In order to correct the problem, the American Society of Clinical Oncology has adopted guidelines promoting full, weight-based chemotherapy doses for obese patients, the Associated Press reported.
Doctors should use a patient's size to calculate chemotherapy doses, but often fail to do so with those who are obese, the report said. One reason is concern about how much chemotherapy an obese patient can bear, but research shows that larger people cope with chemotherapy better than smaller people.
Studies suggest that as many as 40 percent of obese cancer patients receive less than 85 percent of the right doses for their size, according to the AP.
The American Society of Clinical Oncology's new advice should be viewed as right-sizing cancer care, said Dr. Gary Lyman, a Duke University oncologist who led the guidelines panel.
"There's little doubt that some degree of undertreatment is contributing to the higher mortality and recurrence rates in obese patients," he told the AP.
There is a problem with obese cancer patients receiving inadequate chemotherapy doses, said Dr. Richard Pazdur, director of the U.S. Food and Drug Administration's office of cancer drugs.
"By minimizing the dose, or capping the dose, we have been undertreating patients," he told the AP.
The issue affects a lot of patients, as 60 percent of Americans are overweight and more than one-third are obese.