Multicancer detection tests show promise, but questions linger about their accessibility

Key takeaways:

• Multicancer detection tests could address several barriers to screening.
• However, experts raised questions about their cost and accessibility.

ORLANDO — Multicancer detection tests have the potential to boost screening rates and reduce mortality, but questions remain about whether they would create additional barriers of their own, according to speakers at OMED.

Jeremy Fischer, DO, FACOFP, program director for the family medicine residency at Henry Ford Macomb Hospital in Michigan, highlighted several recent changes in guidance for several cancer screenings.

For example, the U.S. Preventive Services Task Force lowered the recommended ages to start screening for breast cancer and colorectal cancer, and recommended risk-based strategies over age and smoking history when screening for lung cancer.

Fischer also noted screening for prostate cancer has reached a point of “individualized decision-making with patients.”

Still, current screening rates are “suboptimal,” he said. For example:

• 33% of adults aged 50 to 75 years are not up to date with colorectal cancer screenings;
• 24% of women aged 50 to 74 years did not have a mammogram in the past 2 years; and
• 27% of women aged 21 to 65 years are not up to date with cervical cancer screenings.

He noted screening rates are further impacted by patient barriers such as no continuous source of care, low income, travel distance and no insurance, resulting in higher mortality.

“All of these things add up,” Fischer said.

One solution might be multicancer detection (MCED) tests, which take a sample of blood from the patient and screen for multiple cancers.

“What these tests are looking for is a shared cancel signal, and [whether these] cancer signals tell us which organ [or place] to look in,” said Candace Westgate, DO, MPH, DACOG, medical director of Adventist Health St. Helena.

Evidence has shown that MCED testing could reduce late-stage cancer incidence, 5-year cancer mortality and cancer-related deaths by 76%, 39% and 26%, respectively.

Westgate noted that although there are several MCED tests in development, there is just one available in clinical settings: the Galleri test, which has a 43.1% positive predictive value and 98.5% negative predictive value, according to the manufacturer, Grail. Westgate mentioned that the cancer signal detection rate is 0.95%, based on early real-world data.

The presenters said there are other benefits of MCED tests, including eliminating the association of pain with cancer screenings like mammograms, their potential in asymptomatic populations, and their potential to reduce health inequities.

“If I could say, ‘Here’s a blood test that we could do,’ I believe we would be able to capture more patients,” Fischer said — particularly in underserved areas, where even traditional screening approaches are “more difficult.”

Although new tests like MCEDs can be costly, “you have to compare that to [what it looks like] picking up cancer in early stages because cancer is an incredibly expensive disease to treat,” he said.

However, MCED tests still carry questions like whether they can be implemented into routine care while not discouraging use of other standard-of-care screening methods.

There is also the possibility that MCED tests can create barriers of their own because of issues surrounding their availability, affordability and accessibility.

Ultimately, “I think it’s important that we have to have something that narrows the disparity gap and not something that comes in and creates further disparities,” Fischer said.

References:

• GRAIL presents real-world experience with the Galleri multi-cancer early detection test at 2023 ASCO annual meeting. https://finance.yahoo.com/news/grail-presents-real-world-experience-181500539.html. Published June 3, 2023. Accessed Oct. 11, 2023.
• Westgate C, Fischer J. What primary care physicians need to know about multicancer early detection tests. Presented at: OMED; Oct. 5-8, 2023.