The source of pretreatment serum prostate-specific antigen in clinically localized prostate cancer--T, N, or M?

Salvage brachytherapy for locally recurrent prostate cancer after single-fraction 19 Gy high-dose-rate brachytherapy: toxicity, prostate-specific antigen kinetics, and cancer control

Purpose

To evaluate toxicity, prostate-specific antigen (PSA) kinetics, and cancer control of high-dose-rate brachytherapy (HDR-BT) as a salvage modality for men with locally recurrent prostate cancer, after primary HDR-BT failure.

Material and methods

Twelve patients with biochemical failure and a local relapse after 19 Gy single-fraction high-dose-rate brachytherapy (HDR-BT 19 Gy) were salvaged using two HDR-BT fractions. Salvage treatment consisted of two HDR-BT applications, one week apart, delivering 12 Gy to the prostate per application (HDR-BT 12 × 2).

Results

Median age and initial PSA prior to rescue treatment were 74 years (range, 65-80) and 5.29 ng/ml (range, 2.37-16.40), respectively. Forty-two percent had a low-risk and 58% presented with intermediate-risk prostate cancer. Median follow-up period was 26 months (range, 10-42). Median time to PSA nadir was 12 months, with a median value of 0.21 ng/ml. Most of the patients (11 of 12) achieved a PSA decline ≥ 90%. Acute grade 2 genitourinary (GU) toxicity occurred in 4 patients (33.3%) and none presented with acute gastrointestinal (GI) toxicity. Two patients (16.7%) suffered from late GU grade 2 toxicity. No grade 3 toxicity were recorded. To date, 2 patients (16.7%) have experienced biochemical failure after salvage treatment.

Conclusions

Salvage HDR-BT 12 × 2 is a feasible and well-tolerated treatment, with acceptable toxicity rates for men with locally recurrent prostate cancer, who failed after HDR-BT with 19 Gy. Moreover, PSA kinetics and cancer control after salvage treatment suggest that this strategy might be efficacious in this clinical setting.

Interstitial high-dose-rate brachytherapy as salvage treatment for locally recurrent prostate cancer after definitive radiation therapy: Toxicity and 5-year outcome

PURPOSE

We report our results with interstitial high-dose-rate brachytherapy (HDR-BT) as a salvage therapy option after external beam therapy with or without BT. Emphasis was put on toxicity and 5-year outcome.

METHODS AND MATERIALS

From 2003 to 2011, 29 patients with local failure after previous radiotherapy for prostate cancer were treated with salvage interstitial HDR-BT. The diagnosis of local recurrence was made on the basis of choline positron emission tomography. Salvage HDR-BT was given in three fractions with a single dose of 10 Gy per fraction and weekly. The target volume covered the peripheral zone of the prostate and the positron emission tomography-positive area. Acute and late toxicities were documented according to common terminology criteria for adverse events (CTCAE v 4.0).

RESULTS

Twenty-two patients with minimum followup of 60 months were analyzed. The 5-year overall survival was 95.5% with a disease-specific survival of 100%. The 5-year biochemical control was 45%. Late grade 2 gastrointestinal toxicities were observed in two patients (9%). No grade 3 or higher gastrointestinal late toxicities were observed. Urinary incontinence found in 2 patients (9%) and grade 2 obstruction of urinary tract occurred in one patient (4%).

CONCLUSIONS

Interstitial HDR-BT was feasible and effective in the treatment of locally recurrent prostate cancer after definitive radiotherapy. The long-term toxicity was low and acceptable.

Population-based analysis of salvage radical prostatectomy with examination of factors associated with adverse perioperative outcomes

INTRODUCTION

Salvage radical prostatectomy (SRP) is a potentially curative operation performed for recurrent prostate cancer after radiation therapy (RT). The purpose of this study was to examine perioperative and pathologic outcomes of SRP in a national cohort.

