Pap tests have long saved lives, but they can be uncomfortable—especially for women in remote or underserved communities. Recent innovations, like the HPV vaccine and the rollout of at-home self-sampling in parts of Canada, are opening new possibilities for prevention and earlier detection. These advances show how cervical cancer screening is evolving beyond the traditional clinic exam, offering hope for more comfortable and equitable care.
Dr. Annie Leung, a gynecologic oncologist at the McGill University Health Centre and Assistant Professor in Obstetrics & Gynecology at McGill, cares for patients across the cancer journey while leading research to improve detection through biomarkers like circulating tumor DNA. Her collaborators, which include Dr. Julia Burnier, a liquid biopsy experts, and Dr. Samara Perez, a clinical psychologist with an interest in HPV, are pioneering a non-binary liquid biopsy that could help doctors identify which HPV-positive patients truly need follow-up — reducing unnecessary procedures and moving Canada closer to eliminating cervical cancer.
In this interview, she shares her journey and what’s next for women’s health innovation.
Dr. Leung’s journey to medical school
“I come from an immigrant family from Hong Kong. We had language barriers growing up, and I learned to navigate them through the Canadian healthcare system. But, like many immigrants, accessing care for my family and navigating that for my mom, my two older sisters, and my father was a challenge,” Dr. Annie Leung explains. “Things like getting my mom a mammogram, my sister getting her first pap test, were difficult, but I had an interest in health, and I learned how to navigate through that. I sympathized with what some of the challenges were, and I became interested in science and technology.”
But medicine wasn’t where Leung began. 
“I did my studies in system design engineering at Waterloo. I loved math, loved physics, and I was interested in building devices, and I liked working with my hands. Biomed and core engineering didn’t really come up until towards the end of my undergrad, and I started looking into it, and was like: ‘this is really cool’.”
After finding her way to medical school after a year at a startup where she helped develop tiny optical and imaging devices, Leung has now brought all her experience together in what she and her team are currently developing and researching.
Why Women’s Health?
“I think I gravitated towards women’s health because it’s so pervasive how illness affects women. I think we’ve all heard it in different ways, but when a woman gets sick, the whole family and her community are impacted. And that’s so, so true – even to this day.” Leung goes on to explain the ripple effect of making a woman healthier. “Her children are going be taken care of, her parents, her partner, all those people within her circle. I felt a great reward with that. That’s kind of how I landed in gynecologic oncology.”
Complexity of Screening for and Eradicating Cervical Cancer
“I had a chance to go to Uganda as a medical student, and then to Brazil as an obstetrics and gynecology trainee. I saw that cervical cancer was a huge problem. It wasn’t really on my radar at that point, because in school, at least in textbooks, we know that there is an HPV vaccine that can eliminate cervical cancer, and we see that in a really well-organized program, like Australia has, they’re going to achieve elimination very soon – in the next 5 to 10 years.” Leung said.
Seeing the discrepancy and knowing that there’s a way to eradicate cervical cancer, Leung began to ask herself. “Why is this so difficult? Why are people still experiencing cervical cancer?” She admits that it got her engineering wheels turning. Particularly with the discomfort and inconvenience of pap smears. “It’s a problem on multiple levels that made the complexity really interesting to me.”
This complexity comes from a number of factors. One that some associate pap smears with shame, and don’t want to see a doctor. Two, the speculum exam is simply uncomfortable and invasive. Three, women often don’t put themselves first, in favour of addressing more immediate needs. “Women tend to put themselves second, third, fourth, last,” she said, continuing: “It’s like, ‘I have to take care of my family, I can’t take a bike ride to the closest clinic, which is two hours away for a pap test. That’s just not something that I’m thinking about right now. I have more immediate needs; my family needs food on the table.’” And lastly, four, there’s the stigma that HPV is a sexually transmitted disease.
Vaccine Hesitancy and Repercussions of Misunderstanding HPV
Leung explains that HPV has a marketing problem, that it hasn’t been explained to the public and to families in a way that removes the stigma.
