Doctors say at-home screening for HPV could be an opportunity to 'eliminate a cancer'
As Pap smears are phased out for screening, HPV self-swabs called a safe, accurate measure
Women should be offered take-home kits to screen for cervical cancer, doctors say in new guidelines aiming to reduce discrimination in health care.
Provinces are moving away from Pap smears for screening, which is recommended at least once every three years for women aged 30 to 69. A doctor sweeps up cells in the cervix to spot lesions caused by the human papillomavirus (HPV). The abnormalities provide an early warning of changes that can become cancerous without treatment.
Instead of the Pap, a relatively new HPV test is being rolled in several provinces. The test detects high-risk types of the virus. Those aged 25 and 65 are offered it every five years, with slight variations from province to province.
Self-swabs for HPV — similar to the at-home rapid tests for the virus that causes COVID-19 — could significantly boost early detection, says Dr. Aisha Lofters, a scientist and family physician at Women's College Hospital in Toronto, and a co-author of a paper published in Monday's issue of the Canadian Medical Association Journal.
At-home HPV testing would help overcome barriers such as being unable to take time off work for medical appointments, having a history of sexual trauma or a lack of awareness, Lofters said.
"This could be a really meaningful alternative to increase screening rates while doing so in a safe and comfortable manner."
Pap smear accuracy is around 60 per cent. But in HPV testing, which looks at DNA of the virus, the accuracy can rise to 90 per cent. Cancer scientists say that's why the older Pap screening needs to be repeated more often.
With the HPV test, doctors can be more confident that a negative result means the woman is in the clear, said Dr. Gina Ogilvie. She led pilot projects trials on the rollout of at-home tests across British Columbia.
"You have the same accuracy as if a clinician got that specimen," Ogilvie said of B.C.'s experience after sending out 10,000 kits for self-collection in rural and urban areas.
Success abroad
Cervical cancer screening hasn't reached everyone.
Australia led the way with self-testing for HPV, where it's been a success.
Ogilvie's found similar gains working directly with Indigenous leaders in her province as well as South Asian women in Surrey. People can request kits, which are sent to homes. Groups hosting screening events may also order them.
In the U.S., uptake also improved after cancer agencies brought in self-collection in low-income areas.
"I think we have a chance to actually eliminate a cancer," Ogilvie said. "The fact that we have a screening tool that is even better, that can allow us to identify precancerous lesions earlier, get folks in treatment and prevent these unnecessary deaths, I think is incredibly exciting and motivating."
At the Society of Obstetricians and Gynaecologists of Canada (SOGC), Dr. Diane Francoeur called the move to HPV tests for cervical cancer screening one of the greatest revolutions for women after the introduction of the birth control pill in the 1960s.
Even with vaccinations to protect against HPV, Francoeur, the society's Ottawa-based CEO, said screening needs to continue because immunizations won't reach everyone.
"My biggest wish for myself is that you should be able to go to the pharmacy and get these tests free like we had with the COVID test," said Francoeur.
"The sad part is we've been waiting for years and it takes forever because every province will have their own program."
Across Canada, the shortage of staff like specialists and lab technologists will get worse, meaning women who wait for a cervical cancer diagnosis will suffer, Francoeur said.
Cancer eradication goal
Dr. Craig Earle serves as CEO of the Canadian Partnership against Cancer, a federally funded group that works with provincial cancer agencies. Their shared goal is eliminating cervical cancer by 2040.
Earle, a medical oncologist, said the switch to HPV has a lot of potential to address equity issues. But for provinces, it also represents a sea change that requires a new type of lab infrastructure and staffing.
WATCH | Pap smears delayed:
"It's not just snap your fingers and switch," Earle said. "Who follows up with the results? What if you don't have a family doctor? There's a whole thinking through of how would this actually work that needs to be in place."
Colorectal cancer change
To that end, the new guideline's 15 screening recommendations prioritize having people automatically enrol with a family doctor or nurse practitioner, just like parents register their child at the local school.
For other cancers, the authors' suggestions include:
- Talking to patients about doing at-home colorectal cancer screening with stool starting at age 45 instead of the current recommendation of age 50. In part, that's because the disease is starting to happen in younger people and recent immigrants are less likely to be screened than those born in Canada. In the U.S., Black people are less likely to have surgery for colorectal cancer than white people, research suggests.
- Removing the cost of bowel preparations for colonoscopy screenings.
- Prioritizing outreach efforts for lung cancer screening in adults aged 50 to 80 who have smoked the equivalent of a pack a day for 20 years.
Earle noted that a lung screening program being introduced in Saskatchewan will first roll out in the province's north, where smoking and lung cancer rates are highest, rather than defaulting to starting in Regina.
"It may be more difficult, but that's where the need is," Earle said. "The idea is that by setting things up in that way, hopefully it can't help but at least mitigate the effect that we sometimes see of widening disparities."
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With files from CBC's Christine Birak