Prostate-specific antigen for pretreatment prediction and posttreatment evaluation of outcome after definitive irradiation for prostate cancer

PSA reduction as predictor of biochemical relapse in low and favourable intermediate prostate cancer treated with radical radiotherapy

PURPOSE

Radiation therapy (RT) is standard treatment for localized prostate cancer (PCa). Prostate-specific antigen (PSA) kinetics, particularly PSA reduction (PSAr) after RT, are emerging as significant prognostic indicators for biochemical control. This retrospective multi-institutional study explores the correlation between PSAr and biochemical relapse-free survival (BRFS). This retrospective multi-institutional study explores the correlation between PSAr and biochemical relapse-free survival (BRFS).

METHODS

251 low-to-intermediate risk PCa patients treated with RT only were analyzed. Isoeffective RT schedules were: 39 fractions × 2 Gy, 28 × 2.55 Gy, 16 × 3.5 Gy, 5 × 7 Gy. Main objective was BRFS, defined as the time from PSA nadir (PSAn) to PSAn plus 2 ng/ml. PSAr was defined as the percentage of total PSA reduction from baseline. The optimal PSAr cut-off value was defined as 90%. Patients were stratified by PSAr, baseline PSA, Gleason Score (GS), and RT schedules.

RESULTS

GS was 3 + 3 in 120 (48%) patients and 3 + 4 in 131 (52%) patients. After a median follow-up of 36 months (30-48), 2 and 5-year BRFS were 97.3% and 95.2%, respectively, in patients with PSAr ≥ 90% and 89.5%, 61.5% in patients with PSAr < 90% (p = 0.00). In the responder population, median time to PSAr 90% was 24 months and the median time to PSAn was 28.7 months (20-38). At univariate and multivariate analyses, PSAr was the only significant predictor of BRFS [HR 6.519 (95% IC 1.9-22.2), p = 0.003].

CONCLUSIONS

PSAr could be a reliable prognostic factor for long-term biochemical control. This study underscores the potential of PSAr as a tool for risk stratification and personalized follow-up strategies in PCa management.

Extreme-risk prostate adenocarcinoma presenting with prostate-specific antigen (PSA)>40 ng/ml: prognostic significance of the preradiation PSA nadir

PURPOSE

To examine the impact of patient, disease, and treatment characteristics on survival outcomes in patients treated with neoadjuvant androgen deprivation therapy (ADT) and radical external-beam radiotherapy (RT) for clinically localized, extreme-risk prostate adenocarcinoma with a presenting prostate-specific antigen (PSA) concentration of >40 ng/ml.

METHODS AND MATERIALS

A retrospective chart review was conducted of 64 patients treated at a single institution between 1991 and 2000 with ADT and RT for prostate cancer with a presenting PSA level of >40 ng/ml. The effects of patient age, tumor (presenting PSA level, Gleason score, and T stage), and treatment (total ADT duration and pre-RT PSA level) characteristics on rates of biochemical disease-free survival (bDFS), prostate cancer-specific survival (PCSS), and overall survival (OS) were examined.

RESULTS

Median follow-up time was 6.45 years (range, 0.09-15.19 years). Actuarial bDFS, PCSS, and OS rates at 5 years were 39%, 87%, and 78%, respectively, and 17%, 64%, and 45%, respectively, at 10 years. On multivariate analysis, the pre-RT PSA level (≤0.1 versus >0.1 ng/ml) was the single most significant prognostic factor for bDFS (p=0.033) and OS (p=0.018) rates, whereas age, T stage, Gleason score, and ADT duration (≤6 versus >6 months) were not predictive of outcomes.

CONCLUSION

In prostate cancer patients with high presenting PSA levels, >40 ng/ml, treated with combined modality, neoadjuvant ADT, and RT, the pre-RT PSA nadir, rather than ADT duration, was significantly associated with improved survival. This observation supports the use of neoadjuvant ADT to drive PSA levels to below 0.1 ng/ml before initiation of RT, to optimize outcomes for patients with extreme-risk disease.

Outcomes for patients with high-grade prostate cancer treated with a combination of brachytherapy, external beam radiotherapy and hormonal therapy

OBJECTIVE

To assess the outcomes for patients with Gleason score 8-10 prostate cancer treated with brachytherapy, external beam radiotherapy (EBRT) and hormonal therapy (HT).

PATIENTS AND METHODS

In all, 181 patients with Gleason scores 8-10 prostate cancer were treated from 1994 to 2006 with a (103)Pd implant (prescription dose 100 Gy), 45 Gy of EBRT and 9 months of HT. The median (range) follow-up was 65 (24-150) months; freedom from biochemical failure (FBF) rates were calculated using the Phoenix definition.

RESULTS

The 8-year actuarial FBF, freedom from distant metastases, prostate-cancer specific survival and overall survival were 73%, 80%, 87% and 79%, respectively. The pretreatment prostate-specific antigen (PSA) level significantly affected FBF, with 8-year rates of 72%, 82% and 58% for patients with PSA level of <or=10, >10-20 and >20 ng/mL, respectively (P = 0.006). The PSA level had no significant effect on rates of distant metastases. The Gleason score had the most significant affect on FBF in a multivariate analysis, and was the only factor to significantly affect rates of distant metastases; the 8-year FBF rates were 84%, 55% and 30% for scores of 8, 9 and 10, respectively (P = 0.003). The corresponding freedom from distant metastases and prostate-cancer specific survival rates were 86%, 76%, 30% (P < 0.001) and 92%, 80%, 62.5% (P = 0.003), respectively.

CONCLUSIONS

The 8-year outcomes after this regimen showed favourable biochemical and distant control, as well disease-specific survival rates for patients with Gleason scores of 8-10. This treatment approach should be considered as a viable option for this subset of patients with high-risk disease.

Determinants of change in prostate-specific antigen over time and its association with recurrence after external beam radiation therapy for prostate cancer in five large cohorts

PURPOSE

To assess the relationship between prognostic factors, postradiation prostate-specific antigen (PSA) dynamics, and clinical failure after prostate cancer radiation therapy using contemporary statistical models.

METHODS AND MATERIALS

Data from 4,247 patients with 40,324 PSA measurements treated with external beam radiation monotherapy in five cohorts were analyzed. Temporal change of PSA after treatment completion was described by a specially developed linear mixed model that included standard prognostic factors. These factors, along with predicted PSA evolution, were incorporated into a Cox model to establish their predictive value for the risk of clinical recurrence over time.

RESULTS

Consistent relationships were found across cohorts. The initial PSA decline after radiation therapy was associated with baseline PSA and T-stage (p < 0.001). The long-term PSA rise was associated with baseline PSA, T-stage, and Gleason score (p < 0.001). The risk of clinical recurrence increased with current level (p < 0.001) and current slope of PSA (p < 0.001). In a pooled analysis, higher doses of radiation were associated with a lower long-term PSA rise (p < 0.001) but not with the risk of recurrence after adjusting for PSA trajectory (p = 0.63). Conversely, after adjusting for other factors, increased age at diagnosis was not associated with long-term PSA rise (p = 0.85) but was directly associated with decreased risk of recurrence (p < 0.001).

CONCLUSIONS

We conclude that a linear mixed model can be reliably used to construct typical patient PSA profiles after prostate cancer radiation therapy. Pretreatment factors along with PSA evolution and the associated risk of recurrence provide an efficient and quantitative way to assess the impact of risk factors on disease progression.

Salvage radical prostatectomy for radiorecurrent prostate cancer: Indications and results

AIMS

A rise in the incidence of radiorecurrent prostate cancer is to be expected, since approximately one third of early prostate cancer cases are nowadays treated with a radiotherapy modality. One possibility in treating radiorecurrent prostate cancer is salvage prostatectomy. Our objective was to look into our own experience with salvage radical prostatectomy and to analyse outcome and morbidity.

METHODS

A computer search through our hospital database identified 11 patients who underwent a salvage radical prostatectomy for radiorecurrent cancer over the last 15 years. All data were retrospectively analysed and confronted with the literature.

RESULTS

Although the surgery was mostly difficult, there were no intraoperative complications. Bladder neck stricture is the most common postoperative complication (18%). Continence rates are worse than in classical radical prostatectomy. All patients lost potency, since no attempt was made to spare the neurovascular bundles. With a mean follow-up of 6.9 years, biochemical disease-free survival rates was 55%, while overall and cancer-specific survival was 91%.

CONCLUSION

While most patients with radiorecurrent prostate cancer will be treated by many experts with hormonal therapy, a salvage radical prostatectomy can give a second chance for cure in carefully selected patients.

Evolving Role of Surgery, Radiation, Hormone Therapy, and Chemotherapy in High-Risk Locally Advanced Prostate Cancer

Locally advanced prostate cancer encompasses several disease states that vary in the risk for progression and recurrence after initial treatment. Further, the optimal treatment strategies for locally advanced prostate cancer are continuing to evolve, reflecting the complex nature of this disease state. For many patients, clinical experience demonstrates that a combined approach of locally directed therapy and systemic therapy is likely to provide better long-term outcome than single-modality therapy. Randomized studies have established hormone ablation with external-beam radiation as an important form of treatment for this group of patients. However, additional progress needs to be made, particularly in the subgroup of patients with very high-risk disease features. As the optimal integration of local and systemic treatments becomes more clearly defined, the long-term prognosis for patients with high-risk locally advanced prostate cancer will improve.

