How Does HPV Testing Compare To The Pap Test For Cervical Cancer Screening?
March 26, 2008
In a new collaborative study, the BC Cancer Agency, an agency of the Provincial Health Services Authority (PHSA), is trying to determine if a test for Human Papilloma Virus (HPV) can replace the standard Pap test as the primary method of cervical cancer screening, allowing women to be screened more effectively and less frequently.
The HPV FOCAL Study - the first long term and largest study of its kind in North America ??” is conducted in collaboration with another PHSA agency, the BC Centre for Disease Control, as well as the UBC Department of Family Medicine and the Faculty of Medicine, McGill University department of Epidemiology, and about 100 family doctors in Greater Vancouver.
“Over the last 20 years, it has become apparent that infection from HPV is the primary cause of cervical cancer,” says Dr. Andy Coldman, BC Cancer Agency Vice President of Population Oncology, and Principal Investigator of the study. “If we can test for the presence of high-risk strains of this virus, we believe we can identify women who are truly at risk for developing cervical cancer and its precursors.”
“If HPV is found, we know a woman may be at higher risk. We can then further analyze her cervical sample with Pap testing in the laboratory to see what treatment, if any, she may require,” adds Dr. Coldman.
The study aims to enroll 33,000 participants over the next seven years. Women age 25-65 who attend one of the over 100 participating family practices will have the opportunity to be part of the study. Participants will have a cervical sample taken by their family doctor during their regular screening appointment, with appropriate follow-up depending on the test results. The sample is collected from a woman the same way as a Pap smear is obtained - the only difference is how the sample is processed in the laboratory.
The Pap test requires technicians to examine samples under a microscope to look for abnormal cells. The HPV test is read by a machine that detects presence or absence of DNA for high-risk strains of HPV.
“The Pap test is an effective screening tool, but it’s not perfect,” adds Dr. Coldman. “We believe the HPV test is superior to the Pap test as a screening tool, but its true benefits are still unknown until we compare it directly to the standard screening test in a large study.”
To compare HPV testing to the Pap test, cervical samples from study participants will be randomly assigned to one of the following testing methods:
- Pap test (using a liquid based collection medium)
- HPV test, and screened again in two years if no HPV is found
- HPV test, and screened again in four years if no HPV is found
For Janet Abe, whose parents were both diagnosed with cancer within three months of each other six years ago, taking part in a study that could help improve cancer outcomes in the future was an easy decision.
“This was really a no-brainer,” says Abe, a 38-year-old magazine production manager. “It’s so simple. I would be going for my regular Pap test anyway, but now I can participate in a study that could potentially make a difference for women and their families down the road.”
The HPV FOCAL Study, funded by the Canadian Institutes of Health Research, is currently offered only in Greater Vancouver. For more information and to learn which family doctors are participating in the study, please call 604-707-5955 or hpvfocal@bccancer.bc.ca.
HPV is very common and there are usually no symptoms. Most sexually active adults will have had an HPV infection at some time in their lives but it usually goes away on its own within 24 months without any problem, and without a person knowing they had it. For some women, HPV does not go away. Over time, long term infection with high risk types of HPV can cause abnormal cervical cells that may progress to cervical cancer.
A vaccine for HPV has been approved to prevent the two most common types of HPV linked to cervical cancer but it will not treat women who have already been exposed to HPV. The vaccine will not fully protect everyone and it doesn’t prevent all types of cervical cancer. Therefore, regular screening is still extremely important, even for woman who have been vaccinated.
In 2007, an estimated 144 BC women were diagnosed with cervical cancer and 45 died from the disease.
The BC Cancer Agency, an agency of the Provincial Health Services Authority, is committed to reducing the incidence of cancer, reducing the mortality from cancer, and improving the quality of life of those living with cancer. It provides a comprehensive cancer control program for the people of British Columbia by working with community partners to deliver a range of oncology services, including prevention, early detection, diagnosis and treatment, research, education, supportive care, rehabilitation and palliative care. The BC Cancer Foundation raises funds to support research and enhancements to patient care at the BC Cancer Agency.
BC Cancer Agency
