Locally recurrent prostate tumors following either radiation therapy or radical prostatectomy have changes in Ki-67 labeling index, p53 and bcl-2 immunoreactivity.

Abstract

We compare the biological phenotype of recurrent prostatic tumors after definitive local therapy (radiation or radical prostatectomy) with that of the same tumors before treatment. Cellular proliferation (Ki-67 labeling index), p53 nuclear reactivity and bcl-2 immunoreactivity were determined in pretreatment and posttreatment tumor specimens from 13 patients with local tumor recurrence following radiation, and in 18 patients with local tumor recurrence following radical prostatectomy. Mean Ki-67 labeling index increased approximately 2-fold in locally recurrent tumors after radiation (10.5 versus 5.6%, p=0.0008) or surgery (6.0 versus 3.2%, p=0.0025) when compared with pretreatment tumors. We noted p53 nuclear reactivity in a significantly higher proportion of recurrences than in pretreatment tumors following radiation (54 versus 8%, p=0.032) and surgery (39 versus 5%, p=0.022). Although bcl-2 immunoreactivity was also seen in a higher proportion of recurrent tumors, this difference did not reach statistical significance for either radiation or surgery. Recurrent tumors following either radiation or surgery differ significantly from the corresponding pretreatment tumors with respect to cellular proliferation and p53 nuclear reactivity.