Many Obese Cancer Patients Not Receiving Their Full Dose of Chemo

Lower cancer survival rates among obese patients may be in part because many are not receiving enough chemotherapy.

"A substantial proportion of patients receiving chemotherapy who are overweight or obese are under-dosed, under-treated," KABC reported Dr. Gary Lyman, an oncologist at Duke University, as saying.

Lyman led a panel that created a set of guidelines urging physicians to administer full, weight-based doses for those who are obese.

First introduced in May 2012, the guidelines have been officially adopted by the American Society of Clinical Oncology.

One reason doctors have been shorting heavier patients is the fear of harming the heart and blood system, Lyman told The Associated Press.

As Jennifer Griggs, a breast cancer specialist from the University of Michigan who also worked on the guidelines, told the AP, "You're three times the size of the average person, but it doesn't mean your heart is."

According to the new guidelines, however, "Concerns about toxicity or overdosing in obese patients with cancer, based on the use of actual body weight, are unfounded."

Far more concerning are the lower survival rates among obese individuals who develop cancer. In all, health officials estimate that 40 percent of obese patients receive less chemo than they need, which, according to Griggs, "could make it as if they didn't even get treated at all ... so they go through the whole ordeal with no benefit, in the extreme case."

A study by Lyman published in the journal Nature in August found that a 20 percent reduction in chemo doses cut remission and cure rates by half in animal subjects. What's more, their tumors were more likely to develop resistance to the drugs as a result.

With nearly 60 percent of Americans overweight and one-third obese, the researchers point out that this is not a marginal issue.

"By minimizing the dose, or capping the dose, we have been undertreating patients," Dr. Richard Padzur, the FDA's cancer drug chief, said.