Prospective evaluation of Ki-67 labeling in predicting the recurrence and progression of superficial bladder...

We studied a series of superficial transitional cell carcinoma of the bladder to assess whether the Ki-67 labeling index predicts recurrence and progression in a cohort of patients treated by transurethral resection alone or receiving adjuvant intravesical bacillus Calmette-Guerin therapy (BCG).

From 1989 to 1990, we prospectively studied 70 consecutive cases of superficial transitional cell carcinoma of the bladder using Ki-67 immunostaining. The tumors were 43 pTa and 27 pTl. Thirteen were treated with transurethral resection only and 57 received adjuvant intravesical BCG. The median follow-up times was 64 months. The threshold index values of Ki-67 for recurrence and progression were determined using ROC curves. The relative predictive values of the Ki-67 labeling index and tumor characteristics for recurrence and progression were evaluated using Cox's proportional hazards model.

A cutoff value of 13% was determined. The recurrence free survival rate at 5 years was 68% for cases with a Ki-67 labeling index of 13 or higher and 71% for those with an index of less than 13 (NS). The progression-free survival rate at 5 years was 43% in cases with an index of 13 or higher and 89% in those with an index of less than 13 (p<0.0001). Using multivariate analysis the Ki-67 labeling index is an independent risk factor for tumor progression with a relative risk of 4.61 (p<0.05).

When BCG is used for high and intermediate risk superficial bladder cancers, the Ki-67 labeling index is an independent predictive factor of progression but not of recurrence.