As we move into the third year of the global pandemic researchers are beginning to see broader impacts on public health beyond acute cases of COVID-19. New research is warning of increases in cancer deaths over the coming years as pandemic-related delays to diagnoses are leading to cases being caught at significantly later stages.
Back in 2020, a few months into the pandemic, researchers started flashing the warning lights on an emerging problem. Across the months of March and April in 2020 researchers saw rates of cancer diagnoses drop by nearly 50 percent.
At the time researchers warned of future post-pandemic waves of late-stage cancer cases causing problems in an already over-loaded healthcare system. A pair of cancer researchers from the University of Melbourne said in April 2020 they would expect to see future surges in new cancer diagnoses as COVID-19 restrictions ultimately begin to relax.
“We expect that these delays in cancer incidence will significantly affect the survival of patients diagnosed during COVID times and have significant impacts on the health service capacity required to deal with later stage cancers,” the duo predicted.
Several newly published studies are now expanding on those early pandemic concerns, reporting on the drops in cancer screenings seen over the past couple of years and estimating how that could impact cancer mortality in the near future.
In the journal Cancer, a team of researchers investigated the rates of cancer screening tests in 748 US locations between April and June 2021. They compared monthly screening test volumes in that period to rates seen before the pandemic began.
Almost all the sites analyzed saw continuing deficits in rates of cancer screenings compared to pre-pandemic levels. Deficits in colorectal cancer screenings were found in 80 percent of facilities, for example, and similar deficits were found in cervical, lung and breast cancer screening rates.
Another newly published study, this time in the Canadian Medical Association Journal (CMAJ), created a simulation to model the future effects of cancer surgery delays on patient survival. Using an average increase in surgery wait-times of seven extra days the model estimated 10-year survival rates for all cancers dropping by almost one percent.
Increasing cancer surgery wait-times to 21 days compared to pre pandemic levels saw 10-year survival rates drop by up to 1.6 percent. In terms of total life-years lost among cancer patients due to surgery delays, the researchers estimate between 843 and 1,539 life-years were lost in a cohort of around 20,000 cancer patients followed during the pandemic.
“Although de-escalation of cancer surgeries during the pandemic may be required to protect vulnerable populations and create health care capacity, these slowdowns are associated with a risk of unintended harm,” the researchers concluded in the new study. “Careful management of health care resources is critical during times of resource constraint to mitigate unintended consequences.”
Contrasting these estimates on the impact of the pandemic on survival in already diagnosed cancer patients, a study published in February in JAMA Network Open investigated the staging of cancer diagnoses at Moores Cancer Center at the University of California San Diego Health. The study looked at the differences in stage 1 and stage 4 cancer diagnoses between the end of 2019 and the end of 2020.
The researchers saw a notable drop in stage 1 breast cancer diagnoses across 2020 compared to the prior year: 63.9 percent in 2019 compared to 51.3 percent in 2020. And a distinct rise in stage 4 breast cancer diagnoses was also detected year on year: 1.9 percent of all breast cancer diagnoses were classified stage 4 in 2019 compared to 6.2 percent in 2020.
Looking at early data from the first few months of 2021 the researchers also noted the trend increasing with eight percent of all breast cancer patients diagnosed between January and March classified with stage 4 disease.
“There is increasing concern that one effect of the pandemic is the growing number of patients who are being diagnosed for the first time with late, incurable stages,” said Kathryn Ann Gould, an oncologist at Moores Cancer Center. “Patients who have delayed preventative care during the pandemic should be encouraged to discuss age appropriate cancer screening with their primary care providers as soon as possible.”
The cancer screening study was published in the journal Cancer.
The cancer surgery modeling study was published in the Canadian Medical Association Journal (CMAJ).
The breast cancer staging study was published in JAMA Network Open.
Source: UC San Diego, Canadian Medical Association Journal, Wiley
