In benign hyperplasia marked beta-glucuronidase and N-acetyl-beta-glucosaminidase activity was seen in the prostatic epithelium whereas the reactions for 5 other glycosidases were only slight or negative. The intensity of the reaction for the glycosidases in prostatic carcinoma was dependent upon the degree of the differentiation. The possible importance of glycosidases for the invasiveness of prostatic carcinoma is briefly discussed.

Objective To determine the significance of the minima of prostate‐specific antigen (PSA) levels after orchidectomy in patients with advanced carcinoma of the prostate (stage C and D disease), to thereby discriminate patients who have a statistically significant difference in prognosis and thus individualize their adjuvant treatment. Patients and methods A retrospective analysis of 50 patients (mean age 75.8 years) with extracapsular prostate cancer (58% stage C, 42% stage D disease) was performed. PSA measurement and clinical assessment were continued at 3‐monthly intervals until there was evidence of clinical progression. The minimum values of PSA were determined, the patients grouped at intervals of 1 ng/mL and the groups compared statistically on the basis of disease progression. Results Serum PSA levels decreased in all patients to a minimum after 3–6 months. There was a statistically significant difference in the probability of, and time to, disease progression for PSA minima at 1 ng/mL and 10 ng/mL. Of the 13 patients in group 1 (with PSA minima < 1 ng/mL), 11 stayed in remission during a mean follow‐up duration of 45.9 months. Of 25 patients in group 2 (with PSA minima between 1 and 10 ng/mL) 19 developed progression after a mean remission period of 16.7 months, while all 12 patients in group 3 (with PSA minima > 10 ng/mL) progressed after a mean remission period of 12.5 months. Conclusion Post‐orchidectomy PSA minima are an excellent prognostic factor with significant predictive value. While patients in group 1 tend to have a favourable prognosis after orchidectomy alone, group 2 and 3 patients need adjuvant treatment as early as possible. Group 3 patients, with their high probability of early progression, also form a uniform cohort for studies concerning new therapeutic modalities. If the PSA minimum was included in further examinations, the results of treatment should improve.

Post-orchidectomy PSA minima are an excellent prognostic factor with significant predictive value. While patients in group 1 tend to have a favourable prognosis after orchidectomy alone, group 2 and 3 patients need adjuvant treatment as early as possible. Group 3 patients, with their high probability of early progression, also form a uniform cohort for studies concerning new therapeutic modalities. If the PSA minimum was included in further examinations, the results of treatment should improve.