Mc. Bettencourt et al., KI-67 EXPRESSION IS A PROGNOSTIC MARKER OF PROSTATE-CANCER RECURRENCEAFTER RADICAL PROSTATECTOMY, The Journal of urology, 156(3), 1996, pp. 1064-1068
Purpose: We assessed the cellular proliferation of clinically localize
d prostate cancer by immunohistochemistry using the monoclonal antibod
y MIB to Ki-67 antigen in an attempt to identify associations between
proliferative indexes and disease progression following radical prosta
tectomy. Materials and Methods: Ki-67 proliferative antigen was evalua
ted using MIB 1 monoclonal antibody in archival paraffin embedded radi
cal prostatectomy specimens from 180 patients followed for 1 to 9 year
s (mean 4.4). The percentage of tumor nuclei expressing Ki-67 antigen
was measured and assigned an MIB 1 score (none or rare-negative, 1+-lo
w score and 2 to 4+-high score) and analyzed for prostate specific ant
igen, stage, age, race, grade and serological recurrence postoperative
ly. Results: There was a significant association between MIB 1 score a
nd nuclear grade (p <0.001), Gleason score (p <0.001) and pathological
stage (p = 0.01). Patients with a high MIB 1 score had earlier progre
ssion and a lower 5-year recurrence-free survival rate (44%) than thos
e with negative MIB 1 scores (71%, p <0.001). In multivariate Cox regr
ession analysis with backward elimination, pathological stage (p <0.01
), pretreatment prostate specific antigen (p = 0.04) and MIB 1 score (
p = 0.05) were statistically significant predictors of disease-free su
rvival, and patients with a high MIB 1 score were 3.1 times as likely
to have recurrence as those with a negative score. Controlling for sta
ge, patients with organ confined disease and a high MIB 1 score had a
lower 5-year disease-free survival rate (68%) than those with a low MI
B 1 score (95%, p <0.01). Conclusions: Proliferative activity as measu
red by the Ki-67 proliferative antigen, MIB 1, appears to be a prognos
tic marker of recurrent prostate cancer after radical prostatectomy.