Last year, cancer screening programs around the world ground to a halt as SARS-CoV-2 infection rates surged globally. The effect of this slowdown is now becoming clear.
Thousands of cancer diagnoses are “missing,” and oncologists worry that this will lead to more advanced cancers and higher mortality for years to come.
“I feel like this is an earthquake that’s rocked our health care system. My guess is that you’ll probably still see repercussions of this over the next couple of years at least,” said Sharon Chang, MD, an attending surgical oncologist in the Permanente Medical Group, Fremont, Calif.
She was senior author of a study that analyzed the effects of the slowdown in mammography screening as a result of California’s “shelter-in-place” order on March 17, 2020. In the 2 months that followed, there were 64% fewer breast cancer diagnoses at 21 Kaiser Permanente medical centers, compared with the same period in 2019 (250 vs. 703).
In effect, approximately 450 breast cancer patients had “disappeared,” said coauthor Annie Tang, MD, a research fellow at the University of California, San Francisco, East Bay surgery program.
“What surprised me most from our data was the sheer number of breast cancer patients that were missing,” Dr. Tang said in an interview.
A similar picture has emerged elsewhere.
In Boston, an estimated 1,438 cancerous and precancerous lesions “went missing” during the first 3 months of pandemic shutdown, according to a study from the Massachusetts General Brigham health care system.
In this study, the investigators assessed screening rates for five cancers – breast cancer (mammography), prostate cancer (prostate-specific antigen testing), colorectal cancer (colonoscopy), cervical cancer (Papanicolaou tests), and lung cancer (low-dose CT).
Screening rates during the first peak of the pandemic (March 2 to June 2, 2020) were compared with those during the preceding and following 3 months and during the same 3 months in 2019.
The results showed a pronounced drop in screening rates during the peak pandemic period, compared with the three control periods. Decreases occurred for all screening tests and ranged from –60% to –82%.
There were also significant decreases in cancer diagnoses resulting from the decreases in screening tests, ranging from –19% to –78%.
“Quantifying the actual problem made us realize how much work needs to be done to get us back to prepandemic numbers,” said senior author Quoc-Dien Trinh, MD, FACS, codirector of the Dana Farber/Brigham and Women’s prostate cancer program.
In the Canadian province of Alberta, a similar decrease in cancer diagnoses occurred during the early days of the pandemic.
By the end of 2020, Alberta was “missing” approximately 2,000 cases of invasive cancers and 1,000 cases of noninvasive cancers, Doug Stewart, MD, senior medical director at the Cancer Strategic Clinical Network (SCN) of Alberta Health Services, told this news organization.
Dr. Stewart is able to track cancer diagnoses in Alberta almost in real time through a mandatory cancer registry. Within a month of shutdown, there was a 30% decrease in diagnoses of invasive cancers and a 50% decrease “in the kind of preinvasive cancers that, for the most part, are picked up by screening programs,” said Dr. Stewart.
After the health care system opened up again in the summer, Stewart said, noninvasive cancer diagnoses continued to be 20% lower than expected. There was a 10% shortfall in invasive cancer diagnoses.
The number of diagnoses had returned to normal by December 2020. However, Dr. Stewart is worried that this fact conceals a terrible truth.
The worry is over the backlog. Although the number of diagnoses is now similar to what it was before the pandemic, “people are presenting later, and maybe the cancer is more advanced,” he speculated.
His team at Alberta Health Services is assessing whether the cancers that are being diagnosed now are more advanced. Initial results are anticipated by late April 2021.
In the United Kingdom, there was a similar halt in cancer screening as a result of the country’s lockdown. Researchers now predict an uptick in cancer diagnoses.
Ajay Aggarwal, MD, PhD, consultant clinical oncologist and associate professor at the London School of Hygiene and Tropical Medicine, and colleagues have estimated that at least 3,500 deaths from breast, colorectal, esophageal, and lung cancer will occur during the next 5 years in England that could have been avoided had it not been for the lockdown measures necessitated by the pandemic.
Speaking to this news organization, Dr. Aggarwal warned that these numbers, which are from a modeling study published in August 2020, are “extremely conservative,” because the investigators considered diagnostic delays over only a 3-month period, the analysis involved only four cancers, and it did not reflect deferral of cancer treatment.
“It felt like it was the tip of the iceberg,” Dr. Aggarwal said. He warns that more recent data suggest that “diagnostic delays are probably worse than we predicted.”
He suspects that there is more at play than screening cancellations.
In another study conducted in the United Kingdom, data show “a falling edge of referrals” from primary care to cancer centers early in the pandemic. In that study, investigators analyzed real-time weekly hospital data from eight large British hospitals and found that urgent cancer referrals fell 70% at their lowest point.
“It really surprised me that the urgent referrals dropped so drastically,” said lead author Alvina Lai, PhD, a lecturer in health data analytics at University College London.
She attributed this in part to patients’ adherence to lockdown rules. “Patients are trying to follow government guidelines to stay home and not go to [general practitioners] unless necessary,” Dr. Lai explained in an interview.
Canada, like the United Kingdom, has a publicly funded health care system. Dr. Stewart came to a similar conclusion. “Some patients who have been diagnosed with cancer ... have told me it took them an extra couple of months to even contact the family doc, because they ... didn’t want to bother the family doctor with something that wasn’t COVID, this kind of guilt. They want to do something good for society. You know, most people are just really nice people, and they don’t want to bother the health care system if they don’t have COVID,” Dr. Stewart said.
Shelley Fuld Nasso, CEO of the National Coalition for Cancer Survivorship, a nonprofit organization based in Silver Spring, Md., agreed that screening shutdowns are not the only danger. “While we agree that screening is really important, we also want to make sure patients are following up with their physicians about symptoms that they have,” she said.
“Some of the speculation or concern about increased mortality for cancer is related to screening, but some of it is related to delayed diagnosis because of not following up on symptoms. ... What concerns me is not everyone has that ability or willingness to advocate for themselves,” she said.
Speaking at a press briefing held by the American Society for Radiation Oncology on March 30, Dr. Nasso related a case involving a patient who experienced severe arm pain. In a teleconsultation with her primary care physician, her condition was diagnosed as arthritis. She was subsequently diagnosed in the ED as having multiple myeloma.
Patients who “feel fine” may postpone their checkups to avoid going to the hospital and risking exposure to COVID-19.
“Some patients are still hesitant about returning for their mammograms or coming in if they feel a breast lump,” Dr. Tang said. “That fear of COVID-19 is still out there, and we don’t know how long patients are going to delay.”
In London, Dr. Aggarwal saw a similar response to the pandemic. “People were overestimating quite significantly what their risk of death was from acquiring COVID-19, and I think that balance was never [redressed] explicitly,” he said.
Public health initiatives to rebalance the messaging are now underway.
Public Health England and National Health Service England launched their Help Us Help You campaign in October 2020. The public information campaign urges people to speak to their doctors if they were “worried about a symptom that could be cancer.”
In Canada, the provincial government in Alberta has launched a public awareness campaign that conveys the message, “cancer has not gone away.”
“Cancer is still the No. 1 cause of potential life-years lost, despite COVID,” Dr. Stewart said. “We need to do what we can to make sure there’s no slippage in survival rates.”
Dr. Tang, Dr. Chang, Dr. Lai, Dr. Stewart, and Dr. Aggarwal have disclosed no relevant financial relationship. Dr. Trinh has received personal fees from Astellas, Bayer, and Janssen and grants from Intuitive Surgical.
A version of this article first appeared on Medscape.com.