MATERIALS AND METHODS

The National Cancer Database from 1998 to 2011 was used to identify 408 patients who underwent SRP. We evaluated the demographic data, clinical variables, and pathologic and perioperative outcomes. Primary outcomes of interest were length of stay (LOS) and positive surgical margins (PSM). A multivariable logistic regression model was employed to identify preoperative predictors of LOS ≥ 3 days and PSM following SRP.

RESULTS

Among patients undergoing SRP, the mean age was 62.5 ± 6.8 years, mean prostate-specific antigen (PSA) level was 12.6 ± 15.6 ng/ml, and 64% were categorized as clinical stage T1. External beam RT (89%), followed by brachytherapy (11%), was the most common modalities for primary RT. Most SRPs were performed at high-volume centers (57%) in metropolitan locations (83%). Most patients underwent a lymph node dissection (75%) and the mean node count was 15.0 ± 30.1. On final pathology, 73% had intermediate- or high-grade disease (Gleason score 7 in 43% and Gleason score 8-10 in 30%), 49% had pT3 or pT4 disease, 6.2% had positive lymph nodes, and 34% had PSM. The mean LOS was 3.5 ± 9.9 days, and 43% of patients had a LOS ≥ 3 days. The 30-day readmission rate was 6.5% after SRP, and 30- and 90-day postoperative mortality rates were extremely low at 0.4% (n = 1). On multivariable analysis of the entire cohort, PSA level > 20 ng/ml was an independent predictor of PSM (OR = 3.68, 95% CI: 1.2-10.9, P = 0.018). PSA level > 20 ng/ml (OR = 4.37, 95% CI: 1.2-16.2, P = 0.027) and cT2 or greater disease (OR = 2.52, 95% CI: 1.0-6.2, P = 0.046) were associated with prolonged LOS (LOS ≥ 3d), whereas surgery at an academic facility (OR = 0.30, 95% CI: 0.1-0.8, P = 0.02) reduced the odds of LOS ≥ 3 days.

CONCLUSIONS

In select patients derived from a population-based cohort, SRP results in effective local cancer control with acceptable perioperative outcomes. PSA level > 20 ng/ml is independently associated with PSM and prolonged LOS after SRP. Clinical stage T2 or greater disease is also associated with prolonged LOS, whereas surgery at an academic facility reduced this risk.

A case of definitive therapy for localised prostate cancer: report of a urological nightmare

Radical prostatectomy, external beam radiotherapy and permanent brachytherapy are the most common treatment options for nonmetastatic localised adenocarcinoma of the prostate (PCa). Accurate pretherapeutic clinical staging is difficult, the number of positive cores after biopsy does not imperatively represent the extension of the cancer. Furthermore postoperative upgrading in Gleason score is frequently observed. Even in a localised setting a certain amount of patients with organ-confined PCa will develop biochemical progression. In case of a rise in PSA level after radiation the majority of patients will receive androgen deprivation therapy what must be considered as palliative. If local or systemic progressive disease is associated with evolving neuroendocrine differentiation hormonal manipulation is increasingly ineffective; radiotherapy and systemic chemotherapy with a platinum agent and etoposide are recommended. In case of local progression complications such as pelvic pain, gross haematuria, infravesical obstruction and rectal invasion with obstruction and consecutive ileus can possibly occur. In this situation palliative radical surgery is a therapy option especially in the absence of distant metastases. A case with local and later systemic progression after permanent brachytherapy is presented here.

Long-term oncologic results of salvage radical prostatectomy for locally recurrent prostate cancer after radiotherapy

PURPOSE

Salvage radical prostatectomy (RP) may potentially cure patients who have isolated local prostate cancer recurrence after radiotherapy (RT). We report the long-term cancer control associated with salvage RP in a consecutive cohort of patients and identify the variables associated with disease progression and cancer survival.

METHODS AND MATERIALS

A total of 100 consecutive patients underwent salvage RP with curative intent for biopsy-confirmed, locally recurrent, prostate cancer after RT. Disease progression after salvage RP was defined as a prostate-specific antigen (PSA) level of > or =0.2 ng/mL or by initiation of androgen deprivation therapy. Cancer-specific mortality was defined as active clinical disease progression despite castration. Cox regression analysis was used to evaluate these endpoints. The median follow-up from RT was 10 years (range, 3-27 years) and from salvage RP was 5 years (range, 1-20 years).

