Measuring the Association Between the COVID-19 Pandemic and Cancer Incidence by Sex Using a Quasi-Experimental Study Design.

[PURPOSE] This study examined the association between COVID-19 and cancer incidence by sex in Manitoba, Canada.

[METHODS] We used a population-based quasi-experimental study design and an interrupted time-series analysis to compare the rate of new cancer diagnoses between males and females before (January 2015 until December 2019) and after the start of the COVID-19 pandemic (April 2020 until December 2022).

[RESULTS] A total of 16,200 females and 20,631 males diagnosed with cancer between 2015 and 2022 in Manitoba were included. Colon cancer incidence decreased by 34% for males and females from April to September 2020. Incidence then remained stable for males but decreased by 22% from October 2021 to December 2022 for females. Brain and CNS cancer incidence decreased by 37% for males during 2021 and 2022 but only for females during the last quarter of 2020 and the first quarter of 2021 (77%). Urinary cancer decreased by 18% for males from April 2020 to December 2022 but was stable for females. Head and neck cancers decreased by 22% for males during 2020, but was stable for females. As of December 2022, the largest estimated cumulative differences in the number of cases occurred for males diagnosed with brain and CNS cancer (31.6% deficit for males, 76 cases), urinary cancer (18.4% deficit, 186 cases), and endocrine cancer (52.4% surplus, 56 cases), and females diagnosed with colon cancer (19.7% deficit, 187 cases).

[CONCLUSION] Sex-based differences in the association between age-standardized cancer incidence and the COVID-19 pandemic exist for several cancer sites. Sex-based differences on postpandemic cancer incidence, especially for brain, CNS, urinary, and colon cancers, need follow-up because of the ongoing deficits documented in this study.