20Gy versus 44Gy supplemental beam radiation with Pd-103 prostate brachytherapy: Preliminary biochemical outcomes from a prospective randomized multi-center trial

Low-dose rate brachytherapy for patients with low- or intermediate-risk prostate cancer: A systematic review

INTRODUCTION

We review the current evidence for the role of low-dose rate brachytherapy (PB) in patients with low- or intermediate-risk prostate cancer using a systematic review of the literature.

METHODS

We searched MEDLINE and EMBASE (from January 1996 to October 2011), the Cochrane Library, relevant guideline web-sites, and websites for meetings specific for genitourinary diseases.

RESULTS

Ten systematic reviews and 55 single-study papers met the pre-planned study selection criteria. In the end, 36 articles were abstracted and analyzed for this systematic review. There is no evidence for a difference in efficacy between PB and external beam radiation therapy (EBRT), or between PB and radical prostatectomy (RP). During the 6 months to 3 years after treatment, PB was associated with less urinary incontinence and sexual impotency than RP, and RP was associated with less urinary irritation and rectal morbidity than PB. However, these differences diminished over time. PB conferred less risk of impotency and rectal morbidity in the three years after treatment than EBRT. Iodine-125 and alladium-103 did not differ with respect to biochemical relapse-free survival and patient-reported outcomes.

CONCLUSIONS

PB alone is a treatment option with equal efficacy to EBRT or RP alone in patients with newly diagnosed low- or intermediate-risk prostate cancer who require or choose active treatment.

Evidence-based guideline recommendations on low-dose rate brachytherapy in patients with low- or intermediate-risk prostate cancer

OBJECTIVE

The Genitourinary Cancer Disease Site Group (GU DSG) and Cancer Care Ontario's Program in Evidence-Based Care (PEBC) in Ontario, Canada developed a guideline on low-dose rate brachytherapy (LDR-BT) in patients with early-stage low-grade prostate cancer in 2001. The current updated guideline focuses on the research questions regarding the effect of LDR-BT alone, the effect of LDR-BT with external beam radiation therapy (EBRT) and the selection of an isotope.

METHODS

This guideline was developed by using the methods of the Practice Guidelines Development Cycle and the core methodology was a systematic review. MEDLINE and EMBASE (from January 1996 to October 2011), the Cochrane Library, main guideline websites, and main annual meeting abstract websites specific for genitourinary diseases were searched. Internal and external reviews of the draft guideline were conducted.

RESULTS

The draft guideline was developed according to a total of 10 systematic reviews and 55 full text articles that met the pre-planned study selection criteria. The quality of evidence was low to moderate. The final report reflects integration of the feedback obtained through the internal review (two oncologists and a methodologist) and external review (five target reviewers and 48 professional consultation reviewers) process, with final approval given by the GU DSG and the PEBC.

CONCLUSION

THE MAIN RECOMMENDATIONS ARE: (1) For patients with newly diagnosed low-risk or intermediate-risk prostate cancer who require or choose active treatment, LDR-BT alone is a treatment option as an alternative to EBRT alone or RP alone; and (2) I-125 and Pd-103 are each reasonable isotope options.

Overview of randomized controlled treatment trials for clinically localized prostate cancer: implications for active surveillance and the United States preventative task force report on screening?

Prostate cancer and its management have been intensely debated for years. Recommendations range from ardent support for active screening and immediate treatment to resolute avoidance of screening and active surveillance. There is a growing body of level I evidence establishing a clear survival advantage for treatment of subsets of patients with clinically localized prostate cancer. This chapter presents a review of these randomized controlled trials. We argue that an understanding of this literature is relevant not only to those considering active surveillance but also to those evaluating the merits of screening. In addition, a number of important evidence-based conclusions concerning what should and should not be done can be gleaned from these trials.

