Abstract P5-18-05: Clinicopathological characteristics and prognosis of young patients with ductal carcinoma in situ
Authors: Seki A , Matsuda N , Kajiura Y , Kobayashi D , Hayashi N , Tsunoda H , Suzuki K , Yoshida A , Takei J , Yamauchi H 
Published: May 2019

Abstract
Background: The peak age at diagnosis of breast cancer differs between patients in Asian countries (40 - 50 years), and those in Western countries (60 - 70 years). With the increasing use of screening mammography, the incidence of ductal carcinoma in situ (DCIS) has increased significantly in younger Asian women. Nevertheless, our knowledge of the clinicopathological features and prognosis in young patients with DCIS is relatively limited. We aimed to compare the clinicopathological features of younger patients with that of older patients with DCIS and to evaluate their prognostic factors.Methods: A total of 1445 women were diagnosed with DCIS between the years 2005 and 2015. Patients with the past history of breast cancer and managed without surgery were excluded. The young age group included patients &lt;50 years of age, whereas the old age group included patients ≥50 years of age at diagnosis. We compared the clinicopathological characteristics [tumor size, surgery type, estrogen receptor (ER) and progesterone receptor (PgR) status, HER2 status, nuclear grade, margin status, radiotherapy, endocrine therapy, family history of breast cancer, and screening presentation or presentation with symptoms] and prognosis [disease-free survival (DFS), and overall survival (OS)] between the groups. DFS included the following events: contralateral breast cancer, loco-regional, and distant recurrences. DFS and OS were estimated using the Kaplan–Maier method. The risk factors associated with events were estimated using the log-rank test for univariate analysis. P values &lt; 0.05 were considered statistically significant.Result: Among the 1445 patients diagnosed with DCIS, 1281 were included in this study. The median age at diagnosis was 47 years (range, 22-87 years). The median follow-up time was 72 months (range, 1-162 months). ER and/or PgR status was positive in 1133 patients (88%). HER2 status was positive in 289 patients (23%). Premenopausal status was noted in 867 patients (68%). The median tumor size was 3.0 cm. Of 1281, 202 (18%) patients received endocrine therapy, 846 (66%) received breast conserving surgery, and 724 (86%) received radiation therapy. There were 765 patients (60%) in the young group. Significantly more patients in the young group had low nuclear grades, were ER and/or PgR positive, were HER2 receptor negative, underwent mastectomy, presented with symptoms, and had close/positive margins. Fifty-eight (4.5%) events occurred: 41 (3.2%) contralateral breast cancers, 19 (1.5%) loco-regional recurrences, and one (0.1%) distant metastasis. No death due to breast cancer was reported. On multivariate analysis, the young group (hazard ratio: 2.24, 95% CI: 1.01 - 4.95, P = 0.04), and presentation with clinical symptoms (hazard ratio: 2.09, 95% CI: 1.07-4.10, P = 0.03) significantly correlated with worse DFS. OS was not significantly different between the groups.Conclusion: This was the largest study with young patients with DCIS in the Asian population. We found that age at diagnosis was a significant independent factor associated with DFS. While genetic background also requires consideration, women with DCIS at &lt;50 year of age may require intensive surveillance. This result requires confirmation with longer follow-up.
Citation Format: Seki A, Matsuda N, Kajiura Y, Kobayashi D, Hayashi N, Tsunoda H, Suzuki K, Yoshida A, Takei J, Yamauchi H. Clinicopathological characteristics and prognosis of young patients with ductal carcinoma in situ [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-18-05.