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Radiotherapy Scheme Effect on PD-L1 Expression for Locally Advanced Rectal Cancer

Authors :
Jihane Boustani
Valentin Derangère
Aurélie Bertaut
Olivier Adotevi
Véronique Morgand
Céline Charon-Barra
François Ghiringhelli
Céline Mirjolet
Source :
Cells, Vol 9, Iss 9, p 2071 (2020)
Publication Year :
2020
Publisher :
MDPI AG, 2020.

Abstract

In locally advanced rectal cancer, radiotherapy (RT) followed by surgery have improved locoregional control, but distant recurrences remain frequent. Although checkpoint inhibitors have demonstrated objective response in several cancers, the clinical benefit of PD-1/PD-L1 blockade remains uncertain in rectal cancer. We collected data from biopsies and surgical specimens in 74 patients. The main objective was to evaluate the impact of neoadjuvant RT and fractionation on PD-L1 expression. Secondary objectives were to study the relation between PD-L1 expression and tumor regression grade (TRG), progression-free survival (PFS), overall survival (OS), and CD8 TILs infiltration. Median rates of cells expressing PD-L1 pre- and post-RT were 0.15 (range, 0–17) and 0.5 (range, 0–27.5), respectively (p = 0.0005). There was no effect of RT fractionation on PD-L1+ cell rates. We found no relation between CD8+ TILs infiltration and PD-L1 expression and no difference between high-PD-L1 or low-PD-L1 expression and TRG. High-to-high PD-L1 expression profile had none significant higher OS and PFS compared to all other groups (p = 0.06). Median OS and PFS were higher in biopsies with >0.08 PD-L1+ cells. High-to-high PD-L1 profile and ypT0-2 were significantly associated with higher OS and PFS. This study did not show the differential induction of PD-L1 expression according to fractionation.

Details

Language :
English
ISSN :
20734409
Volume :
9
Issue :
9
Database :
Directory of Open Access Journals
Journal :
Cells
Publication Type :
Academic Journal
Accession number :
edsdoj.0ef3b6be94384845b429c18291315237
Document Type :
article
Full Text :
https://doi.org/10.3390/cells9092071