Assessment of outcomes and novel immune biomarkers in metaplastic breast cancer: a single institution retrospective study

Abstract

Background: Metaplastic breast cancer remains poorly characterized given its rarity and heterogeneity. The majority of metaplastic breast cancers demonstrate a phenotype of triple-negative breast cancer; however, differences in clinical outcomes between metaplastic breast cancer and triple-negative breast cancer in the era of third-generation chemotherapy remain unclear. Methods: We compared the clinical outcomes between women with metaplastic breast cancer and women with triple-negative breast cancer diagnosed between 1994 and 2014. Metaplastic breast cancer patients were matched 1:3 to triple-negative breast cancer patients by stage and age at diagnosis. Distant disease-free survival (DDFS) and overall survival (OS) were estimated using Kaplan Meier methods and Cox proportional hazard regression models. Immune checkpoint markers were characterized by immunohistochemistry in a subset of samples.Results: Forty-four metaplastic breast cancer patients (stage I 14%; stage II 73%; stage III 11%; stage IV 2%) with an average age of 55.4 (± 13.9) years at diagnosis. Median follow-up for the included metaplastic breast cancer and triple-negative breast cancer patients (n = 174) was 2.8 (0.1-19.0) years. The DDFS and OS between matched metaplastic breast cancer and triple-negative breast cancer patients were similar, even when adjusting for clinical covariates (DDFS: HR = 1.64, p = 0.22; OS: HR = 1.64, p = 0.26). Metaplastic breast cancer samples (n = 27) demonstrated greater amount of CD163 in the stroma (p = 0.05) and PD-L1 in the tumor (p = 0.01) than triplenegative breast cancer samples (n = 119), although more triple-negative breast cancer samples were positive for CD8 in the tumor than metaplastic breast cancer samples (p = 0.02). Conclusions:Patients with metaplastic breast cancer had similar outcomes to those with triple-negative breast cancer based on DDFS and OS. The immune checkpoint marker profile of metaplastic breast cancers in this study may prove useful in future studies attempting to demonstrate an association between immune profile and survival.

Metaplastic breast cancer: Prognostic and therapeutic considerations

“…Also, Morgan et al 12 from the Ohio State University, investigated 44 MBCs, with similar outcomes to those with TNBC (174 cases) based on DFS and OS.…”

“…5 The majority of authors agree that MBCs have poorer prognosis as compared to the "classic" TNBC, 2,3,5-9 although this has not been reported universally. [10][11][12] The purpose of this investigation was to retrospectively evaluate a new population of MBC patients, and to compare its clinical evolution, treatments, OS, and prognosis compared with a matched population of TN breast cancer (TNBC) patients.…”

“…The majority of authors agree that MBCs have poorer prognosis as compared to the “classic” TNBC, 2,3,5‐9 although this has not been reported universally 10‐12 …”

Breast prosthetic implant-associated Squamous Cell Carcinoma: A case report and Literature Review

“…Primary SCC of the breast is a rare tumour, accounting for an estimated frequency of 0.1-3.6% of all invasive breast cancers with poor clinical outcomes [9][10][11]. Skin or nipple cancer and metastasis sites should be excluded when SCC is diagnosed [12].…”

An Update on the Molecular Pathology of Metaplastic Breast Cancer

“…or cyto. staining in ≥1% tumor cells; ≥5% staining in peri-tumoral regions 38% tumor cell; 48% tumor immune microenvironment Morgan et al 62 2020 146 TNBC (27 MpBC) SP263 Memb. staining in ≥1% of tumor cells; immune cells MpBC 30% tum, 73% immune; TNBC 10% tum, 59% immune Afkhani et al 49 2019 14 MpBC SP263 >1+ intensity in >1% immune cells 50% immune cells Lien et al 63 2020 82 MpBC SP142 % tumor cells; immune cells as % of tumor area 17% tum; 48% immune cell Kalaw et al 64 2020 125 MpBC E1L3N ≥5% tumor/immune cells displaying cyto.…”