Women with breast cancer who are obese or less educated are twice as likely to get reduced doses of chemotherapy than doctors recommended, jeopardizing survival, according to scientists at the University of Rochester Medical Center.
The research focused on 764 women enrolled in the Awareness of Neutropenia in Chemotherapy Study Group Registry, which is based at Rochester’s James P. Wilmot Cancer Center. The women received treatment between 2002 and 2005 at 115 randomly selected, private oncology practices around the country.
According to researchers, 21 percent of obese and severely obese women received less than 85 percent of the standard dose, compared to less than 10 percent for lean women. More than 32 percent of women who didn’t finish high school saw chemotherapy reduced, compared with 14 percent of high school or college-educated women.
“Simply put, this evidence shows that doctors are likely to reduce the chemotherapy levels for these women, even though there is no solid medical basis to do it,” said Gary Lyman, M.D., M.P.H., principal investigator and director of the ANC Study Group, an Amgen-funded project that leads multi-center studies of cancer patients starting chemotherapy. The University of Rochester Medical Center funded this retrospective study.
Frequent under-treatment with chemotherapy is a well-documented problem. Oncologists are sometimes reluctant to deliver full doses of chemotherapy to an obese woman, despite the calculations based upon her weight that indicate it is appropriate and safe. There are also studies that point to wide variations in oncology practice between different regions of the country.