Objectives Following the initiation of lockdowns to slow the spread of COVID-19 in April 2020, the number of cancer diagnoses in Victoria fell below levels predicted based on historical trends. We evaluated whether the missed cancer diagnoses during the COVID-19 pandemic have since recovered.
Sample and setting Population based cancer registry data of cancer diagnoses up to 31/12/2023 in Victoria, Australia.
Procedures Joinpoint regression was applied to cancer incidence data from 1982 up to 2019 to identify the most recent period of stable trends in age-standardised incidence, for all tumours combined and by tumour stream. Poisson regression was then used to model historical cancer incidence rates by age and sex over this period. This model was applied to population data from 2020–2023 to estimate the expected number of diagnoses. Differences between observed and expected diagnoses were calculated, along with 95% confidence intervals.
Results A stable baseline was unable to be determined for prostate cancer hence it was excluded from these analyses. In total, 7,861 fewer cancer diagnoses (95% CI 7,167–8,554; -6.0% [95% CI -5.5% to -6.5%]) were observed from 1/1/2020 to 31/12/ 2023 than expected. The shortfall varied by year; 2020: -7.1% [-6.6% to -7.6%]; 2021: -4.3% [-3.8% to -4.8%]; 2022: -8.2% [-7.7% to -8.8%]; 2023: -4.3% [-3.8% to -4.9%]. The reduction in diagnoses was similar for males (-5.8% [-5.0% to -6.7%]) and females (-6.1% [-5.4% to -6.8%]), and more pronounced in older age groups. The largest deficits were in melanoma (-2,500 diagnoses; -18%), bowel cancer (-1,700; -10.5%), and breast cancer (-1,600; -6.0%). In contrast, some lower incidence cancers higher-than-expected diagnoses: head and neck (+7.5% [+1.5% to +13.6%]), stomach (+12.7% [+9.8% to +15.6%]), and ovarian cancer (+15.1% [+3.8% to +26.4%]).
Conclusion and clinical implications Missed cancer diagnoses during the pandemic remain unrecovered, with delays linked to poorer prognosis.