Transabdominal ultrasonography in the evaluation of patients with advanced prostatic carcinoma: effects of castration and of chronic administration of a gonadotropin releasing hormone agonistic analogue.

Twenty-two patients with advanced prostatic carcinoma were subjected either to orchiectomy (group I, n = 5) or to chronic administration of a gonadotropin releasing hormone agonistic analogue D, Ser (TBU)6, des Gly-NH2(10) LHRH nonapeptide (HOE 766) (group 2, n = 17). Plasma testosterone was similar in both groups prior to treatment (group 1: 636 +/- 129.29, group 2: 580.85 +/- 37.57; X +/- SE). The levels attained in group I were significantly lower (P less than .05) than those of group 2 through eight weeks of follow-up but were similar by the third month. Prostatic size (cm2) as estimated by transabdominal ultrasonography did not differ between the two groups prior to treatment (group 1: 23.6 +/- 3.35, group 2: 21.4 +/- 1.97; X +/- SE). Both therapies resulted in a decrease of prostatic size that was significantly more pronounced (P less than .05) in group I compared with group 2 by the first and third month; by the six month, there was no statistical difference in the prostatic size attained with either therapeutic modality. Persistent suppression of prostatic size was documented in all patients of group 2 chronically (up to 24 months) treated with HOE 766 even when there was evidence of uninhibited or progressive bony metastases. The above data 1) indicate the efficacy of the HOE 766 in inducing medical castration and prostatic shrinkage in advanced carcinoma of the prostate, 2) document the usefulness of transabdominal ultrasound in the follow-up of such patients, and 3) suggest a relationship between the rapidity of tumor shrinkage and Leydig cell suppression.