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

RapidArc, intensity modulated photon and proton techniques for recurrent prostate cancer in previously irradiated patients: a treatment planning comparison study

Background

A study was performed comparing volumetric modulated arcs (RA) and intensity modulation (with photons, IMRT, or protons, IMPT) radiation therapy (RT) for patients with recurrent prostate cancer after RT.

Methods

Plans for RA, IMRT and IMPT were optimized for 7 patients. Prescribed dose was 56 Gy in 14 fractions. The recurrent gross tumor volume (GTV) was defined on ¹⁸F-fluorocholine PET/CT scans. Plans aimed to cover at least 95% of the planning target volume with a dose > 50.4 Gy. A maximum dose (D_Max) of 61.6 Gy was allowed to 5% of the GTV. For the urethra, D_Max was constrained to 37 Gy. Rectal D_Median was < 17 Gy. Results were analyzed using Dose-Volume Histogram and conformity index (CI₉₀) parameters.

Results

Tumor coverage (GTV and PTV) was improved with RA (V_95% 92.6 ± 7.9 and 83.7 ± 3.3%), when compared to IMRT (V_95% 88.6 ± 10.8 and 77.2 ± 2.2%). The corresponding values for IMPT were intermediate for the GTV (V_95% 88.9 ± 10.5%) and better for the PTV (V_95%85.6 ± 5.0%). The percentages of rectal and urethral volumes receiving intermediate doses (35 Gy) were significantly decreased with RA (5.1 ± 3.0 and 38.0 ± 25.3%) and IMPT (3.9 ± 2.7 and 25.1 ± 21.1%), when compared to IMRT (9.8 ± 5.3 and 60.7 ± 41.7%). CI₉₀ was 1.3 ± 0.1 for photons and 1.6 ± 0.2 for protons. Integral Dose was 1.1 ± 0.5 Gy*cm³ *10⁵ for IMPT and about a factor three higher for all photon's techniques.

Conclusion

RA and IMPT showed improvements in conformal avoidance relative to fixed beam IMRT for 7 patients with recurrent prostate cancer. IMPT showed further sparing of organs at risk.

Radiotherapy for patients with localized hormone-refractory prostate cancer: results of the Patterns of Care Study in Japan

OBJECTIVE

To evaluate the clinical results of radiotherapy (RT) for patients with regionally localized hormone-refractory prostate carcinoma (HRPC).

PATIENTS AND METHODS

As part of a Patterns of Care Study in Japan, a nationwide survey was conducted of RT for patients with prostate adenocarcinoma. We reviewed the detailed information of 140 patients with regionally localized HRPC who received RT between 1996 and 1998, and between 1999 and 2001, in 117 randomly selected institutes in Japan. The median (range) age of the patients was 74 (51-94) years, and their tumours were defined as well (14), moderately (51) or poorly (54) differentiated, or of unknown differentiation (21). The median (range) interval between hormonal therapy (HT) and RT was 32.5 (1.1-168.4) months. Ninety-five patients had T3-4 tumours and 28 had regional lymph node metastases before treatment. The median (range) prostate-specific antigen levels before the initial HT and before RT were 35.0 (1.5-276) and 10.0 (0.06-760.3) ng/mL, respectively. External beam RT was administered, with a median total dose of 66 Gy; 70 patients (50%) received pelvic irradiation.

RESULTS

At a median follow-up of 20.7 months, the 5-year overall and clinical progression-free survival rates (95% confidence interval) were 48.1 (36-60)% and 36.7 (26-47)%, respectively. Although there were distant metastases in 46 patients, only six had local progression. There was late morbidity of grade > or =3 in six patients.

CONCLUSION

To the best of our knowledge, this study comprises the largest series of regionally localized HRPC treated with RT reported to date. RT might have a limited role for HRPC, because in most patients RT failed, with distant metastasis.

Clinical significance and treatment of biochemical recurrence after definitive therapy for localized prostate cancer

PURPOSE

Radical prostatectomy and external beam radiation therapy are the established and definitive interventions for clinically localized prostate cancer. These treatment modalities are yet subject to failure observed first by biochemical recurrence, defined by increases in the serum PSA level. We investigated the significance of biochemical recurrence after definitive therapy and the available salvage therapy options for cancer recurrence.

METHODS

A literature search was performed in PubMed, and applicable studies addressing biochemical recurrence and salvage options after radical prostatectomy or external beam radiation therapy were reviewed.

RESULTS

After radical prostatectomy, a detectable serum PSA level indicates biochemical recurrence. Whether to administer salvage therapy locally or systemically depends largely on prognostic factors including PSA doubling time, Gleason's score, pathologic stage, and the time interval between radical prostatectomy and biochemical recurrence. Early initiation of salvage therapy has been shown to significantly impact on cancer outcomes. After external beam radiation therapy, no single PSA level can define biochemical recurrence. Instead, it has been defined by increases in the PSA level above the nadir. Following radiation therapy, PSA doubling time and Gleason score play important roles in determining the need for local versus systemic salvage therapy.

CONCLUSIONS

After the diagnosis of biochemical recurrence, it is critical to perform a timely clinical assessment using the prognostic factors mentioned above. Prompt initiation of salvage therapy may prevent subsequent clinical progression and prostate cancer-specific mortality.

PSA response signatures - a powerful new prognostic indicator after radiation for prostate cancer?

BACKGROUND

We sought to determine whether inter-patient variations in pattern of PSA changes after radiation exist and, if so, are they prognostically significant.

METHODS

In the Trans-Tasman Radiation Oncology Group (TROG) 96.01 randomized controlled trial, patients with T2b,c,3,4 N0 prostate cancer (PC) were randomised to 0, 3 or 6months maximal androgen deprivation prior to 66Gy to the prostate and seminal vesicles (XRT). Patterns of anatomical site of failure were one of the trial endpoints. Serial serum PSA's were mandated at all follow-up visits. Pattern recognition software was developed to characterize PSA response "signatures" (PRS) after therapy in individual patients.

RESULTS

By 2000, 270 eligible patients were randomised to radiation alone. Individual patient PSA values were observed to descend after radiation according to one of two characteristic "signatures": single exponential (PRS Type 1), non-exponential (PRS Type 2). Compared to PRS Type 1, men with PRS Type 2 (50% of the group) had lower PSA nadir (nPSA) levels (p<.0001), longer doubling times on relapse (p=.006) and significantly lower rates of local (hazard ratio [HR]: 0.47, 95% confidence interval [0.30-0.75], p=.0014) and distant failure (HR: 0.25[0.13-0.46], p<.0001), death due to PC (HR: 0.20[0.10-0.42], p<.0001) and death due to any cause (HR: 0.37 [0.23-0.60], p<.0001). PRS retained its powerful prognostic significance in Cox models that incorporated all key pre-treatment covariates and nPSA.

CONCLUSIONS

PRS reflect the presence of tumor phenotypes that vary substantially in their clinical behavior and response to XRT. Molecular characterization is now necessary.

Determining if pretreatment PSA doubling time predicts PSA trajectories after radiation therapy for localized prostate cancer

INTRODUCTION

To determine if pretreatment PSA doubling time (PSA-DT) can predict post-radiation therapy (RT) PSA trajectories for localized prostate cancer.

MATERIALS AND METHODS

Three hundred and seventy-five prostate cancer patients treated with external beam RT without androgen deprivation therapy (ADT) were identified with an adequate number of PSA values. We utilized a linear mixed model (LMM) analysis to model longitudinal PSA data sets after definitive treatment. Post-treatment PSA trajectories were allowed to depend on the pre-RT PSA-DT, pre-RT PSA (iPSA), Gleason score (GS), and T-stage.

RESULTS

Pre-RT PSA-DT had a borderline impact on predicting the rate of PSA rise after nadir (p=0.08). For a typical low risk patient (T1, GS6, iPSA 10), the predicted PSA-DT post-nadir was 21% shorter for pre-RT PSA-DT<24month compared to pre-RT PSA-DT>24month (19month vs. 24month). Additional significant predictors of post-RT PSA rate of rise included GS (p<0.0001), iPSA (p<0.0001), and T-stage (p=0.02).

CONCLUSIONS

We observed a trend between rapidly rising pre-RT PSA and the post-RT post-nadir PSA rise. This effect appeared to be independent of iPSA, GS, or T-stage. The results presented suggest that pretreatment PSA-DT may help predict post-RT PSA trajectories.

Biological mediators of effect of diet and stress reduction on prostate cancer

BACKGROUND

A 6-month pilot intervention trial was conducted to determine whether adoption of a plant-based diet, reinforced by stress reduction, could reduce the rate of prostate-specific antigen (PSA) increase, a marker of disease progression, in asymptomatic, hormonally untreated patients experiencing consistently increasing PSA levels after surgery or radiation.

