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By almost every measure, far fewer cancers are being diagnosed during the coronavirus pandemic, whether the decline shows up in screening mammograms and colonoscopies or in other tests ordered after troubling symptoms prompt a doctor’s visit.

A research letter published Tuesday in JAMA Network Open notes a steep downward slope in newly identified cases of six common cancer types, based on weekly numbers from Quest Diagnostics. The clinical laboratory’s data add to similar analyses conducted in May and July from the electronic medical records vendor Epic and a July report from the COVID and Cancer Research Network on trends in cancer-related patient encounters.


Compared to Quest’s baseline period from January 2019 through February 2020, during the seven weeks from March 1 through April 18, the mean weekly number of newly diagnosed cancer patients plunged 46.4% for all six types: breast, colorectal, lung, gastric, pancreatic, and esophageal. The biggest drop was 51.8% in breast cancer and the smallest decrease was 24.7% in pancreatic cancer. 

“Patients didn’t have the opportunity to have routine screens because they were told not to go to their doctors for routine visits,” said Harvey Kaufman, Quest’s senior medical director and an author of the study. “And if they had some mild symptoms, they waited or ignored them. The key is that during the real lockdown periods, people who have screenings didn’t have routine visits.”

Patients whose doctors ordered tests for any cause and entered the code for a new cancer diagnosis in that order were included in the Quest analysis, picking up more results than from screening mammograms and colonoscopies alone. Its tests represent a range from 16% of lung cancers to 42% of breast cancers detected in the U.S., as tallied against the national SEER registry. Three-quarters of all Quest patients, in both the baseline and pandemic period, were women and the mean age was 66. Other demographic information, such as race, is not collected by Quest in test orders from physicians so no further breakdown is available.


At the outset of that seven-week timeframe when the pandemic first hit the U.S., federal health officials and cancer societies urged patients to stay home and postpone routine medical care, including mammograms and colonoscopies or other tests that might have inadvertently found cancer. Health systems overwhelmed by Covid-19 patients or preparing for a surge in cases — or both — asked those whose care could wait to delay what they could. 

Skipping cancer screenings, although prudent at the time, sparked alarm from Ned Sharpless, who directs the National Cancer Institute. He warned in a June editorial in Science that delayed cancer diagnosis could lead to as many as 10,000 extra deaths over 10 years in breast and colorectal cancer alone, in effect trading one public health crisis for another.

“We’re very worried about the consequences of … delaying therapy on our patients,” Sharpless told STAT then. “We can’t delay cancer care forever.”

In the spring, Epic reported that screening appointments for cancers of the cervix, colon, and breast plummeted between 86% and 94% in March. In July, screenings were still down but by far less, from 29% to 36% in these three cancers.

The COVID and Cancer Research Network found a significant decrease in all cancer-related patient encounters as a result of the pandemic, defining an encounter as screening, an initial diagnosis, a second opinion, or the start of treatment. Across 20 different U.S. provider institutions with more than 28 million patients, the researchers found an overall drop of 74% in new cases of breast, lung, prostate, colorectal, and hematologic cancers and melanoma in April 2020 compared to April 2019. That report was published in the Journal of Clinical Oncology on July 27. In the network, 43% of patients are seen at institutions in the South, 22% in the Midwest, 18% in the Northeast, and 17% in the West.

Quest’s Kaufman said the company has seen geographic shifts in testing as cases rise and fall across the U.S. and patients stay home. “Our volume in Florida at the moment is slightly softer because a pandemic is hitting Florida hard,” he told STAT on Monday.

The debate over whether early detection causes overtreatment or saves lives has not been settled, but cancer centers want patients to come back. 

Dana-Farber Cancer Institute is encouraging patients to get their delayed screening or other care. Oncologist Andrew Wagner wasn’t surprised by the drop in cancer diagnoses reported by Quest and others, calling it a reflection of a risk-benefit assessment when the risk of exposure to the coronavirus in a hospital outweighed the benefit of screening. But now that safety measures are in place, that balance has shifted in favor of screening tests and other medical visits. 

“I think what is really critically important is that people do feel safe to return to health care environments where we do now have the appropriate equipment in place and screening procedures in place,” he said.

So far, Wagner hasn’t seen evidence of patients’ cancers being diagnosed at a later stage than if they had been tested earlier.

“This delay of a few months probably does not have a significant impact on patients. But we don’t like to delay screening tests,” he said. “It does depend a lot on the biology of the tumors, where some can be really slow-growing, small tumors and a few months has no impact, and then other, more rapidly growing ones where it could make an impact. So we hope we don’t see that. But it’s certainly possible.”

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