Radioimmunoassay for prostatic acid phosphatase in early prostatic carcinoma

Serum acid phosphatase in patients with localised prostatic cancer, benign prostatic hyperplasia or normal prostates

Serum acid phosphatase levels were determined in 247 men with surgically confirmed intracapsular prostatic cancer (30 patients), benign prostatic hyperplasia (BPH) (114 patients) or palpably normal prostates (103 men). Both radioimmunoassay (245 cases) and an enzymatic method (218 cases) were used. Using radioimmunoassay, the mean serum prostatic acid phosphatase (PAP) level was significantly higher in patients with BPH than in patients with intracapsular cancer or men with normal prostates. The weight of hyperplastic tissue removed during operation in the BPH group correlated closely with PAP concentrations. Age or the presence (or absence) of an indwelling catheter had no effect on PAP concentration. Using the enzymatic method, the highest levels of acid phosphatase were also detected in patients with BPH but the difference was less marked. It was concluded that intracapsular cancer does not elevate serum acid phosphatase levels as determined by radioimmunoassay or an enzymatic method. BPH alone leads to significant rises in PAP concentrations. The degree of BPH correlates with PAP levels.

Prostate tumour markers as an aid in the staging of prostatic cancer

Serum acid phosphatase activity (ACP), prostate specific phosphatase (PAP) and prostate specific antigen (PSA) were measured in 100 patients with prostatic cancer. The patients were divided into 4 groups: T1-2 MO, T3-4 MO and M1 patients with less than or equal to 10 or greater than 10 metastatic foci in bone scintigraphy. The mean serum ACP levels were almost identical in the T1-2 MO and T3-4 MO groups and there was no significant difference between the mean PAP values. Significantly higher PSA levels were observed in the MO patients in the extracapsular category compared with those in the intracapsular category. The mean serum levels of all 3 tumour markers were significantly higher in the M1 than in the MO category. PSA seems to be the marker of choice as a diagnostic aid for differentiating between patients with intracapsular and those with extracapsular tumour growth. In prostatic cancer patients with bone metastases these markers were of similar value for staging the disease.

The value of acid phosphatase measurements in predicting extraprostatic cancer growth before radical prostatectomy

Acid phosphatase levels were determined using both an enzymatic method (32 cases) and radioimmunoassay (35 cases) in 35 patients with clinically localised prostatic cancer. All patients underwent total prostatectomy and pelvic lymphadenectomy. In cases of intracapsular prostatic cancer the level of prostatic acid phosphatase (PAP) measured by radioimmunoassay was 1.4 +/- 0.8 micrograms/l. In patients with either local extraprostatic disease or pelvic lymph node metastases the mean level of PAP was 3.5 +/- 2.8 micrograms/l. The difference was statistically significant. The specificity, sensitivity and accuracy of an elevated PAP (greater than 3.0 micrograms/l) in revealing extraprostatic extension of clinically localised prostatic cancer were 100, 37 and 66% respectively. When the enzymatic method was used, the level of acid phosphatase was elevated (greater than 13 u/l) in only 1 case. The specificity, sensitivity and accuracy of the enzymatic method were 100, 6 and 47% respectively. Elevation of PAP predicts, with a high degree of probability, either local extension outside the prostate or lymph node metastases. A normal PAP does not exclude extraprostatic extension of prostatic cancer.

Randomised controlled study of orchidectomy vs long-acting D-Trp-6-LHRH microcapsules in advanced prostatic carcinoma

Safety and efficacy of a slow-release formulation of D-Trp-6-luteinising-hormone-releasing-hormone (D-Trp-6-LHRH) microcapsules were compared with orchidectomy in the initial treatment of advanced prostatic carcinoma. 41 patients were randomly assigned to D-Trp-6-LHRH and 38 to orchidectomy. Suppression of testosterone and reduction in prostatic acid phosphatase levels were similar in both groups. 87% of patients in the D-Trp-6-LHRH group and 81% in the orchidectomy group responded to treatment or showed no deterioration. Side-effects related to the decrease in testosterone were similar in both groups. 3 patients given D-Trp-6-LHRH had a disease "flare" in the first ten days of treatment which resolved completely when testosterone fell to castrate levels. Results of psychological assessment were similar in both groups before treatment, and on follow-up there was a weak trend towards decreased psychological morbidity in the hormone group. The slow-release preparation of D-Trp-6-LHRH microcapsules offers an important alternative in the management of advanced prostatic carcinoma.