Prostate Cancer Consensus Advises How to Use Germline Genetic Testing

Categories: Summer/Fall 2021

Germline genetic testing looks for hereditary, or inherited, cancer gene mutations. In an exciting development for patient care, this type of genetic testing is becoming more available and cost-effective, and physicians now have more tools for providing personalized care. A guideline statement, crafted by a panel of experts, provides guidance on how and when to use germline testing for prostate cancer.

The guideline comes from the Philadelphia Prostate Cancer Consensus Conference, at which 97 multidisciplinary experts thoroughly reviewed scientific evidence on genetic testing and prostate cancer. The statement was published as a scientific paper in June, 2020.

The guideline statement recommends that all men with metastatic prostate cancer or men who have a family history suggesting hereditary prostate cancer undergo genetic testing.

The recommendation that men diagnosed with metastatic disease is driven by recent additions to the precision medicine landscape in prostate cancer. Approximately 12% to 17% of men with metastatic prostate cancer have germline genetic mutations in DNA repair genes. Clinicians are increasingly able to consider these mutations when recommending personalized treatment options.

For example, the FDA has approved two PARP inhibitors drugs (olaparib and rucaparib) to treat men with metastatic castration-resistant prostate cancer who have BRCA genetic mutations. Other treatments are approved to treat men with additional specific genetic mutations, such as ATM or DNA mismatch repair (MMR) genes, and more therapies are currently being explored in clinical trials in which men may be eligible to participate depending upon their genetic testing results.

In addition, certain genetic mutations are associated with increased risks of further disease progression for men with low-risk disease. Data suggest that men with BRCA2 and possibly ATM mutations have higher rates of their screening biopsies showing their cancer having been upgraded to a worse stage while they are on active surveillance. Thus, knowing if a man carries those mutations could help inform treatment and the timing of active surveillance monitoring after being diagnosed.

The guideline also underlines the importance of considering family history of cancers beyond just prostate cancer. For example, hereditary ovarian and breast cancer, as well as Lynch syndrome, have implications for cancer risk for men and their families. For men with BRCA2 genetic mutations and a family history, the guidelines suggests screening begin at age 40 or 10 years before the youngest prostate cancer diagnosis in the family. The statement also suggests men with a family history consider this course of early screening if they carry mutations in HOXB13, BRCA1, ATM, and mismatch repair genes.