Analysis of the Role of PET/CT SUVmax in Prognosis and Its Correlation with 
Clinicopathological Characteristics in Resectable Lung Squamous Cell Carcinoma

Abstract

Background and objective Lung cancer is the leading cause of cancer death in men and women in the world, more than one-half of cases are diagnosed at a advanced stage, and the overall 5-year survival rate for lung cancer is 18%. Lung cancer is divided into non-small cell lung carcinoma (NSCLC) and small cell lung carcinoma (SCLC). Approximately 80%-85% of cases are NSCLC which includes three main types: adenocarcinoma (40%), squamous cell carcinoma (SCC) (20%-30%), and large cell carcinoma (10%). Although therapies that target driver mutations in adenocarcinomas are showing some promise, they are proving ineffective in smoking-related SCC. We need pay more attention to the diagnosis and treatment of SCC. 18F-FDG positron emission tomography (PET)/computed tomography (CT) has emerged as an accurate staging modality in lung cancer diagnosis. The aim of this study is to investigate the role of maximum standardized uptake value (SUVmax) on PET-CT in prognosis and its correlation with clinicopathological characteristics in resectable SCC. Methods One hundred and eighty-two resectable SCC patients who underwent PET/CT imaging between May 2005 and October 2014 were enrolled into this retrospectively study. All the enrolled patients had underwent pulmonary resection with mediastinal lymph node dissection without preoperative chemotherapy or radiotherapy. Survival outcomes were analyzed using the Kaplan-Meier method and multivariate Cox proportional hazards model. Correlation between SUVmax and clinicopathological factors was analysed using Pearson correlation analysis and Spearman rank correlation analysis. Results The patients were divided into two groups on the basis of SUVmax 13.0 as cutoff value, and patients with SUVmax more than 13.0 had shorter median overall survival than patients less than 13.0 in univariate analysis (56 months vs 87 months; P=0.022). There was remarkable correlation between SUVmax and gender, tumor size, tumor-node-metastasis (TNM) stage, neutrophil, NLR, hemoglobin (P<0.05). Multivariate Cox analysis demonstrated that SUVmax (HR=1.714, 95%CI: 1.021-2.876, P=0.042), TNM stage (HR=1.677, 95%CI: 1.231-2.284, P=0.001) were independent predictors for survival. Furthermore, univariate survival analysis showed significant difference by SUVmax in patients of stage I (P=0.045). Conclusion SUVmax may be of importance prognostic factor independent of TNM stage, which was considerable for risk stratification in patients with TNM stage. Besides, there was correlation between SUVmax of primary tumor and clinicopathological characteristics.

Keywords

• PET/CT
• Lung squamous cell carcinoma
• SUVmax
• Prognosis