Prostatic specific antigen

Genitourinary imaging: the past 40 years

During the past 40 years, there has been a dramatic evolution in genitourinary imaging. This evolution has resulted in fundamental changes in the subspecialty. Uroradiology initially focused on radiographic imaging of the urinary tract and was practiced primarily by urologists. After the development of safe intravenous contrast materials, radiologists who focused on the urinary tract and worked closely with urologists forged major advances in urinary tract imaging and intervention. More recently, imaging of the extraurinary genital organs has been added to the subspecialty. Cross-sectional imaging techniques have supplanted radiographic imaging for both urinary and genital imaging. The emergence of the cross-sectional techniques, however, has blurred the traditional organ system-based distinction between gastrointestinal radiology and genitourinary radiology, as both organ systems are imaged simultaneously, and has resulted in a new amalgamation, abdominal radiology, with roots in both specialties. The challenge for the new generation of abdominal radiologists, trained predominantly in cross-sectional techniques, will be to maintain the close interaction with our clinical colleagues that the traditional organ system orientation fostered.

The effects of ejaculation on serum prostate-specific antigen (PSA)

To determine the effects of ejaculation on serum PSA, we measured serum levels just before masturbation and 24 hours and 5 days later in a study group (n=25) aged between 23 and 25 years. In the study group, 16 cases showed a decrease (mean 22.37%, range 10-50%) in serum PSA levels 24 hours after ejaculation, while 6 had higher levels (mean 38.33%, range 21-67%) and 3 had no changes. No relation was found between seminal plasma levels or total amounts expelled of this marker and the difference in serum levels due to ejaculation. In the control group free of ejaculation in the same period determinations of serum PSA levels revealed no significant changes between days 0, 1 and 5. As compared with the control group, the changes in the study group were found to be statistically insignificant. These results may indicate that ejaculation has an insignificant effect on serum PSA levels.

Serum markers for monitoring of prostatic carcinoma

BACKGROUND

Serum TPS (tissue polypeptide-specific antigen) has been observed to be characteristic of carcinoma proliferation, and increased levels of TPS seem to be closely related to tumor progression. In this study we wanted to evaluate the importance of the tumor-marker TPS in the diagnosis and follow-up of patients with prostatic carcinoma, and to compare it with prostate-specific antigen (PSA).

METHODS

We considered 39 patients with clinically confined disease, who underwent neoadjuvant hormonal therapy and thereafter radical prostatectomy, and 45 patients who did not undergo surgery and underwent hormonal adjuvant therapy alone. PSA and TPS were measured at the time of diagnosis and at regular intervals in the follow-up; TPS was measured in a control group of patients as well.

RESULTS

We were able to observe that, in untreated patients, PSA correlates with clinical stage, increasing with increasing tumor stage; a similar correlation was not observed when considering TPS. After androgen ablation we observed a decrease in PSA, but the serum values of TPS remained higher, suggesting that activity still exists inside the tumor. The evaluation of TPS appeared to be of particular interest in the follow-up after radical prostatectomy, especially in patients undergoing hormonal therapy; in fact, we were able to observe that relapse of the disease can be suspected early by the increase of TPS in hormonally treated patients.

CONCLUSIONS

We assert that TPS can add useful information on the state of neoplastic illness, especially in patients following adjuvant androgen-suppressive hormonal therapy, after radical prostatectomy; serial measurements of this marker could be useful in the early diagnosis of a relapse.

Effect of digital rectal examination on plasma prostate-specific antigen (PSA)

Presented are results of determination of plasma PSA before, 1 and 24 hours and 3 weeks after digital rectal examination (DRE) in 130 patients with prostatic adenoma (BPH). Mean pre-examination PSA level was 8.5 ng/ml (max. 27.0 ng/ml, min. 0.3 ng/ml, SD = 6.2). PSA rose at 1 and 24 hr. post-DRE: 9.4 ng/ml (max. 28.9 ng/ml, min. 0.5 ng/ml, SD = 6.7) and 10.7 ng/ml (max. 28.0 ng/ml, min. 0.5 ng/ml, SD = 7.9), respectively.

CONCLUSION

in patients with prostatic adenoma DRE is followed by a rise in plasma PSA, which returns almost to baseline values by 3 weeks.

