The dual role of tumor-infiltrating lymphocytes in her2-positive primary breast cancer: Two sides of the same coin?
Menée à partir de 387 échantillons tumoraux prélevés sur des patientes atteintes d'un cancer du sein HER2+ de stade précoce et traitées par lapatinib et trastuzumab entre 2008 et 2010 (durée médiane de suivi : 3,77 ans), cette étude évalue l'association entre le pourcentage de lymphocytes infiltrant la tumeur au diagnostic et la réponse pathologique complète ou la survie sans événement
Quantifying tumor-infiltrating lymphocytes (TILs) in breast cancer is a frequently used approach to gain insight into the tumor’s immune activity. In this issue of JAMA Oncology, Salgado and colleagues1 evaluated TIL levels as a predictive and prognostic factor in patients participating in the NeoALTTO trial. This is a well-conducted biomarker study measuring 1 prospectively defined marker in a prospectively collected clinical trial cohort by 2 pathologists, renowned for TIL assessment, who analyzed the complete trial cohort, independently adhering to recently published guidelines.2 The results were combined thereafter. The correlation between the assessments of the 2 pathologists was 74%. Salgado and colleagues1 demonstrate that the presence of stromal TILs assessed in pretherapeutic core biopsies prior to the start of neoadjuvant treatment indicate a higher probability of achieving a pathological complete response (pCR), as well as a higher probability of event-free survival.2 In general, factors indicating a higher probability of achieving a pCR, for example, negative hormone receptor status, are associated with a higher chance of relapse but not with better survival. As a matter of fact, in this analysis the correlation between TIL level and survival is linear whereas the correlation between TIL level and pCR is nonlinear. However, this is not further discussed and it can be argued that it is a chance finding because the steep increase in pCR at 5% TILs seems to be confined to the 2 groups with single anti–human epidermal growth factor receptor 2 (anti-HER2) therapy. A couple of other factors might have influenced these results. First, there seems to be no difference in pCR in the group with 5% or less TILs between trastuzumab and lapatinib treatment. Second, lapatinib-treated patients were excluded from the survival analyses, whereas these patients had been included in the pCR analyses. Third, an important part of the therapy was given after surgery and did not influence the pCR rate but only the survival. Last, the follow-up time for patients with a hormone receptor positive–tumor is rather short, at a median of 3.77 years.
JAMA Oncology , commentaire en libre accès, 2014