Analysis of the tumor characteristics in young age breast cancer patients using collaborative stage data of the Korea Central Cancer Registry.

ABSTRACT

PURPOSE: This study aimed to evaluate tumor characteristics in young age (20-39 years old) breast cancer (YABC) patients in Korea. MATERIALS AND METHODS: We identified 10,897 breast cancer patients from 2010 to 2015. The data were collected through 10% systematic sampling of the Korea National Cancer Incidence Database (KNCI DB). Tumor size, lymph node status, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status were collected according to the Collaborative Stage version 2 (CSv2) Data Collection System. RESULTS: Of the 10,897 patients, 1245 (11.4%) were YABC patients. They were found to have larger tumors (T2 41.6% in 20-39 age group vs 36.4% in 40-49 age group vs 36.5% in 50-59 age group vs 38.4% in ≥ 60 age group; T3 10.1% vs 7.3% vs 6.5% vs 6.2%, P < .0001), greater rates of lymph node involvement (41.2% vs 32.7% vs 35.7% vs 32.5%, P < .0001), higher tumor grade (High grade 26.8% vs 19.4% vs 23.5% vs 22.1%, P < .0001), and a larger proportion of triple-negative subtype (18.2% vs 11.0% vs 12.2% vs 13.5%, P < .0001). Compared to the 40-49 age group, breast cancer-related survival (BCRS) rates were worse (91.74% vs 95.04%, P < .0001), and the characteristics of YABC patients were associated with higher risk of death from breast cancer. CONCLUSION: YABC patients have more aggressive tumor characteristics and worse survival rates. Therefore, we need to identify high-risk groups among YABC patients and support active surveillance in them. These findings from a national cohort provide important information for establishing a national cancer care strategy to manage YABC patients.