Abstract P5-02-05: Biology and long-term prognosis of screening detected non-palpable breast cancer by ultrasound in hospital-based Chinese population (2001-2014)

Abstract

Abstract Background: Milestone studies showed that ultrasound (US) was an effective primary screening test for breast cancer both in the western world and in China [PMID: 26712110, 26715161, and 25668012]. Ultrasound has been officially designated to be the initial imaging test for breast cancer screening in Beijing and several other cities in China, due to its improved sensitivity in Chinese women who usually have denser breasts and develop breast cancer earlier than Caucasian counterparts. Study showed that it would take 40 years to screen each woman in the target age group once [PMID: 26808342].The mainstay modality of breast cancer screening in China is the hospital-based opportunistic screening among asymptomatic self-referred women. However, there is little data about the tumor biology and long-term survival of the US-detected non-palpable breast cancer (NPBC) in hospital-based Chinese population. Methods: From January 2001 to December 2014, 3,786 asymptomatic women with positive (BI-RADS 4 and 5) initial screening US underwent biopsies in Peking Union Medical College Hospital, and 572 NPBC in 556 women were diagnosed. Women without dense breasts (defined as BI-RADS category C and D) also received screening mammography (MG) after physical examination and ultrasound. 788 patients with positive (BI-RADS 4 and 5) mammogram (MG) and normal US (BI-RADS 1, 2 and 3) underwent MG-guided biopsies and another 127 NPBC were diagnosed in 126 women. The clinicopathological features, treatment choice, 10-year disease-free survival (DFS) and overall survival (OS) were reviewed and compared between the US-detected and MG-detected NPBC. Prognostic factors of NPBC were identified. Results: Overall, US could detect more invasive NPBC (83.4% vs 54.3%, p<0.001), lymph node positive cancer (19.1% vs 10.2%, p<0.001)and multifocal cancer (19.2% vs 6.3%, p<0.001). In invasive NPBC, US detected more low grade cancer (21.4% vs 10.2%, p=0.001), multifocal cancer (20.7% vs 2.9%, p<0.001), Her2 negative cancer (77.6% vs 62.3%, p=0.001) and larger tumor (pT1c+pT2, 53.3% vs 37.6%, p<0.001). There was no significant difference in immunophenotype/subtype, treatment methods, DFS or OS between US- and MG-NPBC among ductal carcinoma in situ (DCIS), invasive and all NPBC. For all NPBC and the US-NPBC, the common DFS-factors included pT, pN and p53 whereas OS-predictors were pN and immunophenotype/subtype. Table 1. Kaplan-Meier estimates of DFS and OS between US-NPBC and MG-NPBC§.Patients (No.)10-year DFS (%)P value10-year OS (%)P valueAllUS-NPBC (572)90.60.73896.10.142 MG-NPBC (127)92.7 100.0 DCISUS-NPBC (94)100.00.060100.0- MG-NPBC (58)93.8 100.0 InvasiveUS-NPBC (478)88.60.68095.20.239 MG-NPBC (69)92.0 100.0 § Kaplan-Meier survival curves between each two subgroups would be displayed in the poster. Conclusion: Compared to MG, US detected more invasive NPBC with positive lymph node in hospital-based asymptomatic self-referred Chinese women, who could achieve comparable 10-year DFS and OS as MG-detected NPBC. US could serve as the feasible initial imaging modality in hospital-based opportunistic screening Chinese women. Citation Format: Yao R, Pan B, Zhu Q, Xu Q, Zhou Y, Zhang J, Mao F, You S, Lin Y, Shi J, Guan J, Wang X, Zhang Y, Zhang X, Shen S, Zhong Y, Xu Y, Liang Z, Jiang Y, Sun Q. Biology and long-term prognosis of screening detected non-palpable breast cancer by ultrasound in hospital-based Chinese population (2001-2014) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-02-05.