Evaluation of PD-L1 expression in vulvar cancer

Background: The PD-1/PD-L1 inhibitory immune checkpoint seems to have a significant prognostic impact in the evolution of certain cancers such as bronchopulmonary cancer, breast cancer, lymphomas etc. Indeed, it has been suggested that PD-L1 expression was associated with a worse prognosis due to its immunosuppressive activity within tumor tissue. Currently, the evaluation of the expression of these biomarkers is of increasing interest in gynecological cancers. Hence, we proposed to study the expression of PDL1 in vulvar cancer. Our aims were to study the expression profile of PD-L1 in vulvar cancer by immunohistochemistry and to correlate its expression with overall and relapse-free survival rates. Methods: This is a retrospective study conducted at the pathological anatomy and cytology department of the Saleh Azaiez Institute, Tunis, Tunisia involving 55 patients followed for vulvar cancer over a period of 13 years from 2008 to 2021. Clinicopathologic data was collected from medical records and pathology reports. Results: PD-L1 expression in vulvar squamous cell carcinoma was observed in 44% of cases. This expression was noted in 33% of cases in tumor cells and in 11% of cases in lymphocytes. The median follow-up period was 40 months. During this period, 30% of patients relapsed. For all recurrence cases, 77% were during the first two years. The overall survival rate was 68.4% at two years and 50.3% at five years. The recurrence-free survival rate was 63.8% at five years. Overall survival as well as recurrence-free survival were more reduced in the case of PD-L1 expression. However, this difference was not significant (p=0.07). Conclusions: These results, although insufficient, emphasize the prognostic value that PDL1 could play in vulvar cancer as described in the literature. Despite the low numbers and the unavailability of data for some cases, our results encourage carrying out this work on larger populations.