Study of the expression of programmed death ligand 1 (PD-L1) on non-small cell lung cancers (NSCLCs) at Bach Mai Hospital, Vietnam.

Abstract

e13107 Background: Programmed death ligand 1 (PD-L1) expressions is a known predictor for anti-PD1 therapy outcomes. This study is the first study that describe the status of PD-L1 status on Vietnamese non-small cell lung cancers (NSLCs) patients. Methods: Patients who were diagnosed with advanced NSCLCs and PD-L1 testing from 14 Dec 2017 to 14 Dec 2018 at The Pathology Center, Bach Mai Hospital, Hanoi, Vietnam. Study team collected data of age, gender, histopathological types, biopsy sites and PD-L1 expressions. Qualified pathologists interpret levels of PD-L1 via immunohistochemical (IHC) assays Ventana PD-L1 (SP263) with archive formalin-fixed, paraffin-embedded (FFPE) NSCLCs tissues (primary lung tumor or metastases) on VENTANA BenchMark XT. Results: In total 166 patients, the majority were male (73.49%) with male/female ratio is 2.77. Age range from 29 to 85 with median age was 61 years old. The most common histopathological type was adenocarcinoma (n = 143, 86.14%). Other patients including 19 squamous cell carcinoma (11.45%) and 3 patients with “not otherwise specified” (NOS) tissues (2.41%). Overall 127/166 (76.51%) specimens were taken from lung tumors while 39 (23.49%) samples were from lymph node (10), pleura (20), liver (2), pericardia (2), brain (3) and bone (2). Rates of high expression (≥50%), expression (≥1% and ≤49%) and no expression (<1%) of PD-L1 were 26.51%, 31.32% and 42.17%, respectively. In multivariable regression analysis, we did not observe correlation between PD-L1 expression and age (p = 0.25, CI 95%), type of histopathological tissues (p = 0.41, CI 95%), biopsy sites (compare between lung vs non-lung samples, p = 0.89, CI 95%). Male gender has higher chance to have high expression ò PD-L1 with p = 0.0044, CI 95%. In female patients only, age has negative correlation with PD-L1 expression (p = 0.014, CI 95%). Conclusions: We found that male Vietnamese or younger female NSCLCs are likely to have higher PD-L1 expression. Further data on sequential anti PD-L1 treatment after PD-L1 testing is needed for validation the benefit of Ventana PD-L1 (SP263) IHC assay in Vietnamese NSCLC patients.