Clinical significance of the distance between the cricoid cartilage and upper edge of the tumor using PET-CT in cervical esophageal cancer

Cervical esophageal squamous cell carcinoma (CESCC) is less common compared with thoracic esophageal cancer, and few studies have investigated the clinicopathological features of CESCC. The present study analyzed 69 patients with CESCC who underwent various therapies at the University Hospital of Kyoto Prefectural University of Medicine between January 2000 and December 2016. The distance between the inferior border of the cricoid cartilage and upper edge of the tumor was evaluated using positron emission tomography and computed tomography. Positive and negative values indicated oral and anal directions, respectively. Using receiver operating characteristic curves, the cut-off value for laryngeal preservation was calculated as −5 mm. According to this value, the patients were divided into two groups: The short group (distance from the cricoid cartilage ≥-5 mm) and long group (distance from the cricoid cartilage <-5 mm). There were no significant differences in clinicopathological factors between the two groups except for body mass index. In univariate analysis, the 3-year overall survival rate was significantly lower in short group (45.4 vs. 79.6%; P=0.009). In multivariate analysis, short group was an independent prognostic risk factor (hazard ratio=2.65; P=0.039). This may be due to lymphatic flow around the cervical esophagus.