Biochemical outcome for hormone-naïve patients with high-risk prostate cancer managed with permanent interstitial brachytherapy and supplemental external-beam radiation

Role of isotope selection in long-term outcomes in patients with intermediate-risk prostate cancer treated with a combination of external beam radiotherapy and low-dose-rate interstitial brachytherapy

OBJECTIVE

To examine the rates of long-term biochemical recurrence-free survival (BRFS) with respect to isotope in intermediate-risk prostate cancer treated with external beam radiotherapy (EBRT) and brachytherapy.

METHODS

A total of 242 consecutive patients with intermediate-risk prostate cancer were treated with iodine-125 ((125)I) or palladium-103 ((103)Pd) implants after EBRT (range 45.0-50.4 Gy) from 1996 to 2002. Of the 242 patients, 119 (49.2%) were treated with (125)I and 123 (50.8%) with (103)Pd. Multivariate Cox regression analysis was used to analyze BRFS, defined according to the Phoenix definition (prostate-specific antigen nadir plus 2 ng/mL) with respect to Gleason score, stage, pretreatment prostate-specific antigen level, and source selection. Late genitourinary/gastrointestinal toxicities were assessed using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer scale.

RESULTS

At a median follow-up of 10 years, the BRFS rate was 77.3%. A statistically significant difference was found in the 10-year BRFS rate between the (125)I- and (103)Pd-treated groups (82.7% and 70.6%, respectively; P = .001). The addition of hormonal therapy did not improve the 10-year BRFS rate (77.6%) compared with RT alone (77.1%; P = .22). However, a statistically significant difference in the BRFS rate was found with the addition of hormonal therapy to (103)Pd, improving the 10-year BRFS rate for (73.8%) compared with (103)Pd alone (69.1%; P = .008). On multivariate analysis, isotope type ((103)Pd vs (125)I), pretreatment prostate-specific antigen level >10 ng/mL, and greater tumor stage increased the risk of recurrence by 2.6-fold (P = .007), 5.9-fold (P < .0001), and 1.7-fold (P = .14), respectively.

CONCLUSION

(125)I renders a superior rate of BRFS compared with (103)Pd when used with EBRT. Hormonal therapy does not provide additional benefit in patients with intermediate-risk prostate cancer treated with a combination of EBRT and brachytherapy, except for the addition of hormonal therapy to (103)Pd.

Low-dose rate brachytherapy for men with localized prostate cancer

BACKGROUND

Localized prostate cancer is a slow growing tumor for many years for the majority of affected men. Low-dose rate brachytherapy (LDR-BT) is short-distance radiotherapy using low-energy radioactive sources. LDR-BT has been recommended for men with low risk localized prostate cancer.

OBJECTIVES

To assess the benefit and harm of LDR-BT compared to radical prostatectomy (RP), external beam radiotherapy (EBRT), and no primary therapy (NPT) in men with localized prostatic cancer.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (from 1950), and EMBASE (from 1980) were searched in June 2010 as well as online trials registers and reference lists of reviews.

SELECTION CRITERIA

Randomized, controlled trials comparing LDR-BT versus RP, EBRT, and NPT in men with clinically localized prostate cancer.

DATA COLLECTION AND ANALYSIS

Data on study methods, participants, treatment regimens, observation period and outcomes were recorded by two reviewers independently.

MAIN RESULTS

We identified only one RCT (N = 200; mean follow up 68 months). This trial compared LDR-BT and RP. The risk of bias was deemed high. Primary outcomes (overall survival, cause-specific mortality, or metastatic-free survival) were not reported. Biochemical recurrence-free survival at 5 years follow up was not significantly different between LDR-BT (78/85 (91.8%)) and RP (81/89 (91.0%)); P = 0.875; relative risk 0.92 (95% CI: 0.35 to 2.42).For severe adverse events reported at 6 months follow up, results favored LDR-BT for urinary incontinence (LDR-BT 0/85 (0.0%) versus RP 16/89 (18.0%); P < 0.001; relative risk 0) and favored RP for urinary irritation (LDR-BT 68/85 (80.0%) versus RP 4/89 (4.5%); P < 0.001; relative risk 17.80, 95% CI 6.79 to 46.66). The occurrence of urinary stricture did not significantly differ between the treatment groups (LDR-BT 2/85 (2.4%) versus RP 6/89 (6.7%); P = 0.221; relative risk 0.35, 95% CI: 0.07 to 1.68). Long-term information was not available.We did not identify significant differences of mean scores between treatment groups for patient-reported outcomes function and bother as well as generic health-related quality of life.

