title: Indications for pelvic nodal treatment in prostate cancer should change. Validation of the Roach formula in a large extended nodal dissection series.
abstract: OBJECTIVE
  Previous studies have criticized the predicting ability of the Roach formula in assessing the risk of lymph node invasion (LNI) in contemporary patients with prostate cancer (PCa) due to a significant overestimation of LNI rates. However, all those studies included patients treated with limited pelvic lymph node dissection (PLND), which is associated with high rates of false negative findings. We hypothesized that the Roach formula is still an accurate tool for LNI predictions if an extended PLND (ePLND) is performed.
  
  
  METHODS
  We included 3,115 consecutive patients treated with radical prostatectomy and ePLND between 2000 and 2010 at a single tertiary referral center. Extended PLND consisted of removal of obturator, external iliac, and hypogastric lymph nodes. We externally validated the Roach formula by using the area under the receiver operating characteristics curve and calibration plot method. Moreover, we tested the performance characteristics of different formula-generated cutoff values ranging from 1% to 20%.
  
  
  RESULTS
  The accuracy of the Roach formula was 80.3%. The calibration showed only a minor underestimation of the LNI risk in high-risk patients (6.7%). According to the Roach formula, the use of 15% cut off would have allowed 74.2% (2,311/3,115) of patients to avoid nodal irradiation, while up to 32.7% (111/336) of all patients with LNI would have been missed. When the cut off was lowered to 6%, nodal treatment would have been spared in 1,541 (49.5%) patients while missing 41 LNI patients. The sensitivity, specificity, and negative predictive values associated with the 6% cut off were 87.9%, 54%, and 97.3%, respectively.
  
  
  CONCLUSIONS
  The Roach formula is still accurate and does not overestimate the rate of LNI in contemporary prostate cancer patients if they are treated with ePLND. However, the recommended cut off of 15% would miss approximately one-third of patients with LNI. Based on our results, the cut off should be lowered to 6%.
authors.affiliation: Department of Urology, Vita Salute San Raffaele University, Milan, Italy.
authors.forename: Firas
authors.initials: F
authors.lastname: Abdollah
authors.forename: Cesare
authors.initials: C
authors.lastname: Cozzarini
authors.forename: Nazareno
authors.initials: N
authors.lastname: Suardi
authors.forename: Andrea
authors.initials: A
authors.lastname: Gallina
authors.forename: Umberto
authors.initials: U
authors.lastname: Capitanio
authors.forename: Marco
authors.initials: M
authors.lastname: Bianchi
authors.forename: Manuela
authors.initials: M
authors.lastname: Tutolo
authors.forename: Andrea
authors.initials: A
authors.lastname: Salonia
authors.forename: Mariangela
authors.initials: M
authors.lastname: La Macchia
authors.forename: Nadia
authors.initials: N
authors.lastname: Di Muzio
authors.forename: Patrizio
authors.initials: P
authors.lastname: Rigatti
authors.forename: Francesco
authors.initials: F
authors.lastname: Montorsi
authors.forename: Alberto
authors.initials: A
authors.lastname: Briganti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002138:Calibration; D006801:Humans; D008197:Lymph Node Excision / Q000379:methods / Q000706:statistics & numerical data*; D008198:Lymph Nodes / Q000473:pathology / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D010388:Pelvis; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy / Q000379:methods; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery*; D012372:ROC Curve; D012016:Reference Values; D012680:Sensitivity and Specificity
chemical_list: D017430:Prostate-Specific Antigen