“In medicine, we talk about human papillomavirus, which is the cause of the majority of cervical cancer, as a sexually transmitted disease. Absolutely, it is. That is the truth. But what’s not talked about is that eight out of ten individuals who have ever been sexually active have contracted the HPV virus at some point in their lives, so it’s super common. It’s not something to be ashamed of, but we have a taboo in our society.” Leung says. “I think of the HPV vaccine not as the vaccine against sexually transmitted disease, although it is. It’s a cancer prevention vaccine.”
As a result, some people aren’t getting vaccinated or screened, and unfortunately, Leung still sees cervical cancer that can have significant implications for women, including young women who have their dreams of having a family taken away from them.
“I want to prevent cervical cancer from happening.” Leung says, “That takes me to why I got interested in the research aspect.”
Team Goal to Make Screening for HPV Easier
Leung, who describes herself as “a small piece of the puzzle,” works with a team that consists of Dr. Julia Burnier, a close collaborator, Dr. Samara Perez, a clinical psychologist with an interest in HPV, and many clinicians who work with patients and collect samples. Their idea is to make the current care simpler and more convenient by looking at liquid biopsies as a way to detect specific levels of HPV.
“The pap smear is difficult because it requires a patient to come to a clinic, have an internal exam, wait for the results, wait for a phone call, and then, if it’s abnormal, they’re asked to travel and come back for a second exam called colposcopy,” Leung explains.
While it doesn’t sound simple, Leung and her team are taking a more technical approach to try to eliminate the need for those exams with at-home screening. “When I first started, I had a conversation with Dr. Burnier, who was working on liquid biopsy in different types of cancers. Liquid biopsy is the concept that cells in our body slough off different components, which are sometimes called circulating tumour cells. Tumour DNA, or extracellular vesicles – a lot of terminologies, but you can just think of these as packages of components from the cells that are being sloughed off. The other important part is that we use the word tumour, but tumour is a very generic term for just a bunch of cells. It’s not necessarily cancer. It can just be any cells in your body. So what we learned is that cells can send these message components, and we can detect them in things like blood, urine, saliva and vaginal fluid that you can collect. Either by a pap test that a doctor takes, or what we call a self-collected vaginal swab.
What does it mean for patients?
“A self-collected vaginal swab is how we are moving towards cervical cancer screening. So, it’s essentially a Q-tip. A long Q-tip that a woman can insert into her vagina in the comfort of her own home. Send it off to the mail for analysis, and they can get the results,” Leung explains. “Imagine if I can do it on my own time, in the comfort of my own home, and I’m not necessarily scared about the potential discomfort of the exam. The uptake would be higher.”
The first step towards this self-administered test is already in motion in BC. “I think we should be very proud to be Canadian, because British Columbia is actually one of the first places that established self-collection as an accurate and viable option for screening. They’re rolling it out now, so it’s very much a Canadian initiative. It’s happening since January 2025 – it’s hot off the press!”
The difference between the existing test and Leung’s innovation
“The challenge we face with HPV testing is that there are a lot of positive test results that end up being nothing,” Leung explains. “Meaning that your body’s own immune system, just like any virus, like if we have a cold, we clear the cold, we feel better. Some people get the cold, and they get really sick. But that’s the minority. HPV is similar in that a lot of people have the virus. Their own immune system, if otherwise healthy, can clear it. It doesn’t cause any cervical abnormalities.”
That’s for most people. What Leung is working on with her team is to help those who can’t clear the virus know if they have a persistent HPV.
“There is a subset, and the trick is how do we identify that subset of women who are going to have the virus, and cannot clear it, and it’s going to cause a problem on their cervix. That’s the holy grail of knowing who we actually have to take to the clinic and see someone like me or a gynecologist. So right now, the HPV test is a very helpful first tool for screening patients who have what we call a high-risk Human Papillomavirus. There are strains called 16 and 18 that we know are the most common. Those are the people that we really want to see in the clinic. Beyond that, it’s a binary yes-no. Do you have the HPV virus? Yes or no? We would love to be more specific in saying, yeah, you have the virus, but is it at a level or at a point where we need to be worried and you need to see a doctor? Because we don’t want to worry women unnecessarily.”
