Malignant pleural mesothelioma: clinical experience and prognostic value of derived neutrophil-to-lymphocyte ratio and PD-L1 expression

Background Malignant pleural mesothelioma (MPM) is a rare and aggressive tumor, with a poor prognosis. MPM needs to find prognostic factors of survival. We provided the management of patients with MPM and sought to determine whether pre-treatment levels of derived neutrophil-to-lymphocyte ratio (dNLR) as well as PD-L1 expression were reliable prognostic factors of survival. Methods We conducted a single-institution retrospective study, including all patients with MPM treated at La Paz University Hospital between December 2009 and March 2018. Baseline disease, demographics, clinical data, treatment characteristics and complete blood cell counts were collected. We examined dNLR at baseline and data for PD-L1 expression were analyzed in tumor cells by immunohistochemistry. Results We included 25 patients. The median overall survival (OS) was 15.7 months (95% CI 11.3–20.0). 5 patients had a dNLR greater than 3 (20%). Patients with a dNLR greater than 3 had shorter median OS (8.5 months), than patients with a dNLR less than 3 (17.0 months), with statistically significant differences ( p = 0.038). Ten patients (40%) had positive PD-L1 expression (≥ 1%). Patients with positive PD-L1 expression had shorter median OS (8.5 months) than patients with negative PDL1 expression (15.7 months), but without statistically significant association ( p = 0.319). Conclusion The survival data obtained in our sample are consistent with those previously reported. Pretreatment levels of dNLR greater than 3 and positive PD-L1 expression could be significant prognostic factors for poor survival in patients with MPM. Further and prospective studies are needed to explore this relationship and to derive definitive conclusions.