METHODS

A pre-post design was used to examine (1) the effect of intervention on potential mediators of disease progression, including body composition and weight-related biomarkers (sex steroid hormones and cytokines), and (2) whether changes in these variables were associated with change in rate of PSA increase. The baseline rate of PSA increase (from the time of posttreatment recurrence to the start of intervention) was ascertained from medical records. Body composition and biomarkers were assessed at baseline (prior to intervention), during the intervention (3 months), and at the end of the intervention (6 months). Changes in body composition and biomarkers were determined and compared with rates of PSA increase over the corresponding time intervals.

RESULTS

There was a significant reduction in waist-to-hip ratio (P=.03) and increase in circulating sex hormone binding globulin (P=.04). The rate of PSA increase decreased from the preintervention period (PSA slope=0.059) to the period from 0 to 3 months (PSA slope=0.002, P<.01) and increased slightly, although not significantly, from 0 to 3 months to the period from 3 to 6 months (0.029, P=.43).

CONCLUSIONS

Adoption of a plant-based diet and stress reduction may reduce central adiposity and improve the hormonal milieu in patients with recurrent PC. Changes in the rate of increase in PSA were in the same direction as changes in waist-to-hip ratio and opposite those of sex hormone binding globulin, raising the possibility that the effect of the intervention may have been mediated, in part, by these variables.

Predicting biochemical failure and overall survival through intratherapy PSA changes during definitive external beam radiotherapy

PURPOSE

To determine whether intratherapy prostate-specific antigen (itPSA) changes during radiotherapy (RT) predict prostate cancer outcomes.

METHODS AND MATERIALS

We retrospectively identified patients treated with definitive external beam RT without hormonal therapy who had at least two itPSA measurements. We calculated the adjusted ratio of rise (ARR) in itPSA relative to the pretreatment baseline PSA for each patient. This was defined as ln(maximal itPSA + 1)/ln(baseline PSA + 1). We stratified patients according to an ARR of <1 vs. >1.1. This corresponded to an approximately <30% vs. >30% increase in PSA during RT. Univariate and multivariate analyses were performed examining for biochemical failure-free survival (BFFS) and overall survival (OS).

RESULTS

At a median follow-up of 74 months, we identified 307 patients who met our criteria. Univariate analysis revealed that patients with an ARR of <1.1 (n = 182) had statistically significant inferior BFFS and OS compared with those with an ARR of >1.1 (n = 125). The median BFFS and OS for these two groups was 51 vs. 101 months (p = 0.001) and 96 vs. 128 months (p = 0.01), respectively. On multivariate analysis, the effect of ARR on the risk of biochemical failure for patients with an ARR of <1.1 was significant (p = 0.03) only during the first year after RT. In contrast, the effect of the ARR on OS remained significant for a full 5 years (p = 0.05).

CONCLUSION

The results of our study have shown that an ARR of <1.1 predicts for inferior BFFS and OS in patients treated with RT alone. PSA measurement during RT is a novel clinical tool that could be used to identify patients who might warrant more aggressive therapeutic intervention.

[PSA and follow-up after treatment of prostate cancer]

A first serum total PSA assay is recommended during the first three months after treatment. When PSA is detectable, PSA assay should be repeated three months later to confirm this elevation and to estimate the PSA doubling time (PSADT). In the absence of residual cancer, PSA becomes undetectable by the first month after total prostatectomy: less than 0.1 ng/ml (or less than 0.07 ng/ml) for the ultrasensitive assay method and less than 0.2 ng/ml for the other methods. In the presence of residual cancer, PSA either does not become undetectable or increases after an initial undetectable period. A consensus has been reached to define recurrence as PSA greater than 0.2 ng/ml confirmed on two successive assays. After external beam radiotherapy, PSA can decrease after a mean interval of one to two years to a value less than 1 ng/ml (predictive of recurrence-free survival). Biochemical recurrence after radiotherapy is defined by an increase of PSA by 2 ng or more above the PSA nadir, whether or not it is associated with endocrine therapy. After endocrine therapy, the PSA nadir is correlated with recurrence-free survival. PSA is decreased for a mean of 18 to 24 months followed by a rise in PSA, corresponding to hormone-independence. The time to recurrence or the time to reach the nadir and the PSA doubling time after local therapy with surgery or radiotherapy have a diagnostic value in terms of the site of recurrence, local or metastatic and a prognostic value for survival and response to complementary radiotherapy or endocrine therapy. A PSADT less than eight to 12 months is correlated with a high risk of metastatic recurrence and 10-year mortality. The histological and biochemical characteristics in favour of local recurrence are Gleason score less or equal to seven (3+4), elevation of PSA after a period greater than 12 months and PSADT greater than 10 months. In other cases, recurrence is predominantly metastatic. The risk of demonstrating metastasis in the case of biochemical recurrence after total prostatectomy and before endocrine therapy depends on the PSA level and the PSADT. No consensus has been reached concerning the indication for complementary investigations by bone scan and abdominopelvic CT in patients with biochemical recurrence after treatment of localized cancer without endocrine therapy. However, when PSADT greater than six months, the risk of metastasis is less than 3% even for PSA greater than 30 ng/ml. When PSADT less than six months and PSA greater than 10 ng/ml, the risk of metastasis is close to 50%.

Prostate specific antigen kinetics in the management of prostate cancer

PURPOSE

We review the usefulness of prostate specific antigen kinetics (ie prostate specific antigen velocity and doubling time) in the treatment of patients with prostate cancer.

MATERIALS AND METHODS

The MEDLINE database was searched to identify studies investigating prostate specific antigen kinetics in patients with prostate cancer.

RESULTS

Various techniques are available for estimating prostate specific antigen kinetics, but to minimize the impact of prostate specific antigen variability on such calculations at least a 90-day period and preferably more than 2 measurements should be used. There is little to suggest which measure of prostate specific antigen kinetics may be superior since both appear to provide useful prognostic information. Prostate specific antigen velocity is easier to calculate but prostate specific antigen doubling time may have greater biological justification. Retrospective studies show that before treatment prostate specific antigen kinetics provide prognostic information regarding the risk of treatment failure and subsequent death from cancer. Additionally, in patients treated surgically preoperative prostate specific antigen kinetics predict the risk of adverse pathology, while in those undergoing conservative treatment prostate specific antigen kinetics are associated with the risk of progression and need for intervention. In patients with biochemical failure after therapy prostate specific antigen kinetics predict the risk and potential site of clinical recurrence, the likely response to salvage therapy, and the risk of death from cancer. Preliminary assessments also suggest that prostate specific antigen kinetics may serve as a surrogate end point to replace cancer specific mortality.

CONCLUSIONS

Although prospective studies are lacking, the current literature suggests that prostate specific antigen kinetics provide valuable prognostic information, and should be further evaluated in clinical decision making and as a surrogate end point for future trials.

Prostate specific antigen recurrence after definitive therapy

PURPOSE

We estimate that approximately 70,000 men yearly have prostate specific antigen-only recurrence after failed definitive therapy. The ideal salvage therapy for these men is not clear. Treatment must be individualized based on the patient risk of progression, the likelihood of success and the risks involved with the therapy. However, to do so the risks and benefits of the various options must be known. Therefore, we provide a comprehensive overview of the natural history and treatment options for men with prostate specific antigen-only recurrence.

MATERIALS AND METHODS

A literature review and overview of prostate specific antigen-only recurrence after failed definitive therapy was done.

RESULTS

The natural history after prostate specific antigen-only recurrence is long but variable. Median time from prostate specific antigen-only recurrence after radical prostatectomy to prostate cancer death exceeds 16 years, although some men die within 1 year after PSA recurrence. Rapid prostate specific antigen doubling time is the best prognostic factor for poor outcome. Salvage radiation therapy after radical prostatectomy results in a 45% 4-year prostate specific antigen response rate, although long-term outcomes appear poor. To our knowledge the effect on survival is not known. Salvage radical prostatectomy is rarely performed but in the highly selected patient it may provide some benefit. There are no randomized studies of early vs late hormonal therapy for men with prostate specific antigen-only recurrence. A retrospective study suggested delayed metastasis when therapy was begun early but only in men at high risk. This mirrors other data suggesting that men at high risk may derive significant benefits from early hormonal therapy, whereas men at low risk are unlikely to benefit and may be harmed by hormonal therapy.

CONCLUSIONS

Prostate specific antigen-only recurrence is the most common form of advanced prostate cancer. Optimal salvage treatments and timing of these treatments remain controversial.

What dose of external-beam radiation is high enough for prostate cancer?

PURPOSE

To quantify the radiotherapy dose-response of prostate cancer, adjusted for prognostic factors in a mature cohort of men treated relatively uniformly at a single institution.

