All women diagnosed with breast cancer should get genetic testing. That’s the claim in a new piece of research that touches a major area of confusion for women.
As of now, the National Comprehensive Cancer Network‘s established guidelines for who should get genetic testing in relation to breast cancer is limited. And since these guidelines influence how much insurance will pay for such testing, they matter for women. However, a study that was just published in the Journal of Clinical Oncology shows that the limitations of these guidelines are doing a disservice to many people diagnosed with breast cancer and should potentially be broadened.
The study looked at over 1,000 women aged 18-90 who were diagnosed with breast cancer. These women each underwent an 80-gene panel, meaning their DNA was tested for 80 possible genetic markers. Of the women tested, approximately 50% met the NCCN’s current criteria for genetic testing, and the other 50% did not. In a surprising result, 9.39% of women who did meet these guidelines tested positive for a “pathogenic/likely pathogenic (P/LP) variant” (an indicator that their breast cancer was hereditary in nature), but a similar amount, 7.9%, of the women who did not meet the guidelines also tested positive for a P/LP variant.
In other words, the current NCCN-established guidelines excluded nearly half the women who had breast cancers that were, in fact, caused by hereditary factors.
The guidelines were developed when the BRCA-1 gene (the type that Angelina Jolie had when she decided to get her prophylactic mastectomy) and the BRCA-2 gene were the only two markers doctors looked for when it came to testing for hereditary breast cancer, according to one of the authors of the study, cancer surgeon Dr. Peter Beitsch.
There are now as many as 30 genetic variants that have been shown to be linked to breast cancer, as well as 11 gene mutations, he continues; similarly, testing has become less cumbersome and expensive since these guidelines were established.
So what does this mean? Dr. Beitsch says that it means all women who are diagnosed with breast cancer should be tested for such genetic factors. This can not only impact the treatment she receives, he says, but it can also influence how immediate family members look at their cancer risk and manage that risk throughout their lives.
It’s true that understanding the genetic makeup of cancer is an important element of how it’s treated. For example, one very specific type of gene testing can be done on a survivor’s tumor in a process called genetic sequencing, Dr. Elizabeth Comen, medical oncologist at Memorial Sloan Kettering Cancer Center and medical advisor to SurvivorNet, explained previously. “We take a piece of the tumor, and we look at all the genes that help make up the blueprint of that tumor and try to figure out, what are the mutations that evolved in that cancer, specifically to allow it to grow?”
This information can influence a doctor’s decision on how to treat the cancer, she continues. “It might make certain clinical trials appropriate for a patient—if there’s a new medicine that might target that mutation, or there may already be existing medications that targets that mutation,” that option may be explored.
It’s important to note that inherited cancer, or cancers that are inherited via genetic mutations within a family, only accounts for about 10% of all cancers according to the American Cancer Society—and about 10% of breast cancers specifically, according to Dr. Ophira Ginsburg, medical oncologist and Director of the High-Risk Cancer Program at NYU Perlmutter Cancer Center—but that’s still enough to take note. Be sure to talk to your doctor if you think you or your children should undergo genetic testing.