CHICAGO -- A new study suggests that overweight breast cancer patients don't get enough chemotherapy, which might put them at greater risk of cancer recurrence.

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Women who are 20 to 25 percent over their ideal body weight have a 1.3 times greater risk of a recurrence of breast cancer, according to the study, which is published in Monday's issue in the Archives of Internal Medicine.

Doctors typically use weight, height and body-surface measurements to determine the proper doses.

But the study's author said that doctors often avoid that approach with overweight patients, fearing toxic side effects from large doses of the powerful cancer-fighting drugs.

The study, conducted by researchers from the University of Rochester in New York, included more than 9,000 women who underwent breast cancer treatment.

Previous studies have suggested that overweight patients are more likely than lean ones to suffer a recurrence of their breast cancer because fat increases the amount of circulating estrogen, which helps fuel the growth of some tumors.

Study Abstract