THURSDAY, April 28 (HealthDay News) -- Women who have been treated for precancerous cervical lesions should see their cancer risk drop to normal after three "all clear" screening test results, Dutch researchers say.

These women can then resume screening for cervical cancer on the same schedule as the general population, they added.

"The question is how we should follow women who have been treated for precancerous cervical lesions," said lead researcher Dr. Chris Meijer, from the department of pathology at Vrije University Medical Center in Amsterdam.

The answer appears linked to two years worth of normal test results following treatment.

In the study, Meijer's team looked at the effectiveness of follow-up screening among 435 women who were treated for precancerous cervical lesions between July 1988 and November 2004. The women were given Pap tests to screen for cervical cancer and also tested for a virus linked to the cancer -- human papillomavirus, or HPV -- at 6, 12 and 24 months after treatment. If the test results were normal, they resumed normal testing, which in the Netherlands is once every five years.

The risk of developing new precancerous cervical lesions or cervical cancer over five years was 16.5 percent.

However, among women who had three normal Pap and HPV tests, the risk dropped to 3 percent in the same period, which is the same risk seen in women who never had precancerous cervical lesions, the researchers noted.

In addition, Meijer's group found that adding HPV testing made the one year screening unnecessary for women who had had a negative test at six months.

Women treated for precancerous cervical lesions who develop recurring disease need to be screened with Pap and human papillomavirus testing, but the best regimen for long-term follow-up hasn't been clear, the researchers said.

The report was published in the April 27 online edition of The Lancet Oncology.

The American Congress of Obstetricians and Gynecologists recommends that women aged 21 to 30 be screened for cervical cancer every two years and that women over 30 who have had three negative (normal) Pap and HPV tests in a row be screened every three years.

Meijer thinks that even though the protocol for screening women over 30 in the United States is every three years, it can safely be extended to five years.

However, women who have abnormal tests after treatment need additional testing, because their risk of developing the disease again is high over the next five years, Meijer noted.

Commenting on the study, Dr. Elizabeth A. Poynor, a gynecologic oncologist and pelvic surgeon at Lenox Hill Hospital in New York City said that "this provides a framework for how to follow people after they have been treated for precancerous cervical lesions."

For Poynor, the important message is that if a women does not have a recurrence after two years, her risk of developing precancerous cervical lesions reverts to the same risk as women who have never had precancerous cervical lesions -- that is, they have the same risk as other women in the general population.

"These women can go back to accepted population screening in the United States, which is a little bit more stringent [than that in the Netherlands]," she said. "Women two years after being appropriately treated for precancerous cervical lesions can be reassured that they go back down to a population risk."

More information

For more information on cervical cancer, visit the U.S. National Cancer Institute.