How the Pandemic Has Impacted Cancer Screening
Delayed cancer screening due to COVID-19 could mean more cancer-related deaths for years to come
Routine cancer screening is important to identify cancer at an early stage before patients become symptomatic. When detected early, these cancers can be easier to treat, leading to better outcomes. Breast, colorectal, and cervical cancer screening is suggested at regular intervals when patients fulfill certain risk factors such as age. However, during the COVID-19 pandemic, major health agencies and organizations recommended delaying screening appointments to prevent exposure to SARSCoV- 2 and preserve necessary health care resources.
Both the American Cancer Society (ACS) and the American Society of Clinical Oncology (ASCO) issued guidelines in spring 2020 suggesting that patients delay their routine cancer screening until further notice. Understanding the potential effects of these delays, the guidelines from both the ACS and ASCO were updated at the beginning of 2021 to recommend slowly resuming cancer screening as soon as safely possible with the implementation of appropriate infection control measures. However, the initial postponement could still have potential downstream impacts that will affect the landscape of cancer screening and treatment for years to come.
COVID-19 and declines in cancer screening
In a comprehensive study of 2.7 million patients,1 the Epic Health Research Network found that the number of preventive screenings performed for cervical, colon, and breast cancer fell dramatically—between 86 and 94 percent—across the United States during the onset of the COVID-19 pandemic. Between March and June 2020, 285,000 breast cancer, 95,000 colon cancer, and 40,000 cervical cancer exams were missed. An update published in July 2020 showed that these numbers had begun to recover but remained between 29 and 36 percent lower than their pre-COVID-19 levels.2
A separate study of the 20 hospitals that comprise the COVID and Cancer Research Network (CCRN)found similar drops in colon and breast screening of 85 percent and 89 percent, respectively.3 The researchers also identified a corresponding 57 percent decline in new cancer diagnoses overall in April 2020 compared to April 2019. These findings are concerning as they suggest that the decline in cancer screening has led to a high number of missed cancers, which will likely present as more advanced and harder to treat once screening resumes.
Predicted impact of delayed cancer screening
A Canadian study used mathematical modeling to investigate the potential impact of delaying colorectal and breast cancer screening for up to 12 months in response to COVID-19.4 The simulations predicted a surge in cancer cases once screening resumes. The model also demonstrated that screening interruptions would lead to increases in cancers diagnosed at advanced stages, as well as cancer deaths. More advanced cancers require systemic treatments that would increase burdens on the already stressed healthcare system. The longer the screening interruption lasts, the greater the perceived impact.
Modeling by the National Cancer Institute has predicted that there will be an additional 10,000 deaths from breast and colorectal cancer combined over the next 10 years in the United States as a result of delayed cancer screening during the pandemic.5 This one percent increase in cancer mortality is likely an underestimate because it does not consider other cancer types, does not account for nonlethal morbidity from upstaging, and assumes a moderate disruption of fewer than six months for cancer screening. Norman E. Sharpless, Director of the National Cancer Institute, expressed his concern in a Science editorial last year that ignoring life-threatening non-COVID-19 conditions like cancer could turn one public health crisis into many others.5
Addressing the challenges of cancer screening during COVID-19
RESTARTING CANCER SCREENING
The National Cancer Institute’s Population-based Research to Optimize the Screening Process (PROSPR) consortium has made several recommendations to ensure continued cancer screening during the COVID-19 pandemic.6 Their goal is to provide effective, consistent, and universal screening services. To do this, they propose offering screening programs to those at the highest social risk who are less likely to seek screening and those at highest medical risk who are most likely to benefit from screening. PROSPR also recommends customizing cancer screening practices depending on the regional prevalence of COVID-19 and implementing comprehensive infection control measures to protect patients and staff.
AT-HOME CANCER SCREENING
One of the recommendations from PROSPR is broader implementation of remote cancer testing to reduce the need for in-person visits. For most cancers, including breast and cervical, screening needs to be conducted in-clinic because it requires specialized equipment and skilled technicians. Currently, colorectal cancer is the only cancer type that can be screened for at home. Because of their convenience, athome colorectal cancer screening kits have been highlighted by insurance companies during the COVID-19 pandemic.7
At-home colorectal cancer screening tests analyze fecal samples that have been collected and sent in by patients. The fecal immunochemical testing (FIT) kits detect blood in stool while multitarget stool DNA kits such as Cologuard detect cancer biomarkers and blood. Unlike colonoscopies, these kits do not require an invasive procedure, laxatives, or dietary changes. The efficacy of these tests is still being compared to colonoscopies through randomized controlled trials, but companies are making an effort to let consumers know that regardless of performance, the best cancer screening test is the one you can get done right now.
One study out of Michigan Medicine evaluated the impact of at-home colorectal cancer screening during the COVID-19 pandemic.8 They compared the use of colonoscopies, Cologuard, and FIT from March to May 2020 with previous years. While colonoscopies declined by 99 percent, the use of FIT and Cologuard decreased by only 87 and 65 percent, respectively. Based on these results, the authors suggest that the future of cancer screening after COVID-19 could be at home as the convenience could lead to improved compliance with screening schedules. The next step for vendors is to improve current at-home screening kits and develop new kits for other cancer types such as cervical cancer
Opportunities for improved screening
As more people receive vaccines, restarting cancer screening at full capacity is needed for the early detection of cancers that may have arisen over the last year. Identifying these cancers as soon as possible will help curb the impact of the COVID-19 pandemic on cancer screening by offering more treatment options and preventing unnecessary deaths over the coming years.
While the pandemic has presented many challenges for cancer patients, it has revealed opportunities where cancer screening can be improved. At-home cancer testing could help overcome some of the accessibility challenges of cancer screening programs, improve compliance with screening schedules, and lead to the early detection of more cancers. Designing remote testing options for other cancer types including breast and cervical cancers will expand this impact even further.
References
1. “Delayed cancer screenings.”Epic Health Research Network. (2020)
2. Mast, Christopher, and Alejandro Munoz del Rio. "Delayed cancer screenings-a second look." Epic Health Research Network (2020).
3. London, Jack W., et al. "Effects of the COVID-19 pandemic on cancer-related patient encounters." JCO Clinical Cancer Informatics (2020): 657-665.
4. Yong, Jean HE, et al. "The impact of episodic screening interruption: COVID-19 and population-based cancer screening in Canada." Journal of Medical Screening (2020).
5. Sharpless, Norman E. "COVID-19 and cancer." Science (2020): 1290-1290.
6. Corley, Douglas A., et al. "Cancer screening during COVID-19: A perspective from NCI’s PROSPR consortium." Gastroenterology (2020): 999-1002.
7. Jaklevic, Mary Chris. "Pandemic spotlights in-home colon cancer screening tests." JAMA 325.2 (2021): 116-118. 8. Gorin, Sherri N. Sheinfeld, et al. "The future of cancer screening after COVID-19 may be at home." Cancer (2020).
