Breast Cancer Chemo: Lower Dose for Obese?
Study Questions Dose Reductions for Overweight Patients
June 13, 2005 -- Overweight or obese women with breast cancer may benefit from getting a full dose of chemotherapy, says a new study in the Archives of Internal Medicine.
However, some doctors may be reducing chemo doses for such patients, say the researchers, who included Jennifer Griggs, MD, MPH, of the University of Rochester.
"Overweight and obese women with breast cancer often receive intentionally reduced doses of adjuvant chemotherapy," say Griggs and colleagues. Receiving a full, weight-based dose "is likely to improve the outcomes in this group of patients," they write in the journal's June 13th edition.
That's especially important these days, with obesity rising in the U.S., according to the study.
What's Weight Got to Do With It?
breast cancer surgery. Breast cancer is the most common cancer among U.S. women, except for nonmelanoma skin cancers. More than 211,000 new cases will be diagnosed this year, says the American Cancer Society.
is widely used after
Obesity is a risk factor for developing breast cancer. It can also worsen the prognosis for breast cancer patients, say Griggs and colleagues. But they don't want to oversimplify matters. Many factors are involved in the obesity-breast cancer association, they say.
Doctors may cut chemo doses for patients who aren't in good health (apart from their cancer). Some small studies have shown that some chemotherapy drugs linger longer in the bodies of obese patients, but Griggs and colleagues say "there is little evidence to support the use of dose reductions in these patients."
Chemotherapy Dose-Weight Study
Griggs' study looked at doses of two chemotherapy drugs -- doxorubicin and cyclophosphamide -- in more than 9,600 women with breast cancer treated at about 900 practices.
Most were healthy, except for their breast cancer; few had other serious medical problems. They were treated from 1990 to 2001.
More than six out of 10 women were overweight or obese (31% overweight, 17% obese, and 14% severely obese), says the study. Chemo doses were reduced for 37% of the severely obese women, 20% of obese women, and 11% of overweight women.
Overweight is defined as a
or BMI of 25-29.99; a BMI of 30-39.99 is obese, and 40 or higher is morbid or severe obesity.