RESULTS

Overall, the 5-year progression-free probability was 55% (95% confidence interval, 46-64%), and the median progression-free interval was 6.4 years. The preoperative PSA level was the only significant pretreatment predictor of disease progression in the multivariate analysis (p = 0.01). The 5-year progression-free probability for patients with a preoperative PSA level of <4, 4-10, and >10 ng/mL was 86%, 55%, and 37%, respectively. The 10-year and 15-year cancer-specific mortality after salvage RP was 27% and 40%, respectively. The median time from disease progression to cancer-specific death was 10.3 years (95% confidence interval, 7.6-12.9). After multivariate analysis, the preoperative serum PSA level and seminal vesicle or lymph node status correlated independently with disease progression.

CONCLUSIONS

Greater preoperative PSA levels are associated with disease progression and cancer-specific death. Long-term control of locally recurrent prostate cancer after definitive RT is possible when salvage RP is performed early in the course of recurrent disease.

Prostate biopsy status and PSA nadir level as early surrogates for treatment failure: analysis of a prostate cancer randomized radiation dose escalation trial

PURPOSE

A positive biopsy after external beam radiotherapy in patients free of any evidence of treatment failure is not synonymous with eventual recurrence. Although biopsy positivity is a predictor of outcome, the utility of biopsy status as a surrogate end point, the effect of radiation dose on biopsy status, and the interrelationships of these associations to prostate-specific antigen (PSA) nadir level are not well-defined. These issues were investigated in a cohort of men with Stage T1-T3 prostate cancer who were randomized to receive between 70 Gy and 78 Gy and were prospectively biopsied at about 2 years after the completion of radiotherapy (RT).

METHODS AND MATERIALS

Of the 301 assessable patients in the trial, 168 underwent planned sextant or greater prostate post-RT biopsies in the absence of biochemical or clinical failure; this group constituted the study cohort. Of the 168 patients, 87 were in the 70-Gy arm and 81 in the 78-Gy arm. Biopsies were classified into four groups: negative (no tumor), atypical/suspicious cells (not diagnostic of carcinoma), carcinoma with treatment effect (CaTxEffect), and carcinoma without treatment effect (CaNoTxEffect). Any diagnosis of carcinoma in the specimen was classified as biopsy positive. Freedom from failure (FFF) included biochemical failure and/or clinical failure. Kaplan-Meier curves were calculated from the completion of RT. For those alive in the study cohort, the median follow-up was 65 months.

RESULTS

The rate of biopsy without tumor was 42%; with atypical cells, it was 28%, with CaTxEffect 21%, and with CaNoTxEffect 9%. The overall biopsy positivity rate (CaTxEffect + CaNoTxEffect) was 30%; 28% in the 70-Gy group and 32% in the 78-Gy group (p = 0.52). The distribution of PSA nadir levels was 73% <or=0.5, 20% >0.5-1.0, 5% >1.0-2.0, and 1% >2.0 ng/mL. Significantly more patients randomized to 78 Gy had a PSA nadir of <or=0.5 ng/mL (80% vs. 67%; p = 0.02). No relationship was found between PSA nadir level and prostate biopsy status. The 5-year FFF rate for those classified as biopsy negative was 84% and for those biopsy positive was 60% (p = 0.0002). Radiation dose did not significantly alter FFF rates by prostate biopsy status. Nadir PSA level correlated with FFF, although this was dependent on the inclusion of the 2 patients with a PSA nadir >2.0 ng/mL.

CONCLUSION

For patients free of treatment failure at the time of prostate biopsy 2 years after RT, the prognosis of no tumor cells was the same as that of atypical/suspicious cells and CaTxEffect was the same as CaNoTxEffect. The biopsy positivity rate was not altered by dose, suggesting that most of the outcome differences between the 70-Gy and 78-Gy groups were due to events occurring before prostate biopsy at 2 years and/or were not entirely dependent on biopsy status. Biopsy status is a strong prognostic factor, but, as an early end point, it may be misleading. PSA nadir appears to have little clinical value in patients treated to doses of >/=70 Gy who are failure free 2 years after RT.

