Nomograms for predicting long-term overall survival and cancer-specific survival in patients with major salivary gland cancer: a population-based study

// Yun Li 1, * , Jun Ju 2, * , Xiaoxiao Liu 3, * , Tao Gao 1, 4 , Zhidong Wang 5 , Qianwei Ni 1 , Chao Ma 1 , Zhenyan Zhao 1 , Yixiong Ren 1 , Moyi Sun 1 1 State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi’an, China 2 Department of Otolaryngology Head and Neck Surgery, Navy General Hospital, Beijing, China 3 Department of Stomatology, Fengtai Hospital, Peking University First Hospital, Beijing, China 4 Department of Stomatology, The First Hospital of Yu Lin, Shaanxi, China 5 Department of Health Statistics, School of Preventive Medicine, Fourth Military Medical University, Xi’an, China * These authors contributed equally to this paper and should be regarded as co-first authors Correspondence to: Moyi Sun, email: moyisun@163.com Keywords: nomograms, major salivary gland cancer, overall survival, cancer-specific survival, head and neck Received: August 31, 2016     Accepted: January 04, 2017     Published: January 30, 2017 ABSTRACT In this study, we aimed to develop and validate nomograms for predicting long-term overall survival (OS) and cancer-specific survival (CSS) in major salivary gland cancer (MSGC) patients. These nomograms were developed using a retrospective cohort ( N =4218) from the Surveillance, Epidemiology, and End Results (SEER) database, and externally validated using an independent data cohort ( N =244). We used univariate, and multivariate analyses, and cumulative incidence function to select the independent prognostic factors of OS and CSS. Index of concordance (c-index) and calibration plots were used to estimate the nomograms’ predictive accuracy. The median follow-up period was 34 months (1–119 months). Of 4218 MSGC patients, 1320 (31.3%) died by the end of the follow-up; of these 1320 patients, 883 (20.9%) died of MSGC. The OS nomogram, which had a c-index of 0.817, was based on nine variables: age, sex, tumor site, tumor grade, surgery performed, radiation therapy and TNM classifications. The CSS nomogram, which had a c-index of 0.829, was based on the same nine variables plus race. External validation c-indexes were 0.829 and 0.807 for OS and CSS, respectively. Based on SEER database, we have developed nomograms predicting five- and eight-years OS and CSS for MSGC patients with perfect accuracy. These nomograms will help clinicians customize treatment and monitoring strategies in MSGC patients.