Before COVID emerged in 2020, the leading cause of premature death in the US was cancer. About 40 percent of Americans receive a cancer diagnosis in their lifetimes, amounting to over 600,000 American deaths in an average year. The impact of cancer, much like COVID, disproportionately impacts racial/ethnic minority communities. Cancer represents a “chronic pandemic,” in which we need new tools to bend the mortality curve and reduce persistent disparities.
But one pandemic seems to have exacerbated another when new red flags emerged in late 2020, with publications cropping up every few weeks reporting an unnerving observation: Stage of cancer at diagnosis was becoming later and later. When cancer is caught early at localized stages, outcomes are generally favorable with better opportunities for potentially curative intervention. When cancer is diagnosed at a late stage, after spreading into the blood and distant parts of the body, outcomes are worse and cures are generally impossible. Cancer screening is essential to catching cancers early, but today we have cancer screenings for just five cancers, with no available screening tests for the cancers responsible for over 70 percent of cancer deaths in the US.
We can see a future where we make the transition away from screening for individual cancers to screening individuals for all cancers.
As the pandemic worsened and population anxiety grew in 2020, routine medical visits, including those for available cancer screening, steeply declined. In one study, examining comparative screening rates between spring 2020 and spring 2019, the sharpest decline was observed in April 2020, as screenings for breast, colorectal, and prostate cancers declined by 90.8 percent, 79.3 percent, and 63.4 percent, respectively. Delayed screenings resulted in diagnostic delays and, for many patients, later-stage diagnoses. Quest Diagnostics reported that the mean weekly number of newly diagnosed breast cancer patients fell by more than half (nearly 52 percent) for March and early April 2020, compared with figures before the pandemic. Across the Kaiser Permanente Northern California system, in the two months after California instituted its initial stay-at-home order, 64 percent fewer patients were diagnosed than during the same period a year prior. Further, more patients diagnosed in the 2020 period presented with symptomatic disease (78 percent vs. 37 percent) and at a more advanced stage (78 percent vs. 64 percent). Modeling suggests a grim downstream impact from delayed screenings. Ned Sharpless, director of the National Cancer Institute, noted that the effect of COVID-19 on cancer screening and treatment for breast and colorectal cancer—which together account for about one-sixth of all cancer deaths—suggests almost 10,000 excess deaths over the next decade from breast and colorectal cancer alone.
Since the start of the COVID pandemic, data have shown the importance of preventive medicine and cancer screenings in saving lives. We need to get cancer screenings back on track, but we also must work to build a more resilient and equitable cancer care system and reexamine the current paradigm for early detection.
Striking the right balance between highly accurate, sensitive testing and widespread population detection has been front and center as we looked to gain control of the COVID public health crisis. To do this, we needed to open the aperture from just looking at test characteristics (like sensitivity) to looking more broadly at infection detection rates in the population. The same approach needs to be taken with the other public health crisis in the US: cancer. If we are to make a real public health impact in cancer, we need to dramatically improve the cancer detection rate in the population.
It is well recognized that improving early cancer detection can really put a dent in the cancer mortality curve. But, early cancer detection is suffering from a common ailment in medicine and public health: the streetlight effect. We are looking for five cancers “over here” under the streetlight where we have screening tests, but 70 percent of cancer deaths are occurring “over there,” in the dark where we aren’t looking for cancer. We simply are not detecting enough cancer in the population through existing screening tools, meaning most cancers are still detected only when symptoms present—too late—when outcomes are generally poor.
New technology is on the horizon that can extend the benefits of early detection to more cancers. Multi-cancer early detection technology has the ability to screen for more than 50 types of cancer, via a single blood draw. This technology is a complement to single cancer screenings. The COVID pandemic has been a huge disruption on America’s cancer screening performance, illuminating the need for new approaches to cancer screening that fill the significant unmet need in this country, to aid in closing existing disparities in cancer care, and improve public health through improved early cancer detection.