External validation of the pathological nodal staging score in upper tract urothelial carcinoma: A population-based study.
To externally validate our previously developed pathological nodal staging model (pNSS) that allows quantification of the likelihood that a patient with pathologic node-negative status has, indeed, no lymph node metastasis (LNM).



We analyzed data from 2,768 patients treated with radical nephroureterectomy (RNU) and lymph node dissection (LND) using the Surveillance, Epidemiology, and End Results database from 1988 to 2010. We estimated the sensitivity of pathologic nodal staging using a beta-binomial model and developed a new pNSS. Then, we compared these findings with those of the initial cohort.



The mean and median numbers of lymph node (LN) removed were 5 and 2, respectively (interquartile range = 5) in the validation cohort, though 66.5% of the patients (n = 1814) were pN0. Similar to the development cohort, the probability of missing a LNM decreased as the number of nodes examined increased in the validation cohort. If only a single node was examined, 35% of patients would be misclassified as pN0 while harboring LNM. Even when 5 nodes were examined, 8% would be misclassified. The probability of having a positive node increased with advancing pathological T stage in both the cohorts. Patients with pT0-Ta-Tis-T1 disease in both cohorts would have more than a 95% chance of a correct pathologic nodal staging with 2 examined nodes. However, if a patient has pT3-T4 disease, more than 12 examined LNs are needed to reach 95% accuracy.



We confirmed that the number of examined nodes needed for adequate staging depends on pT category. We externally validated our previous pNSS in a population-based database, which could help in the clinical decision-making regarding adjuvant chemotherapy administration.
Department of Urology, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, NY; Department of Urology Cochin Hospital, APHP, Paris Descartes University, Paris, France.
Evanguelos
E
Xylinas
Department of Urology, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, NY; Department of Urology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Luis
L
Kluth
Department of Urology, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, NY; Department of Urology, University Hospital Basel, Basel, Switzerland.
Malte
M
Rieken
Department of Urology, Pitie-Salpetriere Hospital, Assistance Publique-Hôpitaux de Paris, Faculté de Médecine Pierre et Marie Curie, University Paris 6, Paris, France.
Morgan
M
Rouprêt
Department of Urology, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, NY.
Bashir
B
Al Hussein Al Awamlh
Department of Urology, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, NY.
Thomas
T
Clozel
Department of Urology, University of Montreal, Montreal, Quebec, Canada.
Maxine
M
Sun
Department of Urology, University of Montreal, Montreal, Quebec, Canada.
Pierre I
PI
Karakiewicz
Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY.
Mithat
M
Gonen
Department of Urology, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, NY; Department of Urology, Medical University of Vienna, Vienna, Austria. Electronic address: sfshariat@gmail.com.
Shahrokh F
SF
Shariat
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002295:Carcinoma, Transitional Cell / Q000556:secondary* / Q000601:surgery; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology* / Q000601:surgery; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009367:Neoplasm Staging; D009392:Nephrectomy; D011336:Probability; D018426:SEER Program; D014513:Ureter / Q000601:surgery; D014516:Ureteral Neoplasms / Q000473:pathology* / Q000601:surgery
Lymphadenectomy; Pathological nodal staging score; SEER; Upper tract urothelial carcinoma; Validation