Most Older Adults With Cancer Are Not Getting Genomic Testing

Most older adults with cancer are not receiving a test that can help their care team choose treatment, according to a study published in JAMA Network Open.

Researchers reviewed Medicare records for 391,151 patients age 66 and older who were diagnosed with lung, breast, colorectal, prostate or endometrial cancer between 2016 and 2023. Across those eight years, 91.4% did not receive genomic testing.

Testing did become more common over time. In 2016, 6% of patients were tested. By 2023, that number had risen to 16.7% — still fewer than 1 in 5.

What is genomic testing, and why does it matter?

Genomic testing looks for changes in the genes of a tumor, or for gene changes a person inherited. Those changes can tell a doctor whether a targeted treatment is likely to work.

More and more cancer treatments approved by the Food and Drug Administration (FDA) are only prescribed when a specific gene change or biomarker is present. Without testing, a doctor may not know that one of those treatments is an option.

Not everyone needs genomic testing, and the study could not tell which patients were candidates for it. But the researchers noted that testing remained far from universal, and that how often it was used varied widely from one cancer type to another.

What is next-generation sequencing?

Next-generation sequencing, or NGS, checks many genes at once from a single tumor sample. Older tests usually look for just one or a few gene changes, so NGS gives a fuller picture of what is driving a tumor.

Most patients in the study who were tested did not receive NGS. They received older, more limited tests instead. NGS alone accounted for less than 1% of patients through 2020, rising to 2.1% by 2023.

Medicare began covering tumor NGS nationally in March 2018 and inherited, or germline, testing in January 2020. Before then, coverage decisions were made regionally, so what a patient could get depended in part on where they lived.

Which cancers had the highest testing rates?

• Lung cancer: Had the highest testing rate for most of the study, rising from 12.8% in 2016 to 21.4% in 2021. It also had the highest NGS use, reaching 9.2% by 2023.
• Breast cancer: Had the highest overall testing rate by 2023, at 28.6%. Most of that increase came from tests other than NGS. Fewer than 5% of tested patients with breast cancer received NGS.
• Prostate cancer: Had the lowest testing rates, between 2.8% and 5.1%. Patients with prostate cancer made up the largest share of those who went untested, at 37.3%.

Colorectal and endometrial cancers each reached 2% NGS use.

Why is NGS used less often for some cancers?

Differences in treatment options and guidelines likely explain much of the gap, the researchers said.

Lung cancer has several gene changes that can be matched to targeted drugs, and national guidelines recommend comprehensive tumor NGS for patients with non-small cell lung cancer. Even so, use fell short of what guidelines call for.

Prostate and endometrial cancers have fewer gene changes that can be matched to a targeted treatment, and their testing guidelines came later.

Cost and coverage may also matter. The researchers pointed to earlier research finding that nearly one-fourth of cancer-related NGS claims in Medicare were denied.

Who was less likely to be tested?

Where patients lived: Most testing happened among patients in metropolitan areas, who made up 77.3% of those tested. The researchers called geographic gaps an area needing attention.

Age: Earlier research has found that younger patients with cancer are more likely to be tested and more likely to have a gene change that can be treated with a targeted drug. The lower rates among older adults may represent a disparity, the researchers said.

Race and ethnicity: This study found no differences in testing based on race, ethnicity or sex, though earlier studies had found lower rates of inherited genetic testing in some groups. The researchers said Medicare coverage, income, access to care, geography and the limits of billing data could all have shaped what they saw.

What can patients take from this?

If a patient has recently been diagnosed, it may be worth asking your care team whether genomic or biomarker testing is recommended for your cancer type, whether NGS is an option, and how the results could affect treatment choices. The researchers focused on tests done within six months of diagnosis, because that is when results are most likely to guide treatment.

How the study was done

Researchers reviewed Medicare billing records from Jan. 1, 2016, through Dec. 31, 2023, drawn from a 20% nationally representative sample of patients enrolled in Medicare Parts A and B. Half of the patients were female (50.6%), and 31.8% were older than 75. Patients who died within 30 days of diagnosis were not included.

Study limitations

The study cannot prove that Medicare coverage changes caused testing to rise. Wider availability of testing and growing familiarity among clinicians may also have played a part.

Medicare billing records do not include details such as cancer stage, biomarker status or test results, so researchers could not tell how many untested patients would have qualified for testing. Some tests may have been missed if they were billed under codes the researchers did not track. The findings also reflect traditional Medicare and may not apply to patients with Medicare Advantage or commercial insurance.

More work is needed to understand the value of expanding NGS and to address the barriers keeping patients from testing, the researchers said.

Reference

1. Kang SY, Zhang R, Kim C, et al. "Genomic Testing Uptake Among Medicare Beneficiaries With Cancer." JAMA Network Open. Published July 29, 2026.

For more news on cancer updates, research and education, don't forget to subscribe to CURE®'s newsletters here.