par De Schepper, Maxim;Vincent-Salomon, A.;Christgen, Matthias;Van Baelen, Karen;Richard, François;Tsuda, Hitoshi;Kurozumi, Sasagu;Brito, Maria Jose;Cserni, Gabor;Schnitt, Stuart J;Larsimont, Denis
;Kulka, Janina;Fernandez, Pedro Luis;Rodríguez-Martínez, Paula;Olivar, Ana Aula;Melendez, Cristina;Van Bockstal, Mieke M.R.;Kovacs, Aniko;Varga, Zsuzsanna;Wesseling, Jelle;Bhargava, Rohit;Boström, Pia;Franchet, Camille;Zambuko, Blessing;Matute, Gustavo;Mueller, Sophie;Berghian, Anca;Rakha, Emad EA;van Diest, Paul;Oesterreich, Steffi;Derksen, Patrick P.W.B.;Floris, Giuseppe;Desmedt, Christine 
Référence Modern pathology
Publication Publié, 2022


Référence Modern pathology
Publication Publié, 2022
Article révisé par les pairs
Résumé : | Invasive lobular carcinoma (ILC) represents the second most common subtype of breast cancer (BC), accounting for up to 15% of all invasive BC. Loss of cell adhesion due to functional inactivation of E-cadherin is the hallmark of ILC. Although the current world health organization (WHO) classification for diagnosing ILC requires the recognition of the dispersed or linear non-cohesive growth pattern, it is not mandatory to demonstrate E-cadherin loss by immunohistochemistry (IHC). Recent results of central pathology review of two large randomized clinical trials have demonstrated relative overdiagnosis of ILC, as only ~60% of the locally diagnosed ILCs were confirmed by central pathology. To understand the possible underlying reasons of this discrepancy, we undertook a worldwide survey on the current practice of diagnosing BC as ILC. A survey was drafted by a panel of pathologists and researchers from the European lobular breast cancer consortium (ELBCC) using the online tool SurveyMonkey®. Various parameters such as indications for IHC staining, IHC clones, and IHC staining procedures were questioned. Finally, systematic reporting of non-classical ILC variants were also interrogated. This survey was sent out to pathologists worldwide and circulated from December 14, 2020 until July, 1 2021. The results demonstrate that approximately half of the institutions use E-cadherin expression loss by IHC as an ancillary test to diagnose ILC and that there is a great variability in immunostaining protocols. This might cause different staining results and discordant interpretations. As ILC-specific therapeutic and diagnostic avenues are currently explored in the context of clinical trials, it is of importance to improve standardization of histopathologic diagnosis of ILC diagnosis. |