The Incidence of Occult Malignancy in Contralateral Risk Reducing Mastectomy Among Affected Breast Cancer Gene Mutation Carriers in South Korea

• Published in: Journal of breast cancer Vol. 28; no. 1; pp. 1 - 10
• Main Authors: Lee, Cho Eun, Shin, Dong Seung, Kim, Ki Jo, Nam, Seok Jin, Kim, Seok Won, Yu, Jonghan, Chae, Byung Joo, Lee, Se Kyung, Ryu, Jai Min, Mun, Goo-Hyun, Pyon, Jai-Kyong, Jeon, Byung-Joon, Woo, Kyongje, Lee, Jeong Eon
• Format: Journal Article
• Language: English
• Published: Korea (South) Korean Breast Cancer Society 01.02.2025; 한국유방암학회
• Subjects: Original; 일반외과학; Genes, BRCA2; Genes, BRCA1; Breast Neoplasms; Prophylactic Mastectomy
• ISSN: 1738-6756; 2092-9900
• DOI: 10.4048/jbc.2024.0219

Breast cancer gene ( ) mutation is a well-known risk factor for breast cancer, and clinical interest in prophylactic mastectomy has increased in recent years. We investigated patients who were mutation carriers and underwent contralateral risk-reducing mastectomy (RRM), focusing on the incidence of occult malignancy after contralateral RRM. Prospectively collected data of patients with breast cancer treated at a single institution were retrospectively reviewed. Patients who underwent RRM with mutation who underwent RRM between January 2010 and November 2023 were included in this study. Among patients who underwent contralateral RRM, those with a primary cancer diagnosis were included, and those with occult malignancy on the contralateral RRM side were reviewed additionally. The demographics and pathologies of both primary breast cancer and occult malignancies were evaluated. In our institution, 925 patients were identified as mutation carriers, and 320 patients underwent contralateral RRM along with primary breast cancer surgery. mutation occurred more frequently (54.8%) in the overall mutation cohort. Furthermore, we reviewed 320 patients diagnosed with breast cancer and detected as mutation carriers who underwent contralateral RRM; high proportion of them were mutation carriers. Interestingly, we found a low incidence of only seven patients (2.2%) with occult malignancy on contralateral RRM side, which is different from that reported in other nations. The incidence of occult malignancy in the contralateral breast of breast cancer patients with breast cancer with mutation is significantly low, and may be influenced by several factors. Increased utilization of screening and advancements in diagnostic technologies in South Korea have reduced the chance of occult malignancy in RRM, and a variety of pathologic examination methods may affect the rate of incidence.