Validation of the 2009 TNM version in a large multi-institutional cohort of patients treated for renal cell carcinoma: are further improvements needed?
BACKGROUND
A new edition of the TNM was recently released that includes modifications for the staging system of kidney cancers. Specifically, T2 cancers were subclassified into T2a and T2b (< or =10 cm vs >10 cm), tumors with renal vein involvement or perinephric fat involvement were classified as T3a cancers, and those with adrenal involvement were classified as T4 cancers.


OBJECTIVE
Our aim was to validate the recently released edition of the TNM staging system for primary tumor classification in kidney cancer.


METHODS
Our multicenter retrospective study consisted of 5339 patients treated in 16 academic Italian centers.


METHODS
Patients underwent either radical or partial nephrectomy.


METHODS
Univariable and multivariable Cox regression models addressed cancer-specific survival (CSS) after surgery.


CONCLUSIONS
In the study, 1897 patients (35.5%) were classified as pT1a, 1453 (27%) as pT1b, 437 (8%) as pT2a, 153 (3%) as pT2b, 1059 (20%) as pT3a, 117 (2%) as pT3b, 26 (0.5%) as pT3c, and 197 (4%) as pT4. At a median follow-up of 42 mo, 786 (15%) had died of disease. In univariable analysis, patients with pT2b and pT3a tumors had similar CSS, as did patients with pT3c and pT4 tumors. Moreover, both pT3a and pT3b stages included patients with heterogeneous outcomes. In multivariable analysis, the novel classification of the primary tumor was a powerful independent predictor of CSS (p for trend <0.0001). However, the substratification of pT1 tumors did not retain an independent predictive role. The major limitations of the study are retrospective design, lack of central pathologic review, and the small number of patients included in some substages.


CONCLUSIONS
The recently released seventh edition of the primary tumor staging system for kidney tumors is a powerful predictor of CSS. However, some of the substages identified by the classification have overlapping prognoses, and other substages include patients with heterogeneous outcomes. The few modifications included in this edition may have not resolved the most critical issues in the previous version.
Novara
Giacomo
G
University of Padua, Padua, Italy.
Ficarra
Vincenzo
V
Antonelli
Alessandro
A
Artibani
Walter
W
Bertini
Roberto
R
Carini
Marco
M
Cosciani Cunico
Sergio
S
Imbimbo
Ciro
C
Longo
Nicola
N
Martignoni
Guido
G
Martorana
Giuseppe
G
Minervini
Andrea
A
Mirone
Vincenzo
V
Montorsi
Francesco
F
Schiavina
Riccardo
R
Schiavina
Roberto
R
Simeone
Claudio
C
Serni
Sergio
S
Simonato
Alchiede
A
Siracusano
Salvatore
S
Volpe
Alessandro
A
Carmignani
Giorgio
G
D000368:Aged; D002292:Carcinoma, Renal Cell / Q000145:classification / Q000473:pathology* / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000145:classification / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000592:standards*; D012189:Retrospective Studies