A pair of studies today estimated the COVID-19 pandemic's potential effects on cancer deaths, with one predicting rising US cancer deaths over the next decade owing to screening deficits, and the other suggesting that cancer surgery delays in Ontario could lead to poorer survival rates.
To accommodate surges of critically ill COVID-19 patients, many healthcare facilities around the world canceled or delayed appointments for other indications, including cancer. Before COVID-19 vaccines were available, patients with nonemergent conditions also were advised to stay home rather than risk infection in crowded hospitals or clinics.
The unintended consequences of these public health measures are still being measured.
Median 18% drop in colorectal cancer screening
In the first study, published in Cancer, a team led by Northwestern University researchers conducted a national quality-improvement (QI) study on the return to cancer screening among 748 accredited US cancer programs from April through June 2021. They used prepandemic and pandemic monthly screening test volumes (MTVs) to identified screening gaps.
Most facilities reported gaps in monthly screenings for colorectal cancer (104 of 129 [80.6%]), cervical cancer (20/29 [69.0%]), breast cancer (241/436 [55.3%]), and lung cancer (98/220 [44.6%]).
The median relative changes in MTVs were -17.7% for colorectal cancer, -6.8% for cervical cancer, -1.6% for breast cancer, and 1.2% for lung cancer. No geographic differences were seen.
These findings prompted participating cancer programs to start 814 QI projects to break down barriers to cancer screening, including screening resources. While the effects of these projects on screening rates through 2021 are still being evaluated, the estimated numbers of potential MTVs, should all facilities reach their target goals, could be 57,141 for breast cancer, 6,079 for colorectal cancer, 4,280 for cervical cancer, and 1,744 for lung cancer.
"Cancer screening is still in need of urgent attention, and the screening resources made available online may help facilities to close critical gaps and address screenings missed in 2020," the researchers wrote.
In a press release from Wiley, publisher of the journal, corresponding author Heidi Nelson, MD, of the American College of Surgeons, said that the team hopes that the QI programs will prevent many cancer deaths.
"From the perspective of what this means about our programs, we now know that we can turn to our accredited programs in times of crisis to help address large-scale cancer problems," she said. "Knowing how enthusiastic these accredited programs are for working collaboratively on national level problems, we expect to release one or two quality improvement projects each year going forward."
10-year survival could fall up to 0.9%
To assess the effect of COVID-19–related cancer surgery delays on survival, University of Toronto researchers built a microsimulation model using real-world population data on cancer care in Ontario from 2019 and 2020.
The study, published in the Canadian Medical Association Journal (CMAJ), estimated cancer surgery wait times over the first 6 months of the pandemic by simulating a slowdown in operating room capacity (60% operating room resources in month 1, 70% in month 2, and 85% in months 3 to 6), compared with simulated prepandemic conditions with 100% resources.
The model population consisted of 22,799 patients awaiting cancer surgery before the pandemic and 20,177 new referrals. Average wait time to surgery before the pandemic was 25 days, compared with 32 days after. As a result, 0.01 to 0.07 life-years were lost per patient across cancer types, translating to 843 life-years lost among cancer patients.
The largest percentages of life-years lost were among patients with nonprostate genitourinary (0.07 life-years lost), gastrointestinal (0.05), and head and neck cancers (0.05), all of which carry a high risk of death. Ten-year survival fell by 0.3% to 0.9% across all studied cancer types in the pandemic model compared with the prepandemic era, with the greatest change in patients with hepatobiliary cancers (26.0% before vs 25.1% after).
In a scenario of a 60% reduction in surgical resources for cancer patients in the first 6 months of the pandemic, incremental increases in wait time of 10 to 21 days over prepandemic wait times translated to 0.1 to 0.11 life-years lost per patient and reductions in 10-year survival of 0.3 to 1.6 percentage points across cancer types. The changes indicate the loss of 1,539 life-years.
In a different scenario in which surgical resources were reduced to 60% for the first 2 months of the pandemic and raised to 75% for the next 4 months, wait times were shorter than under the first scenario (incremental increase, 8 to 19 days), leading to the loss of fewer (1,306) life-years.
The study authors called for future studies to characterize the additional impact of pandemic-related diagnostic delays and changes in cancer stage on cancer survival.
"Pandemic-related slowdowns of cancer surgeries were projected to result in decreased long-term survival for many patients with cancer," they wrote. "Measures to preserve surgical resources and health care capacity for affected patients are critical to mitigate unintended consequences."
