MONTREAL -- While the prospect of mass vaccination has raised hopes of the COVID-19 crisis soon waning, oncologists and cancer researchers say one of its grim legacies may be a lingering increase in cancer mortality rates.

The pandemic caused a "dramatic" drop in cancer screenings such as mammograms and colonoscopies, leading to fewer diagnoses, according to Dr. Gerald Batist, the head of the Segal Cancer Centre at Montreal's Jewish General Hospital.

"It just looks like less people were diagnosed, and they were, but there weren't fewer people with that diagnosis," Batist said in a phone interview. "They simply weren't found."

According to a report released last month, the Quebec government estimates that some 4,119 people with cancer went undiagnosed due to a drop in screening programs. At the Cedars Cancer Centre of the MUHC, new patients were down 22 per cent compared with the previous year, while the number of cancer surgeries declined 11 per cent.

The trend was similar in other provinces. In Alberta, for example, the number of new invasive cancer diagnoses reported to the provincial cancer registry declined 10 per cent relative to 2019 after the pandemic hit, according to Alberta Health Services, which noted that those numbers would be expected to increase due to a growing and aging population.

Even Nova Scotia, which has comparatively few COVID-19 cases, saw a 15 per cent reduction in the number of cancer surgeries booked over the summer, likely due to a shutdown in screening services and people having trouble accessing their primary care physicians, according to the senior director of the province's Cancer Care program. Dr. Helmut Hollenhorst said it is possible that the temporary suspension of cancer screening programs and other services during the first wave may result in more patients being diagnosed at a later stage in the future, but there is no data yet to confirm this.

Batist said that in Montreal during the first wave, doctors were forced to triage cancer patients, deciding which ones could wait longer for surgeries without affecting their prognosis -- an anxiety-inducing prospect for patients and physicians alike.

"We felt for the most part that our judgments were right," he said. "And for some cases, it was detrimental to the patients."

Batist said it will take a couple of years to know whether the interruptions will have a negative impact on survival rates. But he says that, anecdotally, he and other doctors are seeing newly diagnosed patients come in with more advanced cancers, perhaps reflecting a delay in screening.

Diane Van Keulen, a 60-year-old lung cancer patient from Beaverton, about an hour north of Toronto, knows the impact the pandemic can have on patients.

At the beginning of August, after a recent bout of chemotherapy, she resisted going to the emergency room for three weeks out of fear of catching the virus, despite severe gastrointestinal and heart issues. When her husband finally insisted on taking her into the hospital on Aug. 22, she learned that her symptoms were due to one of her tumours having tripled in size within weeks.

"I delayed my own potential recovery and treatment because I was too terrified to go into the waiting room," she said in a phone interview.

Van Keulen is now on a new drug that is helping. But she wonders what might have happened had she gone to hospital earlier. "Rather than the tumours growing as big as they did, they would have been a bit smaller when I started this treatment, and maybe the treatment would have been more effective," she said.

Cancer advocates say the pandemic has affected patients in countless ways, from the stress of delayed treatments to the difficult logistics of hotel stays for multi-day treatments.

For many, one of the hardest parts has been having to face life-altering appointments alone due to restrictions on visitors and travel bans, according to Jackie Manthorne, the president and CEO of the Canadian Cancer Survivor Network.

"One woman from P.E.I. (told me) her family's on the Prairies, and she can't go there and they can't go to P.E.I.," Manthorne said. "She's afraid she won't see them again."

Van Keulen says that her cancer is advanced enough that none of her treatments were delayed. But she says her care still suffered, partly because most doctors' appointments shifted online, depriving her physician of the ability to observe her condition.

During the pandemic's second wave, Batist says, hospitals have started to catch up on delayed procedures. In recent weeks, the number of patients hospitalized with COVID-19 has dropped, freeing up resources.

Cancer research has also suffered during the pandemic due to the cancellation of major fundraisers, lab closures and the shift of some resources toward the COVID-19 effort. Last year, the Canadian Cancer Society's research budget was slashed due to a drop in fundraising, even though government funding was maintained, according to the group's vice-president for research.

"It does have an immediate and very strong effect on the charitable sector, and their ability to continue with their research funding at the same level," Dr. Judith Bray said in a phone interview.

While the group managed to shift to online fundraising, and labs are getting back to work, she says it will be a while until they're at full pace.

But Batiste and Bray maintain that the pandemic's impact on cancer research has not been all negative.

Both noted that COVID-19 has increased global research collaboration, sped up processes, created a push for open-access publications and highlighted the crucial role of scientists -- all of which can help cancer research in the future.

Bray notes that some of the therapies studied to fight the pandemic could potentially help cancer patients as well, noting that the mRNA technology used in the COVID-19 vaccines was originally developed in the oncology field.

"I do think that in the end, research overall, scientific research and particularly health research will benefit from some of the things we've had to do," she said.

This report by The Canadian Press was first published Jan 4, 2021

Correction:

This is a corrected story. A previous version said Nova Scotia has seen a reduction in the number of new cancer patients. The reduction is, in fact, in the number of cancer surgeries performed over the summer.