Braquiterapia de alta taxa de dose no tratamento do carcinoma da próstata: análise da toxicidade aguda e do comportamento bioquímico

OBJETIVO: Analisar a resposta bioquímica nas variáveis volume prostático, valor do antígeno prostático específico (PSA), escores de Gleason, estádio, risco da doença e hormonioterapia. MATERIAIS E MÉTODOS: No período de fevereiro de 1998 a julho de 2001, 46 pacientes com câncer de próstata foram tratados com radioterapia, numa combinação de teleterapia e braquiterapia de alta taxa de dose (BATD). A idade variou de 51 a 79 anos (média de 66,4 anos). O estádio T1c foi o mais freqüente: 30 (65%). O escore de Gleason era abaixo de 7 em 78% dos pacientes. O PSA variou de 3,4 a 33,3, estando abaixo de 10 em 39% das vezes. O volume prostático médio foi de 32,3 cc. Um total de 28% dos pacientes recebeu hormonioterapia. A dose de teleterapia variou de 45 a 50,4 Gy, associada a quatro frações de BATD de 4 Gy. RESULTADOS: O seguimento variou de 6 a 43 meses. Quatro pacientes perderam seguimento e quatro morreram (um por doença). Dos 39 pacientes analisados, 76% apresentaram PSA menor que 1,5. Nenhuma das variáveis analisadas foi estatisticamente significante (p > 0,05) com relação ao controle bioquímico. CONCLUSÃO: A utilização de BATD foi eficiente no tratamento do câncer de próstata e, neste estudo, as variáveis consideradas como fatores prognósticos não interferiram no controle bioquímico.

Radiotherapy in prostate cancer treatment

Prostate cancer is a complex disease, with many controversial aspects of management in almost all stages of disease. The natural history of this tumor is variable and is influenced by multiple prognostic factors. Radical prostatectomy and radiotherapy are standard treatment options for disease limited to the prostate. The data in literature does not provide clear- cut evidence for the superiority of any treatment. Neo- adjuvant or adjuvant hormonal therapy improves local control and survival in locally advanced disease. The patients treated with radiotherapy would have a relatively long life expectancy, not great risk factors for radiation toxicity and a preference for radiotherapy. The advantages of radiotherapy are that it has a significant potential for cure, it is well tolerated in the majority of men especially when the modern techniques of conformal radiotherapy and intensity modulated therapy are used and it is non-invasive therapeutic options with no anesthesia risk. Expected complications like radiation cystitis, impotence and proctitis are registered in about 1% of patients.

Assessing the impact of an alternative biochemical failure definition on radiation dose response for high-risk prostate cancer treated with external beam radiotherapy

PURPOSE

The American Society for Therapeutic Radiology and Oncology (ASTRO) biochemical failure definition has recently been compared with various alternative definitions. We assessed the effect of using an alternative failure definition on the dose-response characteristics of high-risk prostate cancer treated with radiotherapy alone.

METHODS AND MATERIALS

This study included 363 high-risk prostate cancer patients treated with external beam radiotherapy alone from 1987 to 1999. These patients have one or more of the following: 1992 American Joint Committee on Cancer (AJCC) digital rectal examination (DRE) stage > or = cT3, prostate-specific antigen (PSA) > 20 ng/mL, and/or biopsy Gleason score > or = 8. We previously reported the dose response based on the ASTRO definition for these patients. In this study, a biochemical failure is defined as a PSA rise > or = 2 ng/mL above the current nadir PSA (CN + 2). The failure date is defined as the time at which the event occurred (i.e., the call date).

RESULTS

Using CN + 2, the tumor control probability (TCP) continues to decrease with time as opposed to reaching a plateau as with the ASTRO definition. At 5 years, TCD50 (95% CI), the dose to achieve 50% tumor control, for high-risk prostate cancer, is 70.4 (68.0-72.9) Gy using CN + 2 [ASTRO: 75.5 (70.7-80.2) Gy]. The relative slope, gamma50 (95% CI) is 1.8 (0.8-2.8) [ASTRO: 1.7 (0.7-2.7)]. Recursive partitioning again identified two subgroups: PSA < vs. > or = 13 ng/mL (ASTRO: PSA < or = vs. > 20 ng/mL). The difference in TCD50 between the two subgroups is about 20 Gy at 5 years (ASTRO: about 15 Gy at 5 years).

CONCLUSION

This analysis using the CN + 2 failure definition continues to show a dose response for the high-risk group of patients. However, the dose-response characteristics differ from those estimated using the ASTRO definition. We observed that the position (TCD50) and steepness (gamma50) of the dose-response curve changed with time as long as the TCP continued to decrease. This suggests that the dose response characteristics derived from data with longer follow-up may be different from those derived with shorter follow-up using the CN + 2 or similar failure definitions which do not back-date the failure. These changes in dose-response characteristics as well as the time dependence of dose response should be noted when investigators design dose escalation trials for the high-risk prostate cancer patients.

Combined modality treatment in the management of high-risk prostate cancer

PURPOSE

The efficacy of a multimodality protocol using neoadjuvant and concomitant hormonal therapy, brachytherapy, and three-dimensional conformal external beam radiotherapy (RT) in high-risk prostate cancer was evaluated using biochemical outcomes and posttreatment biopsy results.

METHODS AND MATERIALS

Between February 1994 and November 1999, 132 high-risk patients were treated with combined hormonal therapy (9 months), permanent radioactive seed brachytherapy, and external beam RT, with follow-up ranging from 36 to 88 months (median, 50 months). The eligibility criteria were any of the following: Gleason score 8-10, initial prostate-specific antigen (PSA) level >20 ng/mL, clinical Stage T2c-T3, or positive seminal vesicle biopsy, or two or more of the following: Gleason score 7, PSA level >10-20 ng/mL, or Stage T2b. Twenty percent of patients had a positive seminal vesicle biopsy before therapy. Negative laparoscopic pelvic lymph node dissections were performed in 44% of patients.

RESULTS

The actuarial overall freedom from PSA failure rate was 86% at 5 years. The freedom from PSA failure rate at 5 years was 97% for those with a Gleason score of < or =6 (35 of 36), 85% for a Gleason score of 7 (50 of 59), and 76% for a Gleason score of 8-10 (28 of 37; p = 0.03). A trend was noted toward worse outcomes in seminal vesicle biopsy-positive patients, with a 5-year freedom from PSA failure rate of 74% vs. 89% for all other patients (p = 0.06). Posttreatment prostate biopsies were performed in 47 patients and were negative in 96% at the first biopsy and 100% at the last biopsy.

CONCLUSION

Trimodality therapy with androgen suppression, brachytherapy, and external beam RT for high-risk prostate cancer results in excellent biochemical and pathologically confirmed local control.

Avaliação da resposta bioquímica no câncer inicial de próstata: experiência uninstitucional comparando teleterapia exclusiva ou associada à braquiterapia de alta taxa de dose

OBJETIVO: Análise comparativa da resposta bioquímica em pacientes submetidos à teleterapia exclusiva ou associada à braquiterapia de alta taxa de dose para tumores localizados da próstata. MATERIAIS E MÉTODOS: De novembro de 1997 a janeiro de 2000, 74 pacientes foram submetidos à teleterapia com 45 Gy e reforço com braquiterapia de alta taxa de dose com irídio-192 e dose de 16 Gy em quatro inserções (BT). Estes foram comparados a 29 pacientes submetidos à teleterapia com 45 Gy e reforço com arcoterapia e dose mediana de 24 Gy (RT) entre outubro de 1996 e fevereiro de 2000. Nos dois grupos houve associação ocasional de hormonioterapia neoadjuvante. Sobrevida atuarial livre de doença em três anos (SB3) e fatores prognósticos pré-tratamento da resposta bioquímica, como o antígeno prostático-específico inicial (PSAi), escore de Gleason da biópsia de próstata (EG) e estádio clínico (EC), foram analisados. RESULTADOS: O seguimento mediano foi de 25 meses para o grupo RT e 37 meses para o BT. Na análise atuarial, a SB3 foi de 51% e 73% (p = 0,032) para RT e BT, respectivamente. Na análise estratificada pelo PSAi, a SB3 para RT e BT foi de 85,7% e 79,1% (p = 0,76) para PSAi < 10 ng/mL e de 38% e 68% (p = 0,023) para PSAi > 10 ng/mL, respectivamente. Quando estratificado pelo EG, a SB3 para RT e BT foi de 37% e 80% (p = 0,001) para EG < 6 e 78% e 55% para EG > 6 (p = 0,58); estratificando-se pelo EC, a SB3 para RT e BT foi de 36% e 74% (p = 0,018) para EC < T2a e 73% e 69% para EC > T2a (p = 0,692), respectivamente. O risco relativo bruto de recidiva bioquímica foi de 2,3 (95% IC: 1,0-5,1) para os pacientes tratados com RT, em relação à BT; quando ajustado pelo PSAi e EG, o risco relativo de recidiva bioquímica foi de 2,4 (95% IC: 1,0-5,7). CONCLUSÃO: A modalidade de tratamento foi fator prognóstico independente de recidiva bioquímica, com maior controle bioquímico associado à BT. Nossos resultados preliminares sugerem que o maior benefício com BT foi obtido nos pacientes com PSAi > 10 ng/mL, EC < T2a e EG < 6.