A review of low-dose-rate prostate brachytherapy--techniques and outcomes

Prostate cancer is the most common male cancer in the United States and the second leading cause of male cancer death. The main therapeutic modalities for the treatment of prostate cancer are surgery, external beam radiation therapy, hormonal therapy, and brachytherapy. In recent years, brachytherapy has been increasingly utilized for the treatment of early-stage prostate cancer. Technological advances, including improvements in imaging, planning, and postimplant quality assessment by dosimetry have led to widespread use of brachytherapy. Outcomes for prostate brachytherapy have been shown to be equivalent, in selected patients, to those of other treatment modalities for prostate cancer, including radical prostatectomy and external beam radiation therapy. Further, prostate brachytherapy has quality-of-life benefits in comparison to these other treatment modalities, particularly in the domain of sexual function. This paper describes the history of low-dose rate brachytherapy; current techniques for brachytherapy implantation and postoperative dosimetric evaluation; recent outcomes studies; recent quality-of-life analyses; and current and future prostate brachytherapy developments, including open clinical trials. As research in prostate brachytherapy continues, it is likely that this modality will play an increasingly important role in the treatment of early-stage prostate cancer patients in the future.

Evaluation of rectal bleeding factors associated with prostate brachytherapy

PURPOSE

To analyze rectal bleeding prognostic factors associated with prostate brachytherapy (PB) or in combination with external-beam radiation therapy (EBRT) and to examine dosimetric indications associated with rectal bleeding.

MATERIALS AND METHODS

The study included 296 patients followed up for >36 months (median, 48 months). PB was performed alone in 252 patients and in combination with EBRT in 44 patients. PB combined with EBRT is indicated for patients with a Gleason score >6. The prescribed dose was 144 Gy for monotherapy and 110 Gy for PB + EBRT (44-46 Gy).

RESULTS

Although 9.1% who received monotherapy had 2.3% grade 2 rectal bleeding, 36.3% who received combined therapy had 15.9% grade 2 rectal bleeding. Combined therapy was associated with higher incidence of rectal bleeding (P = 0.0049) and higher percentage of grade 2 bleeding (P = 0.0005). Multivariate analysis revealed that R-150 was the only significant factor for rectal bleeding, and modified Radiation Therapy Oncology Group (RTOG) grade in monotherapy and biologically equivalent dose (BED) were significant for combined therapy. Moreover, grade 2 rectal bleeding increased significantly at D90 > 130 Gy.

CONCLUSION

Although R-150 was the significant prognostic factor for rectal bleeding and modified RTOG rectal toxicity grade, BED was the significant prognostic factor for modified RTOG rectal toxicity grade.

Primary causes of death after permanent prostate brachytherapy

PURPOSE

To evaluate the primary causes of death in low-risk (low-risk), intermediate-risk (intermediate-risk), and high-risk (high-risk) patients undergoing permanent prostate brachytherapy with or without supplemental therapies.

METHODS AND MATERIALS

From April 1995 through November 2004, a total of 1,354 consecutive patients underwent prostate brachytherapy. All patients underwent brachytherapy >3 years before analysis. Of the patients, 532 (39.3%) received androgen deprivation therapy and 703 (51.9%) received supplemental radiation therapy. The median follow-up was 5.4 years. Multiple parameters were evaluated as predictors of cause-specific, biochemical progression-free, and overall survival.

RESULTS

The 10-year cause-specific survival was 97.0% (99.7%, 99.0%, and 90.1% for low-risk, intermediate-risk, and high-risk patients). Overall survival was 76.7% (82.5%, 78.3%, and 67.6% for low-, intermediate-, and high-risk patients, respectively). The cumulative death rate for cardiovascular disease was 11.5% (8.7%, 9.3%, and 19.8% for low-, intermediate-, and high-risk patients). The death rate from second malignancies (nonprostate cancer) was 7.2% and was not substantially different when stratified by risk group. Death from all other causes was 6.5% for the entire cohort but 1.3%, 5.0%, and 10.8% for low-, intermediate-, and high-risk patients. In multivariate analysis, death from prostate cancer was best predicted by Gleason score and risk group, whereas death from cardiovascular disease, nonprostate cancer, and all other causes were most closely related to patient age and tobacco use.

CONCLUSIONS

Although cardiovascular mortality was the predominant cause of death, prostate cancer was responsible for approximately 10% of all deaths. In particular, overall survival was poorest in the high-risk group. Although high-risk patients were most likely to die of prostate cancer, the divergence in overall survival between high-risk and lower-risk patients primarily resulted from an excess of cardiovascular deaths. Changes in lifestyle to improve cardiovascular health may improve overall survival in patients with clinically localized prostate cancer.

