2Department of Pathology, Gazi University Faculty of Medicine, Ankara-Türkiye
3Department of Radiation Oncology, Gazi University Faculty of Medicine, Ankara-Türkiye
4Department of Radiation Oncology, Ataturk Chest Diseases and Chest Surgery Training and Research Hospital, Ankara-Türkiye
5Department of Radiation Oncology, Ankara Bilkent City Hospital, Ankara-Türkiye
6Department of Radiation Oncology, Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Istanbul-Türkiye DOI : 10.5505/tjo.2022.3523 OBJECTIVE
The discovery of PD-L1 receptors triggered a great interest in immunotherapeutics for the management of locally advanced non-small-cell lung cancer (NSCLC). The efficacy of immunotherapeutics for overall survival (OS) in locally advanced NSCLC has been proven in several clinical trials. However, no data exist for the relationship between radiotherapy (RT) response and programmed death-ligand (PD-L1) receptor positivity in the literature. In this regard, we aimed to investigate the predictor value of PD-L1 receptors for RT response.
METHODS
Eighty patients who were diagnosed as having locally advanced NSCLC were selected from among patients
in whom PD-L1 status was assessed in the Gazi University pathology laboratory. The relationship
between PD-L1 and progression-free survival (PFS), OS, metastasis-free survival (MFS), RT response,
and RT doses was evaluated using Kaplan-Meier and Cox regression analysis. Chi-square and t-tests
were used for descriptive statistics.
RESULTS
The median follow-up was 16.1 months. The mean age was 61.1 years. PD-L1 positivity was detected in
34 patients. One year and 2-year OS and PFS ratios were found as 87%, 54% and 65%, 30%, respectively.
The median OS and PFS were 26.8 and 15.1 months, respectively. There was no statistically significant
difference between PD-L1 receptor status and OS and PFS (p=0.736 and p=0.372, respectively). In the
PD-L1 positive subgroup analysis for OS, doses higher than 60 Gy (n=28, mean dose 64.6±1.53) were
found superior to the 60 Gy dose (n=6) (p=0.034). The median MFS was 33 months.
CONCLUSION
PD-L1 status did not seem to be a predictor for RT response. However, despite the low number of
patients in the 60 Gy group, our study showed that dose-escalation could improve survival in PD-L1
positive locally advanced NSCLC.