title: Development of a New Classification Method for Penile Squamous Cell Carcinoma Based on Lymph Node Density and Standard Pathological Risk Factors: The ND Staging System.
abstract: OBJECTIVE
  In this study, we evaluated the role of lymph node density (LND) and validated whether LND increases the accuracy of survival prediction when combined with the American Joint Committee on Cancer (AJCC) pathological node (N) staging system for penile cancer (7(th) edition).
  
  
  METHODS
  A total of 270 Chinese penile cancer patients treated between March 1999 and October 2014 were retrospectively analyzed. LND was analyzed as a trichotomous variable for the prediction of DSS in this cohort. We developed a new prediction model, which we refer to as the ND staging system, that is based on LND and pathological N staging. The predictive accuracy of this model was further assessed using the concordance index.
  
  
  RESULTS
  LND was correlated with the laterality of lymph node metastasis, extranodal extension, pelvic lymph node metastases, and pathologic tumor (T) and N stages (P<0.05). In separate multivariate Cox regression models, the LND (hazard ratio [HR], 1.966, 95% confidence interval [CI], (1.112-3.473, P=0.020) yielded independent effects on the outcome. According to the LND classification, the 3-year disease-specific survival (DSS) rates for patients with LNDs <7.0%, 7.0 to 16.9%, and ≥17.0% were 90.9%, 66.5%, and 22.2%, respectively (P<7.0%; 7.0%-16.9% =0.006; P7.0-16.9%; ≥17.0% =0.001). The corresponding rates were 95.7%, 76.7%, and 28.1% for the ND1, ND2, and ND3 patients, respectively (PND1-ND2 =0.047; PND2-ND3 <0.001). The indexes indicated that the accuracy of the pathological ND category that incorporated LND was significantly increased.
  
  
  CONCLUSIONS
  LND was associated with some prognosticators and is thus a prognostic factor. The ND staging system that incorporates the LND better reflects the prognoses of penile cancer patients.
authors.affiliation: 1. Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China; 2. State Key Laboratory of Oncology in Southern China, Guangzhou, P. R. China; 3. Collaborative Innovation Center of Cancer Medicine, Guangzhou, P. R. China.
authors.forename: Zai-Shang
authors.initials: ZS
authors.lastname: Li
authors.affiliation: 1. Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China; 2. State Key Laboratory of Oncology in Southern China, Guangzhou, P. R. China; 3. Collaborative Innovation Center of Cancer Medicine, Guangzhou, P. R. China.
authors.forename: Kai
authors.initials: K
authors.lastname: Yao
authors.affiliation: 4. Department of Urology, Affiliated Tumor Hospital of Xinjiang Medical University, Urumchi, P. R. China.
authors.forename: Peng
authors.initials: P
authors.lastname: Chen
authors.affiliation: 5. Department of Urology, Cancer Center of Guangzhou Medical University, Guangzhou, P. R. China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.affiliation: 6. Department of Urology, Dong Guan People's Hospital, Guang Dong, P. R. China.
authors.forename: Qi-Wu
authors.initials: QW
authors.lastname: Mi
authors.affiliation: 1. Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China; 2. State Key Laboratory of Oncology in Southern China, Guangzhou, P. R. China; 3. Collaborative Innovation Center of Cancer Medicine, Guangzhou, P. R. China.
authors.forename: Jie-Ping
authors.initials: JP
authors.lastname: Chen
authors.affiliation: 1. Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China; 2. State Key Laboratory of Oncology in Southern China, Guangzhou, P. R. China; 3. Collaborative Innovation Center of Cancer Medicine, Guangzhou, P. R. China.
authors.forename: Yong-Hong
authors.initials: YH
authors.lastname: Li
authors.affiliation: 1. Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China; 2. State Key Laboratory of Oncology in Southern China, Guangzhou, P. R. China; 3. Collaborative Innovation Center of Cancer Medicine, Guangzhou, P. R. China.
authors.forename: Chuang-Zhong
authors.initials: CZ
authors.lastname: Deng
authors.affiliation: 1. Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China; 2. State Key Laboratory of Oncology in Southern China, Guangzhou, P. R. China; 3. Collaborative Innovation Center of Cancer Medicine, Guangzhou, P. R. China.
authors.forename: Zhuo-Wei
authors.initials: ZW
authors.lastname: Liu
authors.affiliation: 1. Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China; 2. State Key Laboratory of Oncology in Southern China, Guangzhou, P. R. China; 3. Collaborative Innovation Center of Cancer Medicine, Guangzhou, P. R. China.
authors.forename: Zi-Ke
authors.initials: ZK
authors.lastname: Qin
authors.affiliation: 1. Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China; 2. State Key Laboratory of Oncology in Southern China, Guangzhou, P. R. China; 3. Collaborative Innovation Center of Cancer Medicine, Guangzhou, P. R. China.
authors.forename: Fang-Jian
authors.initials: FJ
authors.lastname: Zhou
authors.affiliation: 1. Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China; 2. State Key Laboratory of Oncology in Southern China, Guangzhou, P. R. China; 3. Collaborative Innovation Center of Cancer Medicine, Guangzhou, P. R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Han
keywords: lymph node density; lymph node metastasis; penile neoplasm; prognosis; staging system