Serum testosterone is not a correlate of prostate cancer lymph node involvement, but does predict biochemical failure for lymph node positive disease

Previously we found that serum testosterone (serum-T) correlated with the development of distant metastasis in patients with clinically localized prostate cancer treated with radiotherapy. In this report, the relationship of serum-T to lymph node positivity and to patient outcome for patients with regional lymph node involvement treated with androgen ablation alone was investigated. Serum-T was available in 514 of 854 men with clinically localized prostate cancer who underwent pelvic lymphadenectomy at M.D. Anderson Cancer Center between 1984 and 1993. Pretreatment prostatic acid phosphatase (PAP) and prostate specific antigen (PSA) were assayed in 98% and 95% of patients, respectively. Androgen ablation was achieved via orchiectomy or a luteinizing hormone releasing hormone agonist. Median follow-up was 66 months for the node positive subgroup (n = 92). Serum-T did not correlate with palpable stage, Gleason score, pretreatment PSA, or lymph node involvement. Age ⩽ 60 years and pretreatment PAP > 0.8 mU/ml correlated significantly with higher serum-T. In lymph node positive patients treated with androgen ablation, higher serum-T levels corresponded to both pretreatment PSA > 10 ng/ml and PAP > 0.8 mU/ml. Serum-T predicted for biochemical failure, but not metastatic relapse or overall survival. Actuarial 5-year biochemical failure rate was 73% for serum T > 500 ng/dl and 57% for serum-T ≤ 500 (p = 0.009). Multivariate analysis showed serum-T to be an independent correlate of rising PSA, both as a continuous (p = 0.001) or categorical (p = 0.037) variable. Serum-T did not significantly correlate with lymph node positivity, and therefore is not a marker for regional disease spread. However, serum-T was significantly associated with biochemical failure in node-positive patients treated with androgen ablation alone.

External beam radiotherapy dose response of prostate cancer

PURPOSE

To determine the external beam radiotherapy dose response of palpable Stage T1-T4, mostly Nx, patients with adenocarcinoma of the prostate.

METHODS AND MATERIALS

There were 938 men consecutively treated between 1987 and 1995 who had pretreatment prostate specific antigen (PSA) levels. Posttreatment failure was defined as disease recurrence and/or two elevations in PSA on consecutive follow-up visits. The radiotherapy technique consisted of a four-field box with a small four-field reduction after 46 Gy in 844 patients (total dose of 60-70 Gy) or with a six-field conformal boost after 46 Gy in 94 patients (total dose of 74-78 Gy). Neoadjuvant or adjuvant androgen ablation was not used in any patient. Median follow-up was 40 months.

RESULTS

The mean and median radiotherapy doses for the entire group were 67.8 +/- 13.3 Gy (+/-SEM) and 66 Gy. The mean radiotherapy dose was higher in those who had Stage T3/T4 disease, Gleason scores of 8-10, or pretreatment PSAs of > 4 ng/ml. In general, patients with more aggressive pretreatment prognostic features were treated to higher doses; yet, those that relapsed or had a rising PSA were treated to significantly lower doses. Actuarial analyses were facilitated by dividing patients into three dose groups: < or = 67, > 67-77, and > 77 Gy. The actuarial freedom from failure rates at 3 years were 61, 74, and 96% for the low, intermediate, and high dose groups. Stratification of the patients by pretreatment PSA revealed that dose was a significant correlate of freedom from relapse or a rising PSA for those with PSAs > 4-10, > 10-20, and > 20 ng/ml. The only patients in which an improvement in outcome was not related to higher doses were those with a pretreatment PSA < or = 4 ng/ml. Dose was significantly associated with freedom from failure for Stage T1/T2 and Stage T3/T4 patients, as well as for those stratified by Gleason score. Multivariate analysis using Cox proportional hazards models showed that dose was an independent and highly significant predictor of relapse or a rising PSA.

