Fate of seminal vesicles and prostate after medical castration: how long is the optimal duration of neoadjuvant treatment for prostate cancer before radiation?

OBJECTIVES

To clarify the morphological alteration of prostate and seminal vesicles (SV) quantitatively after testosterone ablation, we investigated the prostate volume (PV) and the SV volume (SVV) using transrectal ultrasonography.

METHODS

Between July 2002 and October 2004, we prospectively investigated 29 prostate cancer patients. The medical castration group included 21 patients (42 SV and 21 prostate; median Gleason sum, 74 years) who were diagnosed as having T1b to T3aN0M0 prostate cancer and underwent androgen ablation with a luteinizing hormone-releasing hormone (LH-RH) analogue and chlormadinone acetate. As normal controls, 8 patients (16 SV and 8 prostate; median age, 68.5 years) with T1aN0M0 prostate cancer without any other additional treatment were enrolled in this study. We measured both PV and SVV in these groups with transrectal ultrasonography.

RESULTS

Both PV and SVV significantly decreased in the medical castration group (PV: 28.4 +/- 9.3 mL to 17.0 +/- 5.3 mL, SVV: 3.5 +/- 1.8 mL to 1.9 +/- 1.0 mL; median, 6 months), whereas those in the control group were maintained (PV: 16.6 +/- 5.7 mL to 16.5 +/- 5.3 mL, SVV: 2.5 +/- 1.0 mL to 2.6 +/- 1.6 mL; median, 12 months). In longitudinal assessment, mean PSA, PV, and SVV were significantly reduced gradually up to 12 months after medical castration.

CONCLUSIONS

Not only PV but also SVV was significantly reduced after medical castration. Moreover, size reduction continued up to 12 months in SV, with especially marked reduction seen through the first 6 months. These results demonstrated that optimum duration for androgen ablation before radiotherapy is at least 6 months, and up to 12 months for the maximum effect.