Purpose: In recent studies, it has been shown that BRCA mutation carriers are prone to earlier onset of DCIS and invasive breast cancer, with a higher prevalence of DCIS in BRCA carriers than non carriers. Most of BRCA-associated tumors have DCIS present, favouring the existence of a premalignant pathway. However, DCIS in those studies was diagnosed with mammography (calcifications).
In the last decade MRI screening has become an important tool for screening and early detection in BRCA mutation carriers. MRI can detect DCIS usually as non-mass enhancement, even if non-calcified on mammography.
The aim of our study was to analyze BRCA patients with DCIS on MRI biopsy and the MRI presentation.
Material and Methods: Retrospective study of BRCA patients with pure DCIS diagnosed with MRI biopsy between 2015 until 2019 at the Sheba Medical Center. Clinical and imaging information were collected. All MRI and mammography studies were analyzed by a fellowship trained radiologist. Patients with calcifications on a second look mammography were excluded.
Results: A total of 950 BRCA carriers underwent surveillance MRI. Of those, 22 had a diagnosis of DCIS on MRI biopsy. 14 (64%) patients were BRCA1 gene mutation carriers, while 8 (36%) were BRCA2 gene mutation carriers. Median age of BRCA1 patients was 40 (+/-20) years old, which was statistically significant lower than of BRCA2 patients, which was 66 (+/-8) years old (p<.05). The most common MRI presentation was non mass enhancement. BRCA1 patients were more commonly hormone receptors negative (9 patients-64%) and had high grade DCIS (all patients), while BRCA2 patients were more commonly hormone receptors positive (5 patients-63%) and had more commonly intermediate grade DCIS (5 patients-63%).
Conclusion: MRI detected non calcified DCIS is more common in BRCA1 gene mutation carriers, and present earlier than in BRCA2 patients, usually as a high grade disease. This finding is opposite to calcified DCIS detected on mammography, which is more common in BRCA2 carriers.
