Some women at long-term cervical cancer risk

By Michael Kahn

LONDON (Reuters) - Women treated for pre-cancerous lesions are at increased risk of developing cervical or vaginal cancer for at least another 25 years, according to a study suggesting that follow-up tests fall dangerously short.

Using data from Sweden's national cancer registry, the researchers said on Friday women who have had severe lesions in the cervix are more than twice as likely to develop one of the two cancers than women in the general population.

The findings underscore the need for follow-up tests to continue for at least 25 years after treatment, far longer than the current five or 10 years standard in most European countries, said Bjorn Strander, a gynaecologist at Sahlgren's University Hospital in Sweden, who led the study.

"This is a warning to the healthcare system to keep track of these women," he said in a telephone interview. "It has not been known these women remain at risk for such a very long time."

Most cases of cervical cancer are caused by the sexually transmitted human papilloma virus and is the second most common type of cancer in women. Vaginal cancer is far more rare, with about 13,000 women diagnosed each year.

Women in many countries have an annual Pap smear to check for early signs of these lesions, which are easily removed if caught before they develop into cancer.

Nonetheless cervical cancer kills 300,000 each year, mostly in developing countries. Merck and Co's Gardasil and GlaxoSmithKline's Cervarix vaccines protect people against certain strains of HPV, but not all.

In their study, the researchers mined the National Swedish Cancer Register for information recorded from 1958 to 2002 on more than 132,000 women diagnosed with pre-cancerous lesions.