Distribution of tumor subtypes in bilateral breast cancer: Comparison between synchronous and metachronous cancer. Issue 1 (15th October 2020)

• Record Type: Journal Article
• Authors: Kim, Haeyoung; Lee, Hyebin; Choi, Doo Ho; Park, Won; Cho, Won Kyung; Nam, Seok Jin; Lee, Jeong Eon; Kim, Seok Won; Lee, Sei Kyung; Cho, Eun Yoon; Cho, Soo Youn
• Is Part Of: Asia-Pacific journal of clinical oncology. Volume 18:Issue 1(2022)
• Page Start: 28
• Page End: 34
• Publication Date: 2020-10-15
• Subjects: breast neoplasm -- epidemiology -- metachronous second primary neoplasm -- neoplasms, multiple primary -- triple‐negative breast neoplasm; Oncology -- Pacific Area -- Periodicals; Cancer -- Treatment -- Pacific Area -- Periodicals; Cancer -- Pacific Area -- Periodicals; Cancer -- Treatment -- Periodicals; 616.9940095
• DOI: 10.1111/ajco.13444
• Languages: English
• ISSNs: 1743-7555

Abstract

Abstract: Aim: This study was performed to evaluate patterns of breast cancer subtypes in Korean patients with synchronous (SBC) or metachronous bilateral breast cancer (MBC). Methods: We retrospectively reviewed records of 302 patients with SBC ( n = 161) or MBC ( n = 141) who received curative surgery at our hospital between 1995 and 2013. Expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) was determined by immunohistochemistry (IHC) staining. We categorized breast cancers into the following subtypes: ER+ or PR+, HER2− (i.e., luminalA); ER+ or PR+, HER2+ (i.e., luminalB HER2+); ER−, PR− and HER2+ (i.e., HER2‐enriched); ER−, PR− and HER2− (i.e., triple negative, TN). Results: More patients with MBC were ≤40 years at the time of breast cancer diagnosis than patients with SBC (34.6% vs. 19.3%, P < 0.01). The proportion of subtypes in SBC and MBC were as follows: luminalA, 65.8% vs. 45.0%; luminalB, HER2+, 9.0% vs. 8.5%; HER2‐enriched, 4.1% vs. 12.1%; and TN, 11.2% vs. 31.2%, respectively ( P < 0.01). The 10‐year overall survival rate in patients with SBC and MBC was 89.0% and 93.6%, respectively. The 10‐year disease‐free survival rate in patients with SBC and MBC was 79.6% and 80.9%, respectively. Locoregional recurrence was found in 2.5% of patients with SBC and 9.9% of patients with MBC. Distant metastasis occurred in 8.7% of patients with SBC and 4.9% of patients with MBC. Conclusion: The distribution of breast cancer subtypes was different between SBC and MBC. TN‐subtype was profoundly more frequent in MBC whereas luminal‐subtype was most frequently found among SBC. Abstract : The pattern in distribution of breast cancer subtypes was different between SBC and MBC. Patients with MBC were more likely to be young, have a family history of cancer and have TN subtype than SBC.