A research letter published in JAMA Network Open reported a steep decline in newly identified cases of six common cancer types, based on data from Quest Diagnostics. The report compared the mean weekly number of new cases of breast, colorectal, lung, gastric, pancreatic, and esophageal cancers in the period of March 1 through April 18, 2020, with new cases in the baseline period of January 2019 through February 2020.
In March and April, the average number of new cases during this period dropped 46.4% compared with baseline, the authors reported.
New breast cancer diagnoses declined by 51.8%, representing the largest downturn among the group. Pancreatic cancer had the smallest decrease in new cases, at 24.7%.
"Patients didn't have the opportunity to have routine screens because they were told not to go to their doctors for routine visits … and if they had some mild symptoms, they waited or ignored them," said study coauthor Harvey Kaufman, MD, Senior Medical Director at Quest Diagnostics. "The key is that during the real lockdown periods, people who have screenings didn't have routine visits."
These findings are in line with analyses conducted by electronic medical records vendor Epic in May and June, as well as a July report from the COVID and Cancer Research Network. Epic reported that screenings for cervical, colon, and breast cancer dropped between 86% and 94% in March. The COVID and Cancer Research Network found that screenings were still down 29% to 36% for these three cancer types, and that there still is a general decrease in all cancer-related screenings, diagnoses, and treatment.