In a simulation-based study reported in The Lancet Oncology, Ward et al estimated that delay in diagnosis due to the COVID-19 pandemic in Chile will lead to an early surge of newly diagnosed cancers at later stages, resulting in excess mortality over the next 10 years.
As stated by the investigators, “The COVID-19 pandemic has strained health system capacity worldwide due to a surge of hospital admissions, while mitigation measures have simultaneously reduced patients’ access to health care, affecting the diagnosis and treatment of other diseases such as cancer. We estimated the impact of delayed diagnosis on cancer outcomes in Chile using a novel modeling approach to inform policies and planning to mitigate the forthcoming cancer-related health impacts of the pandemic in Chile.”
Study Details
The study involved modeling of breast, cervical, colorectal, prostate, and stomach cancers in Chile that simulates cancer incidence and progression, stage-specific cancer detection, and survival probabilities in a nationally representative virtual population. The model was calibrated to empirical data on monthly detected cases, stage at diagnosis, and 5-year net survival. The impact of COVID-19 on cancer detection and on excess mortality through 2030 was estimated by comparison with a no COVID-19 scenario.
In addition to a large projected surge in diagnosed cancer cases, we found that delays in diagnosis will result in worse cancer stage at presentation, leading to worse survival outcomes.— Ward et al
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Key Findings
Modeling results indicate a dramatic decrease in the number of newly diagnosed cancer cases during the COVID-19 pandemic waves in 2020 and 2021, resulting in a large short-term increase in subsequently diagnosed cases as detection probabilities return to normal.
For the five cancer types studied together, it was estimated that there would be an additional 3,198 cases (95% uncertainty interval [UI] = 1,356–5,017) diagnosed in 2021 compared with the no COVID-19 scenario, representing a 14% increase in new diagnoses. In 2022, an estimated additional 2,674 new cases (95% UI = 1,318–4,032) will be diagnosed, representing a 10% increase vs the no COVID-19 scenario. For 2022 to 2030, there will be an estimated total of 2,073 excess cases (95% UI = −86 to 4,310) due to the backlog of undetected cases in 2020 and 2021.
Due to COVID-19–related delayed diagnosis, worse stage distribution is projected for cancers detected from 2020 to 2022. The stage migration during this period is estimated to result in 3,542 excess cancer deaths (95% UI = 2,236–4,816) from 2022 to 2030 vs the no COVID-19 scenario, with the greatest numbers of excess deaths being those due to colorectal cancer (1,389 excess deaths, 95% UI = 364–2,567) and breast cancer (869 excess deaths, 95% UI = 418–1,301).
Most of the excess deaths (3,299 deaths, 95% UI = 2,151–4,431) are projected to occur between 2022 and 2024, with estimated excesses of 10.4% for breast cancer, 10.6% for cervical cancer, 12.4% for colorectal cancer, 17.2% for prostate cancer, and 6.0% for stomach cancer.
The investigators concluded, “In addition to a large projected surge in diagnosed cancer cases, we found that delays in diagnosis will result in worse cancer stage at presentation, leading to worse survival outcomes. These findings can help to inform surge capacity planning and highlight the importance of ensuring appropriate health system capacity levels to detect and care for the increased cancer cases in the coming years, while maintaining the timeliness and quality of cancer care. Potential delays in treatment and adverse impacts on quality of care, which were not considered in this model, are likely to contribute to even more excess deaths from cancer than projected.”
Zachary J. Ward, PhD, of the Center for Health Decision Science, Harvard T.H. Chan School of Public Health, is the corresponding author for The Lancet Oncology article.
Disclosure: The study was funded by the Harvard T.H. Chan School of Public Health. For full disclosures of the study authors, visit thelancet.com.