CONCLUSION

This retrospective review strongly indicates that radiotherapy dose to the prostate is critical to the cure of prostate cancer, even for favorable patients with pretreatment PSAs of > 4-10 ng/ml, Stages T1/T2, or Gleason scores of 2-6. Final confirmation awaits the results of our randomized trial.

Kinetics of serum prostate-specific antigen after external beam radiation for clinically localized prostate cancer

BACKGROUND AND PURPOSE

To determine the kinetics of serum prostate-specific antigen (PSA) after radiation therapy of localized prostate cancer and to evaluate whether such kinetics provide prognostic information.

MATERIALS AND METHODS

Eight hundred forty-one men with serial PSA determinations who underwent external beam radiation without androgen ablation were analyzed to determine postradiation PSA kinetic parameters (half-life and doubling time) and to correlate these parameters with disease outcome. Non-linear regression techniques were used to determine half-lives and doubling times.

RESULTS

The postradiation serum PSA data fitted well to first order kinetic models. The median PSA half-life was 1.6 months (range 0.5-9.2 months). There was no correlation between half-life and T-stage or Gleason grade. A significant but quantitatively weak correlation was present between the pretreatment PSA level and half-life; lower pretreatment levels were associated with longer half-lives. Half-life did not correlate with disease outcome whether the endpoint was local recurrence, distant metastasis or rising PSA. In 263 men with a rising postradiation PSA profile the median PSA doubling time was 12.2 months (range 0.8-80.2 months). Faster doubling times were significantly associated with higher T-stage, higher Gleason grade and higher pretreatment PSA levels. Thus, patients with initially adverse disease developed faster rising PSA values after treatment than patients with less adverse disease. The most striking correlation was between rapid doubling time and the likelihood of metastatic relapse. Patients who developed metastases had a median PSA doubling time of 4.2 months compared to a median doubling time of 11.7 months in patients who developed local recurrence. Overall, patients with a PSA doubling time of less than 8 months had a 7-year actuarial metastatic rate of 54%, while patients with a PSA doubling time exceeding 8 months had only a 7% metastatic rate. Particularly ominous was the combination of a doubling time shorter than 8 months which began to rise within the first year; by 3 years 50% of these men had metastases and all were actuarially projected to develop such relapse by 6.5 years.

CONCLUSIONS

Overall, the clinical utility of postradiation serum PSA kinetics was small. There were no discernible uses for PSA half-life. In patients with a rising PSA profile the faster the kinetics the more adverse the disease. Doubling times shorter than 8 months, especially if the rise begins in the first year, predict for metastatic relapse. However, in the absence of decisively useful treatment for metastatic prostate cancer the virtues of the early detection of metastases remain unclear.

Combined external beam irradiation and external regional hyperthermia for locally advanced adenocarcinoma of the prostate

PURPOSE

To determine the safety and efficacy of combined external beam irradiation and external regional hyperthermia in the treatment of adenocarcinoma of the prostate.

METHODS AND MATERIALS

From 1987 to 1994, 30 patients received combined external beam irradiation and external regional hyperthermia for locally advanced prostate cancer. The results of the 21 patients with newly diagnosed (n = 18) or locally recurrent (n = 3) adenocarcinoma are reported herein. No patient had evidence of distant metastases. Total radiotherapy doses of 65-70 Gy to the prostate were planned using a four-field box technique. Hyperthermia treatments were delivered using an annular phased array microwave device. The treatment goal was to achieve temperatures > or = 42 degrees C in all measured points within the prostate.

RESULTS

Of the newly diagnosed patients, 16 out of 18 (89%) had T3 or T4 tumors, 11 out of 18 (61%) had Gleason scores of 7-9, and the mean pretreatment Prostate Specific Antigen (PSA) was 69 ng/ml. The median follow-up of all 21 patients was 36 months. None of the patients achieved the treatment goal of all intratumoral temperatures > or = 42 degrees C. The mean CEM 43 T90 was 2.34 min. The disease-free survival at 36 months is 25%; 12 out of 18 (67%) of the patients have relapsed. The only significant predictor of relapse was pretreatment PSA. There were no complications > Grade 3.