PATIENTS AND METHODS

The study cohort consisted of 1,530 men treated with three-dimensional conformal external-beam radiotherapy between 1989 and 2002. Patients were divided into four isocenter dose groups: <70 Gy (n = 43), 70-74.9 Gy (n = 552), 75-79.9 Gy (n = 568), and > or =80 Gy (n = 367). The primary endpoints were freedom from biochemical failure (FFBF), defined by American Society for Therapeutic Radiology and Oncology (ASTRO) and Phoenix (nadir + 2.0 ng/mL) criteria, and freedom from distant metastases (FFDM). Multivariate analyses were performed and adjusted Kaplan-Meier estimates were calculated. Logit regression dose-response functions were determined at 5 and 8 years for FFBF and at 5 and 10 years for FFDM.

RESULTS

Radiotherapy dose was significant in multivariate analyses for FFBF (ASTRO and Phoenix) and FFDM. Adjusted 5-year estimates of ASTRO FFBF for the four dose groups were 60%, 68%, 76%, and 84%. Adjusted 5-year Phoenix FFBFs for the four dose groups were 70%, 81%, 83%, and 89%. Adjusted 5-year and 10-year estimates of FFDM for the four dose groups were 96% and 93%, 97% and 93%, 99% and 95%, and 98% and 96%. Dose-response functions showed an increasing benefit for doses > or =80 Gy.

CONCLUSIONS

Doses of > or =80 Gy are recommended for most men with prostate cancer. The ASTRO definition of biochemical failure does not accurately estimate the effects of radiotherapy at 5 years because of backdating, compared to the Phoenix definition, which is less sensitive to follow-up and more reproducible over time.

Survival benefit for early hormone ablation in biochemically recurrent prostate cancer

PURPOSE

To determine whether early initiation of androgen ablation in patients with biochemically recurrent prostate cancer, but without clinically evident metastases, is associated with improved overall or disease-specific survival. To describe subgroups, based on PSA kinetics, which are most likely to benefit from early androgen ablation.

MATERIALS AND METHODS

A retrospective cohort of 124 patients, who were definitively treated by external beam radiotherapy between 1988 and 1999, and subsequently received androgen ablation for biochemical (92 patients) or clinically metastatic (32 patients) failure, was reviewed. Median follow-up time was 6.2 years. Overall survival, disease-specific survival, and hormonal control were examined and compared for patients whose hormone ablation was started early (prostate-specific antigen [PSA] <or=15 ng/ml or PSA doubling time >7 months) or late in the course of their biochemical failure.

RESULTS

All patients had biochemical response to hormone initiation, with a median PSA nadir of 0.05 ng/ml. Early initiation of hormone ablation resulted in statistically significant improvement in all outcome measures. Multivariate analysis indicated that PSA doubling time at hormone initiation was the most consistent predictor of outcome. The 5-year overall survival was 78% for patients whose androgen ablation was initiated at doubling time <or=7 months and 93% for patients when initiated at doubling time >7 months. Mean survival improved from 84.9 +/- 4.6 (doubling time <or=7) to 115.3 +/- 8.4 months (doubling time >7). Survival for patients started on hormones with doubling time <5 months was similar to that of patients with clinical metastases.

CONCLUSIONS

This survival benefit justifies the use of androgen ablation in patients whose doubling time approaches 7 months. A randomized trial is needed to confirm these findings, investigate potential benefit for patients with longer doubling times, and gather data on the morbidity of early hormone ablation, including quality of life issues.

Prostate cancer gene therapy clinical trials

Despite recent advances in early detection and treatment, prostate cancer is still the second leading cause of cancer death in men in the United States, and approximately 27,000 men will die from it this year. Better treatments are needed for aggressive forms of localized disease and hormone-refractory metastatic disease. Recently, several gene therapy strategies have generated provocative results in early-stage clinical trials, raising the possibility that gene therapy may have the potential to affect both localized and metastatic disease. Much work lies ahead. Nevertheless, for the time being, these studies provide hope that gene therapy may someday earn a place in the management of prostate cancer.

Five-year follow-up of trial of replication-competent adenovirus-mediated suicide gene therapy for treatment of prostate cancer

Replication-competent adenovirus-mediated suicide gene therapy is an investigational cancer treatment that combines the oncolytic actions of human adenoviruses with the cytotoxic effects of chemo-radiosensitizing genes. Previously, we reported the short-term effects of this therapy in men with local recurrence of prostate cancer after definitive radiotherapy. With a median prostate-specific antigen (PSA) follow-up of 5 years, we report here the effect of the gene therapy on prostate-specific antigen doubling time (PSADT), a surrogate end point with significant prognostic power. When considering all evaluable subjects, the PSADT increased following the gene therapy from a mean of 17 to 31 months (median 16 to 22 months) (P=0.014). Assuming that salvage androgen suppression therapy androgen suppression therapy (AST) was uniformly initiated at a PSA of 15 ng/mL, the gene therapy would have delayed the projected onset of salvage therapy by an average of 2 years. The results indicate that replication-competent adenovirus-mediated suicide gene therapy may provide a potential long-term benefit to patients, as shown by a lengthening of the PSADT, and delay in when salvage therapy is indicated. Given the high morbidity associated with AST, we believe this approach could provide an attractive treatment option for selection of patients experiencing PSA relapse following definitive therapy.

Patient selection, cancer control, and complications after salvage local therapy for postradiation prostate-specific antigen failure

Among men who experience prostate-specific antigen (PSA) failure after external beam radiation or brachytherapy (RT), many will harbor occult micrometastases; however, a significant minority will have a true local-only failure and, thus, potentially may benefit from a salvage local therapy. Those most likely to have a local-only failure initially have low-risk disease (PSA < 10 ng/mL, Gleason score < or =6, clinical T1c or T2a tumor status), pretreatment PSA velocity < 2.0 ng/mL per year at the time of initial presentation, interval to PSA failure > 3 years, PSA doubling time > 12 months, negative bone scan and pelvic imaging, and positive rebiopsy. In addition, men with presalvage PSA levels > 10 ng/mL, presalvage T3/T4 disease, or presalvage Gleason scores > or =7 on a rebiopsy sample without significant RT effects are unlikely to be cured by salvage local therapy. Based on a review of all series of post-RT salvage prostatectomy, cryosurgery, and brachytherapy published in English since 1990, morbidity can be substantial. Although urinary incontinence appeared to be greater after salvage prostatectomy (41%) or cryosurgery (36%) than after brachytherapy (6%), patients who received salvage brachytherapy faced a 17% risk of grade 3 or 4 genitourinary complications and a fistula risk that averaged 3.4% across all series. From this review, the authors concluded that prospective randomized studies are needed to determine the relative efficacy of the 3 major local salvage modalities and that additional research is needed to identify factors associated with an increased risk of significant complications to improve patient selection and to augment the benefit/risk ratio associated with attempts to cure local-only recurrences after radiation therapy.

Magnetic resonance image-guided salvage brachytherapy after radiation in select men who initially presented with favorable-risk prostate cancer

BACKGROUND

The authors prospectively evaluated the late gastrointestinal (GI) and genitourinary (GU) toxicity and prostate-specific antigen (PSA) control of magnetic resonance imaging (MRI)-guided brachytherapy used as salvage for radiation therapy (RT) failure.

METHODS

From October 2000 to October 2005, 25 men with a rising PSA level and biopsy-proven, intraprostatic cancer at least 2 years after initial RT (external beam in 13 men and brachytherapy in 12 men) who had favorable clinical features (Gleason score < or =7, PSA < 10 ng/mL, negative pelvic and bone imaging studies), received MRI-guided salvage brachytherapy to a minimum peripheral dose of 137 gray on a phase 1/2 protocol. Estimates of toxicity and cancer control were calculated using the Kaplan-Meier method.

RESULTS

The median follow-up was 47 months. The 4-year estimate of grade 3 or 4 GI or GU toxicity was 30%, and 13% of patients required a colostomy and/or urostomy to repair a fistula. An interval < 4.5 years between RT courses was associated with both outcomes with a hazard ratio of 12 (95% confidence interval [95% CI], 1.4-100; P = .02) for grade 3 or 4 toxicity and 25 (95% CI, 1.1-529; P = .04) for colostomy and/or urostomy. PSA control (nadir +2 definition) was 70% at 4 years.

CONCLUSIONS

The current results indicated that MRI-guided salvage brachytherapy in men who are selected based on presenting characteristics and post-failure PSA kinetics can achieve high PSA control rates, although complications requiring surgical intervention may occur in 10% to 15% of patients. Prospective randomized studies are needed to characterize the relative cancer control and toxicity after all forms of salvage local therapy.

Prostate-Specific Antigen Kinetics After Brachytherapy or External Beam Radiotherapy and Neoadjuvant Hormonal Therapy

OBJECTIVES

To characterize the kinetics of prostate-specific antigen (PSA) after radiotherapy (RT) and neoadjuvant hormonal therapy (NHT) for localized prostate cancer.