Hazards of dose escalation in prostate cancer radiotherapy

PURPOSE

To assess the benefit of escalating the dose in definitive prostate cancer radiotherapy vs. the associated risk of complications.

MATERIALS AND METHODS

Between 1987 and 1999, 1087 patients with clinical Stage T1b-T3 adenocarcinoma of the prostate were definitively irradiated without hormonal therapy and had a pretreatment serum prostate-specific antigen (PSA) and Gleason score recorded. The median follow-up was 65 months. Doses ranged from 64 to 78 Gy, with the treatment techniques corresponding to the year of therapy and the prescribed dose. A total of 301 patients were treated on a randomized protocol to either 70 or 78 Gy. Also, 163 patients were treated with three-dimensional conformal therapy and had dose-volume histograms available for review.

RESULTS

Tumor stage, grade, pretreatment PSA level, and radiation dose were all independent predictors of PSA disease-free survival (PSA-DFS) in multivariate analysis. The hazard rate for biochemical failure peaked at 1.5-3 years after radiotherapy. Although a statistically significant dose effect on PSA-DFS was found in the pretreatment PSA levels of those with both < or =10 ng/mL and >10 ng/mL, in those with a pretreatment PSA < or =10 ng/mL, the improvement in outcome was only seen going from a dose level of 64-66 Gy to 68-70 Gy with a 5-year PSA-DFS rate of 66% vs. 81% (p <0.0001). This was also confirmed by the data from the randomized patients who showed no difference in outcome whether treated to 70 Gy or 78 Gy. In patients with a pretreatment PSA level >10 ng/mL, a statistically significant improvement was found in disease-free outcome among the 64-66-Gy, 68-70-Gy, and 78-Gy levels. PSA-DFS was approximately 50% better at each higher dose level at 5 and 8 years after treatment. The dose had a statistically significant impact in both intermediate- and high-risk groups. Rectal morbidity was both dose and volume related. Although at 5 years after therapy, the Grade 2-3 rectal complication rate was twice as high for patients treated to 78 Gy than to 70 Gy, 26% vs. 12%, this risk could be markedly diminished by adhering to dose-volume constraints.

CONCLUSIONS

In intermediate- and high-risk prostate cancer patients, although it appears that radiation-dose escalation may improve PSA-DF outcome, the price paid in treatment morbidity can be high without adequate attention to dose-volume constraints of normal tissue. Care must be taken to consider not only the hazard of tumor recurrence but also that of complications.

Salvage prostatectomy in patients who have failed radiation therapy or cryotherapy as primary treatment for prostate cancer

Asymptomatic prostate-specific antigen (PSA) recurrence after radiation therapy for prostate carcinoma poses a diagnostic and therapeutic dilemma for clinicians. Patients with locally recurrent disease can consider treatment options of salvage surgery, cryotherapy, watchful waiting, or androgen deprivation. Of these options, only salvage surgery has been shown to result in long-term disease-free survival for selected patients. However, salvage surgery is associated with significant morbidity, including urinary incontinence and rectal injuries. Ideally, salvage surgery outcomes can be optimized with careful patient selection according to clinical stage, serum PSA levels before radiation and surgery, the medical condition of the patient, and clear expectations of the physician and patient. Among patients with locally recurrent disease, those with localized prostate carcinoma amenable to radical prostatectomy before radiation or cryotherapy would be the most suitable candidates for salvage surgery.

Do older men benefit from curative therapy of localized prostate cancer?

PURPOSE

Prior decision-analytic models are based on outdated or suboptimal efficacy, patient preference, and comorbidity data. We estimated life expectancy (LE) and quality-adjusted life expectancy (QALE) associated with available treatments for localized prostate cancer in men aged >/= 65 years, adjusting for Gleason score, patient preferences, and comorbidity.

METHODS

We evaluated three treatments, using a decision-analytic Markov model: radical prostatectomy (RP), external beam radiotherapy (EBRT), and watchful waiting (WW). Rates of treatment complications and pretreatment incontinence and impotence were derived from published studies. We estimated treatment efficacy using three data sources: cancer registry cohort data, pooled case series, and modern radiotherapy studies. Utilities were obtained from 141 prostate cancer patients and from published studies.

RESULTS

For men with well-differentiated tumors and few comorbidities, potentially curative therapy (RP or EBRT) prolonged LE up to age 75 years but did not improve QALE at any age. For moderately differentiated cancers, potentially curative therapy resulted in LE and QALE gains up to age 75 years. For poorly differentiated disease, potentially curative therapy resulted in LE and QALE gains up to age 80 years. Benefits of potentially curative therapy were restricted to men with no worse than mild comorbidity. When cohort and pooled case series data were used, RP was preferred over EBRT in all groups but was comparable to modern radiotherapy.

CONCLUSION

Potentially curative therapy results in significantly improved LE and QALE for older men with few comorbidities and moderately or poorly differentiated localized prostate cancer. Age should not be a barrier to treatment in this group.

What does postradiotherapy PSA nadir tell us about freedom from PSA failure and progression-free survival in patients with low and intermediate-risk localized prostate cancer?

OBJECTIVES

To determine whether the post-external beam radiotherapy (RT) prostate-specific antigen nadir (nPSA) improves our ability to predict freedom from PSA failure, progression-free survival (PFS), and overall survival. Controversy regarding the importance of nPSA after external beam RT as a prognostic indicator for patients with localized prostate cancer has continued.

METHODS

This analysis was based on the data from 748 patients with low and intermediate-risk localized prostate cancer treated with external beam RT alone. Patients were categorized by nPSA quartile groups with cutpoints of less than 0.3, 0.3 to less than 0.6, 0.6 to less than 1.2, and 1.2 ng/mL or greater. Both univariate and multivariate analyses were used to determine the significance of nPSA on PSA failure (American Society for Therapeutic Radiology Oncology consensus definition), PFS (death after PSA failure), and overall survival (death from any cause).

RESULTS

Freedom from PSA failure was strongly associated with nadir quartile groups (P <0.0001). PFS was also significantly different statistically among nadir quartile groups (P = 0.02). No statistically significant difference was found in overall survival associated with nPSA at this point.

CONCLUSIONS

nPSA is a strong independent predictor of freedom from PSA failure and PFS in patients with low and intermediate-risk localized prostate cancer treated with RT alone. Longer follow-up and larger patient numbers are required to confirm these observations.

Permanent Prostate Brachytherapy in Men with Clinically Localised Prostate Cancer

Permanent prostate brachytherapy techniques are associated with excellent biochemical control for patients with localised prostate cancer. Ten-year data show that permanent prostate brachytherapy is compatible with external beam irradiation or radical prostatectomy. However, treatment protocols and techniques for prostate brachytherapy vary between centres and there is little conformity of treatment protocols. The selection of patients for monotherapy or combined external beam irradiation and brachytherapy is controversial. The role of neoadjuvant androgen deprivation also remains unanswered in patients with localised prostate cancer. In addition, post-implant dosimetry may in fact be more significant for predicting outcome than the addition of adjuvant therapies, and should be a requirement when performing prostate brachytherapy. Data now seem to support specific computed tomography (CT)-based criteria to evaluate implant quality and delivered dose to the prostate. Unfortunately, prostate oedema and poor imaging techniques are limiting factors for evaluating implant dosimetry. Treatment planning techniques that use new treatment planning computers may assist in improving the implant procedure and dosimetry and are now available.

Dose-response for biochemical control among high-risk prostate cancer patients after external beam radiotherapy

INTRODUCTION

The literature on dose-response characteristics of high-risk prostate cancer has been scarce in this era, when these patients are treated with hormone therapy along with radiotherapy. In this study, we estimated the dose-response of prostate-specific antigen (PSA) control probability in high-risk prostate cancer patients treated with radiotherapy alone.

METHODS AND MATERIALS

The data set contains information on 363 high-risk prostate cancer patients who were treated with external beam radiotherapy without hormonal treatment between February 1987 and September 1998. These patients have one or more of the following adverse prognostic features: digital rectal examination stage > or =cT3, PSA >20 ng/mL, and biopsy Gleason score > or =8. These patients had biopsy-proven adenocarcinoma of prostate and were staged according to the 1992 AJCC staging system that was based on digital rectal examination. The logistic model was fitted to the data at various time points after treatment, and the dose-response parameters were estimated.

RESULTS

The dose required to have 50% tumor control, TCD50 (95% confidence interval), for high-risk patients is 75.5 (range: 70.7-80.2) Gy. The gamma 50 (95% confidence interval) is 1.7 (range: 0.7-2.7) around 75.5 Gy. Recursive partitioning analysis based on the null Martingale residuals identifies two subgroups within the high-risk group. The TCD50 estimates of the two subgroups (PSA < or = vs. >20 ng/mL) differ by 15 Gy at 5 years. There is a dose response in both subgroups.

