Abstract: Objective To investigate the predictive value of pre⁃operative platelet distribution width (PDW) to tumor size (TS) ratio (PdwTR) on the disease⁃free survival (DFS) in non⁃metastatic lung adenocarcinoma patients. Methods A total of 198 patients of non⁃metastatic lung adenocarcinoma diagnosed pathologically after surgical treatment were collected in Hainan Hospital of PLA General Hospital from December 2012 to December 2020. The patients were divided into low PdwTR group and high PdwTR group, according to the optimal cut⁃off value of PdwTR determined by receiver operating characteristic (ROC) curve. The effectiveness of PdwTR, PDW and TS in predicting DFS was evaluated by time⁃dependent ROC curve, and the association between PdwTR and DFS was analyzed by Cox proportional hazard model. Results The optimal cut⁃off point of PdwTR was 7.45, the sensitivity and specificity of PdwTR for 3⁃year DFS were 93.90% and 61.20%, respectively. In addition, the area under ROC curve for PdwTR was 0.83 (95%CI: 0.75-0.90). The results of log⁃rank test showed that the DFS of low PdwTR group was lower than that of high PdwTR group (log⁃rank χ²=28.99, P<0.001). After the adjustment for potential confounding factors such as age, gender, BMI, CEA level, T stage, N stage, TNM stage, NLR, LMR, and PNI by Cox regression model, the high PdwTR group showed a 93.0% decrease in the risk of recurrence compared to the low PdwTR group (HR=0.07, 95%CI: 0.02-0.33, P=0.001). Conclusions  Low preoperative PdwTR is independently associated with poor DFS in patients with non⁃metastatic lung adenocarcinoma, and can be used as a predictor of DFS.

Key words:  Lung adenocarcinoma, Platelet distribution width, Tumor size, Disease?free survival, Prognosis