METHODS

The PSA kinetics of 75 consecutive patients who had undergone RT and NHT (median time 4 months) were followed up for a minimum of 24 months after treatment. RT included a permanent iodine-125 implant (n = 29), a temporary iridium-192 implant as a boost to external beam RT (n = 21), and sole external beam RT (n = 25). A median number of 11 PSA levels per patient were analyzed.

RESULTS

After a first nadir (median level 0.1 ng/mL 3 months after RT), rising PSA levels were found in 83% of patients and progressively rising PSA levels until the end of follow-up or salvage hormonal therapy for 21% of patients. The PSA levels dropped again after one (23%), two (21%), or more (17%) consecutive increases up to a median level of 0.6 ng/mL (median time 16 months after RT), so that a nadir of 0.1 ng/mL was reached for a second time (median time 35 months after RT). A first nadir of less than 0.1 ng/mL, a PSA increase of less than 1 ng/mL, and a longer PSA doubling time (median time 10 months) were strongly predictive for long-term biochemical control.

CONCLUSIONS

Temporarily rising PSA levels can be expected for most patients after primary RT and NHT following a first nadir. The increasing effects of testosterone owing to NHT withdrawal have a stronger effect than RT in the first months after treatment.

Management of high risk metastatic prostate cancer: defining risk at the time of initial treatment failure

PURPOSE

Even as improvements in therapy success continue, initial treatment for prostate cancer fails in a substantial proportion of patients with apparently localized disease. However, the optimal approaches to defining biochemical failure and determining its clinical significance remain unclear.

MATERIALS AND METHODS

A focused review and search of current literature were performed regarding biochemical recurrence and risk stratification after initial therapy for prostate cancer.

RESULTS

Multiple definitions exist for prostate specific antigen failure after therapy for localized and metastatic prostate cancer. The timing of prostate specific antigen recurrence as well as prostate specific antigen kinetic characteristics, such as prostate specific antigen velocity and most significantly prostate specific antigen doubling time, impacts the prediction of posttreatment cancer specific and overall survival after biochemical recurrence is detected. In addition, as with determining the recurrence risk, Gleason score and pathological stage also can predict the survival likelihood.

CONCLUSIONS

In most cases biochemical prostate specific antigen recurrence is the initial indicator of treatment failure and eventual progression but prostate specific antigen recurrence alone does not predict clinically significant events. As with determining the risk likelihood, pathological data and prostate specific antigen kinetic characteristics can help predict patient survival.

Adoption of a plant-based diet by patients with recurrent prostate cancer

The Western diet has been associated with prostate cancer incidence as well as risk of disease progression after treatment. Conversely, plant-based diets have been associated with decreased risks. A pilot clinical trial of a 6-month dietary change and stress reduction intervention for asymptomatic, hormonally untreated patients experiencing a consistently rising PSA level, the first sign of recurrence of prostate cancer after surgery or radiation therapy, was conducted to investigate the level of intake of plant-based foods and the relationship between intake and the change in the rate of PSA rise. A pre-post design was employed in which each patient served as his own control. In this multifaceted intervention, patients and their spouses were encouraged to adopt and maintain a plant-based diet. The prestudy rate of PSA rise (from the time of posttreatment recurrence to the start of the study) was ascertained by review of patients' medical records. Dietary assessments were performed and prostate-specific antigen (PSA) levels ascertained at baseline, prior to the start of intervention, and at 3 and 6 months. Changes in numbers of servings of plant-based food groups were calculated and compared with rates of PSA rise over the corresponding time intervals. Median intake of whole grains increased from 1.7 servings/d at baseline to 6.9 and 5.0 servings/d at 3 and 6 months, respectively. Median intake of vegetables increased from 2.8 servings/d at baseline to 5.0 and 4.8 servings/d at 3 and 6 months, respectively. The rate of PSA rise decreased when comparing the prestudy period (0.059) to the period from 0 to 3 months (-0.002, P < .01) and increased slightly, though not significantly, when comparing the period from 0 to 3 months to the period from 3 to 6 months (0.029, P = .4316). These results provide preliminary evidence that adoption of a plant-based diet is possible to achieve as well as to maintain for several months in patients with recurrent prostate cancer. Changes in the rate of rise in PSA, an indicator of disease progression, were in the opposite direction as changes in the intake of plant-based food groups, raising the provocative possibility that PSA may have inversely tracked intake of these foods and suggesting that adoption of a plant-based diet may have therapeutic potential in the management of this condition.

Unification of a common biochemical failure definition for prostate cancer treated with brachytherapy or external beam radiotherapy with or without androgen deprivation

PURPOSE

Minimal data are available regarding selection of an optimal biochemical failure (BF) definition for patients treated with brachytherapy, external beam radiotherapy (EBRT), and combinations of these treatments with or without androgen deprivation (AD). We retrospectively analyzed our institution's experience treating localized prostate cancer in an attempt to determine a BF definition that could be applied for these various treatment modalities.

METHODS AND MATERIALS

A total of 2376 patients with clinical stage T1-T3 N0 M0 prostate cancer were treated with conventional dose (median, 66.6 Gy) EBRT (n = 1201), high-dose (median, 75.6 Gy) adaptive radiation therapy (n = 465), EBRT + high-dose-rate brachytherapy boost (n = 416), or brachytherapy alone (n = 294) between 1987 and 2003. A total of 496 patients (21%) received neoadjuvant AD with radiation therapy. There were 21924 posttreatment prostate-specific antigen (PSA) measurements. Multiple BF definitions were tested for their sensitivity, specificity, positive predictive value (+PV), and negative PV (-PV) in predicting subsequent clinical failure (CF) (any local failure or distant metastasis), overall survival (OS), and cause-specific survival (CSS). Median follow-up was 4.5 years. The date of BF was the date BF criteria were met (e.g., date of third rise).

RESULTS

A total of 290 patients (12%) experienced CF at a median interval of 3.6 years (range, 0.2-15.2 years). The 5- and 10-year CF rates were 12% and 26%, respectively. Three consecutive rises yielded a 46% sensitivity and 84% specificity for predicting CF. The 10-year CF for those 475 patients who experienced three rises (BF) was 37% vs. 17% for those patients who did not meet these criteria (biochemically controlled [BC]). For all patients, the following definitions were superior to three rises for predicting CF for both +PV, and -PV: n + 1 (> or =1 ng/mL above nadir), n + 2, n + 3, threshold 2 (any PSA > or =2.0 ng/mL at or after nadir), threshold 3, threshold 4, and threshold 5. For the subset of patients treated with EBRT alone, the n + k definitions and threshold k definitions maintained superior predictive capacity. However, the threshold k definitions seemed to maintain a slightly greater separation in 10-year CF rates (43% for BF vs. 13% for BC = 30% difference for threshold 3). Surprisingly, all definitions generally had better predictive capacity for those patients who received brachytherapy or neoadjuvant AD vs. EBRT alone. The endpoints appeared similar for n + 1 vs. threshold 3 and n + 2 vs. threshold 4 in EBRT alone patients, but for brachytherapy or neoadjuvant AD patients, there were similarities for n + 2 vs. threshold 3 and n + 3 vs. threshold 4. This may be a reflection of the lower nadir levels in patients receiving AD (median <0.1 ng/mL vs. 0.2 ng/mL for brachytherapy vs. 0.8 ng/mL for EBRT alone, p < 0.01). When examining CF correlation for the various classes of BF definitions, the threshold k definitions clearly demonstrated the greatest area under the receiver operating characteristic curve, followed by the n + k definitions. For OS, the threshold k definitions again demonstrated the greatest area under the curve, followed by definitions based on specific nadir cutoffs (nadir > or =k ng/mL).

CONCLUSIONS

Biochemical failure definitions applying a PSA threshold at or after the nadir (e.g., threshold 3) demonstrated the highest association with CF, OS, and CSS for all assessed treatment modalities. Definitions incorporating a PSA increase above the nadir value (e.g., nadir + 2 ng/mL) were also superior for all modalities. In general, BF definitions have greater predictive capacity for clinical outcome with brachytherapy or neoadjuvant AD than EBRT alone, possibly because of less "noise" from production of background PSA.

First-year PSA kinetics and minima after prostate cancer radiotherapy are predictive of overall survival

PURPOSE

We analyzed whether first-year prostate-specific antigen (PSA) kinetics and minima are predictive of overall survival (OS).

METHODS AND MATERIALS

The data set contained 1,174 patients treated with external beam radiotherapy (RT) from 1987 to 2001. The relative rate of change (lambda) in post-RT PSA values during the first year (13.5 months) was computed using regression analysis of ln(PSA) vs. time. We also computed the PSA minimum (mPSA) reached during the same period. Recursive partitioning analysis was used to identify the relevant cutpoints for the factors being investigated for its association with survival: age, pretreatment PSA, radiation dose, relative rate of change in PSA post-RT, and 1-year PSA minimum. For each of the other factors stage, Gleason score and risk group, all possible cutpoints were considered in the multivariate analyses. Significant factors were considered in the multivariate analyses to identify independent predictors for overall survival.

