Preradiotherapy Prostate-specific Antigen Research Articles

Postprostatectomy External Beam Irradiation

Background: A significant proportion of patients will be found to have extracapsular disease and/or detectable prostate specific antigen (PSA) values after radical prostatectomy. The role of postoperative radiotherapy to the prostatic tumor bed remains controversial. Methods: Ninety patients were treated at the Joint Center for Radiation Therapy after radical prostatectomy. The medium dose to prostatic fossa was 64.0 Gy. Medium follow‐up was 28.9 months (from time of prostatectomy). Failure after radiotherapy is defined as a persistently detectable PSA level or the development of a detectable PSA level after radiotherapy. None of the patients received androgen ablative therapy until documented postradiotherapy failure. Presurgical PSA levels, Gleason score, pathological findings at surgery, and preradiotherapy PSA levels were analyzed as predictors of PSA failure. Results: A presurgical PSA of >20.0 ng/ml is associated with PSA failure after radiotherapy (p = 0.0239). Preoperative Gleason score, PSA at time of radiotherapy or pathological findings at surgery do not predict for subsequent PSA failure. Conclusion: Postprostatectomy radiotherapy to the prostatic fossa is unlikely to provide long‐term PSA‐defined, disease‐free survival for patients who undergo prostatectomy with a presurgical PSA of >20 ng/ml. Regardless of findings at surgery, these patients have a high rate of developing PSA failure.

Radiotherapy for regionally localized hormone refractory prostate cancer

Patients with regionally localized hormone refractory adenocarcinoma of the prostate are often referred for radiotherapy to relieve local symptoms, prevent further local progression, or prevent impending urinary tract obstruction. However, the merits of radiotherapy for this patient population have not been documented. In this retrospective series, the results of 29 such patients treated at our institution between 1987-1992 are reviewed. Prior to androgen ablation, the majority of these patients (79%) had Stage D0 or D1 disease. After androgen ablation, radiotherapy was given to 16 (55%) for progressive symptoms (mostly urinary obstructive), 11 (38%) for palpable local progression in the absence of symptoms, and 2 for a rising prostate specific antigen (PSA) profile without palpable disease. None of the patients had distant metastasis at the time of radiotherapy. The median dose to the prostate was 66 Gy and the median follow-up after radiotherapy was 43 months. Following local-regional radiotherapy, the actuarial rate of local failure at 4 years was only 39%. However, 80% had disease progression or a rising PSA in this time period. The actuarial survival at 4 years following radiotherapy was 39%. Univariate analyses of potential prognostic factors revealed that preandrogen ablation Gleason score, preradiotherapy PSA, and preradiotherapy prostatic acid phosphatase (PAP) were predictive of patient outcome. Most importantly, doses above 60 Gy to the prostate at standard fractionation were associated with symptom-free local control in 90% of patients at 3 years. The majority of the patients were treated using limited fields (n = 20). The regionally localized hormone refractory prostate cancer patients described benefited from high dose, continuous course, local radiotherapy in that excellent local control rates were obtained for an extended period. Because the majority of these patients fail with distant metastasis within 4 years, this treatment represents an aggressive approach to palliation that is justified by the maintenance of freedom from local symptoms.

Measurement of weekly prostate specific antigen levels in patients receiving pelvic radiotherapy for nonprostatic malignancies

Purpose : To study the response of nonmalignant prostatic tissue to ionizing irradiation in terms of the resultant changes in serum prostate specific antigen (PSA) levels. Methods and Materials : Weekly serum PSA values were determined during radiotherapy (RT)_in nine patients (“treatment group”) without clinical evidence of prostate cancer (PC), and who received pelvic RT for other indications. Slopes fr the rate of change in PSA was determined using model: log PSA = β0 + β1 ∗week + β2 ∗week 2 + error. These results are compared with 17 normal volunteers (“control group”) who were not exposed to ionizing irradiation. an attempt is made to compare any similarities and differences in subsets of 64 T1–T4NOMO PC patients who received pelvic RT. Results : An elevation in the serum PSA levels were noted in eight of nine patients in the “treatment group” with a median time of 4.2 weeks to reach the maximum serum PSA values. After an initial increase, PSA values declined. In some patients, manifold increase in PSA was noted, for exampel, from 1.8 to 13.5 ng/ml and 3.3 to 9.8 ng/ml in two patients. The PSA increase ranged from 50–650%. The median slope was 0.601 week −1 (range 0.192–3.045 week −1). No such increases were seen in the “control group” (median slope = 0.03 week −1; range, 0.18–0.13 week −1). When diffrences between the mean increase/decrease for each week compared to pretreatment values were analyzed, the irradiated group had statistically significant elevations in the PSA for weeks 3 ( p = 0.034), 4 ( p = 0.24). A similar ternd of increasing PSA levels during radiotherapy was noted in prostate cancer patients whose initial PSA values were ≤ 20 ng/ml: whereas positive slopes (i.e., increasing PSA levels during radiotherapy course) was seen in 7.1% of those with > 20 ng/ml preradiotherapy PSA values, such trends were seen in52.7% of those with ≤ 20 ng/ml preradiotherapy PSA values. Conclusion : (a) Incidental exposure of noncancerous prostate to ionizing irradiation appears to lead to an initial elevation followed by a decline in serum PSA. (b) Similar elevations in serum (PSA) levels are seen in over 50% of prostate cancer patients with ≤ 20 ng/ml pretreatment PSA. (c) Acinal cell death and sudden release of PSA into the circulation is the most likely explanation for our observations, although other mechanism cannot be excluded. (d) Our observations have to be considered in modeling PSA kinetics induced by RT and in correlating such kinetics to long-term outcomes. (e0 Our findings in the control group indicate that there appears to be no significant variation in serum PSA over many weeks under physiological conditions in normal healthy ambulatory men.

Current status of prostate-specific antigen in the radiotherapeutic management of prostatic cancer

The current data involving the use of prostate-specific antigen (PSA) in the radiotherapeutic management of localized prostatic cancer is reviewed. Controversies and ongoing debate notwithstanding, a number of general conclusions have been made. (1) PSA as a screening test has increased prostate cancer detection rates and is recommended as part of routine screening to supplement digital rectal examination. (2) Preradiotherapy PSA levels are correlated with tumor stage but also provide prognostic information that is independent of tumor stage and histological grade. (3) Following the completion of radiotherapy, PSA levels must decline to normal values to assure a successful treatment outcome. Disagreement persists as to what constitutes a normal PSA value after radiotherapy, and in what time frame after treatments such a level must be achieved. (4) Different proposed models of PSA decline after radiotherapy are discussed, but it remains premature to assess their relative success as predictors of subsequent clinical events. (5) Postradiotherapy prostate biopsy results (negative versus positive) correlate reasonably well with post-treatment PSA status (normal versus elevated). (6) The management of patients with a rising PSA following radiotherapy must be individualized, with early hormonal intervention being an attractive, although unproven, therapeutic option for selected patients. (7) PSA data confirm the value of adjuvant radiotherapy for positive surgical margins and strengthens the indications for its use. (8) Preliminary data regarding PSA levels following transperineal interstitial brachytherapy implantation of the prostate appear favorable.