Prostatic acid phosphatase: comparison of radioimmunoassay and enzyme activity assay

The usefulness of serum acid phosphatase in monitoring patients with advanced prostate carcinoma

The usefulness of serum acid phosphatase (SAP) in monitoring patients with advanced prostate carcinoma has been questioned. We reviewed a series of 59 patients with stage D2 prostate carcinoma. All patients had extended follow-up through at least one clinical relapse, or death. Responses to a variety of therapies were characterized as absent, subjective, or objective. All patients with an elevated pre-treatment SAP that fell to normal following therapy had prolonged survivals and improved prognoses. Conversely, all patients with an elevated SAP which did not normalize following therapy had poorer survivals. Among 36 objective responses to therapy, the SAP was elevated prior to or simultaneous with disease progression in 33 (93% sensitivity). In each ease where the pretreatment SAP normalized following therapy, any subsequent elevation in SAP above normal was always associated with clinical evidence of disease progression (100% specificity). Changes in SAP following therapy correlate well with both disease regression and disease progression in patients with advanced prostatic carcinoma.

Prognostic factors in survival free of progression after androgen deprivation therapy for treatment of prostate cancer

We analyzed 110 patients with metastatic prostate cancer (stage D2) to determine the associations between interval until progression and the pretreatment testosterone level, extent of bone metastases, performance status, race, age and pretreatment level of prostatic acid phosphatase. The median followup was 21 months (4 to 89 months). All patients received androgen deprivation therapy when metastases were identified. This multivariate analysis demonstrated that the pretreatment serum testosterone was the most significant variable (p less than 0.01) associated with interval until progression and the extent of bone metastases observed on the bone scan was the second most important variable (p less than 0.05). Age, race and prostatic acid phosphatase were not significantly correlated with the interval free of progression. Performance status was significantly correlated but it was nonsignificant in the multivariate analysis if the model already included testosterone level and extent of metastasis. Patients with a pretreatment testosterone level of less than 300 ng. per 100 ml. and more than 6 areas of increased uptake on the bone scan had the most rapid progression. We conclude that serum testosterone and extent of bone metastases are the most important of the analyzed factors in terms of interval to progression in patients with prostate cancer following androgen deprivation.

Determination of acid phosphatase in biological fluids using a new substrate, 2,6-dichloro-4-nitrophenyl phosphate

A new substrate, 2,6-dichloro-4-nitrophenyl phosphate (DCNP-P), is used for the determination of acid phosphatase (EC 3.1.3.2) in serum and urine. It was hydrolyzed by acid phosphatase to 2,6-dichloro-4-nitrophenol (DCNP) and phosphoric acid. At a pH of 4.5-6.0, the absorption of DCNP liberated by acid phosphatase was much higher than that of p-nitrophenol, which is commonly used as an aglycone in the acid phosphatase assay. By using DCNP-P as a substrate for acid phosphatase activity, determinations can be made without the colour reaction which requires the addition of an alkaline solution, and can be determined by the rate assay that does not require measurement of sample blanks in serum or urine. This method using DCNP-P is highly sensitive and is the most suitable for the rate assay of acid phosphatase activity in biological fluids.

Elevated prostatic acid phosphatase: a prognostic factor for stage C adenocarcinoma of the prostate

The clinical course of 25 patients with clinical stage C adenocarcinoma of the prostate who had pre-treatment elevations of the prostatic acid phosphatase (Roy test) was analyzed retrospectively. All patients were treated with definitive external beam radiation therapy at our hospital between 1974 and 1980. Of the 25 patients 17 (68 per cent) have had disease progression. The median time to treatment failure for this group was 27 months (range 10 to 101 months), and the over-all median survival for these patients has not been reached (range 16 to 120 months). Local control of disease was achieved in 84 per cent (21 of 25) of the patients. The control group consisted of 75 consecutive age-matched patients with normal pre-treatment prostatic acid phosphatase levels whose disease was identically staged and treated at our hospital from July 1977 to January 1979. The median time to disease progression in this group has not yet been reached. Of these 75 patients 24 (32 per cent) have had disease progression within a median time of 38 months. Therefore, an elevated pre-treatment prostatic acid phosphatase value is a harbinger of systemic disease and indicates that radiotherapy will be significantly (p equals 0.002) less effective as a definitive local therapeutic modality.

Tissue polypeptide antigen (TPA) as a prognostic aid in human prostatic carcinoma

Serum levels of tissue polypeptide antigen (TPA) and prostatic acid phosphatase (PAP) in serum, the presence or absence of skeletal metastases, tumor grade, patient age, and erythrocyte sedimentation rate (ESR) were determined in 50 patients with prostatic adenocarcinoma before onset of any therapy. Crude survival rates were estimated for a 5-year period after the time of diagnosis. The prognostic value was estimated by means of the log rank test and multivariate life table analysis. The TPA, PAP, tumor stage, and ESR all appeared to be useful as prognostic markers. Tumor grade and patient age were not significantly related to crude survival. The TPA proved to be the most reliable prognostic marker in single test estimates as well as in a multivariate life table analysis (p less than 0.01).