CONCLUSION

We recognize that this study has the usual limitations of a retrospective study that includes treatment policy change that spanned a long time frame. However, our data strongly suggest a benefit of dose escalation for all the patients in the entire high-risk group. There is a steep dose response in PSA control probability around a modern dose of 78 Gy. A 5-Gy dose increase beyond 78 Gy may improve PSA control by about 10%.

Long-term results after external beam radiation therapy for T1-T2 localized prostate cancer

The incidence of organ-confined and early-stage prostate cancer has increased. The external beam radiation therapy has proven to be a good therapeutic option in terms of biochemical survival and overall survival. It has been modified throughout the years; consequently, the available data on the long-term efficacy of external beam radiation therapy are difficult to compare with the commonly used improved radiation strategies. Intensity-modulated conformal radiotherapy and three-dimensional conformal radiotherapy result in better tumor control at a lower complication rate. External beam radiotherapy seems to be favored in intermediate- and high-risk groups for relapse of prostate cancer and radical prostatectomy is favored in the low-risk group. However, they score similarly in terms of general health-related quality of life after treatment.

Hazard rates of disease progression after external beam radiotherapy for clinically localized carcinoma of the prostate

PURPOSE

We established hazard rates for disease progression at different intervals after external beam radiotherapy alone in patients with clinically localized prostate cancer. We determined the likelihood of biochemical failure in those free of disease 5 years after radiotherapy and identified those at risk for early versus late biochemical failure.

MATERIALS AND METHODS

We reviewed the records of 964 patients treated with full dose external beam radiotherapy alone for T1 to T4, NxM0 prostate cancer. Followup prostate specific antigen (PSA) was measured 3 months after the completion of radiotherapy and every 3 to 6 months thereafter. Yearly hazard rates for biochemical failure were calculated each followup year.

RESULTS

Median followup of the whole study group was 48 months. Overall 5 and 10-year biochemical disease-free survival rates were 63.7% and 53.6%, respectively. Patients had a peak overall hazard rate 2 years after treatment. The hazard rate then decreased until year 6, when it increased slightly and remained elevated even at year 10. This late increase in the overall hazard rate was associated with late increases in the hazard rate in men with favorable prognostic factors, namely pretreatment PSA less than 10 ng./ml., Gleason score less than 5, clinical T stage T1 or T2, posttreatment PSA nadir less than 0.99 ng./ml. or radiation dose less than 68 Gy. In 13 of the 307 patients (3.9%) with biochemical failure the failure occurred more than 5 years after initial treatment.

CONCLUSIONS

The peak risk of biochemical failure is 2 years after radiotherapy. Patients are at slight but persistent risk for biochemical failure more than 5 years after treatment. Hazard rate calculations beyond the median followup of 4 years can underestimate the true hazard.

[Clinical and biological surveillance after radiotherapy for localized prostate cancer]

Serum PSA is an excellent marker of disease status after external beam radiotherapy or brachytherapy for patients with prostate carcinoma. A low PSA nadir < or = 1 even < or = 0.5 ng/mL has been shown to be as a surrogate end point for disease control. Three successive increases of this marker after achieving the nadir defines recurrence as recommended by the American Society for Therapeutic Radiology and Oncology. The biochemical relapse or PSA failure after treatment precedes clinical disease relapse by several months. PSA profile or kinetics may have implications for patterns of failure and prognosis. Prostate post-radiotherapy biopsies should not be part of routine follow-up as its interpretation is frequently problematic. Other exams should not be performed unless clinical symptoms are present. Post-radiotherapy relapse treatment has generally no curative intent.

Preliminary toxicity and prostate-specific antigen response of a Phase I/II trial of neoadjuvant hormonal therapy, 103Pd brachytherapy, and three-dimensional conformal external beam irradiation in the treatment of locally advanced prostate cancer•

PURPOSE

Standard therapies for locally advanced prostate cancer have resulted in suboptimal disease control rates. A Phase I/II trial was designed for patients with positive seminal vesicle biopsies, prostate-specific antigen (PSA) >15 ng/ml, Gleason score > or =8 or clinical classification T2c-T3 to improve local control and to test the tolerance of the prostate to high-dose radiation by using neoadjuvant hormonal therapy, 103Pd brachytherapy, and conformal three-dimensional external beam radiation therapy (EBRT). This article outlines treatment-related morbidity and PSA response to this regimen and analyzes the effect of escalating doses of brachytherapy.

METHODS AND MATERIALS

Forth-three patients with T1c-T3 prostate cancer were enrolled in a Phase I/II trial from March 1994 through September 1997. Follow-up ranged from 12 to 64 months (median, 32 months). Pretreatment PSA ranged from 2.1 to 202 ng/ml (median, 16 ng/ml). Seventy-seven percent (33 of 43) of patients had high-grade tumors (score > or =7). Seventy-four percent (32 of 43) had stage > or =T2c. A total of 21 (49%) patients had positive seminal vesicle biopsies. Treatment consisted of hormonal therapy for 3 months with leuprolide and flutamide followed by a 103Pd implant and, 2 months later, 59.4 Gy of three-dimensional EBRT. Hormonal therapy was continued for 9 months. The planned 103Pd dose was escalated from 57 Gy (13 patients) to 77 Gy (13 patients) to 86 Gy (17 patients).

RESULTS

The actuarial freedom from PSA failure (PSA>0.5 ng/ml) at 4 years was 74%. There were no significant differences found when analyzing patients by presenting PSA or seminal vesicle status. There was a trend toward improved outcome with higher doses delivered to the prostate via the implant. Patients receiving doses > or =65 Gy (31 patients) had a freedom from PSA failure rate at 4 years of 89.5%, compared with 52.5% for those receiving doses <65 Gy (10 patients; p=0.08). The last PSA values for those patients free from PSA failure were < or =0.1 ng/ml in 25 (69%), >0.1-0.2 ng/ml in 5 (14%), and >0.2-0.5 ng/ml in 6 (17%). The actuarial freedom from developing Grade 2 proctitis was 75% at 4 years. There was a trend toward increased proctitis with increasing prostate implant doses. Patients with doses < or =70 Gy (n=12) had a 92% freedom from Grade 2 proctitis compared with 67.5% for those with doses delivered to 90% of the gland from a dose-volume histogram of >70 Gy (n=29) (p=0.15). There were no cases of Grade 3 or 4 proctitis. The 3-year actuarial preservation of sexual potency rate was 43%.

CONCLUSIONS

The preliminary results from this regimen show an improvement in PSA control for this group of locally advanced prostate cancer patients over more standard therapies. To maximize control while minimizing toxicity, doses of 65-70 Gy of 103Pd should be used when 59.4 Gy of three-dimensional EBRT is delivered. Longer follow-up will be needed to further substantiate these findings.

External-beam radiotherapy in the management of carcinoma of the prostate

BACKGROUND

External-beam radiotherapy (EBRT) has been used in the treatment of adenocarcinoma of the prostate gland for more than 30 years. Well-documented clinical series have demonstrated the effectiveness of EBRT in achieving both cause-specific survival and freedom from biochemical (prostate-specific antigen [PSA]) progression.

METHODS

The indications and expected treatment results for treatment by EBRT in the management of adenocarcinoma of the prostate gland are reviewed. The treatment of early-stage disease definitively by EBRT alone or as complement to radioactive seed implant is emphasized. In the management of locally advanced disease, the use of EBRT with combined androgen ablation is discussed as definitive therapy and also as indicated in the postoperative adjuvant management of surgically identified pathologic stage T3 disease.

RESULTS

The relative clinical benefit of EBRT compared with the mostly predictable and well-defined moderate side effects, which are manageable in most instances by conservative measures treatment, is well established. Advances in defining radiation-beam parameters have led to more effective and safer treatment for prostate cancer.

CONCLUSIONS

EBRT has historically been a mainstay in the management of prostate cancer. It remains a useful and indicated treatment modality in patients with early-stage, locally advanced, and metastatic disease.

A retrospective analysis of the results of p(65) + Be neutrontherapy for the treatment of prostate adenocarcinoma at the cyclotron of Louvain-la-Neuve. Part I: Survival and progression-free survival

PURPOSE

To retrospectively evaluate survival, progression-free survival (PFS) and biological response in a series of patients irradiated with mixed neutron/photon beams for locally advanced prostate cancer in our institution.

PATIENTS AND METHODS

Three hundred and eight patients were treated between January 1990 and December 1996. Fifty-five of these were recruited for pT3 or pN1 tumors after radical prostatectomy. Neoadjuvant androgen deprivation was given in 106 patients. The treatment protocol consisted of a mixed photon/neutron irradiation in a two-to-three proportion, up to a total equivalent dose of 66 Gy (assuming a clinical RBE value of 2.8). Pre- and post-treatment PSA determinations were available in practically all cases. Study endpoints were overall survival (OAS) and progression-free survival (PFS). The Cox proportional hazard regression model was used to investigate the prognostic value of baseline characteristics on survival and progression-free survival were a progression was defined as local, regional, metastatic or biological progression. Mean age was 69 years (49-86); mean pretreatment PSA was 15 (0.5-330) in all patients and 14 (0.5-160) in those receiving neoadjuvant hormonotherapy; seven patients only had an initial PSA < or = 4 ng/mL; 15% were T1, 46% were T2, 28% were T3 or pT3 and 4% were T4 (7% unspecified); WHO grade of differentiation was I in 38%, II in 38% and III in 14% (5% unspecified).

