Chemotherapy prolongs life for older adults with most types of cancer, but not for women over the age of 80 with breast cancer, according to a US study.
Researchers examined data on 14,440 older women diagnosed with Stage I to IIIA hormone receptor-negative breast cancer, and 26,893 men and women diagnosed with Stage III colon cancer.
“The effectiveness of chemotherapy decreased with age in participants with breast cancer”
Among the women who had breast cancer, chemotherapy reduced the risk of death from all causes by 30% for women ages 65-69, 26% for women ages 70-74 and 24% for women ages 75-79.
However, for women over the age of 80, chemotherapy did not significantly reduce the risk of mortality, found the researchers from the University of Texas.
Men and women with colon cancer did not experience the same trend. Chemotherapy remained effective for colon cancer patients until the age of 89.
The exception was when women over the age of 80 with breast cancer were treated with a combination of received doxorubicin (Adriamycin) and cyclophosphamide (Cytoxan.
This small group of patients experienced a 29% reduced mortality risk between the ages of 80 and 84.
“The effectiveness of chemotherapy decreased with age in participants with breast cancer, in whom chemotherapy appears to be effective until age 79 except for the doxorubicin-cyclophosphamide combination,” said the study authors.
Lead author Professor Xianglin Du said: “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.”
The study results were published this month in the Journal of American Geriatrics Society.