Abstract P3-02-05: Subtypes of screen-detected invasive breast cancer and symptomatic invasive breast cancer and their impact on survival

Abstract

Abstract Background: Breast cancer is a worldwide problem which urgently requires solution, in many countries still being the most common cause of malignancy associated death. The screening program aims to detect early breast cancer to improve survival. We investigated the clinicopathrogical characteristic including intrinsic subtypes and outcome of patients with screen-detected invasive breast cancer (S-DIBC) compared with those with symptomatic invasive breast cancer (SIBC). Material and Methods: From January 2005 to December 2011 840 patients with invasive breast cancer who underwent surgery at our hospital were included. There were 195 S-DIBCs and 645 SIBCs. We retrospectively reviewed the clinical and pathologic data. Ki-67 LI was categorized as low (<14%) and high (> or = 15%). Tumors were classified into four groups based on the expression of ER, PgR, Ki-67 and HER2 as follows: luminal A (ER+ and/or PR+, and HER2− and Ki67 low), luminal B (ER+ and/or PR+, and HER2+ or Ki67 high), HER2 disease (ER−, PR−, HER2+), and triple negative (ER−, PR−, HER2−). Overall survival (OS) and relapse-free survival (RFS) curves were generated using the Kaplan- Meier method. Survival comparisons were made with the log-rank test, the level of significance was taken to be 0.05. SPSS 18.0 software package was used for statistical analysis. Results: S-DIBC was associated with smaller tumor size, less lymph node involvement, and earlier stage compared with SIBC (P < 0.001). Significantly more tumors were positive for hormone receptors in the S-DIBC group as compared to the SIBC group (ER+,83.5% vs.75.1%, p = 0.017; PgR+, 73.4% vs. 60.6%, P = 0.009), with a greater proportion of the luminal A subtype in the S-DIBC group (S-DIBC: Luminal A 59.0%, Luminal B 25.6%, HER2 disease 4.6%, triple negative 10.8%; SIBC group: Luminal A 46.5%, Luminal B 30.0%, HER2 disease 6.6%, triple negative 16.8%). Patients with S-DIBC had better prognosis [5-year OS: 100% (S-DIBC) vs. 95.5% (SIBC), p = 0.005, 5-year RFS: 98.5 vs. 92.1%, p = 0.004]. Tumors detected with screening generally had more favorable outcomes than symptomatic cancers regardless of subtypes [5-year OS: (S-DIBC) Luminal A 100%, Luminal B 100%, HER2 disease 100%, triple negative 100%; (SIBC) Luminal A 95.9%, Luminal B 93.3%, HER2 disease 95.5%, triple negative 84.1%)]. Conclusions: Our results suggest that subtype distribution of S-DIBC differs from that of SIBC. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-02-05.