RESULTS

The median follow-up was 2.8 years (0-7.8). Five-year overall survival (OAS) was 79% (95% CI: 71-87%) and 5-year progression-free survival (PFS) was 64% (95% CI: 54-74%) for the entire series. PFS in patients with an initial PSA > or = 20 ng/mL was the same. PFS could be predicted by two optimal Cox regression models, one including histological grade (p = 0.003) and initial PSA (p = 0.0009) as cofactors, the other including histological grade (p = 0.003) and T stage (p = 0.02). The main prognostic factors for overall survival were PSA and age. Biological responses with PSA < 1.5 ng/mL, < 1 ng/mL and < 0.5 ng/mL at any time after treatment were documented in 70%, 61% and 47% of the patients, respectively.

CONCLUSION

Five-year OAS was 79%, PFS was 64%, and biological response was 70% for prostate cancer patients treated with mixed photon/neutron beams as applied at Louvain-la-Neuve, which are good results as compared with the literature. The usual prognostic factors were confirmed.

Chemical disease-free survival in localized carcinoma of prostate treated with external beam irradiation: comparison of American Society of Therapeutic Radiology and Oncology Consensus or 1 ng/mL as endpoint

PURPOSE

To compare postirradiation biochemical disease-free survival using the American Society of Therapeutic Radiology and Oncology (ASTRO) Consensus or elevation of postirradiation prostate-specific antigen (PSA) level beyond 1 ng/mL as an endpoint and correlate chemical failure with subsequent appearance of clinically detected local recurrence or distant metastasis.

METHODS AND MATERIALS

Records of 466 patients with histologically confirmed adenocarcinoma of the prostate treated with irradiation alone between January 1987 and December 1995 were analyzed; 339 patients were treated with bilateral 120 degrees arc rotation and, starting in 1992, 117 with three-dimensional conformal irradiation. Doses were 68--77 Gy in 1.8 to 2 Gy daily fractions. Minimum follow-up is 4 years (mean, 5.5 years; maximum, 9.6 years). A chemical failure was recorded using the ASTRO Consensus or when postirradiation PSA level exceeded 1 ng/mL at any time. Clinical failures were determined by rectal examination, radiographic studies, and, when clinically indicated, biopsy.

RESULTS

Six-year chemical disease-free survival rates using the ASTRO Consensus according to pretreatment PSA level for T1 tumors were: < or = 4 ng/mL, 100%; 4.1--20 ng/mL, 80%; and > 20 ng/mL, 50%. For T2 tumors the rates were: < or = 4 ng/mL, 91%; 4.1--10 ng/mL, 81%; 10.1--20 ng/mL, 55%; 20.1--40 ng/mL, 63%; and > 40 ng/mL, 46%. When postirradiation PSA levels higher than 1 ng/mL were used, the corresponding 6-year chemical disease-free survival rates for T1 tumors were 92% for pretreatment PSA levels of < or = 4 ng/mL, 58--60% for levels of 4.1--20 ng/mL, and 30% for levels > 20 ng/mL. For T2 tumors, the 6-year chemical disease-free survival rates were 78% in patients with pretreatment PSA levels of 4--10 ng/mL, 45% for 10.1--40 ng/mL, and 25% for > 40 ng/mL. Of 167 patients with T1 tumors, 30 (18%) developed a chemical failure, 97% within 5 years from completion of radiation therapy; no patient has developed a local recurrence or distant metastasis. In patients with T2 tumors, overall 45 of 236 (19%) had chemical failure, 94% within 5 years of completion of radiation therapy; 4% have developed a local recurrence, and 10%, distant metastasis. In patients with T3 tumors, overall, 24 of 65 (37%) developed a chemical failure, 100% within 3.5 years from completion of radiation therapy; 4% of these patients developed a local recurrence within 2 years, and 12% developed distant metastasis within 4 years of completion of irradiation. The average time to clinical appearance of local recurrence or distant metastasis after a chemical failure was detected was 5 years and 3 years, respectively.

CONCLUSION

There was a close correlation between the postirradiation nadir PSA and subsequent development of a chemical failure. Except for patients with T1 tumors and pretreatment PSA of 4.1--20 ng/mL, there is good agreement in 6-year chemical disease-free survival using the ASTRO Consensus or PSA elevations above 1 ng/mL as an endpoint. Although the ASTRO Consensus tends to give a higher percentage of chemical disease-free survival in most groups, the differences with longer follow-up are not statistically significant (p > 0.05). It is important to follow these patients for at least 10 years to better assess the significance of and the relationship between chemical and clinical failures.

Is there a subset of patients with PSA > or = 20 ng/ml who do well after conformal beam radiotherapy?

To determine if there is a subgroup of patients with pretreatment PSA > or = 20 ng/ml with a favorable outcome after external beam radiation therapy. We analyzed retrospectively treatment outcomes of 129 patients with pretreatment PSA > or = 20 ng/ml treated in our department from 2/88-8/94. Median patient age was 70 years (range 51-89 years). Tumor stage was T1/T2ab in 68, T2c/T3 in 61 patients. Initial Gleason grade was < 7 in 82 and > or = 7 in 47 patients. Median PSA was 35 ng/ml (mean 45 ng/ml, range 20-191 ng/ml). Ninety-seven patients received four-field conformal external beam radiation therapy. No patient received surgery or hormonal therapy prior to treatment. Median central axis dose was 73 Gy (range 68-79 Gy). Covariates considered in univariate and multivariate analyses included central axis dose, pretreatment PSA, presence of perineural invasion, Gleason score, palpable tumor stage and patient age. bNED failure was defined as a PSA > or = 1.5 and rising on two consecutive determinations. Median follow up was 50 months (range 3-100 months). Overall bNED control for the entire patient population was 22% at five years. Of the covariates analyzed, dose (P < 0.01), stage (P < 0.01), Gleason Score (P < 0.01), and the presence of PNI (P = 0.01) were significant on multivariate analysis. Based on these results, patients could be stratified into two distinct groups. Group I consisted of 19 patients with favorable features including T1/T2ab disease, Gleason Score 2-6, no perineural invasion treated to a dose > 73 Gy to the central axis. Patients in Group II had at least one of the above poor prognostic features or were treated to central axis doses < 73 Gy. The bNED control was significantly higher for patients in Group I than those in Group II (58% vs. 23%, P = 0.0027). There appears to be a favorable subgroup of patients with PSA > or = 20 ng/ml where treating to doses over 73 Gy to the central axis is warranted (four-year bNED rate of 58%). However, because of the small patient numbers, these results will need to be validated with longer follow up.

3D conformal radiation therapy (3DCRT) for high grade prostate cancer: a multi-institutional review

PURPOSE

To evaluate the results of 3DCRT and the effect of higher than traditional doses in patients with high grade prostate cancer, we compiled data from three institutions and analyzed the outcome of this relatively uncommon subset of prostate cancer patients.

METHODS AND MATERIALS

The 180 patients with Gleason score 8- 10 adenocarcinoma of the prostrate were treated with 3DCRT at the Univer sity of Michigan Health System, University of California-San Francisco, or Fox Chase Cancer. Eligible patients had T1-T4 NO or NX MO adenocarci noma with a pretreatment PSA. Pretreatment characteristics included: me dian age 72 years, 60.6% Gleason score 8 tumors, 57.6% T1-T2, and median pretreatment PSA 17.1 ng/ml (range 0.3-257.1). The total dose received was <70 Gy in 30%, 70-75 Gy in 37%, and >75 Gy in 33%, 27% received adju vant or neoadjuvant hormonal therapy. The median follow-up was 3.0 years for all patients and 16% of patients were followed up for at least 5 years.

RESULTS

The 5-year freedom from PSA failure was 62.5% for all patients and 79.3% in T1-T2 patients. Univariate analysis revealed that T-stage (T1-T2 vs. T3-T4), pretreatment PSA, and RT dose predicted for freedom from PSA failure. A 5-year overall survival for all patients was 67.3%. Only RT dose was predictive of 5-year overall survival on univariate analysis. Because a significant association was seen between T-stage and RT dose, the Cox proportional hazards model was performed separately for T1-T2 and T3-T4 tumors. None of the prognostic factors reached statistical significance for overall survival or freedom from PSA failure in T3-T4 patients or for overall survival in T1-T2 patients. Lower RT dose and higher pretreatment PSA predicted for PSA failure on multivariate analysis in T1-T2 patients.

CONCLUSION

This retrospective study from three institutions with experience in dose escalation suggests a dose effect for PSA control above 70 Gy in patients with T1-T2 high grade prostate cancer. These results are superior to surgery and emphasize the need for dose escalation in treating Gleason 8-10 prostate cancer.

Palladium-103 brachytherapy for prostate carcinoma

PURPOSE

A report of biochemical outcomes for patients treated with palladium-103 (Pd-103) brachytherapy over a fixed time interval.

