title: Disease-specific survival after radical lymphadenectomy for penile cancer: prediction by lymph node count and density.
abstract: OBJECTIVE
  To investigate the value of removed lymph node (LN) count and LN density (LND) for predicting disease-specific survival (DSS) rate following radical lymphadenectomy in patients with penile cancer.
  
  
  METHODS
  We retrieved data from 146 patients who were surgically treated between 2002 and 2012. receiver-operating characteristic curve analysis was used to calculate the optimal cutoff value of LN count and LND for predicting DSS rate. LND was analyzed as a categorical variable by grouping patients with pN+tumors into 2 categories. Multivariate Cox regression analysis was used to test the effect of various variables on DSS rate based on collinearity in various models.
  
  
  RESULTS
  Median follow-up was 42 months. Overall, 75 patients (51.4%) had pN0 disease, and 71 patients (48.6%) had pN+disease. The optimal cutoff value of LN count and LND were 16% and 16%, respectively. Among patients with pN0 tumors, the number of LNs removed (≥16 LNs) was an independent significant predictor of DSS rate in univariate and multivariate analyses (all P<0.05). Stratifying pN+ patients as above versus below the LND threshold demonstrated significant differences in 5-year DSS: 81.2% versus 24.4% (P < 0.001). In multivariate models including known prognostic factors, LND was a statistically significant independent predictor of DSS rate (hazard ratio = 4.31 and 3.96 for above vs. below the LND threshold, respectively).
  
  
  CONCLUSIONS
  The removal of at least 16 LNs was associated with a significantly longer DSS rate in patients with pN0 penile cancer. Additionally, an LND above 16% is an independent predictor of DSS rate in patients with pN+tumors. Further independent validation is required to determine the clinical usefulness of LN count and LND in this patient population.
authors.affiliation: Department of Urology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Zai-shang
authors.initials: ZS
authors.lastname: Li
authors.affiliation: Department of Urology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Yao
authors.affiliation: Department of Urology, Affiliated Tumor Hospital of Xinjiang Medical University, Urumqi, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Chen
authors.affiliation: Department of Urology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Zi-jun
authors.initials: ZJ
authors.lastname: Zou
authors.affiliation: Department of Urology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Zi-Ke
authors.initials: ZK
authors.lastname: Qin
authors.affiliation: Department of Urology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Zhuo-Wei
authors.initials: ZW
authors.lastname: Liu
authors.affiliation: Department of Urology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Yong-Hong
authors.initials: YH
authors.lastname: Li
authors.affiliation: Department of Urology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Fang-Jian
authors.initials: FJ
authors.lastname: Zhou
authors.affiliation: Department of Urology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China; Department of Urology, Affiliated Tumor Hospital of Xinjiang Medical University, Urumqi, China. Electronic address: hanhui@sysucc.org.cn.
authors.forename: Hui
authors.initials: H
authors.lastname: Han
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D015331:Cohort Studies; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008197:Lymph Node Excision / Q000379:methods*; D008198:Lymph Nodes / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D017063:Outcome Assessment, Health Care / Q000379:methods / Q000706:statistics & numerical data; D010412:Penile Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D011379:Prognosis; D016016:Proportional Hazards Models; D015996:Survival Rate; D055815:Young Adult
keywords: Lymph node excision; Lymph nodes; Penile neoplasms; Penis; Prognosis