The common practice of limiting germline genetic testing to cancer patients diagnosed before age 50 misses 72% of those with inherited pathogenic variants, a large new study finds. Researchers sequenced nearly 40,000 solid tumor patients across 32 cancer types and found hereditary variants at every age. Experts say it's time to move toward universal germline testing for all cancer patients, regardless of age.
The age-50 rule for cancer genetic testing has a major blind spot. A landmark study published in Cancer Discovery, based on germline sequencing of 39,184 unselected solid tumor patients at Memorial Sloan Kettering Cancer Center, found that restricting hereditary cancer testing to those diagnosed before age 50 would miss 72% of all pathogenic variant carriers — including 68% of those with moderate- or high-penetrance variants that significantly elevate lifetime cancer risk.
Across all 32 tumor types studied, 16.3% of patients harbored a germline pathogenic variant. While younger patients had higher rates (18.4% in early-onset vs. 12.3% in late-onset), the data make clear that inherited cancer risk doesn't disappear with age — about 5% of late-onset patients still carried high- or moderate-penetrance variants.
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Why it matters: Identifying a hereditary variant doesn't just affect the patient — it can trigger cascade testing for family members who haven't yet developed cancer, opening the door to early surveillance and prevention. Experts are calling for universal germline testing to become the new standard of care across oncology.