METHODS AND MATERIALS

Two hundred thirty patients with clinical stage T1-T2 prostate cancer were treated with Pd-103 brachytherapy and followed with prostate-specific antigen (PSA) determinations. Kaplan-Meier estimates of biochemical failure on the basis of two consecutive elevations of PSA were utilized. Multivariate risk groups were constructed. Aggregate PSA response by time interval was assessed.

RESULTS

The overall biochemical control rate achieved at 9 years was 83.5%. Failures were local 3.0%; distant 6.1%; PSA progression only 4.3%. Significant risk factors contributing to failure were serum PSA greater than 10 ng/ml and Gleason sum of 7 or greater. Five-year biochemical control for those exhibiting neither risk factor was 94%; one risk factor, 82%; both risk factors, 65%. When all 1354 PSA determinations obtained for this cohort were considered, the patients with a proportion of PSAs < or = 0.5 ng/ml continued to increase until at least 48 months post-therapy. These data conformed to a median PSA half-life of 96.2 days.

CONCLUSIONS

Prostate brachytherapy with Pd-103 achieves a high rate of biochemical and clinical control in patients with clinically organ-confined disease. PSA response following brachytherapy with low-dose-rate isotopes is protracted.

The dual-isotope ProstaScint imaging procedure: clinical experience and staging results in 145 patients

PURPOSE

Whole-body, regional planar, and SPECT imaging using the In-111-labeled monoclonal antibody capromab pendetide (In-111 MAb; ProstaScint) has been shown to increase the detection of early disease spread in patients with prostate cancer. However, recognition of metastatic tumor sites can be difficult, especially if the involved nodes are near blood vessels. We have developed an alternate approach to the identification of metastatic sites that is based on a single simultaneous In-111 MAb and Tc-99m RBC SPECT acquisition of the pelvis and abdomen on day 5 after injection. We have also developed software that dynamically subtracts the Tc-99m RBC data set (vascular component) from the In-111 MAb data set (prostate and lymph node component), which allows for easier identification of metastatic sites.

METHODS

We evaluated the effectiveness of ProstaScint for staging 145 patients with prostate cancer, 19 newly diagnosed and 126 with recurrence, using these two modifications.

RESULTS

With clinical follow-up in 13 of 19 (68%) patients with primary disease, 10 of 13 (78%) had organ-confined disease. With follow-up in 64 of 126 (51%) patients with possible recurrent disease, 49 of 64 (77%) were found to have prostatic fossa activity only. Disease stage was deemed more advanced in 3 of 13 (22%) patients with primary cancer and in 13 of 64 (20%) of those with recurrent disease based on ProstaScint findings when all other imaging tests were inconclusive. Six patients with recurrent disease had negative results of their scans. In the 16 patients with more advanced disease, 3 of 59 lesions (5%) were documented as false positive, and there were no reported cases of false-negative findings.

CONCLUSIONS

Using both the dual-isotope procedure and the subtraction analysis software with the ProstaScint examination provides additional information for staging primary and possibly recurrent prostate cancer compared with standard imaging techniques.

The cost effectiveness of 3D conformal radiation therapy compared with conventional techniques for patients with clinically localized prostate cancer

BACKGROUND

We previously demonstrated the advantages of three-dimensional conformal radiation therapy (3DCRT) in improved rates of biochemical (bNED) control in certain subsets of patients with clinically localized prostate cancer. However, in this era of cost consciousness and limited resources, the cost effectiveness of 3DCRT compared with conventional external beam irradiation (CRT) remains unexamined.

METHODS AND MATERIALS

Between October 1, 1987 and November 30, 1991, 193 patients with clinically localized prostate cancer received definitive external beam irradiation at Fox Chase Cancer Center. The 1998 Medicare fee schedule was used to determine treatment charges and to provide a reference for a national comparison. Complete charges for pretreatment work-up, treatment, and follow-up were tabulated for each patient. The mean total charges (MTC) using the Lin method of estimating medical costs was used to analyze and compare costs between groups. A matched case/control analysis was performed to further evaluate the effect of cost between techniques. The median follow-up was 72 months (range 3-118).

RESULTS

The overall 5-year actuarial rate of bNED control was 41% and 53%, respectively, for the CRT and 3DCRT patients (p = 0.03). The MTC for the CRT patients was $10,544.53. For the 3DCRT patients, the MTC was $8,955.48. The sample mean of the total costs from the observed deaths for the two patient groups by follow-up interval ranged from $9,800.63 to $59,635.01 for the CRT patients to $17,259.00 to $24,250.38 for the 3DCRT patients. No statistically significant difference in cost was observed between groups using the matched case/control analysis.

CONCLUSION

Initial work-up and treatment costs were greater for patients treated with 3DCRT compared with patients treated with conventional techniques. However, with longer follow-up, the mean total cost of treatment was not statistically different between the two treatment groups. Because of improved rates of bNED control for these patients and the increased costs associated with the treatment of a greater fraction of patients with recurrent disease following CRT, 3DCRT was cost effective for patients with clinically localized prostate cancer.

Defining biochemical cure for prostate carcinoma patients treated with external beam radiation therapy

BACKGROUND

The authors retrospectively reviewed their institution's long term experience with conventional external beam radiation therapy (RT) for localized prostate carcinoma to identify criteria associated with long term biochemical cure.

METHODS

Between January 1987 and December 1994, 871 patients were treated with external beam RT alone for clinically localized prostate carcinoma at William Beaumont Hospital, Royal Oak, Michigan. All patients received only external beam RT to a median total dose of 66.6 grays (Gy) (range, 59.4-70.4 Gy). No patient received hormonal therapy unless treatment failure was documented. The median follow-up was 5.0 years (range, 0. 2-11.8 years). Biochemical failure was defined according to the American Society for Therapeutic Radiology and Oncology Consensus Panel definition.

RESULTS

In the entire study group, 380 patients experienced biochemical failure at a median interval of 1.5 years after the completion of RT. The 5-year and 7-year actuarial rates of biochemical control were 50% and 48%, respectively. On multivariate analysis, a higher pretreatment prostate specific antigen (PSA) level, higher Gleason score, higher clinical T classification, higher nadir level, and shorter time interval to nadir all were associated significantly with biochemical failure (P < 0.001). The median intervals to biochemical failure for patients with pretreatment PSA levels </= 3.9 ng/mL, 4.0-19.9 ng/mL, and >/= 20.0 ng/mL were 2.2 years, 1.5 years, and 1.2 years, respectively (P < 0. 001). The median intervals to biochemical failure for patients with Gleason scores of 2-4, 5-7, and 8-10 were 1.8 years, 1.5 years, and 1.1 years, respectively (P < 0.001). Only 6 patients failed beyond 5 years after treatment even though 136 patients were at risk for failure beyond this point. When restricting analysis to 643 patients (74%) with >/= 3 years of PSA follow-up, the median nadir level for biochemically controlled patients was 0.6 ng/mL and occurred at a median interval of 1.9 years after RT versus a median nadir level of 1.3 ng/mL (P = 0.002) occurring at a median interval of 1.0 years (P < 0.001) in those patients who experienced biochemical failure. Patients were divided into subgroups based on their PSA nadir level and time to nadir. The 5-year actuarial biochemical control rates for patients with nadir values of </= 0.4 ng/mL, 0.5-0.9 ng/mL, 1. 0-1.9 ng/mL, 2.0-3.9 ng/mL, and >/= 4.0 ng/mL were 78%, 60%, 50%, 20%, and 9%, respectively (P < 0.001). The 5-year actuarial biochemical control rates for patients who reached their nadir at < 1.0 years, 1.0-1.9 years, 2.0-2.9 years, and >/= 3.0 years were 30%, 52%, 64%, and 92%, respectively (P < 0.001). All 52 patients who achieved a nadir of </= 0.4 ng/mL and required >/= 2.0 years to reach this nadir had biochemically controlled disease.

CONCLUSIONS

These results suggest that a patient has a high likelihood of biochemical cure after treatment for prostate carcinoma with conventional doses of external beam RT if he has not demonstrated biochemical failure within 5 years of treatment. Patients with lower pretreatment PSA levels and lower Gleason scores may require longer follow-up than those with less favorable characteristics to achieve the same certainty of cure. Patients who achieve a PSA nadir </= 0.4 ng/mL and require >/= 2.0 years to reach this nadir have the highest probability of cure.

The importance of adequate follow-up in defining treatment success after external beam irradiation for prostate cancer

PURPOSE

We reviewed our institution's experience treating patients with localized prostate cancer with external beam radiation therapy (RT) to determine how differences in the length of follow-up affect the determination of treatment outcome using the American Society for Therapeutic Radiology and Oncology (ASTRO) Consensus Panel Definition of biochemical failure (BF).