Customized Dose Prescription for Permanent Prostate Brachytherapy: Insights From a Multicenter Analysis of Dosimetry Outcomes

PURPOSE

To investigate the biochemical control rate in patients undergoing permanent prostate brachytherapy as a function of the biologically effective dose (BED) and risk group.

METHODS AND MATERIALS

Six centers provided data on 3,928 permanent brachytherapy patients with postimplant dosimetry results. The mean prostate-specific antigen level was 8.9 ng/mL. (125)I was used in 2,293 (58%), (103)Pd in 1,635, and supplemental external beam radiotherapy in 882 (22.5%) patients. The patients were stratified into low- (n = 2,188), intermediate- (n = 1,188), and high- (n = 552) risk groups and into three BED groups of < 140 Gy (n = 524), 140-200 Gy (n = 2284), and >200 Gy (n = 1,115). Freedom from biochemical disease progression (biochemical freedom from failure [bFFF]) was determined using the American Society for Therapeutic Radiology Oncology and Phoenix definitions and calculated using the Kaplan-Meier method, with factors compared using the log-rank test.

RESULTS

The 10-year prostate-specific antigen bFFF rate for the American Society for Therapeutic Radiology Oncology and Phoenix definitions was 79.2% and 70%, respectively. The corresponding bFFF rates for the low-, intermediate-, and high-risk groups was 84.1% and 78.1%, 76.8% and 63.6%, and 64.4% and 58.2%, respectively (p < 0.0001). The corresponding bFFF rate for the three BED groups was 56.1% and 41.4%, 80% and 77.9%, and 91.1% and 82.9% (p < 0.0001). The corresponding bFFF rate for the low-risk patients by dose group was 69.8% and 49.8%, 86% and 85.2%, and 88.1% and 88.3% for the low-, intermediate, and high-dose group, respectively (p <0.0001). The corresponding bFFF rate for the intermediate-risk patients by dose group was 52.9% and 23.1%, 74.1% and 77.7%, and 94.3% and 88.8% for the low-, intermediate-, and high-dose group, respectively (p < 0.0001). The corresponding bFFF rate for high-risk patients by dose group was 19.2% and 41.7%, 61.8% and 53.2%, and 90% and 69.6% for the low-, intermediate-, and high-dose group, respectively (p < 0.0001).

CONCLUSIONS

These data suggest that permanent brachytherapy dose prescriptions can be customized to risk status. In low-risk patients, achieving a BED of >or=140 Gy might be adequate for prostate-specific antigen control. However, high-risk disease might require a BED dose of >or=200 Gy.

Optimized Prostate Brachytherapy Minimizes the Prognostic Impact of Percent of Biopsy Cores Involved With Adenocarcinoma

PURPOSE

A higher percent of positive biopsy cores predicts poor biochemical failure-free survival. The highest dose covering at least 90% of the prostate is a standard method of measuring implant quality. We tested the hypothesis that the percentage of positive biopsy cores loses its adverse prognostic impact in patients who receive implants with a highest dose covering at least 90% of the prostate of 100% or greater of the prescription dose.

MATERIALS AND METHODS

A total of 568 patients with intermediate to high risk adenocarcinoma of the prostate who were previously treated with brachytherapy in a prospective, randomized study were evaluated. The relationship between the percentage of positive biopsy cores, the highest dose covering at least 90% of the prostate and biochemical failure was examined.

RESULTS

At a median followup of 50 months the rate of 5-year biochemical failure-free survival was 87% for the entire group and 92% vs 81% for patients with less than 50% vs 50% or greater positive biopsy cores (log rank p = 0.009). The mean highest dose covering at least 90% of the prostate was statistically lower in failing vs nonfailing cases (p = 0.03). Gleason score, prostate specific antigen, 50% or greater positive biopsy cores and the highest dose covering at least 90% of the prostate were the only statistically significant predictive factors for biochemical failure-free survival on multivariate Cox regression analysis. When regression analysis was restricted to the 237 patients who received implants with a highest dose covering at least 90% of the prostate of 100% or greater, 50% or greater positive biopsy cores lost predictive value but prostate specific antigen and Gleason score remained independent prognostic factors.

