Young Adults With Early-onset Cancer Are More Likely To Benefit From Genetic Testing

According to a new study presented at the 2020 Virtual Annual meeting of the American Association for Cancer Research (AACE) Phase II, young adult cancer patients with early-onset disease often carry germline mutations and can benefit from germline gene testing.

Young adults, defined as those between 18 and 39 years of age, face unique challenges despite having only 4% of their tumours. In this population, it is particularly important to determine whether a young cancer patient has inherited cancer susceptibility syndrome. Understanding this genetic information can significantly influence the risk of second primary tumors and requires enhanced cancer surveillance measures. Young people who may use genetic information to identify family members at risk, including younger siblings or even children, should be genetically tested and take appropriate cancer screening or prevention measures.

Early-onset cancer is a unique group of young cancer patients who typically develop tumors such as breast, colon, pancreatic, kidney and ovarian cancers at an older age.

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Researchers at Memorial Sloan-Kettering Cancer Center evaluated germline mutations in 877 patients with early-onset cancer and 324 patients with typical young adult cancers, most commonly sarcomas, brain, testicular and thyroid cancers. They found that germline mutations were “very common” in early-onset cancer patients, 21 per cent of whom had germline mutations. In the remaining young adult cancer patients, on the other hand, the prevalence of germline mutations was low, at 13 percent.

Professor Elaine R. Mardis, former President of the AACR, said the findings were “surprising” because germline mutations – genetic susceptibility to disease or pathogenicity – were significantly higher (21%) in early-onset cancer patients than previously thought, and these early-onset cancer patients had tumor types that were more often diagnosed in the elderly.

The most common mutations in the early-onset cancer group were BRCA1, BRCA2, ATM, CHEK2, and Lynch syndrome related genes. TP53 mutations were more common in young adults, consistent with li-Fraumeni syndrome.

The increase in germline mutations in adults with early-onset cancer “supports the role of genetic testing independent of tumor type.”