A analysis published in the journal JAMA Network Open has found new cancer diagnoses in the United States dropped by nearly 50 percent across the months of March and April. Experts warn these delayed diagnoses could lead to a spike in avoidable cancer deaths over the coming years.
The analysis comes from researchers at Quest Diagnostics, a large clinical testing company that counted the weekly volume of physician-ordered tests for six common cancer types (breast, colorectal, lung, pancreatic, gastric, and esophageal) between January 2018 and April 2020.
Up to March 1st this year, Quest labs, on average, detected 4,310 new cancer cases every week. That dropped to 2,310 new weekly cases across the March/April pandemic period. Breast cancer diagnoses displayed the most notable decrease, dropping 52 percent during the early phase of the pandemic.
This is obviously only one company’s data, and only six common types of cancer, but the conclusions mirror several other recent studies from various countries around the world.
A Dutch study conducted early in the pandemic saw cancer incidence rates drop by 40 percent during the pandemic peak in The Netherlands.
Cancer Research UK saw urgent cancer diagnostic referrals from GPs drop by 75 percent over the past few months, and in the Australian state of Victoria one report suggested a drop of around 30 percent in new cancer reports during times of local lockdown.
Why does this all matter? Because, as the authors of the Quest Diagnostics analysis put it, “cancer does not pause.” Delays in cancer diagnoses result in the disease being caught at later stages, leading to poor clinical outcomes and additional weight on health care systems.
“Diagnostic delays are critical in determining the outcomes for many cancers,” explain a pair of cancer researchers from the University of Melbourne. “For instance, someone with a stage one lung cancer who experiences a diagnostic delay of about two months will be diagnosed with stage two lung cancer instead, with significant impact on overall survival. But it also changes the demand for more extensive surgery, radiotherapy and systemic drug treatment.”
It is difficult to quantify the downstream consequences of these delays to diagnoses and disruptions to treatments. One early analysis suggested a 20-percent rise in cancer mortality may occur in England over the next 12 months. That is more than 6,000 additional deaths, and it only considered new cancer diagnoses. Another study, still in pre-print, examined data from the United States and estimated over 33,000 avoidable cancer deaths could occur over the next year.
Looking forward, the challenges for health care practitioners around the world are immense. The repercussions of the pandemic for the general health of the world’s population will need significant attention over the coming years. It won’t just be a game of catching the diseases that are going undiagnosed right now, but enhancing the efficiency of pre-existing services.
“It is insufficient to only talk about restarting elective treatments,” write the University of Melbourne researchers. “Instead, we need to be analyzing the potential impact of our response to COVID-19 on delays in cancer diagnosis, and prioritize the demand for cancer health services to maximize survival and quality of life.”
The new study was published in the journal JAMA Network Open.
