Effects of endocrine therapy on the primary lesion in patients with prostate carcinoma as evaluated by endorectal magnetic resonance imaging

Abstract

Little effort has been made at the quantitative and qualitative evaluation of patients with prostate carcinoma, including downsizing and downstaging of the primary lesion, after conservative therapy. The current study was undertaken to investigate the qualitative and quantitative effects of endocrine therapy on the primary prostate carcinoma using magnetic resonance imaging (MRI). The primary prostate carcinoma was evaluated by endorectal MRI approximately 4 months after the initiation of endocrine therapy in 48 patients with histologically confirmed prostate carcinoma detected by endorectal MRI before therapy. The volumes of the prostate gland, the carcinoma, and the noncarcinomatous components were reduced to 60.2 +/- 2.7%, 25.5 +/- 2.9%, and 83.2 +/- 6.3% of their pretreatment volumes respectively after endocrine therapy, indicating that the tumors are more susceptible to endocrine therapy than the nontumorous components. The number of prostate carcinomas that demonstrated low signal intensity compared with the normal peripheral zone on T2-weighted images decreased after endocrine therapy and the number of carcinomas with enhancement of T1-weighted contrast-enhanced images increased after therapy. Seven of the 48 patients underwent downstaging after endocrine therapy, based on the endorectal MRI evaluation. The results of the current study suggest that downsizing and occasionally downstaging of the carcinoma may occur after endocrine therapy in patients with prostate carcinoma. In addition, the androgen sensitivity of the prostate carcinoma tissue is relatively high compared with the residual noncancerous prostate gland.