There were more than 140,000 new cancer cases diagnosed in Canada during the first year of the pandemic, but a sharp drop in rates among the most common cancers suggests that many cases may have gone undiagnosed.
After adjusting for age and population changes, the incidence rate was 449.5 new cancer cases per 100,000, which is more than 12 per cent lower than the average annual rate of incidence between 2015 and 2019.
In 2019, the incidence rate was
Data looked at the incidence rates of cancer during 2020, a year that saw huge disruptions to the regular flow of the health-care system due to COVID-19.
Even three years later, around one in four cancer patients are still experiencing cancelled or postponed appointments.
In 2020, there were 140,330 total new cancer cases diagnosed and reported to the Canadian Cancer Registry. Cancer diagnoses among men fell more than among women, with the rates among men declining by around 13 per cent compared to around 11 per cent for women.
Although lower rates of cancer may sound like a good thing, the sudden drop between 2019 and 2020 is more likely to be indicative of fewer cases of cancer being discovered, rather than the actual rates of cancer incidence dropping.
At the beginning of the COVID-19 pandemic, the fear of contracting the virus led to many Canadians avoiding going to health-care facilities outside of clear emergencies. This, along with cancelled appointments and reshuffling of health-care priorities, left many regions underserved.
鈥淪creening service disruptions, difficulties accessing primary care services, and fewer in-person appointments due to lockdowns and travel restrictions, all may have impacted the registration of new cancer cases in the Canadian population,鈥� the StatCan report stated.
The impact of the pandemic is reflected in the month-by-month data, StatCan鈥檚 report reveals.
In the months following the first introduction of public health measures in March 2020, the number of new cancer diagnoses took a nosedive.
There were 11,510 new cancer cases in March, which dropped to 8,640 in April and 9,235 in May. By June, as the initial wave of COVID-19 and public health measures eased, the number returned to 11,585, with the remaining months seeing relatively steady numbers.
The four most common cancers in Canada are breast, lung, prostate and colorectal. In 2020, all four of these saw significantly lower rates than in previous years. The least significant drop was in breast cancer rates, which fell by around 11 per cent, while the biggest difference was in prostate cancer rates, which fell by 18 per cent compared to the 2015-19 average.
Other cancers that saw the incidence rates plummet included melanoma of the skin (-18.2 per cent), thyroid (-16.1 per cent), kidney and renal pelvis (-10.7 per cent) and urinary bladder (-9.8 per cent).
StatCan noted in the data that similarly low incidences of cancer were reported by the United States鈥� National Cancer Database, showing this trend is not unique to Canada.
Among the few cancers that saw increasing rates in 2020 were oropharyngeal cancer 鈥� also known as throat cancer 鈥� and anal cancer, which saw an increase in incidence rates by 13.9 per cent and 3.5 per cent, respectively, compared to the previous five-year average. The increase in anal cancer was mostly due to a rising number of cases being diagnosed in women.
The incidence rate for acute myeloid leukaemia, which is the most common blood and bone marrow cancer within the adult population, increased by 2.2 per cent as well in 2020.
StatCan noted that, due to delays in reporting this type of disease incidence, this data set is missing around 1,500 cases, adding that cancer cases identified solely through death certificates haven鈥檛 been reported by Manitoba since 2013 and are missing for Ontario for 2020.