RESULTS

The median value of lambda was -1.0 years(-1) (range, -11.0-5.1 years(-1)). The 1-year minimum had a median of 0.8 ng/mL (range, 0.01-30.9 ng/mL). Recursive partitioning analysis and Cox proportional hazards analyses identified the following pretreatment or treatment factors adversely related to OS: age, Gleason score, stage, and dose. First-year mPSA > or = 4 ng/mL and lambda > 0 were post-RT independent prognostic factors for worse OS.

CONCLUSION

First-year post-RT PSA kinetics and minima are early response parameters predictive of overall survival for prostate cancer patients. These factors may be useful in selecting patients for early salvage therapy.

Molecular load of pathologically occult metastases in pelvic lymph nodes is an independent prognostic marker of biochemical failure after localized prostate cancer treatment

PURPOSE

Thirty percent of patients treated with curative intent for localized prostate cancer (PC) experience biochemical recurrence (BCR) with rising serum prostate-specific antigen (sPSA), and of these, approximately 50% succumb to progressive disease. More discriminatory staging procedures are needed to identify occult micrometastases that spawn BCR.

PATIENTS AND METHODS

PSA mRNA copies in pathologically normal pelvic lymph nodes (N0-PLN) from 341 localized PC patients were quantified by real-time reverse-transcriptase polymerase chain reaction. Based on comparisons with normal lymph nodes and PLN with metastases and on normalization to 5 x 10(6) glyceraldehyde-3'-phosphate dehydrogenase mRNA copies, normalized PSA copies (PSA-N) and a threshold of PSA-N 100 or more were selected for continuous and categorical multivariate analyses of biochemical failure-free survival (BFFS) compared with established risk factors.

RESULTS

At median follow-up of 4 years, the BFFS of patients with PSA-N 100 or more versus PSA-N less than 100 was 55% and 77% (P = .0002), respectively. The effect was greatest for sPSA greater than 20 ng/mL, 25% versus 60% (P = .014), Gleason score 8 or higher, 21% versus 66% (P = .0002), stage T3c, 18% versus 64% (P = .001), and high-risk group (50% v 72%; P = .05). By continuous analysis PSA-N was an independent prognostic marker for BCR (P = .049) with a hazard ratio of 1.25 (95% CI, 1.001 to 1.57). By categorical analysis, PSA-N 100 or more was an independent variable (P = .021) with a relative risk of 1.98 (95% CI, 1.11 to 3.55) for BCR compared with PSA-N less than 100.

CONCLUSION

PSA-N 100 or more is a new, independent molecular staging criterion for localized PC that identifies high-risk group patients with clinically relevant occult micrometastases in N0-PLN, who may benefit from additional therapy to prevent BCR.

Celecoxib Versus Placebo for Men With Prostate Cancer and a Rising Serum Prostate-Specific Antigen After Radical Prostatectomy and/or Radiation Therapy

Purpose

To assess the biologic activity of celecoxib, a selective cyclooxygenase-2 inhibitor, in men with recurrent prostate cancer using change in prostate-specific antigen (PSA) doubling time (PSADT) as the primary outcome variable.

Patients and Methods

Participants had histologically confirmed prostate cancer, no recent hormone therapy, rising serum PSA after radical prostatectomy and/or radiation therapy, and no radiographic evidence of metastases. Patients were randomly assigned to celecoxib (400 mg by mouth twice daily) or placebo. Treatment continued until disease progression or until adverse effects stopped treatment. A positive outcome was defined as post-treatment PSADT of more than 200% baseline PSADT with no new metastases.

Results

The study was terminated early after information about the cardiovascular safety of celecoxib prompted review of ongoing clinical studies. Before discontinuation of the study, 78 men were assigned randomly to either celecoxib or placebo. Eight (20%) of 40 men in the placebo group and 15 (40%) of 38 men in the celecoxib group had post-treatment PSADT of more than 200% of baseline PSADT with no new metastases (P = .08). Mean PSA velocity increased by 3.0% for the placebo group and decreased by 3.4% for the celecoxib group (P = .02).

Conclusion

Although the primary efficacy objective was not met, this study provides some evidence for biologic activity of celecoxib in prostate cancer. Compared with placebo, celecoxib significantly decreased mean PSA velocity and tended to increase the proportion of men who doubled their PSADT.

Clinical trials in patients with biochemically relapsed prostate cancer

In this section there is a wide diversity of mini-reviews, covering several areas of interest for readers. Authors from the USA write about clinical trials in patients with biochemically relapsed prostate cancer, again bridging the divide between medical oncologists and urologists who specialise in urological oncological surgery. The second paper is a joint one from Germany and the USA, bringing the reader up to date with advances in the treatment of stress urinary incontinence. Finally there are two papers from Australia describing the use of positron emission tomography in renal cancer and in prostate cancer.

No immediate treatment after biochemical failure in patients with prostate cancer treated by external beam radiotherapy

OBJECTIVES

The treatment of patients with asymptomatic prostate cancer with biochemical failure (BF) remains controversial. The early introduction of hormonal therapy causes important secondary effects and increases costs. Our general policy has been to follow-up patients with low prostate-specific antigen (PSA) levels and a long PSA doubling time without therapy. We report our experience using such an approach.

METHODS

Between 1992 and 2000, 676 patients with localized prostate cancer were treated with radical radiotherapy, with or without adjuvant hormonal therapy at our institution. Asymptomatic patients with BF, no clinical evidence of metastatic disease, a low PSA level, and long PSA doubling time were considered for follow-up without immediate hormonal therapy. The prognostic factors such as stage and Gleason score were not considered when electing follow-up without additional therapy. The follow-up included at least two annual visits with physical examination and PSA determination.

RESULTS

With a median follow-up of 85 months, 285 patients (42%) had BF. In 178 of these men, the rising PSA level was the only abnormality. Of these, 113 were followed up without additional therapy and 65 received hormonal therapy. Of the 113 patients in the untreated group, 101 (89%) were alive and asymptomatic at the last follow-up visit and 12 (11%) had died of causes other than prostate cancer. The long-term outcomes were similar in both groups.

CONCLUSIONS

Expectant management, without initial hormonal therapy, may be a reasonable option for selected patients with prostate cancer who present with BF without metastatic disease after radical external beam radiotherapy. This decision is important because the early introduction of hormonal therapy is associated with side effects and is expensive.

Utility of prostate-specific antigen kinetics in addition to clinical factors in the selection of patients for salvage local therapy

A detectable and rising prostate-specific antigen (PSA) level after radical prostatectomy or a rising PSA above the nadir value after radiation therapy may represent a local failure, distant failure, or both. Determining the site or sites of failure is critical for selecting the appropriate salvage therapy. Nevertheless, although PSA failure precedes clinically evident failure by several years, determining the source of the biochemical failure is often not possible using currently available diagnostic studies. Selecting the optimal therapeutic approach may be guided by the initial clinical factors (eg, T-category, PSA, biopsy Gleason score). If the patient has had a radical prostatectomy, then the pathologic outcomes of the surgery (eg, pathologic T-category and prostatectomy Gleason score, nodal and margin status) may provide further information. Beyond pretreatment clinical and post-treatment pathologic factors, PSA kinetics, and specifically a pretreatment PSA velocity > 2 ng/mL/year, an interval to PSA failure < 3 years and a post-treatment PSA doubling time < 3 months place a man at increased risk for metastases and subsequent prostate cancer-specific mortality, making these men poor candidates for local-only salvage therapy. Therefore, the optimal candidate for local-only salvage therapy is a man whose pretreatment PSA velocity was 2 ng/mL/year or less, interval to PSA failure exceeds 3 years, and post-treatment PSA doubling time is at least 12 months, and who did not have biopsy or prostatectomy Gleason score of 8 to 10 or seminal vesicle or lymph node involvement.

Time to Detectable Metastatic Disease in Patients with Rising Prostate-Specific Antigen Values following Surgery or Radiation Therapy

PURPOSE

To determine factors associated with the development of radiographic metastatic progression for patients with recurrent prostate cancer following surgery and/or radiation therapy with prostate-specific antigen (PSA) doubling times of <12 months.

EXPERIMENTAL DESIGN

One hundred and forty-eight patients with rising PSA values after primary therapy and a PSA doubling time of <12 months enrolled on clinical protocols were followed and monitored at protocol-specified intervals with examinations, PSA determinations, and imaging studies that included a computed tomography or magnetic resonance imaging and bone scan until metastases were detected. Metastasis-free survival was estimated using the Kaplan-Meier method and factors predictive of progression-free survival were estimated using the proportional hazards model. A nomogram based on the Cox model was constructed.

