Study raises renewed alarm about missed cancer diagnoses during pandemic

Oncologists have been warning about dangerous gaps in cancer care since the start of the COVID-19 pandemic. Now, a nationwide study based on data from Veterans Affairs hospitals is raising new alarms.

Since March 2020, COVID-19 has caused a disruption in surgeries and treatments for patients with cancer. At different periods during the pandemic, some states have also required health care facilities to suspend elective procedures, many of which include cancer screenings, to preserve resources during COVID surges.

"This is an area of tremendous concern," Dr. Norman "Ned" E. Sharpless, director of the National Cancer Institute, said in an interview in Cancer Prevention Research. "The pandemic has affected cancer screening in a dramatic way...a massive screening deficit over the last 12 months-millions of screening events have been missed," Sharpless added.

Compared with yearly averages in 2018 and 2019 as a baseline, the number of completed colonoscopies dropped by 45%; proportions of prostate biopsies decreased by 29% ;and cystoscopies for diagnosing bladder cancer decreased by 21% in 2020, according to the study, published online on the National Center for Biotechnology Information's site.

The study's researchers estimated that new diagnoses for prostate, lung, colorectal and bladder cancers among the veterans whose data was analyzed also plummeted by 13%, in 2020.

The declines in cancer screening and diagnoses were already striking in the initial months of the pandemic as the country reeled from the first wave of COVID-19 infections. Screening for breast, colorectal and prostate cancers dropped sharply in April 2020, and estimates based on statistical models highlight that 3.9 million breast cancer, 3.8 million colorectal cancer, and 1.6 million prostate cancer diagnoses may have been missed due to pandemic disruptions in care across the overall U.S. population, according to data from JAMA Oncology.

The Centers for Disease Control and Prevention also reports that screening tests for breast cancer fell by 87% and 84% for cervical cancer in April 2020.

"Like other cancer centers, we observed a distinct downturn in routine cancer screening at the beginning of the pandemic, which has only partially recovered," Dr. Brian McIver, deputy physician in chief of the Moffitt Cancer Center told ABC News. As a result, some patients were later diagnosed with more advanced stages of cancers that proper screening protocols may have diagnosed earlier, according to McIver.

Calculating the number of missed cancer diagnoses and the proportion of additional patients at risk is difficult and requires additional time for data collection -- an endeavor that national organizations, like the NCI, are actively pursuing and monitoring.

Of course, cancer screening tests, which are administered to asymptomatic people and are regularly used for early detection of some types of cancer, are not the only way to catch cancer diagnoses. Patients often learn of their illnesses after developing symptoms and going to their doctors.

But hospitals continue to face challenges in catching up and counteracting existing deficits in important routine cancer screening tests and imaging, numbers of which still have not yet rebounded to pre-pandemic baselines.

"It's unlikely we have the infrastructure to fully catch up," said Sharpless in his interview. The situation is further complicated by patients' own reluctance to seek medical care in the middle of the pandemic.

"There are a lot of moving parts. You have to increase your [healthcare] capacity above the pre-pandemic baseline...[and] the healthcare system is frankly overwhelmed right now," said Dr. Craig Bunnell, chief medical officer at Dana-Farber Cancer Institute to ABC News. "[Then,] you have people who miss their screenings, [who may] continue to delay or skip [appointments] completely."

"There's no reason to believe that cancer incidence is decreased," said Bunnell. Rather, cancers "are likely to be diagnosed at more advanced stages when the treatment options may be fewer."

With the new omicron variant now spreading throughout the country and the potential for another surge of cases during the winter months, physicians urge patients to continue practicing safety measures and to keep their medical appointments if possible. "COVID-19 should not prevent any of us from receiving appropriate medical care, including relevant cancer screenings," says McIver.

Adela Wu, a neurosurgery resident at Stanford Hospital, is a contributor to the ABC News Medical Unit.