Does Genetic Testing Impact Treatment Decisions in Breast Cancer?

A study published in JAMA Oncology found that the knowledge of genetic risk influenced surgical treatment decisions in women younger than 40 years who were diagnosed with breast cancer.

Patients today are increasingly informed and more engaged in their healthcare, with technology and access to healthcare information lending a big hand. As patients understand their risk of susceptibility to cancer, based on counseling, they may make follow-up treatment decisions that could impact their outcomes. In order to understand the relation between these factors, researchers conducted a cross-sectional analysis of data collected from a prospective cohort study called the Helping Ourselves, Helping Others: Young Women’s Breast Cancer Study. Additionally, the researchers tried to understand why some women do not get tested despite clinical recommendation.

A total of 897 women, less than or at 40 years of age were recruited across 11 academic and community medical centers within the United States, according to the paper published in JAMA Oncology. The primary outcomes measures were frequency and trends in the use of BRCA testing and the influence of this information on treatment decisions, comparing those who tested positive versus not for a BRCA mutation. Mutation in the BRCA gene significantly increases a woman’s risk for breast cancer.

The study found that 780 of the 897 women reported having undergone BRCA testing within the year following their breast cancer diagnosis. The authors write that the frequency of testing increased during the study period, with nearly 77% reporting being tested in 2006 and growing to over 95% in 2013. Of those who remained untested (117), just over 31% did not discuss the likelihood of getting tested with either their physician or their genetic counselor, but nearly 37% said they were thinking of getting tested in the future.

“Greater public awareness may have made women more likely to bring up the issue of genetic risk with their physicians, possibly resulting in more testing,” said lead author Soshana Rosenberg, ScD, MPH, from Dana-Farber, in an associated press release.

Only a small proportion of women, 248 of 831 (29.8%) said that the knowledge of genetic risk influenced surgical treatment decisions, and even fewer reported its influence on systemic treatment decisions that included chemotherapy, ovarian suppression, or endocrine treatment. Among those who acknowledged the influence of their risk on treatment decisions, the presence of a BRCA mutation caused many to choose a double mastectomy. The authors note that independent of the mutation status, many women in the study who were diagnosed with breast cancer chose to undergo bilateral mastectomy, even if they were non-carriers.

"We know that developing breast cancer can be especially anxiety-provoking in young women. They may have a sense that because they weren’t ‘supposed’ to develop breast cancer at such an early age, they want to feel that they’re doing everything possible to prevent another occurrence,” according to Rosenberg.

The authors conclude that since awareness about their genetic risk influenced the women’s surgical decisions—and could potentially influence decisions on systemic treatment—counseling and genetic testing should be emphasized in all young women who are diagnosed with breast cancer, per the National Comprehensive Cancer Network guidelines.