RESULTS

Metastatic events were documented in 74% (110 of 148) of patients during the follow-up period. The median progression-free survival was 19 months, with 3- and 5-year metastatic progression-free survival of 32% and 16%, respectively. T stage (P=0.07) and Gleason grade (P=0.006) at the time of diagnosis, PSA values at the time of protocol entry (P<0.001), and PSA doubling time (P<0.001) were associated with progression in univariate analysis. These were combined into a nomogram to assess risk for an individual patient.

CONCLUSIONS

Tumor characteristics at the time of diagnosis, PSA doubling time following relapse, and the PSA value at the time of the protocol are predictive of metastatic progression. Because the PSA value at the time of monitoring was predictive, early treatment to prevent metastatic progression is favored.

Prostate-specific antigen doubling time predicts clinical outcome and survival in prostate cancer patients treated with combined radiation and hormone therapy

PURPOSE

To determine whether prostate-specific antigen (PSA) doubling time predicts clinical outcomes in patients with prostate cancer that has been treated with combined radiation and hormone therapy.

METHODS AND MATERIALS

We reviewed the medical records of 621 men with nonmetastatic prostate cancer treated with radiation therapy and hormone therapy between 1989 and 2003. "Any" clinical failure was defined as any distant, nodal, or local failure, or the use of salvage therapy. "True" clinical failure was defined as any distant, nodal, or local failure. PSA doubling time was calculated by using the log PSA values from patients with a PSA failure as defined by the American Society of Therapeutic Radiology Oncology consensus statement. One hundred thirty-seven men were at intermediate risk for PSA failure (as determined by T2b, Gleason score of 7, or PSA 10.1-0 ng/mL) and 484 men were at high risk for failure (T2c-4; Gleason 8-10; or PSA >20 ng/mL). Pretreatment PSA value, Gleason score, tumor stage, timing and duration of hormone therapy, radiation therapy dose, and PSA doubling time were analyzed for any associations with time to clinical failure by using Cox regression analysis. Estimates of survival were calculated by using the Kaplan-Meier method. Pairwise comparisons were made by using the log-rank test.

RESULTS

Sixty-two men experienced any clinical failure, and 22 men experienced true clinical failure. Multivariate analysis revealed that pretreatment PSA (p = 0.013), Gleason score (p = 0.0019), and a PSA doubling time (PSADT) < or =8 months (p < 0.001) were independently associated with time to any clinical failure. Tumor stage, hormone therapy timing, hormone therapy duration, and radiation therapy dose were not statistically significant on multivariate or univariate analysis. Only hormone therapy duration (p = 0.008) and PSADT < or =8 months (<0.001) were significantly associated with time to true clinical failure. The estimated 5-year rate of any clinical failure was 9.4% for men with a PSADT >8 months and 60.4% for men with a PSA doubling time < or =8 months (p < 0.001). The estimated 5-year rate of true clinical failure was 6.5% for men with a PSADT >8 months and 68.5% for men with a PSADT < or =8 months (p < 0.001). Lower radiation dose was the only significant predictor of PSADT < or =8 months on multivariate regression analysis. The estimated 6-year overall survival rate after PSA failure was 79.1% for men with a PSADT >8 months and 29.7% for men with a PSADT < or =8 months. The median overall survival time for patients with a PSADT >8 months was not reached in this study. The median overall survival time for patients with a PSADT < or =8 months was 61.8 months (p = 0.015).

CONCLUSION

In men with prostate cancer that has been treated with combined hormone and radiation therapy, a posttreatment PSADT of < or =8 months is associated with worse clinical outcomes and may be an early surrogate marker for decreased survival. These patients should be considered for more aggressive salvage therapy protocols.

LIMITATIONS IN THE USE OF SERUM PROSTATE SPECIFIC ANTIGEN LEVELS TO MONITOR PATIENTS AFTER TREATMENT FOR PROSTATE CANCER

PURPOSE

We reviewed the literature to help clarify the benefits and/or hazards associated with monitoring serum prostate specific antigen (PSA) after treatment with surgery or radiation therapy (RT) for nonmetastatic prostate cancer.

MATERIALS AND METHODS

A search was performed for 1990 to 2004 using the MEDLINE database, CancerLit database and reference lists of relevant studies to obtain articles addressing the use of serum PSA to follow patients after treatment for prostate cancer. Studies were reviewed to determine 1) if serial PSA monitoring provides an early and accurate surrogate assessment of cancer cure or treatment failure, 2) if any pattern in the PSA profile after treatment provides conclusive evidence of early local vs systemic failure, 3) the magnitude of the lead time to clinical failure that serial PSA monitoring may provide and 4) if the early identification of biochemical failure (BF) with earlier intervention improves outcome.

RESULTS

Although a lower PSA nadir after treatment with RT has been associated with cancer cure, 5% to 25% of patients ultimately have failure (beyond 5 years) even with the most optimal biochemical response. The most appropriate BF definitions to use after treatment for prostate cancer with RT remains controversial due to substantial differences in their accuracy, sensitivity, specificity and positive predictive value for clinical outcome. No pattern of PSA kinetics after treatment has conclusively been associated with a specific recurrence site. Biochemical failure definitions in patients treated with RT appear to provide a 6 to 18 month lead time to clinical failure but there are only limited published data to suggest that early intervention of any type (androgen deprivation, RT, surgery, etc) impacts survival.

CONCLUSIONS

The overall benefit of monitoring serum PSA after treatment for prostate cancer remains controversial. Considering the potential dangers associated with incorrectly assuming the efficacy of new forms of treatment, the toxicity of administering salvage therapies of uncertain efficacy after BF has been identified and the anxiety associated with tracking posttreatment serum PSA, additional studies must be done to determine the appropriate use of this marker in properly treating patients after therapy.

Biochemical failure as single abnormality in patients with prostate cancer following radical treatment with external radiotherapy: follow-up without immediate treatment

INTRODUCTION

Biochemical failure has been defined as 3 consecutive increases in PSA following curative treatment of prostate cancer. The appropriate management in such cases is controversial. The most usual treatment has been early introduction of hormones. Such patients will live for many years and hormone therapy causes important secondary effects and increases costs. The guideline in our Department of Radiotherapy has been to follow up, with no initial therapy, cases with low PSA and short PSA doubling time. The present study reports this experience.

MATERIALS AND METHODS

528 patients with localized prostate cancer were treated by radical approach between 1992 and 1999, with external radiotherapy, with or without adjuvant hormone therapy. After a median follow-up of 77 months, there were 207 (39%) cases with biochemical failure, 78 of which were followed without therapy after the identification of biochemical failure. All of them were asymptomatic patients and had negative radiographic examinations or did not have imaging exams requested since they presented a favorable outcome. The follow-up included at least 2 annual visits with physical examination and PSA.

RESULTS

Of the 78 patients with biochemical failure followed without initial therapy, 7 died from other causes than prostate cancer and the remaining 71 cases were alive and asymptomatic in the last follow-up. Prognostic factors previous to radiotherapy such as stage and Gleason score were not considered when deciding for follow-up without initial therapy in these cases. The most significant aspects considered for this decision were low PSA value (median PSA on the last visit for the 78 cases was only 3.9 ng/mL) and a slow PSA doubling time (in the present experience the median PSA doubling time was 22.5 months).

CONCLUSION

There seems to be space for expectant management, without initial hormone therapy, in patients with prostate cancer who present biochemical failure and are asymptomatic after radical external radiotherapy. This decision is important, since early introduction of hormones brings late effects and is expensive. Prospective and randomized studies are required to define this issue.

Gene therapy strategies to improve the effectiveness of cancer radiotherapy

Having the ability to alter the genetic makeup of a cancer cell by gene transfer is a potentially powerful strategy for treating human cancer. However, a low efficiency of gene delivery in vivo and poor tumour specificity has prevented the widespread implementation of this technology in the clinic. Despite these formidable obstacles, the first successful application of gene therapy in the treatment of cancer may occur when it is combined with local modalities such as radiation therapy. A small number of gene therapy strategies have been evaluated in clinical trials in combination with external beam radiation therapy. The combined therapy has been well-tolerated and has not exacerbated the side effects of radiation therapy. Gene transfer and tumour cell destruction has been demonstrated in vivo. Although the results await confirmation in larger, prospective Phase III trials, there is suggestive evidence that the combined therapies may be demonstrating better than expected antitumour activity. Our vast knowledge of the molecular defects that drive the cancer process, coupled with our expanding understanding of the genes responsible for tumour cell radioresistance, have spawned the development of rational, targeted gene therapies designed to increase tumour cell radiosensitivity. Here, the results of the clinical trials conducted so far will be reviewed, followed by a description of new approaches under development at present.