Relationship between prostate-specific antigen, prostate volume, retention volume and age in benign prostatic hypertrophy (BPH)

The relationship between plasma PSA, prostatic adenoma mass (AM), retention volume (RV) and age was studied in 112 men with benign prostatic hypertrophy (BPH). Their age ranged from 48 to 85 years. Mean PSA was 6.9 ng/ml (SD 6.6) and did not exceed 10 ng/ml in 81.2% of the patients. Mean AM and RV were 66.2 g (SD 36) and 51.7 ml (SD 1.3), respectively. Increase in PSA level was influenced mainly by RV (r = 0.53) but was found to correlate weakly with AM (r = 0.34) which in turn showed low correlation with RV (r = 0.32). Age did not correlate with PSA, AM and RV (r > or = 0.1). AM and RV influence PSA levels independently and large inter-patient differences are well characterized by SD values.

High dose epirubicin is effective in measurable metastatic prostate cancer: a phase II study of the EORTC Genitourinary Group

39 hormone-resistant prostate cancer patients with bidimensionally measurable metastatic lesions were given epirubicin 100 mg/m2 intravenously every 3 weeks. One patient was ineligible and excluded from analyses. According to WHO criteria, 9 patients (24%) had a partial response, 16 patients (42%) had stable disease (including 3 patients (8%) with a partial response not confirmed 1 month later), 11 patients (29%) had progressive disease, and in 2 patients (5%) response was not evaluated. Toxicity was as expected. Fifty-five per cent of patients had WHO grade 3/4 toxicity for white blood cells, and 3% of patients grade 3 toxicity for platelets. Other toxicities included nausea and vomiting, mucositis and alopecia. 2 patients with pre-existing cardiac disease developed cardiotoxicity (1 grade 2, 1 grade 3). An attempt was made to correlate response with prostate specific antigen (PSA) measurements. A positive trend was seen, but 2 non-responding patients showed a > 50% decrease in value.

What is the 'normal range' for prostate-specific antigen? Use of a receiver operating characteristic curve to evaluate a serum marker

OBJECTIVE

To compare the relative sensitivity and specificity of prostate-specific antigen (PSA) as a test for prostate cancer over a range of PSA values in a variety of patient groups, and to compare the sensitivity and specificity of PSA and prostatic acid phosphatase (PAP).

SUBJECTS AND METHODS

Receiver operating characteristic (ROC) curves (sensitivity plotted against 1-specificity) were constructed to compare the ability of PSA to discriminate men with prostate cancer (n = 257) from those with benign prostatic hyperplasia (BPH) (n = 220) or control patients (n = 164). Receiver operating characteristic curves were also constructed to compare PSA and PAP in 173 men with either BPH or prostate cancer.

RESULTS

When patients with symptomatic BPH and those with advanced prostate cancer are excluded, a PSA of 8 ng/mL has a sensitivity of 94% and a specificity of 98% for prostate cancer. In patients presenting with symptoms suggestive of bladder outflow obstruction, PSA remains a sensitive marker for prostate cancer (93% sensitivity at 10 ng/mL) but its specificity (65%) is poor. PSA is a sensitive test for skeletal metastases but levels of 60-80 ng/mL are required to achieve a specificity of 70% or more. The sensitivity of PSA is far superior to that of PAP.

CONCLUSION

Serum PSA provides good discrimination between patients with and without prostate cancer. The sensitivity and specificity of PSA can be improved by excluding men with symptomatic BPH. The specificity of PSA as a diagnostic test for prostate cancer is reduced in men with symptoms of bladder outflow obstruction. For reasonable sensitivity and specificity, a PSA of 60-80 ng/mL is required for differentiating non-metastatic from metastatic prostate cancer. The ROC curve comparing PSA and PAP provides a graphical demonstration of the superiority of PSA as a tumour marker. The ability of PSA to identify prostate cancer can be improved by selecting out groups of patients and by adjusting the cut-off level of PSA to the population under study.

Prognostic significance of changes in prostate-specific markers after endocrine treatment of stage D2 prostatic cancer

BACKGROUND

The prognostic value was determined of prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) measured before and after endocrine treatment in 57 patients with newly diagnosed Stage D2 prostatic cancer.

METHODS

Therapy included orchiectomy or administration of luteinizing hormone releasing hormone analogues or an antiandrogen.

RESULTS

The absolute pretreatment PSA (elevated in 100% of patients) but not PAP (abnormal in 93%) predicted disease progression (P < 0.0011), i.e., a poor response to therapy. Fifty-three patients responded to androgen deprivation with a decrease in PSA level. This declined to normal at 3 and 6 months in 25% of patients. Forty-nine percent had a greater than 90% decrease in their PSA level. By 1 year, 58% of patients had progressive disease. Both the nadir PSA level and the percent decline from the pretreatment level at 3 and 6 months predicted the progression-free interval (P < 0.001). Patients with a 90% or greater decline in PSA had a prolonged progression-free survival. Serial PAP levels were similarly prognostic.

