Effect of Pretreatment Platelet Parameters on Survival in Limited Disease Small Cell Lung Cancer.

Background: The aim of this study was to investigate the effect of platelet parameters before concurrent chemoradiotherapy (CCRT) on survival of patients with limited disease small cell lung cancer (LD-SCLC). Methods: This study consisted of patients who received CCRT due to LD-SCLC in the oncology clinic between 1997-2017. Examined platelet parameters included total platelet count (TPC), mean platelet volume, platelet distribution width, and platelet-lymphocyte ratio. The cut-off value for TPC was determined as 306x109/U (sensitivity: 62%, specificity: 75.5%), where patients below or equal to this level was classified as Group I, and those above as Group II. Results:The study included 90 patients whose mean age was 59 years (range: 42-83) and male ratio was 80.0% (n=72). Near three-fourths of patients (74.4%) were at clinical stage III. Among stage I-II patients, mOS was found as 126 months for Group I whereas it had not been reached in Group II (p=0.158). Stage III patients showed significantly lower mOS for Group 1 (16 [range: 14.1-17.8] months) compared to that in Group 2 (19.0 [range: 15.6-62.8] months; p=0.002). In multivariate analysis, Eastern Cooperative Oncology Group performance score (p=0.003), clinical stage (p<0.001), prophylactic cranial irradiation (p=0.004), and TPC (p=0.031) was determined as the most significant factors affecting survival. Conclusion: Our study suggests association of high baseline levels of TPC to improved survival in patients scheduled to undergo CCRT for LD-SCLC. Considering easiness and universal availability of TPC measurement, potential utilization of this biomarker may be promising to predict survival, albeit requiring validation by further well-designated prospective studies.