Long-term Survival of Screen-Detected Synchronous and Metachronous Bilateral Non-Palpable Breast Cancer among Chinese women: A Hospital-Based Study (2003-2017)

Abstract

Purpose: Screen-detected unilateral non-palpable breast cancer (NPBC) shows favorable prognosis whereas bilateral breast cancer (BBC), especially synchronous BBC (SBBC) manifests worse survival than unilateral breast cancer (BC). It remains unclear whether screen-detected bilateral NPBC has compromised survival and requires intensified treatment or favorable prognosis and needs de-escalating therapy.Methods: From 2003 to 2017, data from 1,075 consecutive patients with screen-detected 1,107 NPBCs were retrospectively reviewed. There were 988 patients with unilateral NPBC (UniNPBC), and 87 patients with bilateral BC [(N+AnyContra) PBC], including 32 patients with bilateral NPBC (BiNPBC) and 55 patients with ipsilateral NPBC + contralateral palpable cancer [(N+Contra) PBC]. Follow-up time was 48-227 (median 91) months. Clinicopathological characteristics, relapse-free survival (RFS) and overall survival (OS) were compared between UniNPBC and BBC and among synchronous or metachronous BBC subgroups. RFS and OS factors of BBC were identified.Results: Compared to UniNPBC, patients with screen-detected bilateral BC had more invasive, ER negative, PR negative, triple-negative BC as well as less breast conserving surgery, radiotherapy and endocrine therapy. In terms of 10-year RFS and OS rates, BiNPBC, synchronous (SynBiNPBC) and metachronous BiNPBC (MetaBiNPBC) showed similar good prognosis as UniNPBC. However, survival of (N+AnyContra) PBC, (N+Contra) PBC and synchronous (N+Contra) PBC were significantly compromised. RFS factors of BBC included pN3 (p=0.048), lymphovascular invasion (p=0.008) and existence of contralateral palpable interval BC (p=0.008) while the OS relevant factor was pN3 (p=0.018).Conclusion: Screen-detected bilateral NPBC including SynBiNPBC and MetaBiNPBC showed good prognosis as UniNPBC so that the therapy of BiNPBC could be de-escalated and optimized according to UniNPBC. Contrarily, screen-detected ipsilateral NPBC with contralateral palpable BC [(N+Contra) PBC] manifested unfavorable survival worse than UniNPBC (p<0.001) and synchronous (N+Contra) PBC had the worst survival among all subgroups (p<0.001), implying that these were actually bilateral interval BC and required intensified treatment.