Is there an association between the COVID-19 pandemic and cancer incidence?

A recent JAMA Network Open study assessed whether the coronavirus disease 2019 (COVID-19) pandemic, attributable to the transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), influenced cancer incidence in Manitoba, Canada.

Study: Latest Cancer Diagnoses Before and Throughout the COVID-19 Pandemic. Image Credit: Stokkete/Shutterstock.com

Background

The continuing COVID-19 pandemic has massively impacted the worldwide healthcare system. This pandemic resulted within the reorganization of the healthcare system, which included a rise in the usage of virtual consultation, redeployment of cancer care staff, and temporary suspension or reduction in cancer screening. 

COVID-19 has significantly disrupted routine healthcare services, which caused missed or delayed diagnoses of cancer. Consequently, these individuals may very well be diagnosed at advanced stages, compromising their survival.

Due to this fact, it is important to guage how much the cancer care system was affected as a result of disruptions attributable to COVID-19. This insight can be invaluable in formulating effective strategies to stop the system’s vulnerability during future disruptions.

In regards to the study

The present population-based cross-sectional study assessed the association between the COVID-19 pandemic and cancer incidence. This study was conducted in Manitoba, situated in central Canada.

CancerCare Manitoba offers clinical services to all Manitoba residents diagnosed with cancer. Before the onset of the pandemic, around 6,000 individuals were diagnosed with cancer.

Amongst these, 5,000 cancer patients received regular treatment or follow-up care by CancerCare Manitoba.

By the tip of March 2020, the federal government implemented strict COVID-19 restrictions in Manitoba to stop the spread of the SARS-CoV-2 virus.

In Manitoba, COVID-19 cases peaked, i.e., the primary wave occurred in March 2020, the second wave in November 2020, and the third in May 2021. Around 70% of Manitoba residents received full vaccination by October 1, 2021.

This study assessed changes within the rates of latest cancer diagnoses before and after the COVID-19 pandemic.

This study included all cancer diagnoses in Manitoba between 2015 and 2021. All relevant data were obtained from the Manitoba Cancer Registry. 

Study findings

48,378 cancer cases were diagnosed between 2015 and 2021 in Manitoba. The median age of cancer patients was 68 years, and 49.6% were female. Around a 23% decrease in cancer incidence was observed in April 2020, and this rate remained unchanged till June 2020. 

The general age-standardized cancer diagnosis was reduced at the sooner phase of the pandemic. Particularly, a decrease within the incidence rate of melanoma, breast, colon, prostate, urinary, lung, brain, and central nervous system cancers was recorded.

This reduction in cancer incidence rate may very well be as a result of decreased breast and colorectal cancer screening programs in Manitoba between April and May 2020. As well as, a big reduction within the variety of colonoscopies within the region could lead on to a decreased diagnosis.

In contrast, the rise in rectal cancer incidence may very well be related to a central endoscopy waitlist, as most endoscopies are performed in Winnipeg.

The decrease in breast cancer incidence amongst older women may very well be as a result of a discount in the supply of diagnostic mammography, reluctance to hunt medical care through the pandemic, and a rise in mortality rate on this group of people as a result of their higher susceptibility to SARS-CoV-2 infection.

The incidence of lung cancer dropped through the second COVID-19 wave. Nonetheless, this decrease was only observed amongst individuals who were older than 75 years of age.

Melanoma cancer incidence also decreased, which may very well be as a result of reduced primary care visits. The speed of melanoma cancer incidence increased rapidly to pre-pandemic levels over time.

A protracted-term decrease in urinary cancer incidence was observed, with no rate of improvement throughout the pandemic. Brain, central nervous system, and endocrine cancer exhibited reduced incidence rates; nonetheless, these numbers have to be interpreted cautiously due to reduced variety of cases at baseline and inconsistent data.

No association was found between the COVID-19 pandemic and gynecologic and prostate cancer incidence.

Conclusions

Using high-quality, population-based data is considered one of the important thing strengths of this study. Moreover, interrupted time-series evaluation and the inclusion of seasonality are other strengths of this study.

The present study has limitations, including the shortage of adjustments of multiple confounding aspects during evaluation. It also didn’t detect individual cancer incidence rates based on the world of their residence and sex. Since it is a single-center study, the findings lack generalization.

Despite the constraints, this study highlighted that the COVID-19 pandemic caused a big decrease in cancer incidence in Manitoba.

A considerable decrease in colon, breast, and rectal cancer incidence was observed. In the longer term, similar observational studies have to be performed to research how the COVID-19 pandemic affected cancer patients in other regions.