Elevated bone marrow acid phosphatase: the problem of false positives

Bone marrow prostatic specific antigen and prostatic acid phosphatase levels: are they helpful in staging prostatic cancer?

We analyzed serum and bone marrow levels of prostatic specific antigen and prostatic acid phosphatase quantified by double antibody radioimmunoassay in 70 patients. Of the patients 36 had prostatic cancer, including 23 with metastatic disease. There was a significant correlation between the serum and bone marrow levels of prostatic specific antigen and prostatic acid phosphatase independently of the metastases (p less than 0.001). No patient with prostatic cancer and positive bone marrow prostatic specific antigen or prostatic acid phosphatase levels had normal serum levels. Quantification of bone marrow prostatic specific antigen and prostatic acid phosphatase does not provide more information than does serum determination.

Acid phosphatase in prostatic tissue homogenates from patients with benign prostatic hyperplasia and prostatic carcinoma

Acid phosphatase activity biochemically in the primary tumor of 20 patients with prostatic carcinoma, was studied in an attempt to understand the basis for a correlation or lack of correlation between serum and/or bone marrow acid phosphatase levels and the presence and/or clinical behavior of prostatic carcinoma. The enzyme activity was similarly measured in 19 patients with benign prostatic hyperplasia as controls. On the average, enzyme activities were lower (P less than 0.002) in the tissues from patients with carcinoma. There was no correlation of enzyme activity in tumor with the age of the patient, stage of disease, degree of differentiation of the tumor, or serum acid phosphatase activity.

Radioimmunoassayable prostate-specific acid phosphatase in peripheral and bone marrow sera compared in diagnosis of prostatic cancer patients

Measurements of human prostate-specific acid phosphatase by radioimmunoassay in peripheral and bone marrow sera were compared. We studied 20 patients with benign prostatic hyperplasia, 27 with untreated prostatic cancer without bone metastases and 11 with metastases, in addition to 7 with cancer treated by hormonal therapy. The prostate-specific acid phosphatase concentrations in peripheral and bone marrow serum samples were equal and did not exceed the upper limit of our health-associated reference interval, 2.8 microgram. per 1. (mean plus 2 standard deviations) in patients with prostatic hyperplasia. Of 27 prostatic cancer patients without bone metastases the concentration of prostate-specific acid phosphatase was elevated in the peripheral sera of 20 and in the bone marrow sera of 21, and 21 had an extracapsular tumor (stage T3 to T4). Prostate-specific acid phosphatase concentrations were elevated in peripheral and bone marrow serum specimens of all 11 patients with metastases and bone marrow cytology studies were positive in 2. There was no difference in prostate-specific acid phosphatase concentrations in peripheral and bone marrow serum specimens from prostatic cancer patients undergoing hormonal treatment. We conclude that the use of bone marrow serum for the measurement of radioimmunoassayable prostate-specific acid phosphatase in prostatic cancer patients does not provide any further information in regard to the detection of prostatic cancer compared to the use of peripheral serum specimens. Falsely positive findings in bone marrow specimens were not observed with the method used.

Serum and bone marrow radioimmunoassay of acid phosphatase in prostatic cancer

Use of radioimmunoassay (RIA) for determinations of prostatic acid phosphatase has recently received considerable attention because of reported higher sensitivity and specificity than previous enzymatic assays. We have compared the sensitivity and specificity of a commercially available RIA to a highly specific enzymatic assay (thymolphthalein monophosphate) using 37 patients with prostatic cancer and 34 patients with surgically proved benign prostatic hyperplasia. Seventeen of the cancer patients and all 34 of the BPH patients were studied prospectively. We further evaluated specificity by performing the RIA on 25 specimens of bone marrow from patients with nonprostatic disease. Our results indicate the radioimmunoassay is not, at this time, an adequate screening tool, and we question its accuracy in staging patients anymore reliably than by enzymatic assay.