CONCLUSIONS

In spite of the inability to achieve high tumor temperatures, the relapse-free survival rate in this population of patients with very advanced localized prostate cancer treated with radiation therapy plus hyperthermia compares favorably with most series using radiation therapy alone. Further studies aimed at improving the ability to deliver hyperthermia to the prostate are warranted.

Conventional vs. conformal radiotherapy for prostate cancer: preliminary results of dosimetry and acute toxicity

PURPOSE

To compare conformal radiotherapy using three dimensional treatment planning (3D-CRT) to conventional radiotherapy (Conven-RT) for patients with Stages T2-T4 adenocarcinoma of the prostate.

METHODS AND MATERIALS

A Phase III randomized study was activated in May 1993, to compare treatment toxicity and patient outcome after 78 Gy in 39 fractions using 3D-CRT to that after 70 Gy in 35 fractions using Conven-RT. The first 46 Gy were administered using the same nonconformal field arrangement (four field) in both arms. The boost was given nonconformally using four fields in the Conven-RT arm and conformally using six fields in the 3D-CRT arm. The dose was specific to the isocenter. The first 60 patients, 29 in the 3D-CRT arm and 31 in the Conven-RT arm, are the subject of this preliminary analysis.

RESULTS

The two treatment arms were first compared in terms of dosimetry by dose-volume histogram analysis. Using a subgroup of patients in the 3D-CRT arm (n=15), both Conven-RT and 3D-CRT plans were generated and the dose-volume histogram data compared. The mean volumes treated to doses above 60 Gy for the bladder and rectum were 28 and 36% for the 3D-CRT plans, and 43 and 38% for the Conven-RT plans, respectively (p < 0.05 for the bladder volumes). The mean clinical target volume (prostate and seminal vesicles) treated to 95% of the prescribed dose was 97.5% for the 3D-CRT arm, and 95.6% for the Conven-RT arm (p < 0.05). There were no significant differences in the acute reactions between the two arms, with the majority experiencing Grade 2 or less toxicity (92%). Moreover, no relationship was seen between acute toxicity and the volume of bladder and rectum receiving in excess of 60 Gy for those in the 3D-CRT arm. There was also no difference between the groups in terms of early biochemical response. Prostate-specific antigen levels at 3 and 6 months after completion of radiotherapy were similar in the two treatment arms. There was only one biochemical failure in the study population at the time of the analysis.

CONCLUSIONS

Comparison of the Conven-RT and 3D-RT treatment plans revealed that significantly less bladder was in the high dose volume in the 3D-CRT plans, while the volume of rectum receiving doses over 60 Gy was equivalent. There were no differences between the two treatment arms in terms of acute toxicity or early biochemical response. Longer follow-up is needed to determine the impact of 3D-CRT on long-term patient outcome and late reactions.

Prostate cancer and radiation therapy--the message conveyed by serum prostate-specific antigen

PURPOSE

Prostate-specific antigen (PSA) is a powerful pretreatment prognosticator and a sensitive post-treatment outcome measure for clinically localized prostate cancer treated with radiation therapy. Today, the pretreatment serum PSA level appears to supersede both grade and T-stage as a determinant of outcome. This study was undertaken to attempt a reconciliation between the old (pre-PSA) and the new (PSA) data-in particular to address the question of why stage and grade apparently play so little role in this PSA era.

METHODS AND MATERIALS

We analyzed the outcome of two cohorts of men with T1-T4, NO, or NX, MO prostate cancer, one group (648 patients) treated and followed in the pre-PSA era (1966-1988), another group (707 patients) treated and followed in the PSA era (1987-1993)--who received definitive radiation as their only initial treatment. The patterns of relapse and prognostic factors for these groups were compared and contrasted using univariate and multivariate techniques.

