Older Patients With Breast Cancer Less Likely to Benefit From Chemotherapy
HOUSTON, Tex -- August 12, 2015 -- Chemotherapy prolongs life for older adults with most types of cancer, but for women over the age of 80 with breast cancer, the chances of survival due to chemotherapy are significantly lower, according to a study published in the print edition of the Journal of American Geriatrics Society.
"Chemotherapy's reduced effect on the risk of mortality in older breast cancer patients could be due to several factors: tumours 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 lead author Xianglin Du, MD, PhD, Department of Epidemiology, Human Genetics and Environmental Sciences, School of Public Health, University of Texas, Houston, Texas.
Dr. Du and fellow researchers examined data from Surveillance, Epidemiology and End Results (SEER), a Medicare-linked database. The database held information on 14,440 women diagnosed with Stage I to IIIA hormone receptor-negative breast cancer and 26,893 men and women diagnosed with Stage III colon cancer from 1992-2009. All subjects were over the age of 65.
Among the women who had breast cancer, chemotherapy treatment reduced the risk of death from all causes by 30% for women ages 65 to 69, 26% for women ages 70 to 74 and 24% for women ages 75 to 79. For women over the age of 80, chemotherapy did not significantly reduce the risk of mortality.
However, when women over the age of 80 with breast cancer combined chemotherapy and an additional treatment, Adriamycin and cyclophosphamide, they experienced a 29% reduced mortality risk.
While the benefit of chemotherapy in reducing the risk of mortality decreased with age for females with breast cancer, men and women with colon cancer did not experience the same trend. Chemotherapy remained effective for patients with colon cancer until the age of 89.
"Previous clinical trial research has shown that chemotherapy is inefficient for breast cancer patients over the age of 70, but the 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.
SOURCE: University of Texas Health Science Center at Houston