CONCLUSIONS

A total of 50% or greater positive biopsy cores is an independent predictor of poor biochemical failure-free survival in patients treated with brachytherapy. High quality prostate brachytherapy, defined by a highest dose covering at least 90% of the prostate of 100% or greater, minimize the adverse effect of 50% or greater positive biopsy cores on time to biochemical failure.

Primary Gleason pattern does not impact survival after permanent interstitial brachytherapy for Gleason score 7 prostate cancer

BACKGROUND

The impact of primary Gleason pattern was determined on cause-specific (CSS), biochemical progression-free (bPFS), and overall survival (OS) after brachytherapy for Gleason score 7 prostate cancer.

METHODS

From April 1995 to October 2003, 530 patients underwent brachytherapy for Gleason score 3+4 (n = 300) or Gleason 4+3 (n = 230) prostate cancer. All patients underwent brachytherapy more than 3 years before analysis. The median follow-up was 5.7 years. Of the 530 patients, 412 (77.7%) received supplemental external beam radiation therapy (XRT) and 177 (33.4%) received androgen deprivation therapy. bPFS was defined by a prostate-specific antigen (PSA) </=0.40 ng/mL after nadir. Multiple parameters were evaluated as predictors of CSS, bPFS, and OS.

RESULTS

At 10 years, Gleason 3+4 versus 4+3 did not predict for CSS (96.7% vs 93.3%, P = .506), bPFS (97.0% vs 92.9%, P = .085), or OS (77.0% vs 78.0%, P = .933). Cox linear regression analysis demonstrated that clinical stage and radiation dose (D90) predicted for CSS, whereas pretreatment PSA, clinical stage, and prostate size predicted for bPFS. Patient age, diabetes, and tobacco were the strongest predictors for OS. To date, 57 patients have died, with 80.7% due to cardiovascular/pulmonary events or secondary malignancies. Five patients have died of prostate cancer.

CONCLUSIONS

The primary Gleason pattern did not impact CSS, bPFS, or OS in Gleason score 7 prostate cancer. Deaths from cardiovascular/pulmonary disease and second malignancies were 9.6 times more common than death from prostate cancer.

Evidence-based radiation oncology: Definitive, adjuvant and salvage radiotherapy for non-metastatic prostate cancer

The standard treatment options based on the risk category (stage, Gleason score, PSA) for localized prostate cancer include surgery, radiotherapy and watchful waiting. The literature does not provide clear-cut evidence for the superiority of surgery over radiotherapy, whereas both approaches differ in their side effects. The definitive external beam irradiation is frequently employed in stage T1b-T1c, T2 and T3 tumors. There is a pretty strong evidence that intermediate- and high-risk patients benefit from dose escalation. The latter requires reduction of the irradiated normal tissue (using 3-dimensional conformal approach, intensity modulated radiotherapy, image-guided radiotherapy, etc.). Recent data suggest that prostate cancer may benefit from hypofractionation due to relatively low alpha/beta ratio; these findings warrant confirmation though. The role of whole pelvis irradiation is still controversial. Numerous randomized trials demonstrated a clinical benefit in terms of biochemical control, local and distant control, and overall survival from the addition of androgen suppression to external beam radiotherapy in intermediate- and high-risk patients. These studies typically included locally advanced (T3-T4) and poor-prognosis (Gleason score >7 and/or PSA >20 ng/mL) tumors and employed neoadjuvant/concomitant/adjuvant androgen suppression rather than only adjuvant setting. The ongoing trials will hopefully further define the role of endocrine treatment in more favorable risk patients and in the setting of the dose escalated radiotherapy. Brachytherapy (BRT) with permanent implants may be offered to low-risk patients (cT1-T2a, Gleason score <7, or 3+4, PSA <or=10 ng/mL), with prostate volume of <or=50 ml, no previous transurethral prostate resection and a good urinary function. Some recent data suggest a benefit from combining external beam irradiation and BRT for intermediate-risk patients. EBRT after radical prostatectomy improves disease-free survival and biochemical and local control rates in patients with positive surgical margins or pT3 tumors. Salvage radiotherapy may be considered at the time of biochemical failure in previously non-irradiated patients.

