Inflammatory Breast Cancer May Be At High Risk of Germline Mutation
Study suggests that patients with inflammatory breast cancer may be at high risk of germline mutation
The observation that inflammatory breast cancer (IBC) is more prevalent in African Americans, as well as Arab Americans, suggests the involvement of at least some genetic component. An earlier study from Dana Farber showed that 18.1% of patients with IBC referred for testing, tested positive for a germline mutation in BRCA1 or 2. They noted that this was a rate consistent with that seen in breast cancer patients with a strong family history.
The current study is also from the Dana-Farber Cancer Institute and their Inflammatory Breast Cancer Registry. There were 2 cohorts. The first was the clinical cohort from Dana-Farber of which there were 301 patients. The other cohort was taken from the database of Ambry Genetics which had genetic testing with a clinical diagnosis of IBC noted on the intake form.` There were 501 female subjects who were predominately white (70.1%). The median age was 50 years. In the entire cohort, 33.5% were Her2+, whereas 23.8% were triple negative.
Among the clinical cohort from Dana-Farber, 168 women had documented genetic testing. As expected those undergoing testing were 8.6 years younger than those not tested. In those women with triple negative cancer, 23.9% were found to have deleterious mutations. Of those with hormone receptor-positive cancer, 13.1% had a mutation whereas 9.3% of Her2 positive patients had a mutation
When one looks specifically at the age of diagnosis, the prevalence of a mutation was highest in the younger age group. The rate of mutation in women less than 40 (13) with triple negative cancer was 61.5%. Those subjects with ER-, PR+, Her2- disease and those with Her2+ disease had mutations discovered in 28.6% and 11.4% respectively.
In general, it appears on the surface that IBC is associated with a higher rate of germline mutations than seen in non-inflammatory cancers. Absolute conclusions are difficult since many studies include BRCA testing only and do not include the entire panel of breast cancer predisposition genes. One may only conclude that women with IBC may be at a higher risk of carrying a germline mutation compared to those without IBC.