Abstract 1179P
Background
PD-L1 and VISTA (V-domain Ig suppressor of T-Cell Activation) are important checkpoint control points and plays an immunomodulatory role in patients with NSCLC. In addition, radiation has been shown to induce tumor antigen release and increase PD-L1 expression. Therefore, in this study, we aimed to evaluate the expression level of PD-L1 and VISTA after neoadjuvant chemotherapy or chemoradiotherapy in Stage III NSCLC patients.
Methods
The Stage III NSCLC patients who received neoadjuvant chemotherapy or chemoradiotherapy and operated after that therapies were included in the study. The expression levels of PD-L1 and VISTA between pre-and post- treatment tumor tissue was compared.
Results
Thirty four patients were included in the study. PD-L1 level of 64.7% (n=22) patients at the time of diagnosis was <1%, after neoadjuvant chemotherapy / chemoradiotherapy the PD-L1 level of 32.3% (n=11) patients was evaluated as <1%, and an increase in the PD-L1 level was found in 41.1% (n=14) patients after treatment (p= 0.004). Vista level of 58.8% (n=20) patients at the time of diagnosis was <1%, it was found that the Vista level of 35.2% (n=12) patients after neoadjuvant chemotherapy / chemoradiotherapy was <1% and 44% (n=15) patients had an increase in Vista level after treatment (p = 0.025). There was no relationship between VISTA expression and survival (p: 0.53), but high PD-L1 expression at the time of diagnosis was associated with poor prognosis (p = 0.003). Table: 1179P
PD-L1 and VISTA expression levels of first and second biopsies
| First biopsy PD-L1 TPS | Second biopsy PD-L1 TPS | P-value | |||||||
| 0 | 1 | 2 | 3 | 0 | 1 | 2 | 3 | ||
| n | 22 | 3 | 3 | 6 | 11 | 9 | 3 | 11 | 0,004 |
| % | 64,7 | 8,8 | 8,8 | 17,6 | 32,3 | 26,4 | 8,8 | 32,3 | |
| First biopsy VISTA IC | Second biopsy VISTA IC | P-value | |||||||
| 0 | 1 | 2 | 3 | 0 | 1 | 2 | 3 | ||
| n | 20 | 3 | 3 | 8 | 12 | 3 | 5 | 14 | 0,025 |
| % | 58,8 | 8,8 | 8,8 | 23,5 | 35,2 | 8,8 | 14,7 | 41,1 |
Conclusions
Our preliminary results demonstrated that in the stage III NSCLC patients chemotherapy and chemoradiotherapy can be used as immunizers by increasing expression levels of PD-L1 and VISTA.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Turkish Society of Medical Oncology.
Disclosure
All authors have declared no conflicts of interest.