Abstract
BackgroundTriple Negative breast cancer (TNBC) includes a heterogeneous group of tumors with different clinico-pathological features, molecular alterations and treatment responsivity. Our aim was to evaluate the clinico-pathological heterogeneity and prognostic significance of TNBC histologic variants, comparing “special types” to high-grade invasive breast carcinomas of no special type (IBC-NST).MethodsThis study was performed on data obtained from TNBC Database, including pathological features and clinical records of 1009 TNBCs patients diagnosed between 1994 and 2015 in the four most important Oncology Units located in different hospitals in Sardinia, Italy. Kaplan-Meier analysis, log-rank test and multivariate Cox proportional-hazards regression were applied for overall survival (OS) and disease free survival (DFS) according to TNBC histologic types.ResultsTNBC “special types” showed significant differences for several clinico-pathological features when compared to IBC-NST. We observed that in apocrine carcinomas as tumor size increased, the number of metastatic lymph nodes manifestly increased. Adenoid cystic carcinoma showed the smallest tumor size relative to IBC-NST. At five-year follow-up, OS was 92.1, 100.0, and 94.5% for patients with apocrine, adenoid cystic and medullary carcinoma, respectively; patients with lobular and metaplastic carcinoma showed the worst OS, with 79.7 and 84.3%, respectively. At ten-years, patients with adenoid cystic (100.0%) and medullary (94.5%) carcinoma showed a favourable prognosis, whereas patients with lobular carcinoma showed the worst prognosis (73.8%). TNBC medullary type was an independent prognostic factor for DFS compared to IBC-NST.ConclusionsOur study confirms that an accurate and reliable histopathologic definition of TNBC subtypes has a significant clinical utility and is effective in the therapeutic decision-making process, with the aim to develop innovative and personalized treatments.
Highlights
Triple Negative breast cancer (TNBC) includes a heterogeneous group of tumors with different clinico-pathological features, molecular alterations and treatment responsivity
Among TNBC histotypes, the historical morphological entity of medullary carcinoma previously considered as a specific Breast cancer (BC) special type in the category of “carcinoma with medullary features”, is no longer identified as a special type variant and has been recently reconsidered as invasive breast carcinomas of no special type (IBC-NST) with medullary pattern, rather than a distinct morphological subtype; medullary-type pattern is often associated with variable immunohistochemical expression of basal markers [9]
Information was obtained from retrospectively collected TNBC Database on all consecutive patients with Triple Negative breast cancer diagnosis surgically treated in the four most important Oncology Units located in different hospitals in Sardinia, from 1994 to 2015, as previously published [15]
Summary
Triple Negative breast cancer (TNBC) includes a heterogeneous group of tumors with different clinico-pathological features, molecular alterations and treatment responsivity. Our aim was to evaluate the clinicopathological heterogeneity and prognostic significance of TNBC histologic variants, comparing “special types” to high-grade invasive breast carcinomas of no special type (IBC-NST). A marked molecular heterogeneity of breast cancer has been demonstrated by gene expression profiling studies, which identified four major BC “intrinsic” subtypes, including luminal A, luminal B, HER2enriched, and basal-like, showing variable biological, clinical behaviors and response to treatment [2, 3]. Other histologic “special types” (HST), such as metaplastic, apocrine, lobular and adenoid cystic carcinomas, are still included among TNBC These special phenotypes substantially differ in terms of biological behavior and clinical course [8]. Among TNBC histotypes, the historical morphological entity of medullary carcinoma previously considered as a specific BC special type in the category of “carcinoma with medullary features”, is no longer identified as a special type variant and has been recently reconsidered as IBC-NST with medullary pattern, rather than a distinct morphological subtype; medullary-type pattern is often associated with variable immunohistochemical expression of basal markers [9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
