The effects of COVID-19 on Cancer screening
March 10, 2021

Across the globe, the COVID-19 pandemic has negatively impacted healthcare delivery including:

  • delays in elective or non-urgent surgeries and procedures,
  • disruptions to cancer screening, and
  • cessation of routine laboratory tests.

In Canada, the Canadian Institute for Health Information (CIHI) reviewed data from the first wave of the pandemic (March to June 2020), and reported the following COVID-related impacts on health services:

  • increase in care provided virtually, online or by phone,
  • decrease in emergency visits by 50% in April 2020 (by the end of June 2020 visits were at about 85% of June 2019 volumes),
  • decrease of 47% in the number of surgeries performed, compared to March and June 2019 (approximately 335,000 fewer surgeries).

Cancer Care

Of the many disruptions seen in the health systems across the world, one of the most worrisome has been cancer care, from screening and diagnosis through to treatment and monitoring. A survey, conducted on behalf of the Canadian Cancer Survivor Network, included patients, caregivers, and patients in pre-diagnosis, found:

  • 54% of respondents reported having appointments cancelled, postponed, or rescheduled,
  • 15% reported having surgeries/procedures cancelled,
  • 11% reported delays in starting/continuing treatment, and among those enrolled in a clinical trial, and
  • 43% reported it had been put on hold or stopped

A crucial component of cancer management is screening. As noted by the Canadian Cancer Society, there are several benefits to screening programs, primarily to identify and treat cancer before it has spread, which in turn, improves survival. In Canada, routine cancer screening is conducted at a population level for cervical, breast, and colorectal cancer; however, early in the pandemic, there were several disruptions to screening programs across Canada. Below we highlight examples from Alberta, Ontario, and British Columbia:

  • In Alberta, cancer screening programs including mammograms, pap tests, colposcopies, and fecal immunochemical tests were paused in March 2020 and resumed in June 2020.
    • One news article reported: “More than 170,000 tests, including an estimated 40,000 mammograms, were suspended for two months starting at the end of March to allow the health-care system to prepare for an influx of COVID-19 patients.”
    • Other articles cited 20% to 30% drop in the number of new cancer cases diagnosed.
    • To learn more about current changes to health care services in Alberta click here
  • In Ontario, routine cancer screening for breast, cervical, and colon cancer have slowly resumed; with a focus on targeting those at the highest risk for cancer first
    • One news article noted that between March 15 and May 31, 2010, compared to the same period in the same year, there was:
      • decrease of 97% in mammograms through the Ontario Breast Screening Program,
      • decrease of 88% in pap tests through the Ontario Cervical Screening Program, and
      • decrease of 73% in fecal tests performed through ColonCanceCheck
  • In British Columbia, screening services for breast cancer, FIT kit distribution, and non-urgent, non-emergent colonoscopies were temporarily suspended in March 2020.
    • In an interview with Dr. Chi, BC Cancer’s chief medical officer, he reported “Overall, we initially saw an approximate 20 percent decrease in new cancer diagnoses in the first part of the pandemic, however, this has been increasing back to pre-COVID levels.”

The disruption to routine cancer screening services is not yet known, though two modelling studies have estimated that there may be a significant impact on both breast cancer and colon cancer in Canada.

In one study, the authors estimated that a three-month interruption in breast cancer screening could lead to 310 more cases diagnosed at advanced stages and 110 more cancer deaths in 2020-2029; while a six-month interruption could lead to 670 extra advanced cancers and 250 additional cancer deaths. For colorectal cancers, a six-month interruption could increase cancer incidence by 2200 cases with 960 more cancer deaths over the lifetime.

Another modelling study estimated that a 3-month interruption in colorectal screening would result in 1671 additional diagnoses and 799 additional deaths in Canada between 2020 and 2050.

Future research should examine the impact of COVID on cancer care to mitigate long-term consequences for patients with cancer. Active monitoring of screening rates, diagnostic rates, and cancer stage at diagnoses, should be thoroughly conducted locally and nationally to compare to pre-pandemic levels to inform health policy decisions for this vulnerable population.

Read more on the effects of COVID-19 in our blog: Report on virus-neutralizing monoclonal antibodies for the treatment of SARS-CoV-2.