Potential survival advantage with early androgen deprivation for biochemical failure after external beam radiotherapy: The importance of accurately defining biochemical disease status

PURPOSE

We analyzed our experience treating localized prostate cancer to determine the impact of androgen deprivation (AD) on clinical outcome if administered at the time of isolated biochemical failure (BF) vs. after clinical failure (clinical failure), and the associated impact of various BF definitions.

METHODS

A total of 1,201 patients with stage T1-T3N0M0 prostate cancer were treated with external beam radiotherapy (EBRT) to a median dose of 66.6 Gy. Early AD was defined as administration of AD after BF, without evidence of clinical failure. Delayed AD was defined as administration of AD after clinical failure. Multiple BF definitions were tested for capacity to predict subsequent clinical failure. For each BF definition, outcome was compared for BF patients receiving early AD vs. no or delayed AD.

RESULTS

Five-year clinical failure (from date of BF) was 60% for patients who experienced a prostate-specific antigen rise to >/=3 ng/mL above nadir. For these patients, early AD was associated with decreased 5-year local failure (4% vs. 33%), distant metastasis (13% vs. 44%), cause-specific death (9% vs. 24%), and death due to any cause (32% vs. 48%), despite poorer prognostic factors in patients receiving early AD. On multivariate analysis, early AD remained independently significant for each of these end points.

CONCLUSION

The efficacy of AD after BF varies depending on the BF definition. When an optimal BF definition is applied, early AD decreases distant metastasis and improves survival. Prostate-specific antigen elevation to >/=2 or >/=3 ng/mL above nadir seems optimal in establishing clinically significant BF and the timing of AD intervention.

Rise in serum psa of 1.5 ng/mL above 24-month nadir after external beam radiotherapy is predictive of biochemical failure

OBJECTIVES

To determine whether a rise in the serum prostate-specific antigen (PSA) concentration 24 months or later after completion of external beam radiotherapy (EBRT) for prostate cancer could predict for biochemical failure.

METHODS

We evaluated the records of 1006 patients who had undergone full-dose EBRT alone as primary treatment for T1-T4NxM0 prostate cancer at our institution between April 1987 and January 1998. Patients who had biochemical failure--as determined by the American Society for Therapeutic Radiology and Oncology (ASTRO) definition--prior to 24 months after EBRT were excluded. PSA increases of four different magnitudes (0.5, 0.8, 1.0, and 1.5 ng/mL above the 24-month nadir) were evaluated for their ability to predict ASTRO-defined biochemical failure.

RESULTS

A total of 745 patients met the analysis criteria. The rate of ASTRO-defined biochemical failure in patients with a PSA increase of 0.5, 0.8, 1.0, and 1.5 ng/mL above the 24-month nadir was 56%, 64%, 66%, and 71%, respectively. An increase of 1.5 ng/mL or more had a sensitivity of 80% and a specificity of 88% in the prediction of biochemical failure, with an accuracy of 86%.

CONCLUSIONS

A PSA increase of 1.5 ng/mL or more above the 24-month nadir can be used to predict for ASTRO-defined failure after EBRT and may be used to identify patients at risk early-on.

External beam radiotherapy for clinically node-negative, localized hormone-refractory prostate cancer: impact of pretreatment PSA value on radiotherapeutic outcomes

PURPOSE

To analyze the results of clinically node-negative, localized hormone-refractory prostate cancer treated with external beam radiotherapy (EBRT) and to investigate the potential prognostic factors that influenced the therapeutic outcome.

METHODS AND MATERIALS

Fifty-three patients who had developed localized hormone-refractory prostate cancer were treated with EBRT between 1994 and 2001. According to the 1992 American Joint Committee on Cancer clinical stage, 4 patients had T2 and 49 had T3 at the start of RT, and 14 patients had a Gleason score <7, 14 had a Gleason score of 7, and 23 had a Gleason score of 8-10. All patients were treated with EBRT using the unblocked oblique four-field technique, with a total dose of 69 Gy. The fraction dose was 3 Gy three times weekly. The median follow-up after RT was 35 months (range, 8-96 months) and after androgen ablation was 73 months (range, 42-156 months).

RESULTS

Of 53 patients, 15 patients subsequently developed clinical relapse, including locoregional and/or distant metastases. The site of first relapse was bone metastasis in 10, lymph nodes in 3, and local failure in 2 patients; 3 patients died of prostate cancer during the analysis period. The 3-year and 5-year cause-specific survival rate was 94% and 87%, respectively, and the 3-year and 5-year clinical relapse-free survival rate was 78% and 56%, respectively. The univariate analysis revealed that a short prostate-specific antigen (PSA) doubling time and high PSA value at the start of RT and a high Gleason score were statistically significant factors for the risk of clinical relapse. Multivariate analysis demonstrated that the PSA value (PSA <or=15 vs. >or=15 ng/mL) at the start of RT was an independent prognostic factor.

CONCLUSION

EBRT could be a treatment of choice for clinically node-negative, localized, hormone-refractory prostate cancer.

Eligibility and outcomes reporting guidelines for clinical trials for patients in the state of a rising prostate-specific antigen: recommendations from the Prostate-Specific Antigen Working Group

PURPOSE

To define methodology to show clinical benefit for patients in the state of a rising prostate-specific antigen (PSA).

RESULTS

HYPOTHESIS

A clinical states framework was used to address the hypothesis that definitive phase III trials could not be conducted in this patient population.

PATIENT POPULATION

The Group focused on men with systemic (nonlocalized) recurrence and a defined risk of developing clinically detectable metastases. Models to define systemic versus local recurrence, and risk of metastatic progression were discussed.

INTERVENTION

Therapies that have shown favorable effects in more advanced clinical states; meaningful biologic surrogates of activity linked with efficacy in other tumor types; and/or effects on a target or pathway known to contribute to prostate cancer progression in this state can be considered for evaluation.

OUTCOMES

An intervention-specific posttherapy PSA-based outcome definition that would justify further testing should be described at the outset. Reporting: Trial reports should include a table showing the number of patients who achieve a specific PSA-based outcome, the number who remain enrolled onto the trial, and the number who came off study at different time points. The term PSA response should be abandoned.

TRIAL DESIGN

The phases of drug development for this state are optimizing dose and schedule, demonstration of a treatment effect, and clinical benefit. To move a drug forward should require a high bar that includes no rise in PSA in a defined proportion of patients for a specified period of time at a minimum. Agents that do not produce this effect can only be tested in combination. The preferred end point of clinical benefit is prostate cancer-specific survival; the time to development of metastatic disease is an alternative.

CONCLUSION

Methodology to show that an intervention alters the natural history of prostate cancer is described. At each stage of development, only agents with sufficient activity should be moved forward.

Early prostate-specific antigen (PSA) kinetics following prostate carcinoma radiotherapy

BACKGROUND

The goal of the current study was to analyze the prognostic value of early prostate-specific antigen (PSA) kinetics, with PSA assessed as reaching or failing to reach discrete threshold values at fixed time points during follow-up after external-beam radiotherapy (EBRT) for prostate carcinoma.

METHODS

The authors conducted a retrospective review of PSA follow-up for 839 patients treated between May 1987 and December 2000 at the Cleveland Clinic Foundation (Cleveland, OH). They also assessed the impact on bRFS of PSA levels lower than defined threshold values at given time points during follow-up.

RESULTS

During a median follow-up of 74 months (range, 24-189 months), 540 patients (64.4%) maintained bRFS, whereas 299 patients (35.6%) did not maintain bRFS. The median nadir among patients with sustained bRFS was 0.4 ng/mL, with a median time to nadir of 28.9 months. Patients who did not maintain bRFS reached a median nadir of 1.3 ng/mL at a median of 15 months (P < 0.0001 for both nadir level and time to nadir). Reaching PSA thresholds of 3.0, 2.0, 1.0, 0.5, and 0.2 ng/mL at any time during follow-up was correlated with improved bRFS (P < 0.0001, each threshold). Patients whose PSA levels crossed the appropriate thresholds within 3 and 6 months of follow-up, irrespective of the time or level of eventual nadir, exhibited significantly improved bRFS when compared with patients whose PSA levels reached those thresholds at any time during follow-up and patients whose PSA levels never reached those thresholds (all thresholds: P < 0.0001).

CONCLUSIONS

Despite previous conclusions that early PSA assessment may lack prognostic value, the data obtained in the current study suggest that the kinetics of early PSA decline is predictive of long-term bRFS when assessed using a time-and-PSA threshold model. After EBRT for prostate carcinoma, PSA levels below various discrete PSA thresholds were indicative of statistically meaningful long-term outcome differences between experimental arms as early as 90 days after radiotherapy. If the time-and-PSA threshold model is shown to be predictive of prostate carcinoma mortality as well, then it may allow the scientific community to evaluate promising treatment concepts and technologies at a highly accelerated pace.

