Cancers caused by the human papilloma virus rose in the past decade as use of vaccines by Merck & Co. (MRK:US) and GlaxoSmithKline Plc (GSK) that may prevent the tumors was less than recommended by health officials.
The rates of oral, vulva and anal cancers increased from 2000 to 2009, according to a study published today in the Journal of the National Cancer Institute. The incidence of cervical cancer, also tied to HPV, fell in white women while increasing in black women, the report said.
Merck’s vaccine, which came on the market in 2006, and Glaxo’s vaccine, approved in 2009, protect against strains of the sexually transmitted virus that are linked to cancer of the anus, cervix, vagina, vulva, and throat. The U.S. recommends use of the shots in boys and girls ages 11 and 12. Only a third of girls ages 13 to 17 have been fully vaccinated as of 2010, well below the 80 percent rate epidemiologists say is needed to significantly reduce the prevalence of infections.
“Vaccination rates are still quite low in terms of where we need to be to really impact HPV infections,” said Edgar Simard, an author on the study and senior epidemiologist at the Atlanta-based American Cancer Society, in a telephone interview. “If we don’t address these disparities now they will continue to manifest.”
The increase in HPV-related cancers contrasts with a decline in the rate of all new tumors in men, the study found. The rate for all cancers in women was little changed. Cancer deaths continued to drop, falling 1.5 percent a year during the decade. The biggest declines in death rates were in lung, breast, colon and prostate cancers while deaths increased from liver, pancreatic and skin cancers.
Cancer death rates have been falling since the 1990s because of less tobacco use and more screening that can lead to early detection and treatment, the study said.
“We are seeing the trend going in the right direction,” said Brenda Edwards, an author on the study and senior adviser at the National Cancer Institute. “These trends show we haven’t eliminated cancer, but we have managed to be able to diagnosis it and treat it.”
Researchers on the study said they aren’t certain why the HPV vaccination rates remain low, though there are multiple barriers to getting protected. Unlike most vaccines, it isn’t required for school enrollment, putting less pressure on parents to ensure their children get the shot. It also requires three shots, meaning parents will have to take their child to the doctor multiple times.
The lowest HPV vaccination rates were in southern states, including Alabama and Mississippi, and among people without health insurance.
HPV-associated cancer accounted for 3.3 percent of all cancers among women and 2 percent in men in 2009, the study found.
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