Making the Case for Expanding Genetic Testing Guidelines

Categories: Spring 2019
Although prostate cancer is common in the U.S., some men will develop aggressive disease that could metastasize to cause harm or death, while other men will have a disease that grows so slowly that it will never cause harm. Along with their physicians, men diagnosed with prostate cancer need to weigh the risks and benefits of having immediate treatment versus delaying treatment. Yet, it can be challenging to select the best option for each individual patient.
©Dan Oldfield

PSA scores, Gleason scores, and family history all play a role in assessing each patient’s risk for aggressive prostate cancer. Yet, there is great potential to more accurately predict a patient’s risk upon diagnosis.

A current focus in the field of prostate cancer research is identifying genetic mutations that signal a man’s disease is more likely to be aggressive, indicating he should consider curative treatment, such as surgery or radiation, rather than active surveillance. Dr. Catalona’s research is heavily involved in this work, and he and his research collaborators have already made many important discoveries.

Now, authors of a recent study called for revisiting national genetic testing guidelines to include more genetic variants already known to be associated with aggressive disease, as well as continuing to consider a patient’s family history and other factors.

The researchers looked at data on more than 3,600 men with a history of prostate cancer who underwent germline genetic testing. More than 17% of the men had germline genetic variants that research has shown to be linked with aggressive prostate cancer, yet 37% of these patients did not qualify for genetic testing according to guidelines established at the time from the National Comprehensive Cancer Network (NCCN). This means that these patients would not have been referred for genetic testing to more accurately predict the risk of their disease becoming aggressive. The information gained from genetic testing could be critical for personalizing treatment recommendations.

The most well-known germline (inherited) genetic variants linked with aggressive prostate cancer are the socalled breast cancer genes, BRCA1 and BRCA2. Women with BRCA1/2 mutations have a higher risk of developing breast cancer, and men with the same mutations have a higher risk of developing prostate cancer. However, of the men in the study with genetic variants, only 31% had a BRCA1/2 genetic mutation. Other variants found in the patients, which were not included in the genetic testing guidelines, included HOXB13 and DNA mismatch repair deficiency genes.

NCCN guidelines are important because many health insurance companies determine coverage based on NCCN panel recommendations.

JAMA Oncol. 2019 Feb 7. doi: 10.1001/ jamaoncol.2018. 6760. [Epub ahead of print]

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