Challenges of treating incidental synchronous bilateral breast cancer with differing tumour biology

Abstract

A 59-year-old woman with right breast mass was diagnosed with invasive ductal carcinoma (IDC). Workup consisted of bilateral diagnostic mammogram and ultrasound (US); both showed a right breast mass with normal left breast. Core biopsy showed IDC with estrogen receptor negative (ER-)/progesterone receptor negative (PR-) and HER2/neu positive receptor status. The patient underwent carboplatin-based chemotherapy with Herceptin. The mass completely resolved. The patient desired to proceed with bilateral total mastectomy with right sentinel lymph node biopsy (SLNB). Pathology showed complete resolution of the right-sided breast mass without malignancy in right SLN. Incidentally, IDC was found in the left breast specimen, which was ER+/PR+ and HER 2/neu negative. Tumour board consensus was to obtain a left axilla US with MRI in 6 months if the US was unremarkable. Biologically different synchronous bilateral breast cancer poses a difficult clinical challenge for management due to differing responses to treatment. Use of MRI may be a diagnostic option in women who choose contralateral prophylactic mastectomy.

Molecular Subtype Discordance in a Young Woman with Synchronous Bilateral Breast Cancer: A Case Report

“…The initial search registered a total of 95 records, of which 20 were excluded for duplication, 28 for not corresponding to molecular subtype discordance, 20 for lacking case presentations, 8 for not corresponding to breast cancer, and 6 for corresponding to basic science topics. Only four previously published reports of SBBC with molecular subtype discordance were found ( Table 1), illustrating the limited literature available for this entity [4,9,[11][12]. The age at diagnosis in these reports was between 48 and 60 years, making our patient the youngest reported case to date.…”

“…The age at diagnosis in these reports was between 48 and 60 years, making our patient the youngest reported case to date. Discordance in hormone receptor status occurred in all cases, while discordance in HER2+ status occurred in only two cases [4,12]. All cases received neoadjuvant chemotherapy, which was followed by bilateral modified radical mastectomy (MRM) in three patients [4,[11][12].…”

“…Discordance in hormone receptor status occurred in all cases, while discordance in HER2+ status occurred in only two cases [4,12]. All cases received neoadjuvant chemotherapy, which was followed by bilateral modified radical mastectomy (MRM) in three patients [4,[11][12]. Regarding adjuvant therapy, two cases were initiated on hormone therapy for five years [4,11].…”

“…The latter can occur in histological type, grade of differentiation, molecular subtype, and/or clinical staging. Particularly, the presence of two synchronous tumors with differing molecular subtypes introduces notable complexity to the selection of a treatment strategy, as it impacts the expected therapeutic response, risk of recurrence, and prognosis [3][4]. The management of these cases becomes more complex when discordance occurs in hormone receptor status, which is estimated to affect 5% of SBBC cases [5].…”

Synchronous Bilateral Breast Cancer (SBBC): Report of a Case with Review of Literature

“…Esclovon et al [10] reported a 59 years old woman with ER and PR negativity and HER2 /neu positivity on the right breast mass and the opposite results on the incidentally found left breast invasive ductal carcinoma. This different biological behavior mandates different treatment modalities for each side.…”