Ki-67 in screen-detected, low-grade, low-stage prostate cancer, relation to prostate-specific antigen doubling time, Gleason score and prostate-specific antigen relapse after radical prostatectomy.

摘要

OBJECTIVE: To evaluate the correlation of Ki-67 as a proliferation marker to prostate-specific antigen doubling time (PSADT), Gleason score and its possible role as a predictor of PSA relapse after radical prostatectomy in early prostate cancer (PC). MATERIAL AND METHODS: Out of 660 patients detected with PC in the Swedish branch of the European Randomized Study of Prostate Cancer, 270 were managed with active surveillance. During follow-up (mean 63 months), 70 men were treated with radical retropubic prostatectomy (RRP). In 50 of these patients the preoperative PSADT was calculated and archive prostatectomy specimens were stained for Ki-67. The quantification of positive staining cells was performed by counting five to 15 randomly selected microscopic fields using an eyepiece graticule at 400 x magnification and at least 1000 tumour cells were counted for each patient. One pathologist, blinded to the PSADT values, performed the pathological assessment. The correlation between Ki-67, PSADT and Gleason grade was explored. Cox proportional hazard model was used to evaluate the prognostic power for Ki-67 and other markers on the risk of PSA relapse after RRP. RESULTS: Ki-67 was not correlated with PSADT (p=0.45) but was correlated with Gleason grade (p<0.0001). In the Cox proportional hazard model Ki-67 (p=0.03) [hazard ratio (HR) 2.49, 95% confidence interval (CI) 1.07-5.80] and total PSA (p=0.0068) (HR 1.86, 95% 1.19-2.92) were associated significantly with the risk of disease progression. CONCLUSION: In men with screen-detected, clinically low-grade, low-stage prostate cancer, Ki-67 may be a valuable prognostic marker of PSA relapse after radical prostatectomy.