Experts warn of coming epidemic of head and neck tumors caused by sexually-transmitted HPV infections and obesity

While cancer rates continue to drop, two new increasingly common causes of cancer could lead to an epidemic of head and neck cancer, experts warn.

Obesity and the human papillomavirus, or HPV, are the next wave of cancer threats, according to a report released Monday with data from the American Cancer Society, the Centers for Disease Control and Prevention, the National Cancer Institute, and the North American Association of Central Cancer Registries.

Baby boomers already infected with HPV will likely develop cancers from the virus in coming years and the youger generation is not being vaccinated against it at anything close to the recommended rate.

And a third of cancer cases have been linked to obesity, which is a growing health concern with little done to combat it.

The report was published by the Journal of the National Cancer Institute.

From 2000 to 2009 cancer death rates dropped steadily by 1.8 per cent among children and men and 1.4 per cent among women.

Cancer diagnosis rates were stable for women, dipped slightly among men, and went up a tiny 0.6 per cent among children under 14.

'The fact that people are not dying of cancer is clear evidence of progress,' Dr. Otis Brawley of the American Cancer Society told MSNBC. 'But could have a much lower death rate from cancer if we simply got serious about doing all the things that work.

'Over the next 10 years, a combination of high caloric intake and low physical activity is going to surpass tobacco as a cause of cancer deaths. We are not saying anything about that. That is a huge, huge cancer prevention effort that we haven’t gotten off the ground.'

Cancer is just behind heart disease as the number 2 killer of Americans.

Poor diet, lack of exercise, and obesity are linked to roughly a third of U.S. cancers, including breast, colon, and pancreatic cancer.

Most Americans, however, don't realize this and concern themselves more with chemicals and pollution which are in reality only linked to 5 per cent of cancer cases.

Much of the drop in cancer rates can be attributed to the decline of smoking, which causes a third of cancers and was once practiced by 40 per cent of the population in the 1960s but hovers at 20 per cent and falling now.

Researchers are critical that states have done too little to curb both smoking and obesity.

Brawley compared states like Utah and California, with 10 per cent smoking rates, to MIssouri and Kentucky where the rate is 30 per cent.

Utah's Mormon population likely hurts cigarette sales.

'But in California they did some amazing work with advertisements,' Brawley said. 'I wish we were doing that all across the country.'