Is there a specific magnetic resonance phenotype characteristic of hereditary breast cancer?

AIMS AND BACKGROUND: The aim of the study was to investigate the growth rate of inherited breast cancer, to analyze its T2 signal intensity besides kinetic and morphologic aspects, and to verify whether there is any correlation between magnetic resonance imaging phenotype and BRCA status. METHODS: Between June 2000 and September 2009, we enrolled 227 women at high genetic risk for breast cancer in a surveillance program, within a multicenter project of the Istituto Superiore di Sanità (Rome). RESULTS: Thirty-four cancers were detected among 31 subjects. One patient refused magnetic resonance imaging because of claustrophobia. Compared with sporadic disease, hereditary cancer showed some differences, in terms of biologic attitude and semeiotic patterns. These differences were mainly registered for magnetic resonance imaging, where the most frequent radiological variant was represented by the very high T2 signal intensity (73%). Moreover, the size of 8 of the neoplasms showed a significant increase in less than one year, 5 of them in less than 6 months. Six lesions were in BRCA1 patients and the remaining in BRCA2. Furthermore, cancers with a high growth rate also demonstrated a significant increment in T2 signal intensity. CONCLUSIONS: Our results confirmed the high growth rate within BRCA-related breast cancers, especially for BRCA1 mutation carriers. In our experience, we found a specific imaging phenotype, represented by the high T2 signal intensity of hereditary breast cancer. To our knowledge, this is the first report that points out this new semeiotic parameter, which is usually typical of benign lesions. Considering the correlation between high growth rate and high T2 signal intensity, the former seems to be related to the absence of induction of a desmoplastic reaction that could somehow restrict cancer growth.

MRI in the early detection of breast cancer in women with high genetic risk.

AIMS AND BACKGROUND: Women with BRCA1 or BRCA2 germline mutations have an elevated risk of developing breast and/or ovarian cancer. Because of the early onset of the disease, screening of this group of women should start at an earlier age than in the general population. The association of breast magnetic resonance imaging (BMRI) and ultrasonography (US) with mammography (MX) and clinical breast examination (CBE) in the regular surveillance of these individuals has been proposed and seems to improve the early detection of breast cancer. METHODS: Within a multicenter study started by the Istituto Superiore di Sanità (Rome), at the Istituto Nazionale Tumori of Milan (INT) we enrolled 116 women at high genetic risk for breast cancer; they were either BRCA1 or BRCA2 mutation carriers or had a strong family history of breast cancer. They underwent CBE, MX, US and BMRI once a year. RESULTS: Between June 2000 and April 2005, at INT 12 cancers were detected among the 116 screened individuals (10%). In this subgroup, 1 patient refused BMRI and in 2 cases US was not performed. With BMRI we found 11 cancers and 6 of them were detectable only by this technique. In these 6 cases, the size of the disease was less than 1 cm and MX was false negative due to irregularly nodular parenchyma in 4 cases and scar tissue or prosthesis in the other 2. US was not performed in 2 cases and was false negative in 4 cases. Three false positive results were found with BMRI: 1 case was considered suspect but related to hormonal influences; 1 case with the same pattern was sent for second-look US, which gave a negative result and BMRI review after 6 months showed normalization of the parenchyma; in the third case histology revealed the presence of adenosis. No false positive results were registered for MX. CONCLUSIONS: The aim of secondary prevention is the detection of cancer at its earliest stage. BMRI screening in women with BRCA1 or BRCA2 mutations or at high familiar risk appears to be highly sensitive and may detect mammographically occult disease. The accuracy of MR imaging is higher than that of conventional imaging but the technique is flawed by a lower specificity. In order to avoid unnecessary biopsies we believe that the combination of BMRI and conventional imaging can be very useful in screening women with a high genetic risk of breast cancer, especially with second-look evaluation by means of US when BMRI yields the only positive diagnostic result. Second-look US has been demonstrated to be of critical importance both in recognizing false positive BMRI results and in guiding biopsies, when necessary.