DNA test could detect cervical cancer early: study

LONDON (Reuters) - A DNA test for the virus that causes cervical cancer helps detect potentially dangerous lesions earlier than the commonly used pap smear technique, Dutch researchers said on Thursday.

The test could mean fewer screenings for women and ensure that they receive earlier treatment for lesions that might lead to cancer, they said in the journal Lancet.

"It is a better test because you pick up more lesions," Chris Meijer, a pathologist at VU University Medical Centre in Amsterdam, said in a telephone interview. "And because you pick them up earlier, you have more time to treat the women."

In a pap smear, doctors scrape cells from the cervix and examine them under a microscope for abnormalities that could indicate precancerous lesions. The DNA test screens for evidence of infection by high-risk types of the human papillomavirus (HPV) that cause cervical cancer. 

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The Dutch study suggests the DNA test is better at indicating which women are at risk of precancerous lesions and should therefore have a biopsy, Meijer said.

"When you are HPV positive (in the test), the likelihood you have precancerous lesions is quite high," he said. "A (pap smear) is not sensitive enough to detect all the lesions."

Cervical cancer is caused by the HPV virus spread through sexual transmission and is the second most common type of cancer in women.

Merck and Co's. Gardasil and GlaxoSmithKline's Cervarix vaccines protect people against HPV infection. The tumors kill about 300,000 each year, mostly in developing countries.

In the study of more than 17,000 Dutch women aged 29 to 56, the researchers split the women into two groups, with one receiving conventional pap smears and the other getting additional DNA testing.

Five years later, the researchers tested the entire group using both tests and found that DNA screening helped detect 50 percent more of the potentially precancerous lesions.

"On the basis of this data, we suggest that the current screening interval of five years could be extended by at least one year," the researchers said in a statement. "The extension will be advantageous to women because of a reduction in the lifetime number of screening tests and referrals."

The findings indicate that the DNA test could stand as the primary screening method for cervical cancer, Guglielmo Ronco and Nereo Segnan of Italian cancer specialists CPO Piemonte in Turin wrote in a commentary in Lancet.

The results also seem to answer the question of whether the test is effective in helping to detect dangerous lesions, Ronco added in a telephone interview.

"This is an important thing," he said. "Up to now we knew that HPV (testing) allowed us to find more lesions but whether they were relevant wasn't sure."