Previous research has found a similar racial disparity in breast cancer treatment, with blacks more often having the entire breast removed instead of just the cancerous lumps.

It's unclear why the gap exists. But Dr. Allen Chen, who led the new study, said poverty, less education and deep-rooted historical biases could all be at work.

"There could be an underlying distrust among African Americans where they feel anything less than surgery might be considered quote-unquote experimental," Chen, a radiation oncologist at University of California, Davis, told Reuters Health.

He referenced the Tuskegee experiment, conducted by the U.S. government into the 1970s, in which black patients with syphilis went untreated despite assurances to the contrary.

"That sort distrust needs to be addressed or alleviated," Chen said, because voice-preserving treatment for throat cancer, based on radiation and drug therapy, is now the standard.

His study, published in the Archives of Otolaryngology - Head & Neck Surgery, is based on data from a U.S. cancer registry including nearly 5,400 cases of laryngeal cancer between 1991 and 2008.

About 80 percent of whites had voice-preserving treatment, while the rest had their voice box surgically removed - the traditional approach.

Among blacks, 75 percent had the gentler therapy. While that's only a five-percent difference, "I think it's still a gap that needs to be narrowed," Chen said.

The racial disparity remained after the researchers accounted for age, sex and how advanced patients' tumors were, and it didn't disappear in the more recent half of the study either. However, there was no significant gap between whites and Hispanics or Asians.

The study didn't look at income or education, which might explain some of the difference. It's also possible that more blacks lived in areas without access to the resources involved in voice-preserving therapy, which requires cooperation between doctors with different specialties.

While the gentler therapy might be just as effective as putting patients under the knife, surgery does have some advantages.

"It's a one-stop deal," said Chen, whereas it takes several weeks of treatment for drugs and radiation to work.

But if it's a question of people believing treatment other than surgery is experimental, he added, "That perception needs to be changed."

His team is now doing a follow-up study to try to rule out some potential explanations for the findings.

SOURCE: bit.ly/Q09IPj Archives of Otolaryngology - Head & Neck Surgery, July 16, 2012.

• A Permanent Economic Emergency