METHODS AND MATERIALS

From January 1987 through December 1997, 1109 patients with localized prostate cancer were treated with definitive external beam RT at William Beaumont Hospital, Royal Oak, Michigan. All patients received external beam RT to a median total prostate dose of 66.6 Gy (range: 59.4-70.4 Gy). A total of 1096 patients (99%) had sufficient prostate-specific antigen (PSA) follow-up to determine their biochemical status. To test the impact of differences in follow-up on the calculation of BF, 389 patients with at least 5 years of PSA follow-up were selected as the reference group for the initial analysis. BF was then retrospectively determined using the Consensus Panel definition at yearly intervals, ignoring the remainder of each patient's follow-up. The median follow-up for this group of patients was 6.6 years (range: 5.0-11.6 years). In a second analysis, patient cohorts were randomly selected with varying median PSA follow-up intervals in order to more accurately represent a population whose follow-up is distributed continuously over a defined range. Seven cohorts were randomly selected with 200 patients in each cohort. Cohorts were individually identified such that half of the patients (100) had 2 years or less follow-up than the stated time point for analysis and half (100) had up to 2 years more follow-up than the time point chosen for analysis. For example, in the cohort with a median follow-up of 3 years, 100 patients with a PSA follow-up from 1 to 3 years were randomly selected, and 100 patients with a follow-up from 3 to 5 years were randomly selected, thus generating a median follow-up of 3 years for this cohort (range: 1 to 5 years). This process was repeated five times for five random samples of seven cohorts each. Biochemical failure was calculated according to the Consensus Panel definition.

RESULTS

In the first analysis, significantly different rates of biochemical control (varying by 6-21%) were calculated for the same actuarial year chosen for analysis depending only upon the length of follow-up used. For example, the 3-year actuarial rate of biochemical control (BC) varied from 71% when calculated with 3 years of follow-up versus 50.4% with 7 years (p < 0.01). These differences in actuarial rates of BC were observed in all subsets of patients analyzed (e.g., PSA < 10, Gleason < or = 6, n = 132,p < 0.001; PSA < 10, Gleason > or = 7, n = 33, p = 0.03; PSA > or = 10, Gleason < or = 6, n = 109, p < 0.001; and PSA > or = 10, Gleason > or = 7, n = 72, p = 0.002). The absolute magnitude of the difference in actuarial rates of BC was greatest during years 2 (range 18-30%), 3 (range 16-25%), and 4 (range 15-24%) after treatment. In the second analysis using median PSA follow-ups (as defined above), statistically significant differences in actuarial rates of BC were again observed. For example, the 3-year actuarial rate of BC varied from 74.8% with a median follow-up of 2 years versus 49.2% with a median follow-up of 6 years. These dramatic differences in BC were still observed beyond 5 years.

CONCLUSION

When the ASTRO Consensus Panel definition of BF is used to calculate treatment success with external beam RT for prostate cancer, adequate follow-up is critical. Depending upon the length of time after treatment, significantly different rates of BC (varying by 15% to 30%) can be calculated for the same time interval chosen for analysis. These results suggest that data should only be reported if the length of follow-up extends at least beyond the time point at which actuarial results are examined for the majority of patients.

The durability of external beam radiation therapy for prostate cancer: can it be identified?

PURPOSE

We establish criteria to identify a durable response to external beam radiation therapy by calculation of biochemical progression-free probability for patients who attained and maintained defined nadir prostate specific antigen (PSA) levels more than 5 years after treatment.

MATERIALS AND METHODS

A total of 460 patients were treated with external beam radiation monotherapy from 1976 to 1995. Patients with PSA less than 0.5 (group 1) or 0.5 to 1.0 (group 2) ng./ml. more than 5 years after treatment were identified. Treatment failure was defined as 3 consecutive increases in PSA after nadir. Progression-free probability after 60 months was calculated for each group. A comparison was also made to patients achieving the same nadir levels anytime after treatment.

RESULTS

Failure occurred at 133 months in 1 of 26 group 1 patients (4%) and at a median of 76 months in 5 of 26 group 2 patients (19%). At 10 years progression-free probability was 91% for group 1 compared to 72% for group 2 (p = 0.0575). These same nadir levels anytime after treatment were associated with higher failure rates of 55% for group 1 and 72% for group 2.

CONCLUSIONS

If a PSA nadir of less than 0.5 ng./ml. was maintained 5 years after therapy, subsequent failure was rare. Although statistical significance was not reached (p = 0.0575), a higher failure rate was noted if the nadir PSA was 0.5 to 1.0 ng./ml. at 5 years. Thus, patients with PSA 0.5 to 1.0 ng./ml. require careful continued surveillance. Nadir levels less than 1.0 ng./ml. anytime before 5 years were associated with a substantial risk of subsequent progression.

Prostate brachytherapy: treatment strategies

PURPOSE

Patients who present with localized and locally advanced prostate cancer may be candidates for prostate brachytherapy. We evaluated the treatment outcomes in a diverse group of prostate cancer patients who presented with low, moderate and high risk features.

MATERIALS AND METHODS

A total of 301 patients who presented with T1 to T3 prostate cancer were treated with brachytherapy alone or combined with hormonal therapy and/or external beam irradiation. Of these patients 109 at low risk with prostate specific antigen (PSA) 10 ng./ml. or less, Gleason score 6 or less and clinical stage T2a or less were treated with 125iodine alone, 152 at moderate risk with PSA greater than 10 ng./ml., Gleason score greater than 6 or stage T2b or greater were treated with 125iodine or 103palladium or combined implant alone with 5 months of hormonal therapy, and 40 at high risk with PSA greater than 15 ng./ml., Gleason 8 or greater, clinical stage T2c to T3 or positive seminal vesicle biopsy (20) were treated with combination brachytherapy, external beam irradiation and 9 months of hormonal therapy. Patients with a positive seminal vesicle biopsy (T3c disease) and negative pelvic lymph nodes were included in the high risk group, and the walls of the seminal vesicles were also treated with implantation. Followup was performed every 6 months with digital rectal examination and ultrasound evaluation. Prostate biopsy was routinely recommended 2 years after completion of the radiation. Failure was defined as PSA increase on 2 consecutive determinations above 1 ng./ml. or evidence of local recurrence on digital rectal examination, transrectal ultrasound or biopsy. Kaplan-Meier projections were used to calculate progression-free survival rates.

RESULTS

Of the 109 patients at low risk followed from 1 to 7 years (median 18 months) 91% were free of PSA failure at 4 years. No patient experienced urinary incontinence following implantation, although grade 1 to 2 radiation proctitis occurred in 5 (4.5%). Of the 152 patients at moderate risk 73 received implantation and 79 received implantation combined with hormonal therapy. The 4-year biochemical freedom from failure rate for the hormone group was 85% versus 58% for the no hormone group (p = 0.08). The difference was more significant for those with Gleason score 7 or greater (90 versus 43%, p = 0.01) and for those with PSA greater than 10 ng./ml. (87 versus 59%, p = 0.04). Grade 1 to 2 radiation proctitis occurred in 1 of the 79 patients (1.3%) receiving hormonal therapy and in 3 (4%) treated with implantation only. There were no cases of urinary incontinence. Of the 40 patients at high risk 71% were free of biochemical failure at 3 years. Of the 4 patients with failure (10%) 3 (75%) originally had positive seminal vesicle biopsies. Five patients experienced gastrointestinal complications, although none was grade 3 or 4. The actuarial freedom from grade 2 proctitis was 82%. No patient experienced urinary incontinence. Prostate biopsies were negative in 87% of the low risk, 96.8 (hormone group) versus 68.6% (no hormone group) of the moderate risk (p = 0.0023) and 86% of the high risk patients.

CONCLUSIONS

Brachytherapy appears to offer comparable results to external beam irradiation and radical prostatectomy when patients are stratified by disease extent. Adopting a strategy of implant alone, implant with hormonal therapy or implant with hormonal therapy and external beam irradiation in patients who present with low to high risk features can improve the overall results in the more advanced cases.

Conformal proton therapy for early-stage prostate cancer

OBJECTIVES

To assess the effect of proton radiation on clinical and biochemical outcomes for early prostate cancer.

METHODS

Three hundred nineteen patients with T1-T2b prostate cancer and initial prostate-specific antigen (PSA) levels 15.0 ng/mL or less received conformal radiation doses of 74 to 75 cobalt gray equivalent with protons alone or combined with photons. No patient had pre- or post-treatment hormonal therapy until disease progression was documented. Patients were evaluated for biochemical disease-free survival, PSA nadir, and toxicity; the mean and median follow-up period was 43 months.

RESULTS

Overall 5-year clinical and biochemical disease-free survival rates were 97% and 88%, respectively. Initial PSA level, stage, and post-treatment PSA nadir were independent prognostic variables for biochemical disease-free survival: a PSA nadir 0.5 ng/mL or less was associated with a 5-year biochemical disease-free survival rate of 98%, versus 88% and 42% for nadirs 0.51 to 1.0 and greater than 1.0 ng/mL, respectively. No severe treatment-related morbidity was seen.

CONCLUSIONS

It appears that patients treated with conformal protons have 5-year biochemical disease-free survival rates comparable to those who undergo radical prostatectomy, and display no significant toxicity. A Phase III randomized dose-escalation trial is underway to define the optimum radiation dose for early-stage prostate cancer.

The long-term effect on PSA values of incidental prostatic irradiation in patients with pelvic malignancies other than prostate cancer

PURPOSE

To determine the effect of external beam radiation therapy on serum prostate-specific antigen (PSA) production by the benign prostate.

METHODS AND MATERIALS

We studied a cohort of 24 men receiving treatment for cancer of the bladder or rectum. The radiation fields in all cases encompassed the prostate gland, and none of the patients were known to have prostate cancer. All patients had 2 or more PSA estimations obtained in the years following their radiation treatment. A second group of 46 patients who had undergone radical external beam radiation therapy for prostate cancer and who were clinically disease free 8-22 years later were also observed, with a median of 5.8 years of PSA observations.

