[Value of bootstrapping for small series of patients: application to survival analysis for 26 patients followed for bilateral sporadic renal cell carcinoma].
OBJECTIVE
To use Bootstrapping to estimate the Kaplan-Meier survival of sporadic forms of bilateral renal cell carcinoma (RCC).


METHODS
Over a period of 13 years, 759 patients were operated for RCC. 26 patients had bilateral sporadic RCC (3.4%) and 23 of them were reviewed with a median follow-up of 50 months (range: 7.8 to 143.4). The 95% confidence interval (95% CI) of Kaplan-Meier survival was estimated according to the Greenwood (Gw) normalized method and by Bootstrap percentile (B*) with B = 1000.


RESULTS
The overall 1-year and 5-year survival rates were 95.8% (95% CI Gw: [87.6-100] and B*: [92.1-96.4]) and 73.6% (95% CI Gw: [54.9-92.15] and B*: [72.3-86.5%]), respectively.


CONCLUSIONS
For diseases with a low incidence, Bootstrapping can improve the precision of the Kaplan-Meier survival estimate, by providing a narrower CI. This statistical technique provides the clinician with more precise results in a study limited by a small number of patients.
Service d'Urologie, Hôpital Necker-Enfants Malades, Paris, France.
Vincent
V
Hupertan
Morgan
M
Rouprêt
Jean Hugues
JH
Chauchat
Jean Philippe
JP
Bazin
Alexandre
A
Jacquemard
Bertrand
B
Dufour
Arnaud
A
Méjean
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000401:mortality* / Q000601:surgery; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000401:mortality* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000401:mortality* / Q000601:surgery; D016019:Survival Analysis; D015996:Survival Rate