PROGNOSTIC SIGNIFICANCE OF PD-L1 IN HEAD AND NECK SQUAMOUS CELL CARCINOMA- AN AMBISPECTIVE STUDY
Authors: Meena K. , Ravel Naveen , Kokila K. , Arunalatha P. , N. Sathiyamoorthy P. , Ramanan Arun , Rajan Teena , Dheeraj Chodavarapu , Vijayalakshmi Pothala 
Published: September 2023

Introduction: Head and neck squamous cell carcinoma (HNSCC), derived from squamous epithelium of the upper aerodigestive tract, is the most
common malignancy in the head and neck region with over 600,000 new cases diagnosed each year. While many of the HNSCCs may be detected
in early stages, nearly 50% of the patients have lymph node metastasis at the time of diagnosis and 20-30% of the cases tend to have recurrence or
distant metastasis within rst 2 years of treatment of the primary Tumour. Even with multimodality approach with surgery, radiotherapy and
chemotherapy, the outcomes are often dismal in Locally Advanced HNSCC. Hence , identication of novel biomarkers and potential molecular
candidates for targeted therapy is necessary and one such promising candidate is the Immune Checkpoint Regulator Programmed Death Ligand1(PD-L1). The objective of this study is to identify PD-L1 expression in HNSCC and Objectives: to identify the correlation between PD-L1
expression (as estimated by IHC) and clinicopathological parameters—including prognosis—in unresectable, metastatic and recurrent HNSCC
cases presenting to a tertiary care centre in North Chennai
Material And Methods:
STUDY DESIGN- Ambispective study
STUDY SETTING- Government Stanley Hospital, Chennai, Tamil nadu
STUDY DURATION – January,2020 to June,2022
STUDY POPULATION – Patients with biopsy proven unresectable, metastatic or recurrent HNSCC who presented to the Department of Medical
oncology, Government Stanley Hospital during the study period
All the cases with HPE proven unresectable, metastatic and recurrent HNSCC who have not received Radiotherapy or Chemotherapy prior to
sample collection were included in the study. Patient's demographical and clinical characteristics were recorded. PD-L1 was estimated using IHC
method. 95 cases of locally advanced, unresectable or recurrent HNSCC were include Results: d in the study. Median age at diagnosis was 53 years.
Male: Female=6:1. Localisation of the disease was as follows-: Oral cavity-48(50.5%), Oropharynx-15(15.8%), Larynx-16(16.8%),
Hypopharynx-15(15.8%) and 1 case with lesions in all sites. 89 patients presented in locally advanced, inoperable stage and 6 patients underwent
primary radical surgery followed by recurrence. Biopsy samples of all the patients were collected and PD-L1 was estimated by IHC and Combined
Positive Score(CPS). PD-L1 positivity was noted in 38 cases(40%) of which strong intensity(CPS>_20) was noted in 11(11.6%) individuals and
low staining intensity was noted in 27(28.4%) cases. No correlation was observed between PD-L1 positivity and well known causative factors of
HNSCC like tobacco and alcohol. There was no correlation between PD-L1 and tumour stage, lymph nodal involvement, tumour grade, site of the
lesion or Performance status of an individual. A statistically signicant correlation(P<0.05) was noted between PD-L1 status and gender of the
individual. Among 95 cases, response of 47 patients to primary treatment could not be assessed due to ongoing treatment/defaulters/death. Among
the cases assessed, 38 cases(80%) showed residual disease , 6 cases with recurrence and 4 cases progressed while on Denitive Radiotherapy.
Median survival from diagnosis is 5.5 months(Range=1). No statistically signicant correlation was seen between PD-L1 and response to therapy
or Overall survival. Generally, it is assumed that PD-L1 enhances an aggre Conclusions: ssive tumor phenotype by allowing tumor cells to evade
the host immune system by establishing an immunosuppressive microenvironment. Our study could not establish the role of PD-L1 as an
independent prognostic cancer in Locally advanced or Recurrent HNSCC. The high prevalence of PD-L1 in HNSCC may be studied further to
provide complementary therapies targeting the PD-1/PD-L1 pathway, and improve response to treatment.