RESULTS

At a median follow-up of 6.5 years, the relapse patterns in the pre-PSA series were: local in 109 (17%), nodal in 17 (3%), and distant metastatic in 186 (29%). Actuarial local and metastatic rates at 5 years were 13 and 26%, respectively. Local recurrence was only weakly predictable, Gleason grade being the only significant, albeit weak, covariate. Metastatic failure, however, was highly significantly and meaningfully correlated with Gleason grade and T-stage. Because metastasis was the most common adverse end point in this series, overall freedom from progression also correlated with grade and stage. At a median follow-up of 31 months, the patterns of failure in the PSA series were: local in 77 (11%), nodal in 3 (< 1%), and distant metastatic in 24 (3%). Actuarial local and metastatic rates at 5 years were 30 and 6%, respectively. Local recurrence was highly and meaningfully correlated with pretreatment PSA level, which was the only significant determinant of this end point. Metastatic failure was highly correlated with Gleason grade and T-stage, with PSA playing a much lesser, though significant role. The inversion of failure patterns (local vs. distant) between the two series was striking. The high incidence of local failure in the PSA series was almost entirely related to positive prostatic biopsies pursuant to the investigation of the postradiation rising PSA profile. Of the 77 local recurrences, 69 (90%) were identified in this way. Among 99 men with rising PSA values who underwent investigation (CT scans, bone scans, and biopsies), disease was found in 86, and the patterns of disease in these 86 were: local only in 62 (72%), local and metastatic in 7, and metastatic in 17 (20%). The most common event in the PSA series was the rising PSA profile, and this, too, strongly correlated with the pretreatment PSA level.

CONCLUSION

Based on our earlier finding that the major source of pretreatment serum PSA in patients with clinically localized disease is the primary tumour itself and on the findings in the present report, we conclude that the new major message conveyed by serum PSA relates to the primary tumor and its likely outcome. Gleason grade and T-stage remain major determinants of metastatic relapse. The total and permanent eradication of prostate cancer from the prostate with conventional doses of external beam radiation therapy is harder to achieve than generally appreciated.

Prostate-specific antigen and radiation therapy for clinically localized prostate cancer

PURPOSE

This study was undertaken to: (a) define the prognostic significance of pretreatment serum prostate-specific antigen (PSA) levels in localized prostate cancer treated with radiation; (b) define the prognostic usefulness of postradiation PSA levels; (c) evaluate the outcome of radiation using PSA as an endpoint.

METHODS AND MATERIALS

Disease outcome in 707 patients with Stages T1 (205 men), T2 (256 men), T3 (239 men), and T4 (7 men), receiving definitive external radiation as sole therapy, was evaluated using univariate and multivariate techniques.

RESULTS

At a mean follow-up of 31 months, 157 patients (22%) developed relapse or a rising PSA. Multivariate analysis revealed pretreatment PSA level to be the most significant prognostic factor, with lesser though significant contributions due to Gleason grade (2-6 vs. 7-10) and transurethral resection in T3/T4 disease. The following four prognostic groupings were defined: group I, PSA < or = 4 ng/ml, any grade; group II, 4 < PSA < or = 20, grades 2-6; group III, 4 < PSA < or = 20, grades 7-10; group IV, PSA > 20, any grade. Five-year actuarial relapse rates in these groups were: I, 12%; II, 34%; III, 40%; and IV, 81%. Posttreatment nadir PSA was an independent determinant of outcome and only patients with nadir values < 1 ng/ml fared well (5-year relapse rate 20%). Using rising PSA as an endpoint the 461 patients with T1/T2 disease had an actuarial freedom from disease rate of 70% at 5 years, which appeared to plateau, suggesting that many were cured. No plateau was evident for T3/T4 disease.

CONCLUSION

Pretreatment serum PSA is the single most important predictor of disease outcome after radiation for local prostate cancer. Tumor grade has a lesser though significant prognostic role. Postirradiation nadir PSA value during the first year is a sensitive indicator of response to treatment. Only nadir values < 1 ng/ml are associated with a favorable outlook. A significant fraction of men with T1/T2 disease may be cured with radiation. There was no evidence for a cured fraction among patients with T3/T4 disease.