Chemotherapy is less effective on the breast cancer women over the age of 80, according to a study. The researchers from The University of Texas Health Science center at Houston stated the reason for the reduced mortality rate 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.
Researchers examined data on 14,440 women diagnosed with breast cancer and 26,893 men and women diagnosed with colon cancer from 1992-2009. All patients 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 percent for women ages 65 to 69, 26 percent for women ages 70 to 74 and 24 percent for women ages 75 to 79.
The researchers found that chemotherapy did not significantly reduce the risk of mortality for the women over the age of 80. 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), they reported that small group of patients experienced a 29% reduced mortality risk between the ages of 80 and 84.
The study was published in the Journal of American Geriatrics Society.