Jonathan C. IrishDepartment of Otolaryngology – Head and Neck Surgery, Department of Otolaryngology – Head and Neck Surgery, Princess Margaret Cancer Centre and Ontario Health – Cancer Care Ontario, Toronto, Ontario;
Ian J. WitterickDepartment of Otolaryngology – Head and Neck Surgery, Department of Otolaryngology – Head and Neck Surgery, Princess Margaret Cancer Centre and Ontario Health – Cancer Care Ontario, Toronto, Ontario;
Background: Resource restrictions were established in many jurisdictions to maintain health system capacity during the COVID-19 pandemic. Disrupted healthcare access likely impacted early cancer detection. The objective of this study was to assess the impact of the pandemic on weekly reported cancer incidence. Patients and Methods: This was a population-based study involving individuals diagnosed with cancer from September 25, 2016, to September 26, 2020, in Ontario, Canada. Weekly cancer incidence counts were examined using segmented negative binomial regression models. The weekly estimated backlog during the pandemic was calculated by subtracting the observed volume from the projected/expected volume in that week. Results: The cohort consisted of 358,487 adult patients with cancer. At the start of the pandemic, there was an immediate 34.3% decline in the estimated mean cancer incidence volume (relative rate, 0.66; 95% CI, 0.57–0.75), followed by a 1% increase in cancer incidence volume in each subsequent week (relative rate, 1.009; 95% CI, 1.001–1.017). Similar trends were found for both screening and nonscreening cancers. The largest immediate declines were seen for melanoma and cervical, endocrinologic, and prostate cancers. For hepatobiliary and lung cancers, there continued to be a weekly decline in incidence during the COVID-19 period. Between March 15 and September 26, 2020, 12,601 fewer individuals were diagnosed with cancer, with an estimated weekly backlog of 450. Conclusions: We estimate that there is a large volume of undetected cancer cases related to the COVID-19 pandemic. Incidence rates have not yet returned to prepandemic levels.
Submitted September 16, 2021; final revision received November 17, 2021; accepted for publication November 18, 2021. Published online February 1, 2022.
Author contributions:Study design: Eskander, Yu, Hallet, Coburn, Dare, Chan, Singh, Parmar, Earle, Lapointe-Shaw, Krzyzanowska, Hanna, Finelli, Louie, Look Hong, Irish, Witterick, Mahar, Noel, Urbach, McIsaac, Enepekides, Sutradhar. Funding: Eskander, Sutradhar. Data acquisition: Eskander, Li. Data verification: Eskander, Li, Sutradhar. Data analysis and interpretation: Eskander, Li, Sutradhar. Writing – original draft: Eskander, Li, Sutradhar. Critical revision: All authors.
Disclosures: Dr. Eskander has disclosed receiving grant/research support from Merck and serving as a consultant for Bristol Myers Squibb. Dr. Hallet has disclosed receiving speaking honoraria from Ipsen Biopharmaceuticals and Novartis Canada. The remaining authors have disclosed that they have not received any financial consideration from any person or organization to support the preparation, analysis, results, or discussion of this article.
Funding: This work was supported by a Sunnybrook Research Institute and Sunnybrook Foundation COVID-19 Response (A. Eskander, R. Sutradhar). This study was supported by the ICES, which is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care.
Disclaimer: The opinions, results, and conclusions reported in this article are those of the authors and are independent from the funding sources. Parts of the material presented in this article are based on data and information provided by Cancer Care Ontario (CCO) and the Canadian Institute for Health Information (CIHI). The analyses, conclusions, opinions, and statements reported in this article are those of the authors and do not necessarily reflect those of CCO or CIHI. No endorsement by the ICES, Ontario Ministry of Health and Long-Term Care, CCO, or CIHI is intended or should be inferred.
Data availability statement: The dataset from this study is held securely in coded form at ICES. While data sharing agreements prohibit ICES from making the dataset publicly available, access may be granted to those who meet prespecified criteria for confidential access, available at www.ices.on.ca/DAS. The full dataset creation plan and underlying analytic code are available from the authors upon request, with the understanding that the computer programs may rely upon coding templates or macros that are unique to ICES and are therefore either inaccessible or may require modification. The use of the data in this project is authorized under section 45 of Ontario’s Personal Health Information Protection Act and did not require review by a research ethics board. The lead author affirms that the article is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.
Correspondence: Antoine Eskander, MD, ScM, Department of Otolaryngology – Head and Neck Surgery, University of Toronto, 2075 Bayview Avenue, M1-102, Toronto, Ontario, M4N 3M5, Canada. Email: firstname.lastname@example.org
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