External validation of the Mayo Clinic cancer specific survival score in a Japanese series of clear cell renal cell carcinoma.
OBJECTIVE
We validated the Mayo Clinic SSIGN (stage, size, grade and necrosis) score in an independent Japanese sample of patients.


METHODS
Between 1985 and 2006, 406 consecutive Japanese patients underwent nephrectomy for clear cell renal cell carcinoma. The prognostic value of pathological features for disease specific survival was evaluated using the Cox proportional hazards regression model. The predictive ability of the SSIGN score was evaluated using the concordance index.


RESULTS
Median followup in the 406 patients was 56 months. Of the patients 100 died of renal cell carcinoma and the 5-year cancer specific survival rate was 78.4%. All features comprising the SSIGN score were significantly associated with death from renal cell carcinoma on univariate analysis. Primary tumor classification, regional lymph node involvement, distant metastasis and Fuhrman nuclear grade were significantly associated with death from renal cell carcinoma in a multivariate setting. The median SSIGN score in the 406 patients was 3 (range 0 to 15). The concordance index of the SSIGN score was 0.814. The 5-year cancer specific survival rate in patients with a score of 0 to 2, 3 or 4, 5 or 6, 7 to 9 and 10 or more was 96.8%, 92.5%, 78.8%, 57.7% and 18.1%, respectively. The survival rate in the latter 3 groups was higher than reported rates in American and European patients.


CONCLUSIONS
The Mayo Clinic SSIGN score can be applicable to Japanese patients with renal cell carcinoma with a high degree of prognostic accuracy. Future studies are needed to determine whether Japanese patients with moderate and high SSIGN scores survive longer than their American and European counterparts.
Fujii
Yasuhisa
Y
Department of Urology and Human Pathology, Tokyo Medical and Dental University, Tokyo, Japan. y-fujii.uro@tmd.ac.jp
Saito
Kazutaka
K
Iimura
Yasumasa
Y
Sakai
Yasuyuki
Y
Koga
Fumitaka
F
Kawakami
Satoru
S
Kumagai
Jiro
J
Kihara
Kazunori
K
D000046:Academic Medical Centers; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001707:Biopsy, Needle; D002292:Carcinoma, Renal Cell / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D002423:Cause of Death; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007564:Japan; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009392:Nephrectomy / Q000379:methods / Q000401:mortality; D011336:Probability; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016019:Survival Analysis