That’s exactly what they’re working on – a test that can pinpoint the level of HPV a person has, versus a yes/no answer – a level that can determine the next course of action. Not only is this practical for women, it will also have significant implications for how resources are used in the healthcare system. “We also don’t want to overwhelm gynecologists who are trying to take care of women in other ways as well, like menopause symptoms, bleeding, contraception, all the other really, really important initiatives. And we don’t want their clinics to be overwhelmed with trying to sort out abnormal HPV tests that would not ultimately cause cervical issues. Circulating tumour DNA testing is not a binary test. It gives you a level. We don’t have a set threshold, and that’s why this is part of our research.”
Leung goes on to explain that while some women might have a positive result, most of the time it clears. And if the level isn’t too high, the test would allow doctors to monitor it and ask patients to repeat the test in a year because they don’t have a worrisome level. For patients with high levels – levels that might have them at risk for cancer or pre-cancer – this test could help them get care much sooner rather than ending up on a waitlist.
“What circulating tumour DNA offers is a way to know how to prioritize patients. That’s going to help the healthcare system, and also, hopefully, minimize some of the anxiety that comes from doing the testing and uncomfortable exams.“
Along with making it easier to test, Leung and her team are also looking at the types of samples that could be used. “In Montreal, we have a bank of 300 patients who have generously offered their samples with blood, urine, pap, and vaginal swabs. We’re comparing the performance across the different types of samples we’re collecting. We know that some women prefer giving one type of sample over another. Because the choice is power,” Leung says.
“In my practice, McGill is the primary referral site for Northern Quebec, where we have many of our Indigenous patients who have to travel very far for screening and treatment. If we can offer self-sampling paired with information from circulating tumour DNA, can we give them a better sense of whether they need to come for a checkup and make the travel.”
Could the Pap Smear be Eliminated?
“I think it’s important that we are not throwing it away, because one, there is a group of women who feel more comfortable seeing a doctor, talking through the process, and having that exam, and going back to choice is power, if a woman chooses that, I think we should definitely keep offering it. But from a technical standpoint and a cervical cancer elimination standpoint, I can definitely see it’s possible, but we’re not quite there yet,” Leung explains hopefully.
If Clinical Trials Are Now, When Will This Be Available to the Public?
I think if all goes well, scientifically, we can probably prove that the circulating tumor DNA paired with the HPV test is a good option, probably in 5-10 years,” Leung says while acknowledging the time it takes for new drugs, tech, and devices to get Health Canada approval. “It’s going to take some time, but that is the timeline we’re striving for!”
Next Steps?
“We’re publishing the first 130 samples and the results of them. We have another publication coming through for what we call the long-term follow-up for these patients. We also have more of a qualitative implementation angle, where we are interviewing clinicians and patients as to how they see liquid biopsy fitting within the care model, because as we know, having a tool like the vaccine is great, but if no one uses it, then it is not helpful” Leung says outlining how the process to approval goes “And then I have a grant from McGill Global health to do small pilots within the Indigenous communities.”
All of this comes as the World Health Organization made a declaration to eliminate cervical cancer by 2030.
“There is still so much, so much work to be done, even though we have the tools. I’m very, very humbly, a tiny, tiny piece of that. I feel very privileged to be part of it,” Leung explains.
Dr. Leung’s Wish for Women’s Health
“I would love to engage all individuals, no matter how they identify themselves, to see this as a priority … to think about sex and gender issues in your research projects, so that it just becomes second nature, because this is the culture of who we are,” Dr.Leung said. Concluding with “I feel like Canada can be the leader in saying that women’s health is equally important, and I think we can be leaders in showing that there’s no difference.”