Rosiglitazone versus placebo for men with prostate carcinoma and a rising serum prostate-specific antigen level after radical prostatectomy and/or radiation therapy

BACKGROUND

The objective of this study was to assess the biologic activity of rosiglitazone, a peroxisome proliferator-activated receptor gamma agonist that has been approved to treat type 2 diabetes, in men with recurrent prostate carcinoma using change in prostate specific antigen (PSA) doubling time (PSADT) as the primary outcome variable.

METHODS

Men with histologically confirmed prostate carcinoma, no recent hormone therapy, a rising serum PSA level after radical prostatectomy and/or radiation therapy, and no radiographic evidence of metastases were assigned randomly to receive either oral rosiglitazone (4 mg twice daily) or placebo. The treatment was continued until the men developed disease progression or adverse effects. A positive outcome was defined as a posttreatment PSADT > 150% the baseline PSADT and no new metastases.

RESULTS

One hundred six men were enrolled. The median treatment duration was 315 days for men in the placebo group and 338 days for men in the rosiglitazone group (P = 0.28). Forty percent of men in the in the placebo group and 38% of men in the rosiglitazone group had a posttreatment PSADT > 150% of the baseline PSADT and no new metastases (P = 1.00). In exploratory analyses, the rate of a positive outcome remained higher than expected in the placebo group, even when a positive outcome was redefined using more stringent criteria. The time to disease progression was similar between the groups.

CONCLUSIONS

Rosiglitazone did not increase PSADT or prolong the time to disease progression more than placebo in men with a rising PSA level after radical prostatectomy and/or radiation therapy. The unexpected discordance between baseline and posttreatment PSADT in the placebo group reinforced the importance of randomized controlled trials in this setting.

The relationship of increasing radiotherapy dose to reduced distant metastases and mortality in men with prostate cancer

BACKGROUND

The association of increasing radiotherapy (RT) dose with reduced biochemical failure (BF) is accepted widely. However, there is little direct evidence that dose escalation has an impact on distant metastasis (DM) or overall mortality (OM). These associations were examined in the current study.

METHODS

The outcome of 835 patients who were treated at the Fox Chase Cancer Center (Philadelphia, PA) between 1989 and 1997 using 3-dimensional, conformal RT alone (median dose, 74 Gray [Gy]) was analyzed. Stepwise multivariate Cox proportional hazards regression analyses (MVAs) were performed with RT dose included as a covariate along with log-transformed initial pretreatment PSA level, Gleason score, palpation T status, age, and year of treatment (YOT), where indicated. To minimize the effect of YOT, an analysis was performed on a subgroup of 363 patients who were treated prior to 1994.

RESULTS

With a median follow-up of 64 months, there were 220 PSA failures, 44 distant metastases, and 162 deaths. In MVA, RT dose (as a continuous variable) was a significant predictor for BF, DM, and OM. When YOT was included as a covariate, it was related strongly to all endpoints, and the correlations of RT dose with DM and OM were lost. When the effect of YOT was minimized by limiting the MVA to patients who were treated prior to 1994, RT dose again emerged as a significant predictor of DM.

CONCLUSIONS

Escalation of RT dose reduced the rates of BF, DM, and OM significantly in patients with prostate cancer. The inclusion of YOT had a pronounced effect on these correlations that may confound interpretation.

Treatments for improving survival of patients with prostate cancer

Prostate cancer is a heterogeneous disease characterised by a long natural history relative to other solid tumours. With the diagnosis of prostate cancer being made earlier, the emphasis of treatment has shifted from palliation of symptoms to altering disease-related morbidity and mortality and thus improving overall survival. Treatment of prostate cancer increasingly involves an approach that combines local therapies directed at the primary tumour together with systemic therapies to potentiate their effect and to control subclinical metastatic disease. Patients with localised tumours who are at high risk of relapsing with radiation therapy alone are surviving longer because of the addition of adjuvant hormonal therapy. Although a survival benefit in similar patients undergoing prostatectomy has not yet been established, preliminary results indicate that adjuvant hormonal therapy delays relapse. Chemotherapy is an effective palliative modality for patients with hormone- refractory metastatic disease, and recently completed phase III trials will determine if chemotherapy can prolong survival for this group. The role of chemotherapy in patients with locally advanced tumours is also being investigated in randomised clinical trials. Because bone is the dominant site of metastases for most patients with prostate cancer, the development of therapies that can slow tumour growth specifically within bone is a logical strategy. Bisphosphonates and bone-targeted radionuclides are two such approaches that have shown encouraging results even in the most advanced stages of the disease. Although one can now reasonably hypothesise that survival has improved because of recent therapeutic advances, it remains to be conclusively established that cytotoxic or other systemic therapy can extend survival of patients with prostate cancer. Only the results of ongoing randomised trials can definitely establish that more patients with locally advanced and metastatic prostate cancer are living longer.

Prostate-specific antigen doubling time in the identification of patients at risk for progression after treatment and biochemical recurrence for prostate cancer

After primary treatment for clinically localized prostate cancer, biochemical recurrence is usually the first evidence of either local recurrence or metastatic progression. This poses a diagnostic dilemma for both the patient and the physician regarding future therapy. Prostate-specific antigen doubling time (PSADT) is a useful tool in this clinical setting. There have been multiple reports of the utility of PSADT in men with isolated biochemical recurrence after either radical prostatectomy or external-beam radiation therapy. Early observations of PSADT in men with recurrence are reviewed and the current literature is summarized to allow physicians to make an accurate assessment of a patient's risk of progression after isolated biochemical recurrence.

Brachytherapy for prostate cancer

The use of prostate brachytherapy for the treatment of early-stage, low-grade, low-volume carcinoma of the prostate continues to rise. Given the prolonged natural history of these early lesions, treatment failures may take many years or even a decade or more before becoming clinically evident. It is therefore likely that as the brachytherapy data mature, clinicians will be asked to help manage a potentially large cohort of men who have failed this local therapy--a scenario that will provide a number of unique challenges for the treatment of the disease and the management of the lower urinary tract. This article offers a contemporary review and suggestions with regard to the follow-up of patients who have undergone prostate brachytherapy, including low-dose rate permanent implants and high-dose rate temporary implants for the management of localized prostate cancer. In addition, current controversies in defining biochemical failure following radioactive implantation--including important data regarding the "prostate-specific antigen bounce" phenomenon--are discussed. Finally, a comprehensive review of the management of local recurrence following brachytherapy is offered.

Effect of sequencing of androgen deprivation and radiotherapy on prostate cancer growth

PURPOSE

Androgen deprivation (AD) is frequently combined with radiotherapy (RT); however, the optimal sequence in vivo is currently unknown. Previous published work from our laboratory demonstrated that AD with RT was consistent with at least an additive, and possibly supra-additive, effect with the combined approach. We, therefore, performed additional experiments to elucidate the optimal sequence.

METHODS AND MATERIALS

R3327-G Dunning rat prostate tumor cells were grown s.c. in the flanks of Copenhagen rats. Treatment was initiated when the tumor reached approximately 1 cm(3). Temporary AD was performed by a transscrotal orchiectomy followed 14 days later with androgen restoration using s.c. testosterone implants. RT was delivered using (60)Co to 7 Gy. Seven groups, including the controls, were analyzed: Group 1, sham control (Day 0: AD + testosterone); 2, AD control (Day 0: AD, Day 14: testosterone); 3, RT alone on Day 7 (Day 0: AD + testosterone, Day 7 RT); 4, RT alone on Day 3 (Day 0: AD + testosterone, Day 3: RT); 5, RT during AD (Day 0: AD, Day 7: RT, Day 14: testosterone); 6, RT before AD (Day 0: RT, Day 3: AD, Day 17: testosterone); and Group 7, RT after AD (Day 0: AD, Day 14: testosterone, Day 17: RT). The doubling times for tumor growth were calculated for the seven groups from the end of treatment plus 1 day. Differences in doubling time were assessed using analysis of variance, with pair-wise comparisons accomplished using post-hoc Bonferroni tests.

RESULTS

An analysis of the differences in the tumor volume doubling time as measured from the end of treatment suggests that Groups 1 and 7 were statistically different from the other groups (p = 0.02). As expected, the sham control group had the shortest doubling time at 5.4 days and Group 7 (14 days of AD administered before RT) had the longest doubling time at 32.6 days. The findings were similar even after excluding an outlying doubling time of 85 days from Group 7 (p < 0.0001). To assess the effect of sequencing further, only Groups 5 through 7 (excluding the outlier) were compared in an analysis of variance with post-hoc Bonferroni tests. Group 7 (RT after AD) demonstrated a significantly longer doubling time than Groups 5 and 6 (p = 0.0024).

CONCLUSION

The results suggest that neoadjuvant AD may result in prolonged suppression of tumor growth, even after testosterone replacement.