Dosimetric parameters as predictive factors for biochemical control in patients with higher risk prostate cancer treated with Pd-103 and supplemental beam radiation

PURPOSE

To analyze the role of dosimetric quality parameters in maximizing cancer eradication in higher risk prostate cancer patients treated with palladium (Pd)-103 and supplemental beam radiation.

METHODS

One-hundred-seventy-nine patients treated with Pd-103 and supplemental beam radiation, with minimum 2 years follow-up prostate-specific antigen (PSA) values and posttreatment computed tomography scans were analyzed. Dosimetric parameters included the V100 (percent of the postimplant volume covered by the prescription dose), the D90 (the minimum dose that covered 90% of the post implant volume), and the treatment margins (the radial distance between the prostatic edge and the prescription isodose). Treatment margins (TMs) were calculated using premarket software.

RESULTS

Freedom from biochemical failure was 79% at 3 years, with 92 of the 179 patients (51%) followed beyond 3 years. In comparing patients who did or did not achieve biochemical control, the most striking differences were in biologic factors of pretreatment PSA and Gleason score. The V100, D90, and average TM all showed nonsignificant trends to higher values in patients with biochemical control. In multivariate analysis of each of the three dosimetric parameters against PSA and Gleason score, TM showed the strongest correlation with biochemical control (p = 0.19).

CONCLUSIONS

For patients with intermediate and high-risk prostate cancer treated with Pd-103 brachytherapy and external beam radiation, biologic factors (PSA and Gleason score) were the most important determinants of cancer eradication. However, there is a trend to better outcomes among patients with higher quality implant parameters, suggesting that attention to implant quality will maximize the likelihood of cure.

Update on Radiation Therapy in Prostate Cancer

Higher doses of radiation result in improved clinical control of prostate cancer,and the recent advances in prostate cancer radiotherapy are designed to escalate dose while minimizing toxicity. To achieve this goal, tighter treatment margins are needed, which require more accurate delineation of the prostate target and normal tissue at the time of treatment planning and before actual daily treatments. Modem radiation therapy techniques can deposit conformal dose virtually anywhere in the body; however, this precise therapy is of no value if it is not accurately hitting the target. Whether dose escalation is achieved by external beam techniques (eg, IMRT, protons) or brachytherapy, these ba-sic planning and delivery considerations are essentially the same. Future directions in prostate radiation therapy will use even higher radiation doses,alternative fractionation patterns, intraprostatic targets (eg, prostate tumor seen on MRI), and improved patient selection regarding which patients will benefit the most from these advanced techniques.

Risk Factors for the Development of Prostate Brachytherapy Related Urethral Strictures

PURPOSE

We identified clinical, treatment and dosimetric parameters associated with the development of urethral strictures following permanent prostate brachytherapy.

MATERIALS AND METHODS

From April 1995 through April 2003, 1,186 consecutive patients underwent prostate brachytherapy for clinical stage T1b-T3a NxM0 (2002 American Joint Committee on Cancer) prostate cancer. The treatment plan included supplemental XRT in 625 patients (52.7%) and androgen deprivation therapy in 465 (39.2%). Median followup was 4.3 years. Multiple clinical, treatment and dosimetric parameters were evaluated in univariate and multivariate analyses to identify independent predictors for urethral stricture disease.

RESULTS

A total of 29 patients had brachytherapy related urethral strictures. All strictures involved the BM urethra with a 9-year actuarial risk of 3.6% and a median time to development of 2.4 years. The mean radiation dose to the BM urethra was significantly greater in patients with vs without stricture (p = 0.002). On multivariate analysis the BM urethral dose and supplemental XRT predicted urethral stricture. All except 3 patients were successfully treated with urethral dilation or internal optical urethrotomy.

CONCLUSIONS

Brachytherapy related urethral stricture disease correlates highly with the radiation dose to the BM urethra. Careful attention to brachytherapy preplanning and intraoperative execution along with the judicious use of supplemental XRT is essential to minimize the incidence of stricture disease.