Older women with breast cancer are more likely to get lower doses of chemotherapy than younger women, in an effort, presumably, by their doctors to reduce the ill effects of the toxic therapies, according to a study by a University of Rochester Medical Center scientist.
In a review of more than 1,200 women treated at community oncology practices throughout the country, more than 30 percent of women over 65 received reduced doses of chemotherapy, compared to 20 percent of younger women. The study was published online in the journal Cancer.
And, the study showed that many older women weren’t given anthracycline- or taxane-based chemotherapy – the backbone drugs of breast cancer care – at least 22 percent compared with 8 percent of younger women. And aging patients received growth factors that help rebuild patients’ immune systems at a significantly lower rate than the younger women, 18 percent compared with 28 percent.
Breast cancer diagnoses top 230,000 each year in the United States and it’s the second deadliest cancer for women, behind lung cancer. About half of all women diagnosed with breast cancer are over 65.
“Typically older patients are more likely to have other health problems and doctors may be concerned about them and choose to reduce the chemotherapy dose to avoid raising their risk of adverse toxicity or neutropenia,” said Michelle Shayne, M.D., breast oncologist and assistant professor at the Medical Center’s James P. Wilmot Cancer Center. Reducing doses of chemotherapy is considered a factor in poor outcomes for some people.
The data showed comparable toxicity levels between the two groups of patients, likely as a result of the significant chemotherapy dose reductions for the older patients. The prospective observational study centered on 1,224 women diagnosed with Stage 1 to Stage 3 disease treated between 2002 and 2005. Within that group, 207 women were 65 or older.
“We don’t know for sure whether the doctors are actually making these decisions, or to some extent, the patients themselves. And it’s not unreasonable for doctors to look out for their patients and avoid added toxicity,” Shayne said. “But that approach might be undermining the outcome of the older patients.”
Shayne wrote the study and worked with colleagues from Duke University led by Gary H. Lyman, M.D., M.P.H.