Prognostic implications of prostate-specific antigen in patients with locally advanced prostate cancer treated with high energy neutron beam therapy: preliminary results

Radiotherapy options for localized prostate cancer based upon pretreatment serum prostate-specific antigen levels and biochemical control: a comprehensive review of the literature

PURPOSE

To review all the available radiotherapy (RT) literature on localized prostate cancer treatment where serum prostate-specific antigen (PSA) levels were used to both stratify patients and evaluate outcome and determine if any conclusions can be reached regarding an optimal radiotherapeutic management for this disease.

METHODS AND MATERIALS

A MEDLINE search was conducted to obtain all articles in English on prostate cancer treatment employing RT from 1986-1997. Studies were considered eligible for review only if they met all the following criteria: 1) pretreatment PSA values were recorded and grouped for subsequent evaluation, 2) posttreatment PSA values were continuously monitored, 3) definitions of biochemical control were stated, and 4) the median follow-up was given.

RESULTS

Of the 246 articles identified, only 20 met the inclusion criteria; 4 using conformal external beam RT, 8 using conventional external beam RT, and 8 using interstitial brachytherapy (4 using a permanent implant alone, 3 combining external beam RT with a permanent implant, and 1 combining a conformal temporary interstitial implant boost with external beam RT). No studies using neutrons (with or without external beam RT) or androgen deprivation (combined with external beam RT) were identified where patients were stratified by pretreatment PSA levels. Results for all therapies were extremely variable with the 3-5-year rates of biochemical control for patients with pretreatment PSA levels < or = 4 ng/ml ranging from 48 to 100%, for PSA levels >4 and < or = 10 ng/ml ranging from 44 to 90%, for PSA levels >10 and < or = 20 ng/ml ranging from 27 to 89%, and for PSA levels >20 ranging from 14 to 89%. The median Gleason score, T-stage, definition of biochemical control, and follow-up were substantially different from series to series. No RT option consistently produced superior results.

CONCLUSIONS

When data are reviewed from studies using serum PSA levels to stratify patients and to evaluate treatment outcome, no consistently superior RT technique was identified. These data suggest that standard definitions of disease stage (combining clinical, pathologic, and biochemical criteria) and a common definition of biochemical cure (as developed by the American Society for Therapeutic Radiology and Oncology Consensus Panel) need to be adopted to evaluate treatment efficacy and advise patients on the most appropriate radiotherapeutic option for their disease.

Reference range for prostate-specific antigen levels after external beam radiation therapy for adenocarcinoma of the prostate

OBJECTIVES

To determine a reference range for prostate-specific antigen (PSA) in patients who have had external beam radiation therapy for adenocarcinoma of the prostate.

METHODS

Serum PSA levels were serially measured with the Hybritech Tandem-R assay in 35 patients who had completed radiation therapy for a mean of 51 +/- 32 months (range, 10 to 133).

RESULTS

Serum PSA levels that were greater than 2.0 ng/mL (n = 20) continued to rise at a rate of more than 1 ng/mL per year, whereas levels between 0.0 and 2.0 ng/mL (n = 15) remained stable for an average of 71 +/- 32 months (range, 22 to 133). One of these latter 15 patients had a false-negative PSA level when he experienced a biopsy-positive prostate nodule and positive bone scan 43 months after therapy.

CONCLUSIONS

Prostate cancer control after radiation therapy was indicated in most men by a PSA reference range of 0.0 to 2.0 ng/mL. Cancer activity was indicated in all men with levels above this range.

Radiation therapy for prostate cancer confined to pelvis

To evaluate the usefulness of external beam radiotherapy for patients with prostate cancer confined to the pelvis, long-term results and prognostic factors were analyzed. During the period 1975-1989, 44 cases were treated with staging pelvic lymphadenectomy followed by monotherapy using external beam irradiation by Linac X-ray and/or fast neutrons and observed without any treatment until relapse was evident. All patients were followed until death or for a mean of 78.6 mo (range: 36-113 mo) for patients still alive. Four cases died of prostate cancer at 26, 28, 54, and 83 mo from the start of radiation. Eleven cases died of other causes (10-72 mo, mean 36.4 mo). Fourteen cases (31.8%) manifested clinical relapse of cancer; 4 had local relapse, 7 developed bone metastases, and 3 relapsed at lymph nodes. After relapse, endocrine therapy was effective in most cases. The five-year disease-free survival rates of pN0 (32 cases) and pN1 (8 cases) patients were 79.8% and 52.5%, respectively, but that of pN2 (4 cases) was worse. Cause-specific survival was similar between patients with pN0 and pN1 disease, the rate at 5 yr being 92.5% in the former and 100% in the latter. Those with high levels of serum prostate specific antigen (PSA) before treatment and advanced local disease (clinical stage C) showed unfavorable prognoses. The number of argyrophilic nucleolar organizer regions (AgNORs) might be a predictive factor in patients treated with irradiation. In conclusion, prostate cancer patients with stage A2-C, diagnosed as pN0-1 by staging pelvic lymphadenectomy, were successfully treated with external beam radiotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)