Prostate-specific antigen as a serum marker for adenocarcinoma of the prostate

To compare the clinical usefulness of the serum markers prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP), we measured them by radioimmunoassay in 2200 serum samples from 699 patients, 378 of whom had prostatic cancer. PSA was elevated in 122 of 127 patients with newly diagnosed, untreated prostatic cancer, including 7 of 12 patients with unsuspected early disease and all of 115 with more advanced disease. The PSA level increased with advancing clinical stage and was proportional to the estimated volume of the tumor. The PAP concentration was elevated in only 57 of the patients with cancer and correlated less closely with tumor volume. PSA was increased in 86 percent and PAP in 14 percent of the patients with benign prostatic hyperplasia. After radical prostatectomy for cancer, PSA routinely fell to undetectable levels, with a half-life of 2.2 days. If initially elevated, PAP fell to normal levels within 24 hours but always remained detectable. In six patients followed postoperatively by means of repeated measurements, PSA--but not PAP--appeared to be useful in detecting residual and early recurrence of tumor and in monitoring responses to radiation therapy. Prostate massage increased the levels of both PSA and PAP approximately 1.5 to 2 times. Needle biopsy and transurethral resection increased both considerably. We conclude that PSA is more sensitive than PAP in the detection of prostatic cancer and will probably be more useful in monitoring responses and recurrence after therapy. However, since both PSA and PAP may be elevated in benign prostatic hyperplasia, neither marker is specific.

Evaluation of prostate-specific antigen and prostatic acid phosphatase as prostate cancer markers

Prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) have been evaluated in patients with prostate cancer, benign prostatic hypertrophy (BPH), and prostatitis. PSA has proved to be diagnostically more sensitive than PAP for the detection of prostate cancer: 95.0 per cent vs 60.0 per cent for 40 newly diagnosed cancer cases, and 97.1 per cent vs 65.7 per cent for 35 relapsed cases. This also holds true for those patients with early-stage disease: 71.4 per cent vs 0 per cent for 7 Stage A1 cases. The specificities of PSA and PAP are comparable, 96.8 per cent vs 98.9 per cent, respectively. PSA is also more sensitive for monitoring therapy, since it usually rises before PAP and always precedes clinical signs of relapse. Although PSA may be elevated more frequently than PAP in some patients with BPH and prostatitis, it is postulated that these patients with elevated serum PSA and normal serum PAP may fall into a high-risk sub-population which may have early prostate cancer or precancerous conditions not easily detectable by current clinical and diagnostic techniques. Our data suggest PSA is a sensitive useful tumor marker for the diagnosis and management of prostate cancer. In addition, PAP, in combination with PSA, may serve as a useful adjunct for differential diagnosis and confirmation of advanced stage prostate cancer.

Relative reliability of five serially measured markers for prognosis of progression in prostate cancer

During an 8-year period, 1,065 serum specimens were collected from 79 patients with prostate cancer of stages B2 to D1 (group I) and 51 patients with newly diagnosed stage D2 prostate cancer (group II) to evaluate statistically the relative reliability of elevated tumor-associated markers for progressive disease in prostate cancer. Forty of the group I patients and 21 of the group II patients presented a clinical progression of disease during follow-up. With the use of Gail's modification of Cox's regression model, serial acid phosphatase (AcP), total alkaline phosphatase (TAP), bone alkaline phosphatase (BAP), prostatic acid phosphatase (PAP), and prostate-specific antigen (PA) were analyzed. Results from group I patients revealed that only PA (P = .0002) and PAP (P = .0684) were prognostically important markers for detection of imminent disease progression. However, all markers were prognostically important in group II patients. Comparative studies indicated that PA (P = .0052) and PAP (P = .0359) were the more reliable markers for group I patients, whereas PA (P less than .0001), BAP (P = .0007), and PAP (P = .0206) were the more reliable markers for group II patients. Multivariate analyses revealed that, after adjustment for the effect of PA, no other marker was significantly related to the risk of progression. Elevated PA levels were predictive of increased risk 6 months before disease progression in group I patients only (P less than .0001). Overall, the apparent order of prognostic reliability for disease progression was found to be PA greater than PAP greater than BAP greater than AcP greater than TAP.

Ovarian carcinoma: a multivariate analysis of prognostic factors

Five hundred and fifty six women with invasive epithelial ovarian carcinoma were assessed for postoperative treatment between 1966 and 1976. The records of this group were reviewed retrospectively. Sixteen characteristics of the patient and tumor were analyzed for prognostic significance by univariate and multivariate techniques. Tumor grade, the presence of residual disease, and patient performance status are identified as stage-specific independent prognostic factors. These independent factors define patient subsets with good, intermediate, and poor prognosis within each stage. The results show that more effective treatment strategies are required for patients in poor prognosis subsets. Estimates of tumor grade, extent of residual disease, and performance status should be included in reports of treatment outcome.

