Abstract P3-05-30: Survival after Development of Contralateral Breast Cancer

Abstract

Abstract Purpose There are many studies reporting survival after development of contralateral breast cancer(CBC) but with inconsistent results. Also, many studies were based on European or North American population and few on Asian population. However, Korean breast cancer patients have different characteristics such as age distribution. Therefore, purpose of this study is to investigate whether development of CBC has influence on survival in Korean breast cancer population. Methods In this retrospective study, we included patients who were diagnosed with a first primary unilateral non-metastatic breast cancer at Asan Medical Center, Korea, between 1999-2013 followed through 2018. In this population, patients who delveloped CBC during the follow-up period were divided into the CBC cohort, and who did not into the non-CBC cohort. Survival of CBC cohort and non-CBC cohort was compared in the whole study population and in subgroup analysis by interval of CBC development, and breast cancer subtype. Results Over median follow-up of 107 months, 418 patients developed CBC out of 16,251 patients. Development of CBC did not influence overall survival or breast cancer-specific survival. In subgroup analysis by interval of CBC development, patients who developed CBC within one year after diagnosis of the first breast cancer had higher risk for overall death in CBC cohort (hazard ratio 2.58; 95% CI 1.28-5.18), and patients who developed CBC after one year showed no significant difference in survival compared with non-CBC cohort. In subgroup analysis by the subtype, patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative subtype for the first breast cancer showed higher risk for overall death in CBC cohort (hazard ratio 1.88; 95% CI 1.14-3.10) whereas patients with triple negative subtype for the first breast cancer showed lower risk for overall survival in CBC cohort (hazard ratio 0.42; 95% CI 0.19-0.95). Conclusion Development of CBC in Korean breast cancer patients did not have significant impact on survival. However, development of CBC early after diagnosis of first breast or having certain subtype of breast cancer may have affect on survival. Such information can be important information when counseling patients who are considering contralateral prophylactic mastectomy. Citation Format: Hakyoung Kim, Hee Jeong Kim, Yoon Tae In, Seonok Kim, Sae Byul Lee, Jisun Kim, Il-Yong Chung, Beom Seok Ko, Jong Won Lee, Byung Ho Son, Sei Hyun Ahn. Survival after Development of Contralateral Breast Cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-30.