Accelerated tumor proliferation rates in locally recurrent prostate cancer after radical prostatectomy

Purpose: We compared the growth rates of primary cancer and prostatic fossa recurrence after radical prostatectomy. Materials and Methods: Tumor proliferative rates were studied in 26 patients with biopsy proved prostatic fossa recurrences after radical prostatectomy. Proliferation was calculated in the prostatectomy specimens and in recurrent cancer using Ki-67 antibody to detect dividing cells. Results: Mean and median labeling indexes for radical prostatectomy specimens were 2.96 and 2.51, respectively. Labeling indexes in locally recurrent tumors were significantly higher (mean 6.47, median 5.59, p < 0.001). The increase in labeling index between parent and recurrent tumors was unrelated to pathological staging at prostatectomy or interval from radical prostatectomy. Conclusions: Tumors that recur locally after radical prostatectomy appear to have a higher proliferative rate compared to parent tumors.