CONCLUSION

It was concluded that PSA was better than PAP in evaluating patients before and after androgen-deprivation therapy. The nadir level of both markers was an important tool to predict progression-free survival in patients with metastatic prostatic cancer.

Erythrocyte sedimentation rate as a tumor marker in human prostatic cancer. An analysis of prognostic factors in 300 population-based consecutive cases

BACKGROUND

The natural history of prostatic cancer is variable. Our knowledge of prognostic factors is limited; therefore, research is needed.

METHODS

The cases of 300 population-based consecutive patients with a diagnosis of cancer of the prostate were analyzed regarding different prognostic factors (but with special reference to the erythrocyte sedimentation rate [ESR]).

RESULTS

After a mean observation time of 100 months, M category, ESR, grade, performance status, hemoglobin level, and T category were found to correlate with disease-specific death using multivariate analysis. The variables correlating with progression in the multivariate model were M category, ESR, T category, grade, treatment, and age. Patients treated with estrogen had a significantly lower risk (relative hazard, 0.3) of relapse. ESR was highly statistically significant (P less than 0.0001) as a prognostic factor. With the variable in linear form, a 20-mm/h higher level suggested a 29% increased risk, on average, for dying of prostatic cancer (using a best-fit multivariate model). However, the relationship was not linear. After correcting for the effect of other factors, the risk for dying of prostatic cancer was lowest when the ESR was 40-50 mm/h and highest when its values were highest.

CONCLUSIONS

ESR is an indicator of increased risk of progression and death in prostatic cancer. Other prognostic factors such as M and T categories, grade, performance status, hemoglobin level, and age currently are more important when planning treatment. It is possible that the ESR reflects aspects of tumor-host relationship and that both a low and high ESR are markers for patients with receding host defence mechanism.

Prostate specific antigen and bone scan correlation in the staging and monitoring of patients with prostatic cancer

The ability of serum prostate specific antigen (PSA) to predict bone metastases at initial presentation was determined in 146 patients, and in 66 patients during a 3-year period; 14.7% of patients with bone metastases at presentation had a PSA value less than 20 ng/ml. All patients who subsequently developed bone metastases had a PSA greater than 20 ng/ml and the rise in PSA often antedated the detection of bone metastases. Bone scans are still necessary in the initial staging but following diagnosis and treatment can be replaced by serum PSA measurement in monitoring patients with prostatic cancer.

Identification of metastatic disease by T category, gleason score and serum PSA level in patients with carcinoma of the prostate

Pre-operative serum prostate specific antigen (Tandem-R assay), T category, Gleason score and the metastatic (M1) status of a consecutive series of 60 patients with newly diagnosed carcinoma of the prostate were studied prospectively. The results revealed that, of these variables, pre-operative serum PSA (greater than 100 ng/ml) was the single most important indicator of metastatic disease, with 100% predictive value. With this alone, 83.3% of M1 disease could be correctly identified. For the remaining 17%, however, we advocate a high index of suspicion if the tumour is T3-T4 category on digital rectal examination (predictive value = 71.4%) and has a high grade with a Gleason score 8-10 (predictive value = 81%).

Tumour markers in prostatic cancer

Prostate cancer is now the third commonest cancer in men. Extensive clinical trials comparing acid phosphatase, alkaline phosphatase (ALKP) and prostate specific antigen (PSA) have shown that PSA is the most sensitive and specific of the tumour markers available for prostate cancer. Caution is needed when comparing the results from different assay methods, there is no international standard for PSA. In the management of localised disease, radical treatment can reduce the PSA levels to less than 0.4 ng/ml, similar results can be obtained for a varying duration in patients sensitive to androgen withdrawal. Raised levels greater than 0.4 ng/ml after radical prostatectomy are indicative of residual disease. PSA is valuable in monitoring deferred treatment or the effects of hormone manipulation and give an indication of the prognosis and early warning of recurrence. In extensive metastatic disease the combination of PSA and ALP reflects the tumour activity. Less than 15 hot spots on the scintigram at presentation and a PSA less than 10 ng/ml 3 to 6 months after commencing treatment is associated with prolonged survival. The role of PSA in population screening for early prostatic cancer is uncertain; early results suggest it can be used in combination with digital rectal examination and ultrasonic examination of the prostate. The effect of a PSA decision level at 4 or 10 ng/ml has a considerable influence on the pick up rate.