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

The prostate: diagnostic evaluation of metastatic disease

One of the single most important considerations in clinical management of the patient with prostate cancer is whether or not metastatic disease is present. The identification of metastatic disease in a patient with newly diagnosed prostate cancer represents an absolute contraindication to definitive local therapies such as radial prostatectomy or radiation therapy. Similarly, the identification of metastatic disease in a patient with disease recurrence after definitive local therapy represents an absolute contraindication to salvage radiotherapy or cryosurgery. Patients with metastatic disease do not benefit from definitive therapy, and the cost and morbidity associated with such treatment should therefore be avoided in these patients. Because of the significance of metastatic disease to clinical management, it is important for the diagnostic radiologist to be aware of important considerations in the metastatic work-up of patients with newly diagnosed prostate cancer and patients with suspected cancer recurrence after definitive local therapy.

Detection of tumor cells in bone marrow of patients with prostatic carcinoma by immunocytochemical techniques

We used a mixture of antisera to prostatic specific acid phosphatase, prostatic specific antigen, epithelial membrane antigen and cytokeratin to examine multiple marrow aspirates from patients with local (15) and metastatic prostatic carcinoma (15), and benign prostatic hypertrophy (10). We found moderate to large numbers of tumor cells in the bone marrow of 11 of 15 (73 per cent) patients with known metastatic disease and small numbers of abnormal cells in 2 of 15 (13 per cent) patients with apparently local disease. No tumor cells were found in patients with benign prostatic hypertrophy, and only 2 patients with metastatic disease had tumor cells in the bone marrow when conventional hematomorphological preparations were examined. These findings suggest that immunocytochemistry can increase the detection rate of metastatic prostatic carcinoma cells. Further followup of larger numbers of patients with local carcinoma will reveal whether the presence of micrometastases denotes a poor prognosis.

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.

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.

Bone marrow acid phosphatase by radioimmunoassay: 3 years of experience

Clinical followup of 112 patients staged by the immunochemical determination of prostatic acid phosphatase from bone marrow aspirates is presented. This represents a 94 per cent (112 of 118) retrieval rate of a group studied more than 2 years previously. Of the 11 patients judged to be at high risk 4 (36 per cent) have suffered bony metastases, whereas only 3 of 86 patients (3 per cent) with normal bone marrow acid phosphatase by radioimmunoassay have done so. An additional 184 patients with carcinoma and 77 controls have been studied. Although radioimmunoassay greatly improves specificity in bone marrow aspirates a few falsely positive results can occur. This finding may be secondary to cross reaction from leukocyte acid phosphatase and/or interference from lipid.

Immunological detection of metastases from prostatic adenocarcinoma

In six patients with known prostatic adenocarcinoma, extraprostatic (metastatic) tumor was suspected on radiographic or radionucleotide studies. When cytological examination of tissue obtained by needle aspiration or biopsy was nondiagnostic, radial gel immunodiffusion was used to identify the presence of prostatic acid phosphatase in the tissue. Four specimens demonstrated prostate-specific acid phosphatase activity, permitting the diagnosis of metastatic prostatic adenocarcinoma. The technique is simple and highly specific.

Radioimmunoassay of bone marrow prostatic acid phosphatase

The clinical value of prostate acid phosphatase (PAP) measurements in the bone marrow aspirate of patients with prostatic adenocarcinoma has been unclear. Using a radioimmunoassay (RIA) to measure PAP, we have evaluated this potential indicator of occult metastases in 127 controls and in 300 patients with prostatic adenocarcinoma. Elevations of the tumor marker were found in 9%, 10%, 19%, and 82% of patients with stages B, C, D1, and D2 adenocarcinoma respectively. Clinical follow-up ranging from 7 to 43 months (average 23 months) was available for 97 patients without any initial indication of metastasis by bone scan. In this group 11 patients had elevated levels of bone marrow acid phosphatase (BMAP) by RIA and four developed radiological evidence of bone metastasis 21-25 months following initial staging. However, only three of the 86 patients with normal BMAP levels have developed bone metastasis. Our results indicate that measurement of bone marrow PAP by immunological methods has prognostic significance. Dilution of the bone marrow aspirate by peripheral blood, however, may limit the application of this technique.

Clinical significance of serum and bone marrow acid phosphatase

Currently available immunochemical assays for the determination of serum prostatic acid phosphatase have improved the reliability of this biological marker in carcinoma of the prostate. Although the value of such methods for screening the general population is questionable, a certain percentage of elevated serum levels is observed in patients with localized disease. The significance of such findings is unclear at the present time. Recent evidence suggests that in elevated bone marrow acid phosphatase, using these methods is of predictive value in the future development of metastatic disease.