ARRS 2022 Abstracts

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1619. Imaging and Pathologic Features of Genetic Breast Cancer
Authors * Denotes Presenting Author
  1. Brielle Paolini *; Medical University of South Carolina
  2. Ashley Haney; Medical University of South Carolina
  3. Heather Collins; Medical University of South Carolina
  4. Madelene Lewis; Medical University of South Carolina
Objective:
To describe the association between genetic mutations and imaging features, tumor subtype and tumor receptor status in breast cancer patients.

Materials and Methods:
An IRB-approved, HIPPA-compliant retrospective review was conducted of patients diagnosed with breast cancer between Jan 2010 to Mar 2020. Institutional database and electronic medical records were reviewed for mammography imaging, tumor histology, receptor status, and genetic testing result. Genetic test results were categorized in three groups: negative genetic test, variants of unknown significance (VUS) and positive genetic testing. The positive genetic testing group included Breast Cancer genes 1 and 2 (BRCA 1 & BRCA 2, respectively), Checkpoint kinase 2 (CHEK2), and Partner & Localizer of the BRCA 2 gene (PALBS2) mutations, other known mutations and numerous pathologic variants. Tumor subtype was divided into invasive lobular carcinoma (ILC), ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC), and other. Associations between genetic testing result with specific mammography findings (i.e. architectural distortion, mass, calcification, asymmetry or multiple findings), with cancer subtype, and receptor type (estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER 2)) were examined with chi-squared tests and Fisher’s Exact Test was used in cases with 5 or fewer patients in a group. Statistical significance was considered at the a = .05 threshold and two-sided p-values are reported.

Results:
During the study period,1793 patients were diagnosed with breast cancer and 513 (28.6%) underwent genetic testing. Of the 513 patients, 341 (66.5%) had negative results, 107 (20.9%) had a VUS and 65 patients (12.5%) had a positive genetic result. No significant difference was found between patients with genetic testing result and specific mammography finding, p = 0.48. Additionally, no significant difference was found between genetic testing result and tumor subtype/histology, p = 0.89. Patients with a positive genetic mutation were significantly more likely to be ER receptor positive, PR negative, and similar likely to be HER 2-positive compared to patients with negative genetic testing (p = 0.002, p = 0.006, p= 1.00, respectively) or to patients with a VUS (p= 0.002, p = 0.008, p = 1.00, respectively).

Conclusion:
In this study, patients with positive genetic testing are more likely to have positive ER and negative PR tumor receptor status. Prior studies have shown an inverse correlation between PR load and histologic tumor grade. Thus, our findings underscore the importance of genetic counseling & testing to help identify individuals at higher risk for breast cancer and potentially more aggressive tumors. Notably, our data did not show a significant difference between genetic testing result and specific mammographic finding or tumor subtype. Future work should confirm these findings with larger samples. Nevertheless, radiologists should maintain a high-level of suspicion for all mammographic abnormalities when interpreting examinations of patients with positive genetic testing.