The rate of young, white women being diagnosed with one type of tongue cancer has more than doubled in 30 years, and researchers aren't sure why. The usual suspects, such as tobacco use or human papillomavirus, don't seem to be at work, according to a new study.
The analysis of National Cancer Institute data, which revealed a 111 percent increase in cases of squamous-cell tongue cancer among young white women, found a 43.7 percent increase among young, white men over the same period. Meanwhile, the tongue cancer rates decreased for people of other age groups and ethnicities.
Smoking isn't likely to account for the increase in tongue cancer, because other studies have shown a decrease in tobacco use over the last few decades in the United States, said Dr. Bhisham Chera, an assistant professor of radiation oncology at the University of North Carolina Lineberger Comprehensive Cancer Center.
"I've treated a handful of these patients, and they're all a higher socioeconomic status," Chera told MyHealthNewsDaily. "Most of them — and this is just from what I've examined — are not smokers. They're college-educated, they're health nuts, and they don't have any of the typical risk factors."
Chera also said the cancer-causing human papillomavirus was unlikely to be behind the increase. He and his colleagues studied whether their young, white female patients with tongue cancer tested positive for the virus, which can cause tongue and tonsil cancer. But their preliminary research found no association, Chera said.
The researchers analyzed health data from more than 30,000 people gathered from 1975 to 2007 in the National Cancer Institute's Surveillance, Epidemiology and End Results database. The number of tongue cancer cases rose by 28 percent in people ages 18 to 44 during that time, and increased by 67 percent among white people in that age group, according to the study.
Although the researchers called the rise an "alarming, substantial increase," the cancer is still relatively rare. The researchers found that 32,776 people in the U.S. were diagnosed with any type of oral cancer over the 30-year study, and 6,810 of them had squamous cell tongue cancer.
It's possible that an unidentified virus is causing the cancer in certain groups. To see if this is the case, Chera said, he is collecting tumor samples from his young, white female patients, and will sequence their genes to see if any viral genetic material is hidden in the patients' tumor cells.
Eating disorders may be another factor contributing to the increase in tongue cancers in this specific population, Chera said, because the stomach acid that comes up when a person vomits can induce some cancers. However, more research is needed before eating disorders are highlighted as a potential cause of tongue cancer, he said.
Another possible explanation for the increase is improvement in diagnostic test technology through the years, Chera said.
"The bottom line is, who knows what's causing these cancers? Maybe it's environmental, maybe it's genetic, maybe it's a combo of both," Chera said. “We don't know yet, but we're going to look at it."
Squamous-cell tongue cancer affects the thin cells along the lips and oral cavity, though the cancer can spread deeper into the tissue. It's relatively rare compared with breast, lung or prostate cancer, and is usually treated with surgery (removal of part of the tongue or lymph nodes), followed by radiation or chemotherapy, Chera said.
Oral cancers, including tongue cancer, occur most often in people ages 45 and older, according to the National Cancer Institute.
The study was published this week in the Journal of Clinical Oncology.
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This story was provided by MyHealthNewsDaily, a sister site to LiveScience.