YOUNG ADULTS WITH CANCER SHOULD HAVE GENETIC TESTING

Young adults with early onset cancers often harbor germline mutations and would benefit from germline genetic testing, according to a new study.

"Although representing only about 4% of all cancers, young adults with cancer, defined as those diagnosed with cancer between the ages of 18 and 39, face unique challenges," Dr. Zsofia K. Stadler, of Memorial Sloan Kettering Cancer Center in New York City, said in a presentation at the American Association for Cancer Research (AACR) second virtual annual meeting.

"Identifying whether a young patient's cancer occurred in the setting of an inherited cancer predisposition syndrome is especially important in this population. Knowledge of this genetic information can significantly impact risk of second primary cancers and the need for increased cancer surveillance measures. Young adults may use genetic information to identify at-risk family members, including potentially young siblings or even children who should pursue genetic testing and have positive appropriate cancer screening or prevention measures," Dr. Stadler said.

Patients with early-onset cancer are a distinct group of young-adult cancer patients who develop cancers typically seen at older ages, including breast, colon, pancreas, kidney and ovarian cancer.

Dr. Stadler and colleagues evaluated germline mutations in 877 patients with these "early-onset" cancers and 324 patients with typical "young-adult" cancers, most commonly sarcoma, brain, testicular and thyroid cancer.

They found a "very high prevalence" of germline mutations in patients with early-onset cancers. "Indeed, 21% of these patients harbored the germline variant," Dr. Stadler reported. "On the other hand, in the remainder of young-adult cancer patients, the germline mutation prevalence was lower at 13%."

Briefing co-moderator and AACR past president Dr. Elaine R. Mardis said the "surprising" finding in this study is that the prevalence of these germline mutations is "significantly higher than we had previously thought where about 21% of the early-onset patients - those patients developing tumor types more commonly diagnosed in older adults - have germline susceptibility pathogenic or likely pathogenic variants."

The most common mutations in the early-onset group were BRCA1, BRCA2, ATM, CHEK2, and Lynch syndrome-associated genes. In the young-adult group, germline TP53 mutations were more common, which is consistent with Li-Fraumeni syndrome.

Dr. Stadler said the increased prevalence of germline mutations in adults with early-onset cancer "supports a role for genetic testing irrespective of tumor type."

This study had funding from Memorial Sloan Kettering Cancer Center. The authors have no relevant disclosures.

SOURCE: https://bit.ly/2B2pTfa Association for Cancer Research Virtual Annual Meeting II, presented June 22, 2020.