76P - Tumour infiltrating lymphocytes in inflammatory breast cancer

Date 07 May 2015
Event IMPAKT 2015
Session Welcome reception and Poster Walk
Topics Breast Cancer
Pathology/Molecular Biology
Presenter Cecile Colpaert
Citation Annals of Oncology (2015) 26 (suppl_3): 25-26. 10.1093/annonc/mdv118
Authors C.G. Colpaert1, M. Marsan2, G. Van den Eynden1, P. Vermeulen1, L.Y. Dirix3, S. Van Laere2
  • 1Pathology, GZA Hospitals, 2610 - Antwerp/BE
  • 2Oncology, KUL, 3000 - Leuven/BE
  • 3Faculty Of Medicine And Health Sciences, CORE, 2610 - Antwerp/BE

Abstract

Body

Inflammatory breast cancer (IBC) is a rare, aggressive form of breast cancer. Multimodal treatment including neo-adjuvant chemotherapy (NAT) is the treatment of choice for IBC patients, with pathological complete response (pCR) being one of the most important prognostic factors. Tumour infiltrating lymphocytes (TILs) are an independent predictor of response to NAT in breast cancer (Denkert C 2010). In a search for multigene predictors of pCR in IBC, a 107 gene signature enriched for immunity-related genes was found to distinguish between responders and non-responders (Bertucci F 2014).

Full face H&E stained sections of formalin-fixed paraffin-embedded pre-treatment tumour tissue of 99 IBC patients were evaluated for % stromal TILs (% sTILs: % of stromal area being occupied by TILs) according to recommendations by an international TILs working group (Salgado R 2014). Evaluation was performed by 2 pathologists (CC and GVdE); the mean was used for analysis. Pearson's correlation coefficient between the 2 pathologists for the continuous parameter % sTILs was 0.85 (p < 0.001). Tumours were categorised into molecular subtypes based on immunohistochemically detected hormone receptor (HR) expression and HER2 status according to Cheang M 2009. sTILs were present in all tumours: mean % sTILs was 16.4% (range 1–80%). In 45 tumours, % sTILs was <10% and in 44 tumours % sTILs was between 10 and 40%; 6 tumours were “lymphocyte predominant breast cancers” (LPBC) with % sTILS ≥ 50%.There was no correlation between sTILs and patient age (Pearson's correlation p = 0.16). Mean % sTILs was 11.6% in the HR + HER2-, 18.1% in the HR-HER2 + , 24.6% in the HR-HER2- and 14.4% in the HR + HER2+ tumours. HR + HER2- tumours contained significantly less (p = 0.02) and HR-HER2- tumours significantly more (p = 0.04) sTILs than the other molecular subtypes. There was a significant positive association of % sTILs with pCR after NAT (p = 0.03). pCR was obtained in 8%, 23% and 56% of patients with sTILs <10%, 10-40% and >40%, respectively, and in 86% of the LPBC patients (p = 0.02).

This study shows that IBC tumours do not appear to contain more sTILs than non-IBC tumours (data in non-IBC from Loi S 2013 and Adams S 2014) and that in IBC, as in non-IBC, response to NAT is associated with immunity related processes.

Disclosure: All authors have declared no conflicts of interest.