Age-Related Incidence and Peak Occurrence of Contralateral Breast Cancer

• DOI: 10.1001/jamanetworkopen.2023.47511
• Publication Date: 2023-12-15T16:30:54Z
• Authors: Hakyoung Kim; Tae In Yoon; Seonok Kim; Sae Byul Lee; Jisun Kim; Il Yong Chung; Beom Seok Ko; Jong Won Lee; Byung Ho Son; Young Jin Lee; Sungchan Gwark; Hee Jeong Kim
• Keywords: Cumulative incidence

Importance Young patients with breast cancer have higher risk for developing contralateral (CBC) and epidemiologic characteristics different from those of older patients. Objective To examine the incidence peak occurrence CBC according to age at primary (PBC) surgery. Design, Setting, Participants This cohort study included who were diagnosed underwent surgery unilateral nonmetastatic Asan Medical Center, Korea, between January 1, 1999, December 31, 2013, follow-up through 2018. Data analyzed 2021, April 30, 2023. Patients divided into 2 groups their PBC: younger (≤35 years) vs (>35 years). Main Outcomes Measures The main outcomes cumulative hazard rate in entire population subgroups by subtype, categorized hormone receptor (HR) ERBB2 status. Results A total 16 251 female stage 0 III analyzed; all Korean. mean (SD) was 48.61 (10.06) years; 1318 (8.11%) group, 14 933 (91.89%) group. Median 107 months (IQR, 79-145 months). Compared group had significantly (10-year incidence, 7.1% 2.9%; P < .001) (hazard ratio, 2.10; 95% CI, 1.62-2.74) CBC. rate, which indicates a certain time frame, differed subtype cancer. In HR+/ – increased continuously both groups. triple negative until approximately 10 years then decreased Meanwhile, HR−/ + peaked earlier, especially (1.7 since first 4.8 group). Conclusions Relevance this study, aged 35 or than Moreover, young tended shorter interval These findings might be useful guiding treatment decisions, such as prophylactic mastectomy.