Prognostic importance of prostate-specific antigen for monitoring patients with stages B2 to D1 prostate cancer

To evaluate the prognostic value of prostate-specific antigen (PA) for detection of tumor growth after definitive therapy, 602 sera from 70 patients with stages B2 to D1 prostate cancer (26 of whom recurred) were analyzed in a blind study. Using Cox's proportional-hazards model, a highly significant association was found between serially measured PA and disease-free survival time (p = 0.0002). A positive predictive value of 100% was found for some markedly elevated PA levels and confirmed recurrence of disease. In fact, this study suggested that once a PA level of 88 ng/ml was reached, there was an average time of less than 2 months before a recurrence was clinically confirmed. Tumor growth in patients who recurred was indicated by a PA elevation before recurrence in 92% (24 of 26) as opposed to 20% (9 of 44) in disease-free patients. Additionally, in these 24 of 26 patients, levels of PA were elevated 12 months (mean lead time) before a confirmed disease recurrence. In patients who were still disease free, serial PA appeared to increase concurrently with putative tumor growth as shown by the initial surgical stage. Generally, the greater the PA level the more advanced was the stage of disease (B2 to D1). These data suggest that PA may be a useful adjuvant marker for monitoring tumor growth in patients with regionally confined prostate cancer.

Immunochemical evaluation of the organ specificity of prostatic acid phosphatase

In a survey of normal and cancerous human tissues we determined the distribution of immunoreactive prostatic acid phosphatase, using rabbit antiserum to acid phosphatase purified from prostatic fluid. In all normal tissues and blood cells studied except leukocytes we found less than 0.1% (expressed as micrograms per gram of wet weight of tissue) of the quantity of immunoreactive prostatic acid phosphatase detected in normal prostate tissue by radioimmunoassay. A small quantity of cross-reactive antigen (2.5 microgram/10(8) cells) was found in leukocytes. In all normal and cancerous nonprostate tissues surveyed by an immunohistochemical technique we detected no immunoreactive prostatic acid phosphatase, except in kidney tissue. Faint but reproducible staining was detected in the lumen of distal tubules and collecting ducts and within interstitial capillaries. Immunoreactive prostatic acid phosphatase was detected in the urine of pre- and post-pubertal males and females. We propose that this material is from serum (low concentrations of immunoreactive prostatic acid phosphatase are present in the serum of men and women) and that it is excreted into urine by the kidneys. Full proof of this must await future experimentation. The specificity of our antiserum for prostatic acid phosphatase was demonstrated by the fact that the Mr 100 000 and 20 000 liver acid phosphatase isoenzymes did not cross with our antiserum in either the radioimmunoassay or double-diffusion analysis. Similarly, preparations of isoenzymes 5A and 5B are human serum albumin did not cross react.

Immunochemical evaluation of the organ specificity of prostatic acid phosphatase

In a survey of normal and cancerous human tissues we determined the distribution of immunoreactive prostatic acid phosphatase, using rabbit antiserum to acid phosphatase purified from prostatic fluid. In all normal tissues and blood cells studied except leukocytes we found less than 0.1% (expressed as micrograms per gram of wet weight of tissue) of the quantity of immunoreactive prostatic acid phosphatase detected in normal prostate tissue by radioimmunoassay. A small quantity of cross-reactive antigen (2.5 microgram/10(8) cells) was found in leukocytes. In all normal and cancerous nonprostate tissues surveyed by an immunohistochemical technique we detected no immunoreactive prostatic acid phosphatase, except in kidney tissue. Faint but reproducible staining was detected in the lumen of distal tubules and collecting ducts and within interstitial capillaries. Immunoreactive prostatic acid phosphatase was detected in the urine of pre- and post-pubertal males and females. We propose that this material is from serum (low concentrations of immunoreactive prostatic acid phosphatase are present in the serum of men and women) and that it is excreted into urine by the kidneys. Full proof of this must await future experimentation. The specificity of our antiserum for prostatic acid phosphatase was demonstrated by the fact that the Mr 100 000 and 20 000 liver acid phosphatase isoenzymes did not cross with our antiserum in either the radioimmunoassay or double-diffusion analysis. Similarly, preparations of isoenzymes 5A and 5B are human serum albumin did not cross react.