118P - PD-L1 expression as prognostic factor for survival after chemoradiotherapy of locally advanced NSCLC

Date 15 April 2016
Event European Lung Cancer Conference 2016 (ELCC) 2016
Session Poster lunch
Topics Cytotoxic agents
Translational Research
Surgical oncology
Non-small-cell lung cancer
Basic Principles in the Management and Treatment (of cancer)
Therapy
Biological therapy
Radiation oncology
Presenter Martina Vrankar
Citation Journal of Thoracic Oncology (2016) 11 (supplement 4): S57-S166. S1556-0864(16)X0004-4
Authors M. Vrankar1, I. Kern2, K. Stanic1
  • 1Department Of Radiotherapy, Institute of Oncology Ljubljana, 1000 - Ljubljana/SI
  • 2Department Of Pathology, University Clinic Golnik, Golnik/SI

Abstract

Background

The standard treatment for inoperable locally advanced non-small cell lung cancer (LA NSCLC) includes concurrent or sequential chemotherapy and radiation therapy. Long term survival rates with these approaches remains only in the order of 15%, therefore new treatment strategies, including immunotherapy, are under investigation, with PD-L1 as one of the major players.

Methods

We evaluated the clinical significance of PD-L1 expression in tumor samples from patients with inoperable LA NSCLC who underwent concurrent chemoradiotherapy in our institution between 2005 and 2010 and correlated their expression with clinicopathologic parameters and outcome of treatment. PD-L1 expression in tumor cells was assessed by immunohistochemistry using rabbit monoclonal antibody SP142 (Ventana, USA). Cutoff value of 5% positive cells regardless of the reaction intensity was taken as positive.

Results

Among 107 patients treated with combined chemoradiotherapy, a total of 44 (36 males and 8 females) had sufficient tissue for immunohistochemical staining. The expression of PD-L1 was demonstrated in 7 tumors, in 6 males and 1 female. No statistical significant differences in patient characteristics, including age, smoking status and gender, were found according to the PD-L1 expression. Radical irradiation with doses of ≥ 60 Gy was completed in significantly higher proportion among PD-L1 negative as compared to PD-L1 positive patients (p = 0.018). The dose intensity of concurrent chemotherapy was significantly lower for cisplatin with 32.1% vs 65.1% and etoposide with 40.0% vs 80.5% for PD-L1 positive and PD-L1 negative patients, respectively. After a median follow up of 92.3 months, 10 patients were still alive, none with PD-L1 expression. Median PFS was 19.9 months in patients without and 10.1 months in patients with PD-L1 expression (p = 0.008). Median overall survival (mOS) was 28.0 and 12.0 months for PD-L1 negative and PD-L1 positive patients, respectively (p = 0.010).

Conclusions

Patients with PD-L1 expression had shorter PFS and mOS after concurrent chemoradiotherapy in LA NSCLC. Unfortunately, only small number of patients had tissue available for the IHC testing, therefore no firm conclusions could be made and further investigation is warranted.

Clinical trial identification

National ethics commitee number: KME 109/04/05, 11.10.2005

Legal entity responsible for the study

Martina Vrankar

Funding

Institut of Oncology Ljubljana

Disclosure

All authors have declared no conflicts of interest.