Bone marrow and acid phosphatase by counterimmune electrophoresis: pre-treatment and post-treatment correlations

The value of bone marrow acid phosphatase in the staging of prostatic cancer has been a controversial issue. A number of investigators have concluded that the enzymatic determinations of bone marrow acid phosphatase are inaccurate because of lack of specificity. The introduction of the immune methods for measuring acid phosphatase has revived interest in the role of immune bone marrow acid phosphatase in pre-treatment staging. Fifty-five patients underwent determination of simultaneous immune bone marrow and serum acid phosphatase before any treatment. While positive values did predict a risk for initial and subsequent metastasis they could not be used to dictate against definitive therapy. Positive bone marrow values were paralleled by positive serum values and provided no additional staging information.

Radical retropubic prostatectomy and pelvic lymphadenectomy for high-stage cancer of the prostate

A series of 340 patients with adenocarcinoma of the prostate treated by bilateral pelvic lymphadenectomy and radical retropubic prostatectomy was reviewed to determine the factors that influence survival and time to progression of disease. Follow-up ranged from 1-12 1/2 years. Factors evaluated were grade, stage, and bulk of tumor; influence of seminal vesical involvement and number of pelvic nodes involved; age of patient; and year of surgery. Tumor grade was the only factor related significantly to patient survival. However, grade, stage, and bulk of tumor were all significantly associated with interval between surgery and disease progression. Furthermore, in Stage C disease, seminal vesical involvement (C+) was an adverse factor for disease progression, particularly among patients with low-grade tumor. This is in contrast to the finding that, among patients with Stage D1 disease, those with seminal vesical involvement experienced more favorable survival times and times to progression of disease when compared with patients without seminal vesical involvement. Overall, patient survival compared favorably with an age-matched control group for all stages, A through D1. Patients with few pelvic nodes involved had a survival experience nearly comparable with that of an age-matched control group. This suggests that pelvic lymphadenectomy might have a therapeutic value and that patients with pelvic nodal disease only, without evidence for metastatic disease, should not be denied radical surgery. The influence of concomitant hormonal manipulation or radiotherapy (or both) on patient survival and disease progression is not conclusively answered in this report.

Bone marrow acid phosphatase in prostate cancer: an assessment by immunoassay and biochemical methods

Comparisons of the bone marrow and serum acid phosphatase values obtained by counter-immunelectrophoresis and the Roy biochemical test were made in 72 patients with and in 13 patients without prostatic cancer. The counter-immunoelectophoresis test, when positive at more than 1 international unit per liter, showed only 4.4 per cent falsely positive results. The Roy biochemical test, which used sodium thymolphthalein monophosphate as the substrate, had 65 per cent falsely positive bone marrow acid phosphatase levels. Conflicting reports regarding the value of bone marrow acid phosphatase determinations in patients with prostatic cancer result from the use of non-specific substrates in biochemical methods for measurement and from the trauma incidental to bone marrow aspiration, which releases many non-prostatic acid phosphatase enzymes. The use of immunoassay such as counter-immunoelectrophoresis minimizes this source of error.

Combined serum and bone marrow radioimmunoassays for prostatic acid phosphatase

Combined serum and bone marrow radioimmunoassays for prostatic acid phosphatase provide a unique means for the early diagnosis and more accurate clinical staging of prostatic cancer. The combined screening technique appears to be helpful, particularly in providing a clinical assessment of the presence or absence of early, subclinical lymphatic and bone marrow metastases. Low titer elevations of bone marrow prostatic acid phosphatase by radioimmunoassay have been observed commonly in clinically understaged C prostatic cancer with normal technetium bone scans, indicating the presence of unrecognized stage D disease with bone metastases. The combined screening method also is of distinct clinical value in the early diagnosis of prostatic cancer and in monitoring the effects of specific therapy. In therapeutically responsive patients marked suppression of serum and bone marrow prostatic acid phosphatase is observed regularly with the radioimmunochemical method under study.

Reliability of bone marrow acid phosphatase as a parameter of metastatic prostatic cancer

The reliability of bone marrow acid phosphatase determination by a spectrophotometric assay and 2 immunochemical methods was evaluated in 40 patients: 20 men with known prostatic carcinoma and 20 men of comparable age without clinical evidence of prostatic cancer. The large percentage of falsely positive results obtained by the colorimetric assay invalidates this method as the sole parameter of metastatic prostatic carcinoma.