Weekly diagnoses for six types of cancer dropped by almost half in March and April when compared with certain baselines, according to a research letter published in JAMA Network Open—a finding that may seem positive on the surface, but likely means that Americans were avoiding care because of the country's coronavirus epidemic, experts say.
For the study, researchers looked at weekly numbers of cancer diagnoses from Quest Diagnostics between March 1 and April 18 and compared them with Quest's baseline period of January 2019 and February 2020.
The data focused on six types of cancer:
- Breast cancer;
- Colorectal cancer;
- Esophageal cancer;
- Gastric cancer;
- Lung cancer; and
- Pancreatic cancer.
The data included patients whose doctors ordered tests for any reason and entered the code for a new cancer diagnosis. These tests represent a significant proportion of weekly incidence estimates for the six cancers in the United States, ranging from 16% of lung cancer cases to 42% of breast cancer cases, when totaled against the national SEER registry.
Overall, the researchers found that the weekly number of newly diagnosed cancer patients had dropped by an average of 46.4% for all six types of cancer from March 1 to April 18 of this year when compared with the baseline periods. The largest decrease occurred in the weekly number of breast cancer diagnoses, which dropped 51.8%, and the smallest decrease occurred among pancreatic cancer diagnoses, which dropped 24.7%.
The study adds to similar research that found declines in the rates of cancer diagnoses and screenings since the start of America's new coronavirus epidemic, which first peaked in the country in March and April, STAT News reports. For instance, a report released by Epic in May found screening appointments for cancers of the cervix, colon, and breast dropped by between 86% and 94% in March, while a report released by the COVID and Cancer Research Network in July found a decrease of 74% in new cases of breast, colorectal, hematologic, lung, and prostate cancers and melanoma in April 2020 when compared with April 2019.
Experts say the research suggests patients avoided getting screened for cancer in response to the coronavirus epidemic.
"Patients didn't have the opportunity to have routine screens because they were told not to go to their doctors for routine visits," Harvey Kaufman, senior medical director for Quest and an author of the new research letter, said. "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."
Ned Sharpless, director of the National Cancer Institute, said the news of people skipping cancer screenings is alarming. In an editorial published in Science, Sharpless warned that delayed diagnoses could lead to as many as 10,000 additional deaths from breast and colorectal cancers over the next decade.
"We're very worried about the consequences of … delaying therapy on our patients," Sharpless said. "We can't delay cancer care forever."
Andrew Wagner, an oncologist at the Dana-Farber Cancer Institute, said he wasn't shocked by the results of the study, saying it reflected patients' risk-benefit analysis when gauging whether to be screened for cancer during an infectious disease epidemic. However, now that hospitals have safety measures in place, Wagner said patients should start getting screened.
"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.
Wagner added that he hasn't seen any evidence to suggest that patients are being diagnosed with cancer at a later stage than they would have had they been tested sooner.
"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" (Cooney, STAT News, 8/4; Vaidya, Becker's Hospital Review, 8/4).