Sunday, November 4, 2007

Some face long-term cervical cancer risk

Women with pre-cancerous lesions may need follow-up tests for 25 years
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 gynecologist 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.

Risk remains steady
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.
They found that 881 women had developed cervical cancer and 111 women had vaginal cancer more than one year following their diagnosis — even after they had their lesions removed.
And the risk remained high for a long time, they said.
“We haven’t investigated why but there are indications it could be because a lack of surveillance,” Strander said. "The risk is quite steady. It does not decrease.”
A woman’s risk also rose if she was older at diagnosis, also possibly due to the healthcare system letting down its guard during follow-up care, Strander said.
The Swedish study, published in the British Medical Journal, did not look at whether a Pap smear or DNA test represented the best way to screen these women but said it merits further study, Strander added.
Two Italian researchers writing in a related editorial agreed the findings should spark further study and said they clearly show current testing guidelines are not sufficient.
“One clear indication is that women treated for (severe pre-cancerous lesions) should continue surveillance beyond the age limit of regular screening,” they wrote.

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