Can renal mass biopsy assessment of tumor grade be safely substituted for by a predictive model?
OBJECTIVE
Fuhrman grade represents a key determinant of the natural history of small renal masses that represent renal cell carcinoma. We tested whether renal mass biopsy prediction of Fuhrman grade in the nephrectomy specimen could be safely substituted for by an accurate statistical model. To date the best available model has shown poor accuracy (55.6%), which is close to flipping a coin (50%) and clearly inadequate for use in clinical practice.


METHODS
We identified 1,139 patients with T1aN0M0 renal cell carcinoma treated with partial or radical nephrectomy at 11 participating institutions from 1989 to 2004. This cohort was used in univariate and multivariate logistic regression models predicting high Fuhrman grade (III-IV) at nephrectomy. Predictors included age at diagnosis, gender, tumor size and symptom classification. Multivariate logistic regression coefficients were used to generate a nomogram.


RESULTS
The rate of Fuhrman grade III-IV in patients with T1aN0M0 renal cell carcinoma was 12.3%. Stratifying patients with Fuhrman grade III-IV by age, gender, histological subtypes and sample size failed to reveal statistically significant differences. On univariate analysis predicting Fuhrman grade III-IV at nephrectomy only tumor size was a statistically significant predictor (p = 0.05). The most accurate multivariate nomogram for Fuhrman grade III-IV prediction was 58.3% (95% CI 57.8-58.9) accurate. Of all tested predictors only tumor size achieved independent predictor status (p = 0.009).


CONCLUSIONS
Our analysis derived in European patients shows that statistical models cannot safely replace renal mass biopsy based prediction of Fuhrman grade III-IV at nephrectomy. Our findings corroborate a report from the United States in which a similar model had 55.6% accuracy. Jointly the studies indicate that statistical models are unreliable and cannot safely be substituted for renal mass biopsy in North American or European patients.
Jeldres
Claudio
C
Department of Urology, University of Montreal, Montreal, Quebec, Canada.
Sun
Maxine
M
Liberman
Daniel
D
Lughezzani
Giovanni
G
de la Taille
Alexandre
A
Tostain
Jacques
J
Valeri
Antoine
A
Cindolo
Luca
L
Ficarra
Vincenzo
V
Artibani
Walter
W
Zigeuner
Richard
R
Mejean
Arnaud
A
Descotes
Jean Luc
JL
Lechevallier
Eric
E
Mulders
Peter F
PF
Perrotte
Paul
P
Patard
Jean-Jacques
JJ
Karakiewicz
Pierre I
PI
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002292:Carcinoma, Renal Cell / Q000473:pathology* / Q000601:surgery; D005544:Forecasting; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology* / Q000601:surgery; D008875:Middle Aged; D015233:Models, Statistical; D009367:Neoplasm Staging; D009392:Nephrectomy; D015203:Reproducibility of Results; D055815:Young Adult