The first round of the Canadian Cervical Cancer Screening Trial, led by Eduardo Franco, Director of the Division of Cancer Epidemiology at McGill's Faculty of Medicine, put the HPV test's accuracy in detecting pre-cancerous lesions at 94.6 percent, compared to 55.4 for the Pap test.
The study is published in the October 18 edition of The New England Journal of Medicine.
The trial, funded by a grant from the Canadian Institutes of Health Research, followed 10,154 women aged 30-69 in Montreal, Quebec and St. John's, Newfoundland from 2002-2005.
"We already knew before conducting this study that the sensitivity of Pap left a lot to be desired," said Franco.
The Papanicolaou (or Pap) test was invented by Georgios Papanicolaou in the 1940s and requires technicians to look under a microscope for abnormalities in cell samples collected from the patient's cervix. It has been the standard screening procedure for cervical cancer for almost 50 years.
The HPV test also requires the collection of cervical samples, but the analysis process is automated and detects the DNA of high-risk HPV strains known to cause cervical cancer.
"Women currently vaccinated against cervical cancer will still need to be screened, because the vaccines that are available now only prevent about 70% of all cervical cancers, and they're primarily for young women," said Franco.
"The HPV test may be ideal for vaccinated women once they reach screening age, because it gives us an opportunity to monitor the protection that the vaccine is supposed to give them," he added.
Cervical cancer kills more than one quarter of a million women worldwide each year.