Nearly one million fewer cancer screening tests were performed in Ontario during the COVID-19 pandemic in 2020 compared to one year prior, provincial data shows, raising concerns that there could be "many cancers" out there that have not yet been detected.
There were 952,355 routine breast, cervical and colorectal screening tests performed from March to December last year, but this was 997,265 fewer tests than the 1,949,620 done during the same period in 2019, according to a QB Briefing analysis of data provided by provincial agency Ontario Health.
The data showed the following for the 10-month period:
- 321,489 fewer mammograms through the Ontario Breast Screening Program (283,819 from 605,308, a 53.1 per cent decrease)
- 368,446 fewer Pap tests through the Ontario Cervical Screening Program (422,425 from 790,871, a 46.6 per cent decrease)
- 307,330 fewer fecal tests through the ColonCancerCheck program (246,111 from 553,441, a 55.5 per cent decrease)
"We know that early detection saves lives, and so by that very measure a decrease in screening programs will have very dire consequences," said Dr. Shady Ashamalla, a surgical oncologist specializing in colorectal cancer and head of the division of general surgery at Sunnybrook Health Sciences Centre. "It's very concerning because it means that there are potentially many, many cancers out there that would be caught with these screening programs that are not detected yet, that will become symptomatic eventually and present to medical care later in their course than normal."
Ashamalla said while the numbers are concerning, they aren't surprising since they confirm what doctors have seen during the past year. While Ashamalla would typically see a combination of pre-, early and late-stage cancers, he said there was a "real swing" at the end of 2020 towards many late-stage cancers.
"I think most cancer doctors would say that they have seen more symptomatic and late-stage presentation cancers than ever before, and I think that completely coincides with a very dramatic decrease in screening," he said.
"We know that screening saves lives," said Ashamalla, stressing that the aim of the province's three screening programs is to identify potential cancers "in their infancy."
"If one waits for a colon cancer to become symptomatic, in general terms that cancer has grown and has likely advanced and the further along that it grows and advances, the less likely a chance of cure," he said.
"Looking back, seeing the degree to which it really shut down is quite stark," Dr. Chris Simpson, Ontario Health's executive vice-president (medical), told QP Briefing, noting an understanding in the medical community at the start of the pandemic that the health-care system needed to create capacity for a possible influx of COVID-19 patients, which meant deferring services like screening.
"I think it’s undeniable that a reduction in screening to this degree is going to lead to the stage-shift phenomenon," said Simpson, referring to concern among cancer specialists about patients presenting to the health-care system with advanced disease.
While there isn't enough data on this yet, Simpson said "it seems pretty logical that there will be consequences, I think, downstream from the reduction in screening volumes and the reduction in upstream care in general."
But he noted a few caveats, the first being that an abnormal screening test doesn't necessarily mean someone has cancer.
"The other variable (is) if screening that was otherwise going to be done did not get done, we don’t know for sure that that person wouldn’t have been diagnosed by some other means in a timely way," Simpson said.
While the breast and cervical screening programs started to see significant decreases in testing in March, the colorectal screening program followed soon after. Screening for all three programs picked up toward the end of last year.
Colorectal screening involves a fecal immunochemical test (FIT), which tests for blood in the stool. The mailing of these kits was paused on March 23, 2020, but LifeLabs resumed this service in July for patients whose requisitions had been on hold, according to Ontario Health. In August, primary care providers were told they could start sending in new requisitions for those at high risk of colorectal cancer and this was expanded to all patients in October.
Simpson and Dr. Linda Rabeneck, vice-president of prevention and cancer control at Ontario Health, which now includes Cancer Care Ontario, pointed to a combination of reasons for the decrease in screening including the government initially mandating a reduction in non-urgent services, fear of contracting COVID-19 in a health-care setting and a stretched system.
On March 19, 2020, Chief Medical Officer of Health Dr. David Williams issued an order known as Directive #2 stating "all non-essential and elective services should be ceased or reduced to minimal levels, subject to allowable exceptions, until further notice." This included cancer screening. Williams amended the directive on May 26 to allow for the gradual resumption of services.
Rabeneck said the "sharp drop" in testing early in the pandemic was "completely consistent" with the directive, but the positive thing was that the numbers started to pick up once it was lifted.
"The testing volume or number of tests each month is improving, but it's not what we need it to be at least as of December ... so we're continuing to monitor it very closely," she said.
She said while all regions experienced similar decreases in screening when the directive was introduced, this wasn't the case when the directive was amended and regions were seeing different rates of transmission and impacts to health services. For example, the Greater Toronto Area, which was hard hit by COVID-19, had lower screening volumes, Rabeneck noted.
Some were reluctant to go for screening during the height of the pandemic, especially since screening is a test people do when they're feeling fine, said Rabeneck. Screening sites also faced additional requirements including the use of personal protective equipment and infection control measures, making it challenging to test the same volume of patients as they would pre-pandemic.
When Directive #2 was issued, Rabeneck said the organization also hit pause on sending out screening invitation letters to target age groups. She said breast screening and colorectal screening invitations restarted in January and February, respectively, and cervical screening invitations will resume in the next month or so.
Rabeneck said she's expecting the difference in the number of screening tests going forward, compared to 2019 numbers, to narrow with the resumption of invitation letters, but tackling the backlog will depend on how the pandemic unfolds.
"That itself is contingent upon the control of the pandemic and relates to, in part, the rollout of the vaccinations and the whether or not there's a third wave," she said. "If we continue along and the vaccinations roll out swiftly ... and we don't have to go back, then we'll be able to continue to tackle this and things will improve."
Ashamalla said it's reassuring to see the numbers start to normalize.
"Hopefully over some period of time things will again reach the baseline where we left off at the end of 2019 where a ... large percentage of the population is getting timely screening, we're catching these cancers early and really doing our best to decrease the rates of cancer in these populations," he said.
Simpson said boosting screening is going to take "an increase in confidence amongst the public" and that vaccines will be part of this.
"I think it’s really important for us to reassure (people) that coming to health-care settings is safe and that if you do have a problem or a concern or a worry or if you’re scheduled for screening, we’ve taken the appropriate precautions to make sure that you’re safe when you’re in our care," he said.
Simpson said people tend to think about surgeries and procedures first when talking about addressing backlogs as part of the pandemic recovery.
"I think we forget sometimes when talking about recovery that it’s the upstream experiences that patients have missed that may generate consequences down the road that haven’t declared themselves yet, and screening is one of those things," he said. "We do know that screening for cervical cancer, screening for breast cancer, screening for colon cancer, those things do pick up disease, and when they pick up disease earlier, then the chances of successful treatment we believe are better."
Rabeneck said that about 5 per cent of people have an abnormal mammogram requiring further testing and about 7 per cent of those with an abnormal mammogram are diagnosed with breast cancer.
Anjum Karimi, a Mississauga resident who volunteered with the Canadian Cancer Society’s Screening Saves Lives program, credits a routine mammogram and a followup ultrasound in 2012 for the discovery of her ductal carcinoma in situ diagnosis, which involves the presence of cancer cells in the lining of the milk ducts of the breast.
"Screening saves lives, do not neglect it," said Karimi, who had a lumpectomy and radiation therapy.
"I feel very lucky and very blessed because it was just the point of a ballpoint pen, that was so small and it was caught in the ultrasound," she said. "If I had delayed it by one year, it might have increased, so I was really lucky that I had gone that year and somebody had caught that."
All the doctors echoed Karimi's message about the importance of screening.
"Our message is if you're due for screening, then follow up and get screened," said Rabeneck.
Photo credits: Ontario Health, Sunnybrook Health Sciences Centre and the Canadian Medical Association.