factors—tumors being less sensitive to chemotherapy, a decrease in dosage as the body gets weaker with age, or chemotherapy killing healthy cells in addition to cancer cells,” said Xianglin Du, MD, PhD, Professor, Department of Epidemiology, Human Genetics, and Environmental Sciences, UTHealth School of Public Health.
Study Details
Dr. Du and fellow researchers examined data from the Medicare-linked database Surveillance, Epidemiology, and End Results (SEER). The database held information on 14,440 women diagnosed with stage I to stage IIIA hormone receptor–negative breast cancer and 26,893 men and women diagnosed with stage III colon cancer from 1992 to 2009. All subjects were over age 65.
Among the women who had breast cancer, chemotherapy treatment reduced the risk of death from all causes by 30% for women aged 65 to 69, 26% for women aged 70 to 74, and 24% for women aged 75 to 79. For women over age 80, chemotherapy alone did not significantly reduce the risk of mortality. However, when women with breast cancer over age 80 received chemotherapy and an additional treatment (doxorubicin and cyclophosphamide), they experienced a 29% reduced mortality risk.
Although the benefit of chemotherapy in reducing the risk of mortality decreased with age for female patients with breast cancer, men and women with colon cancer did not experience the same trend. Chemotherapy remained effective for patients with colon cancer until age 89.
“Previous clinical trial research has shown that chemotherapy is inefficient for breast cancer patients over the age of 70, but those trials have been considered to have small sample sizes. This study, using large sample sizes, shows that there's strong evidence to this finding,” said Dr. Du.
Dr. Du is the corresponding author of the Journal of the American Geriatrics Society.
This study was supported by the Agency for Healthcare Research and Quality and the Cancer Prevention Research Institute of Texas.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