AUTHORS' CONCLUSIONS

Low-dose rate brachytherapy did not reduce biochemical recurrence-free survival versus radical prostatectomy at 5 years. For short-term severe adverse events, low-dose rate brachytherapy was significantly more favorable for urinary incontinence, but radical prostatectomy was significantly more favorable for urinary irritation. Evidence is based on one RCT with high risk of bias.

Role of external beam radiotherapy with low-dose-rate brachytherapy in treatment of prostate cancer

OBJECTIVES

To report a single-institution experience and analysis of the role of supplemental external beam radiotherapy (EBRT) with brachytherapy. EBRT is often used in addition to low-dose-rate brachytherapy in the treatment of prostate cancer, particularly for disease with adverse features.

METHODS

A cohort of 189 consecutive patients, who had undergone low-dose-rate brachytherapy at our institution and who had demographic, disease, and treatment information and a minimum of 2 years of follow-up available, constituted the study group. This cohort was divided into two major groups according to the use of supplemental EBRT. Using two successive prostate-specific antigen rises greater than 1 ng/mL as the definition of failure, biochemical failure-free survival curves were constructed for the EBRT and no-EBRT groups and compared using the log-rank test. Additionally, a multivariate analysis of all major disease and treatment factors was performed using the Cox proportional hazards model.

RESULTS

Despite the greater proportion of adverse disease factors in the EBRT group, the 5-year biochemical failure-free survival rate in the EBRT versus no-EBRT groups was 80% versus 59%, respectively (P < 0.01). On multivariate analysis, the only factor reaching significance in predicting biochemical control was the use of EBRT (P = 0.043).

CONCLUSIONS

In our study, the addition of EBRT conferred a significant biochemical control advantage when added to low-dose-rate brachytherapy. Because our study was not designed to permit detailed subset analyses, more work is needed to determine the precise brachytherapy population that will benefit from this use of supplemental EBRT.

Impact of supplemental external beam radiotherapy and/or androgen deprivation therapy on biochemical outcome after permanent prostate brachytherapy

PURPOSE

To evaluate the impact of supplemental external beam radiotherapy (EBRT) and/or androgen deprivation therapy (ADT) on 8-year biochemical outcome after permanent prostate brachytherapy.

METHODS AND MATERIALS

Between April 1995 and January 2001, 668 consecutive patients underwent brachytherapy using either (103)Pd or (125)I for clinical Stage T1b-T3aNxM0 (2002 American Joint Committee on Cancer) adenocarcinoma of the prostate gland. No patient underwent seminal vesicle biopsy or pathologic lymph node staging. The median follow-up was 58.6 months. Biochemical progression-free survival was defined by the American Society for Therapeutic Radiology and Oncology consensus definition. The clinical, treatment, and dosimetric parameters evaluated for biochemical progression-free survival included supplemental EBRT, ADT, patient age, clinical stage, Gleason score, preimplant prostate specific antigen (PSA), risk group, percentage of positive biopsies, isotope used, prostate volume, planning volume, percentage of target volume receiving 100%, 150%, and 200% of prescribed dose, minimal percentage of dose covering 90% of target volume, tobacco status, hypertension, and diabetes.

RESULTS

For the entire group, the actuarial 8-year biochemical progression-free survival rate was 98.2%, 98.4%, and 88.2% for low-, intermediate-, and high-risk patients, respectively, with a median PSA level of <0.1 ng/mL for all risk groups and ADT and EBRT subgroups. At last follow-up, only 5 patients (0.8%) had died of metastatic prostate cancer. In multivariate analysis, Gleason score, percentage of positive biopsies, and ADT predicted for biochemical outcome in high-risk patients. In low- and intermediate-risk patients, none of the evaluated variables predicted for biochemical outcome. For the entire population, pretreatment PSA level, Gleason score, ADT, and clinical stage predicted for 8-year biochemical progression-free survival, with the percentage of positive biopsies approaching statistical significance.

CONCLUSION

Prostate brachytherapy results in a high probability of 8-year biochemical progression-free survival for low-, intermediate-, and high-risk patients. Although the role of supplemental EBRT could not be adequately evaluated in high-risk patients, it did not improve biochemical outcome in low- and intermediate-risk patients. However, ADT resulted in a statistically significant improvement in progression-free survival for high-risk patients.

