Significant volume of cancer cases have gone undetected in Ontario during the pandemic, study finds

A significant volume of cancer cases have gone undetected during the pandemic, a new study published today in Journal of the National Comprehensive Cancer Network has found.

The study, led by Sunnybrook surgeon-scientist Dr. Tony Eskander, examined weekly cancer diagnoses between Sept. 25, 2016 and Sept. 26, 2020 in Ontario based on data from ICES. At the start of the pandemic in March 2020, there was a 34.3 per cent drop in weekly cancer incidence volume.

In total, 12,601 fewer people were diagnosed with cancer between March 15 and Sept 26, 2020 than expected based on other year’s incidence.

The drop in cancer incidence was seen in cancers diagnosed through screening programs and those without such a program. In Ontario, there are organized screening programs for breast, colorectal and cervical cancers.

The largest drops in volumes were seen in cervix, endocrine, melanoma and prostate cancers.

There was no change in the socioeconomic information of those diagnosed during the pandemic. The volume of cancer diagnoses have not yet returned to pre-pandemic levels.

“Cancer survival rates have improved over the last decade, in part due to the earlier detection of disease,” the authors wrote. “However, screening programs with accessible in-person care have been impacted by the emergency health measures put in place during the COVID-19 pandemic.”

The drop in incidence may also be related to delays in seeking care given public messaging around avoiding an overburdened health system, the authors say. It’s important that public health messaging, physicians and healthcare teams are unified and clear going forward: participate in screening programs and seek care if you have any symptoms.

“We don’t know exactly where these ‘missing cases’ are and the concern is that the people will seek care now when the disease has progressed and it won’t be treatable, operable or curable,” said Dr. Eskander. “It’s important that as the pandemic continues with subsequent waves and continued health measures, we remind people that screening programs are open and effective at detecting cancers earlier. And if your health changes, please seek care.”