Tumor biology, clinicopathological characteristics and prognosis of screen detected T1 invasive non-palpable breast cancer in asymptomatic Chinese women (2001-2014).

Abstract

BackgroundMammography screening usually detects low-risk breast cancer in the western world. However, little is known about the ultrasound and mammography screen-detected T1 invasive non-palpable breast cancer (NPBC) in asymptomatic Chinese women.ResultsWith the increase of tumor size (T1a, b, c), lymph node positivity (8.7%, 18.3%, 26.0%, p = 0.018), pN (p = 0.028) and TNM stage (p = 0.035) increased accordingly. Tumor size (T1a, b, c) was correlated with high Ki-67 index (defined as ≥ 14%, 37.9%, 45.8%, 56.2%, p = 0.017), chemotherapy (20.4%, 35.2%, 57.3%, p < 0.001) and targeted therapy (2.9%, 9.9%, 15.1%, p = 0.008). T1a disease had higher chance of being luminal A and accompanied with ductal carcinoma in situ (DCIS), while T1c tumor being triple-negative and without DCIS. The 5-year disease free survival (DFS) of T1a, b, c NPBC were 99.0%, 96.9% and 92.9%, whereas the 5-year overall survival (OS) were 100.0%, 100.0% and 97.9% respectively. There was no significant difference in 5-year DFS or OS among the T1 NPBC subgroups or subtypes/immunophenotypes.Patients and methodsFrom 2001 to 2014, 4,574 screening positive women received biopsies in Peking Union Medical College (PUMC) Hospital, and 729 NPBC including 437 T1 unilateral invasive NPBC were diagnosed. With a median follow-up time of 32 months (6–163 months), the clinicopathological characteristics, treatment choice, 5-year DFS and OS were compared between T1a, T1b and T1c NPBC. The DFS and OS prognostic factors were identified.ConclusionScreen-detected T1 invasive NPBC could be regarded as low-risk cancer in Chinese women. TNM stage and LN metastasis instead of molecular subtype was identified as the DFS prognostic factors while radiotherapy as the OS predictor.