Permanent Interstitial Brachytherapy for Clinically Organ-Confined High-Grade Prostate Cancer With a Pretreatment PSA < 20 ng/mL

The objective of this study was to determine the effect of biopsy Gleason score 8 and 9 histology on biochemical outcome following a permanent prostate brachytherapy approach that includes multiple periprostatic seeds and supplemental external beam radiation. Forty-six consecutive T1c-T2b (1997 AJCC) patients with Gleason score 8 and 9 prostate cancer who were either hormone naive (33 patients) or received cytoreductive (< or =6 months) hormonal therapy (13 patients) underwent brachytherapy from June 1995 to November 2000. The median patient age was 69.7 years, with a median pretreatment prostate-specific antigen (PSA) of 7.7 ng/mL. The median follow-up was 58 months (range 27-93 months). Forty-five of the patients were implanted with Pd-103 and 44 received supplemental external beam radiation therapy (45 Gy). Biochemical success was defined by either a PSA < or = 0.4 ng/mL after a nadir or by the ASTRO consensus definition. The actuarial 7-year biochemical disease-free survival was 84.8% using either a PSA < or = 0.4 ng/mL or the ASTRO consensus definition. The median postimplant PSA was less than 0.1 ng/mL for both the hormone naive and hormonally manipulated patients. The utilization of hormonal therapy for 6 months or less duration resulted in a statistically nonsignificant improvement in biochemical outcome (92.3% versus 81.8%, P = 0.393). When stratified by pretreatment PSA, 87.9% of patients with a pretreatment PSA < or = 10 ng/mL and 76.9% with a pretreatment PSA > 10 ng/mL (P = 0.377) remained biochemically free of disease. In multivariate analysis, none of the clinical, treatment, or dosimetric parameters predicted for outcome. Following a permanent prostate brachytherapy approach that used multiple periprostatic seeds, the majority of patients with clinically organ-confined Gleason score 8 and 9 prostate cancer remain biochemically free of disease with identical outcomes for both biochemical definitions of success.

Myths and fallacies in permanent prostate brachytherapy

Because there are competing modalities to treat early-stage prostate cancer, the constraints or deficiencies of one modality may be erroneously applied to others. Some valid concerns arising from surgery and external beam therapy, which have been falsely transferred to brachytherapy, are constraints based on patient age, clinical and pathological parameters, patient weight, and size of prostate. Although the constraints have a valid basis in one modality, knowledge of the origin and mechanism of the constraint has provided a means to circumvent or overcome it in brachytherapy. Failures as measured by biochemical no-evidence of disease (bNED) survival may be attributed to extracapsular disease extension. Such extension often expresses itself in surrogate parameters such as a high percentage of positive biopsies, perineural invasion, or the dominant pattern in Gleason score histology. Failures due to such factors may be prevented by implanting with consistent extracapsular dosimetric margins. Some presumed limitations on prostate brachytherapy originated from data on patients implanted in the first few years the procedure was being developed. Most of the urinary morbidity and a significant part of the decrease in sexual function observed may be avoided by controlling the dosimetry along the prostatic and membranous urethra and at the penile bulb.

Permanent interstitial brachytherapy for the management of carcinoma of the prostate gland

PURPOSE

We summarize the permanent prostate brachytherapy literature, including biochemical outcomes, quality of life parameters and areas of controversy.

MATERIALS AND METHODS

The permanent prostate brachytherapy literature was reviewed using MEDLINE searches to ensure completeness.

RESULTS

Using various planning and intraoperative techniques the majority of the brachytherapy literature demonstrates durable biochemical outcomes for patients with low, intermediate and high risk features. For low risk patients there is no advantage to combining supplemental external beam radiation therapy with brachytherapy. In addition, supplemental external beam radiation therapy may not improve biochemical outcomes for patients at intermediate and high risk if the target volume consists of the prostate with a generous periprostatic margin. There is no defined role for adjuvant hormonal manipulation. Although a reliable set of pretreatment criteria to predict implant related morbidity is not available, severe urinary and rectal morbidity is rare. The incidence of brachytherapy induced erectile dysfunction is significantly greater than initially reported but the majority of patients respond favorably to sildenafil.

CONCLUSIONS

Continued refinements in brachytherapy planning and implementation techniques, postimplantation evaluation and continued elucidation of the etiology of urinary, bowel and sexual dysfunction should result in further improvements in biochemical and quality of life outcomes.