RESULTS

Only 3 of the 24 patients in the first group showed a significant rise of > 0.2 ng/ml in their serum PSA levels, with a median of 3.3 years follow-up from the first PSA test. Seven of 24 showed progressive declines, and 14 of 24 showed steady levels. The median PSA for this group was < or = 0.5 ng/ml. Only 6 of the 46 in the second group showed a PSA rise of > 0.2 ng/ml. Thirty-four had stable values, and 6 had further declines. Again, the median PSA for the entire group was < or = 0.5 ng/ml.

CONCLUSION

Recovery of prostatic secretory function is an uncommon event after external beam radiation. The concern that this might significantly confound new definitions of biochemical failure after radical radiation for prostate cancer that are based on progressively rising PSA values thus appears to be unfounded.

Prostate-specific antigen to predict outcome of external beam radiation for prostate cancer: Walter Reed Army Medical Center experience, 1988-1995

OBJECTIVES

To assess the ability of pretreatment and post-treatment prostate-specific antigen (PSA) measurements, clinical tumor stage, tumor grade, Gleason sum, race, age, and radiation dose to predict the recurrence of prostate cancer following external beam radiation therapy (XRT) since the introduction of PSA as a tumor marker at one tertiary care center.

METHODS

The recurrence of prostate cancer among 371 evaluable patients of 389 patients treated with XRT at Walter Reed Army Medical Center was analyzed using Kaplan-Meier survival methodology and Cox multivariable regression models. Serologic (PSA) recurrence was determined using three consecutive rises in PSA after a nadir value. Clinical recurrence was defined as local recurrence (palpable or positive biopsy) and/or distant (radiographically evident) recurrence. Mean and median follow-up is 40.2 and 39.4 months, respectively (range 3.0 to 89.5), and minimum follow-up is 18 months for patients who were alive at the time of analysis. No patient received adjuvant hormonal therapy. Potential prognostic factors evaluated are pretreatment PSA, PSA nadir, age, race, clinical tumor stage, tumor grade, Gleason sum, and radiation dose.

RESULTS

Of the 371 evaluable patients, 125 had disease recurrence. The Kaplan-Meier 5-year disease-free survival (DFS) rates for significant pretreatment variables in univariate analyses are as follows: pretreatment PSA less than 4 (79%), 4.1 to 10 (67%), 10.1 to 20 (57%), 20.1 to 50 (27%), and more than 50 (0%); for clinical tumor Stage T1a-T1c (84%), T2a-T2c (51 %), and T3-T4 (29%); for tumor grade well (58%), moderate (58%), and poor (30%). Four-year DFS rates for Gleason sum are 2 to 4 (82%), 5 (72%), 6 (56%), and 7 to 10 (48%). In multivariable Cox regression analysis with backward elimination of nonsignificant variables, age, race, tumor grade, and radiation dose were eliminated, leaving pretreatment PSA, clinical tumor stage, and Gleason sum as significant prognostic factors. Analysis of a Cox model that included nadir PSA as a time-dependent variable showed it to be the strongest prognostic factor variable in the analysis.

CONCLUSIONS

XRT remains a suitable treatment modality for patients with pretreatment PSA less than 20.0, clinical tumor Stages T1-T2, and Gleason sum 2 to 6 prostate cancer. Patients achieving a nadir value less than 0.5 have more durable treatment outcomes.

Update on the treatment of prostate cancer with external beam irradiation

BACKGROUND

We review the recent changes in the radiotherapeutic management of clinically localized prostate cancer, including the implementation of three-dimensional (3-D) conformal radiation therapy (3DCRT), biochemical disease-free survival (bNED control) using conventional and 3DCRT techniques, and the morbidity of these treatment strategies.

METHODS

The components of 3DCRT are discussed, including patient immobilization, 3-D treatment planning, multileaf collimation, and electronic portal imaging. bNED control rates from institutions using conventional and 3DCRT techniques are compared. The gastrointestinal (GI) and genitourinary (GU) morbidity from prospective trials using conventional doses of radiation are compared to data from 3DCRT series. bNED control rates stratified by pretreatment prostate-specific antigen (PSA) are compared between surgical and radiation series.

RESULTS

bNED control rates (3-5 years) for patients treated with conventional and 3DCRT techniques ranged from 44-70% and 30-72% with pretreatment PSA levels 4-10 and 10-20, respectively. Although direct comparisons are difficult between treatment modalities, no difference in bNED control stratified by pretreatment PSA was observed between surgical and radiation patients.

CONCLUSIONS

Patients with clinically localized prostate cancer treated with 3DCRT demonstrate durable bNED control at 5 years. Conformal radiation techniques, multileaf collimation, electronic portal imaging, and patient immobilization have reduced acute and chronic GI and GU morbidity while allowing safe dose escalation in an effort to further improve local control and overall survival.

Conformal proton therapy for prostate carcinoma

BACKGROUND

The role and optimum dose of radiation to eradicate prostate cancer continues to be evaluated. Protons offer an opportunity to increase the radiation dose to the prostate while minimizing treatment toxicity.

METHODS

Six hundred forty-three patients with localized prostate cancer were treated with protons, with or without photons. Treatments were planned with a 3D planning system; patients received 74-75 CGE (Cobalt Gray Equivalent) at 1.8-2.0 CGE per fraction. Patients were evaluated for response to therapy and treatment-related toxicity.

RESULTS

The overall clinical disease-free survival rate was 89% at 5 years. When post-treatment prostate-specific antigen (PSA) was used as an endpoint for disease control, the 4.5-year disease-free survival rate was 100% for patients with an initial PSA of < 4.0 ng/ml, and 89%, 72%, and 53% for patients with initial PSA levels of 4.1-10.0, 10.1-20.0, and > 20.0, respectively. Patients in whom the post-treatment PSA nadir was below 0.5 ng/ml did significantly better than those whose nadir values were between 0.51-1.0 or > 1.0 ng/ml: the corresponding 5-year disease-free survival rates were 91%, 79%, and 40%, respectively. Minimal radiation proctitis was seen in 21% of patients; toxicity of greater severity was seen in less than 1%.

CONCLUSION

Proton therapy to 74-75 CGE produced minimal treatment-related toxicity and excellent PSA normalization and disease-free survival in patients with low initial PSA levels. A prospective randomized dose-escalation trial is now underway to help define the optimum dose of radiation for patients with early stage prostate cancer.

Ten-year disease free survival after transperineal sonography-guided iodine-125 brachytherapy with or without 45-gray external beam irradiation in the treatment of patients with clinically localized, low to high Gleason grade prostate carcinoma

BACKGROUND

The authors report observed 10-year brachytherapy results in the treatment of 152 consecutive patients with clinically organ-confined prostate carcinoma.

METHODS

One hundred and fifty-two consecutive patients with T1-T3, low to high Gleason grade, prostate carcinoma were treated between January 1987 and June 1988 at Northwest Hospital in Seattle, Washington. Their median age was 70 years (range, 53-92 years). Of these 152 patients, 98 (64%) received an iodine-125 implant alone (Group 1), and the remaining 54 patients (36%), who were judged to have a higher risk of extraprostatic extension, also were treated with 45 gray (Gy) of external beam irradiation to the pelvis (Group 2). No patient underwent lymph node sampling, and none received androgen ablation therapy. Multivariate regression and the Mann-Whitney rank sum test were used for statistical analysis. Preoperative patient data with associated success or failure outcomes at 10 years after treatment were used for training and validating a back-propagation neural network prediction program.

RESULTS

The average preoperative prostate specific antigen (PSA) value, clinical stage, and Gleason grade were 11.0 ng/mL, T2, and 5, respectively. The median posttreatment follow-up was 119 months (range, 3-134 months). Overall survival 10 years after treatment was 65%. At last follow-up only 3 of the 152 patients (2%) had died of prostate carcinoma. Ninety-seven patients (64%) remained clinically and biochemically free of disease at 10 years of follow-up and had an average PSA value of 0.18 ng/mL (range, 0.01-0.5 ng/mL). In these patients a period of 42 months was required to reach the average PSA (0.5 ng/mL). The median to last PSA follow-up was 95 months (range, 3-134 months). Postoperative needle biopsies were negative in 56% of patients, positive in 15% of patients, and not available in 29% of patients. Only 6% of patients developed bone metastasis. At 10 years there was no statistically significant difference in treatment outcome between patients who received iodine-125 alone, and those who received iodine-125 with 45-Gy external beam irradiation (P = 0.08). Nevertheless, in these two groups preoperative PSA, stage, and Gleason grade were significantly different (P < 0.01). In the artificial neural network analysis, pretreatment serum PSA was the most accurate predictor of disease-free survival.

CONCLUSIONS

Percutaneous prostate brachytherapy is a valid and efficient option for treating patients with clinically organ-confined, low to high Gleason grade, prostate carcinoma. Observed 10-year follow-up documents serum PSA levels superior to those reported in several published external beam irradiation series, and comparable to those published in a number of published radical prostatectomy series.