A study of clinical and molecular characteristics in bilateral primary breast cancer

Abstract

BackgroundBilateral primary breast cancer (BPBC) is a rare type of breast cancer. Studies on the clinicopathologic and molecular characteristics of BPBC in a metastatic context are very limited.MethodsA total of 574 unselected metastatic breast cancer patients with clinical information were enrolled in our next‐generation sequencing (NGS) database. Patients with BPBC from our NGS database were regarded as the study cohort. In addition, 1467 patients with BPBC and 2874 patients with unilateral breast cancer (UBC) from the Surveillance, Epidemiology, and End Results (SEER) public database were also analyzed to determine the characteristics of BPBC.ResultsAmong the 574 patients enrolled in our NGS database, 20 (3.5%) patients had bilateral disease, comprising 15 (75%) patients with synchronous bilateral disease and 5 (25%) patients with metachronous bilateral disease. Eight patients had bilateral hormone receptor‐positive (HR+)/human epidermal growth factor receptor‐negative (HER2−) tumors, and three had unilateral HR+/HER2− tumors. More HR+/HER2− tumors and lobular components were found in BPBC patients than in UBC patients. The molecular subtype of the metastatic lesions in three patients was inconsistent with either side of the primary lesions, which suggested the importance of rebiopsy. Strong correlations in clinicopathologic features between the left and right tumors in BPBC were exhibited in the SEER database. In our NGS database, only one BPBC patient was found with a pathogenic germline mutation in BRCA2. The top mutated somatic genes in BPBC patients were similar to those in UBC patients, including TP53 (58.8% in BPBC and 60.6% in UBC) and PI3KCA (47.1% in BPBC and 35.9% in UBC).ConclusionsOur study suggested that BPBC may tend to be lobular carcinoma and have the HR+/HER2− subtype. Although our study did not find specific germline and somatic mutations in BPBC, more research is needed for verification.

Untypical bilateral breast cancer with peritoneal fibrosis on 18F-FDG PET/CT: case report and literature review

“…Family members can understand their genetic risks through genetic counseling and undergo appropriate screening and management based on the recommendations of healthcare professionals. Moreover, studies have found that the infiltrating ductal type is the most common histology in BBC ( 22–24 ). Some studies indicate that the survival rates of patients with unilateral and BBC are comparable ( 25 , 26 ).…”

Nomograms to Predict Individual Potential Benefit from Targeted Therapy for patients with lymph node positive Luminal B (HER2-) breast cancer

“…10 Patients with HR + BC have a higher proportion of contralateral BC than HR-or HER2+, whether synchronous bilateral breast cancer (BBC) or metachronous BBC. 11,12 Currently, patient with BBC whom is considered to have a poorer prognosis and is frighted to physicians and patients, moreover, the number of metachronous BBC is increasing with the prolongation of overall survival of patients with BC, 13 especially in patients with N + Luminal B (HER2-) BC.…”

Mutation of SIVA, a candidate metastasis gene identified from clonally related bilateral breast cancers, promotes breast cancer cell spread in vitro and in vivo

“…Bilateral breast cancers, an uncommon form and accounting for 3–5% of all breast cancers cases, happens when women develop breast cancers in both breasts, with the second primary cancer in the contralateral breast being either synchronous or metachronous [ 3 – 7 ]. Synchronous bilateral breast cancers are diagnosed 6–12 months apart and represent about 1% of breast cancers [ 8 – 10 ]. Clinically, patients with synchronous bilateral breast cancers behaved similarly to those with unilateral breast cancers [ 11 , 12 ].…”