Nationwide Japanese Prostate Cancer Outcome Study of Permanent Iodine-125 Seed Implantation (J-POPS): first analysis on survival

Prostate brachytherapy seed migration to the right renal artery due to right-to-left shunting across a patent foramen ovale

Introduction

The seeds used in brachytherapy for prostate cancer may migrate through the surrounding venous plexus to other sites in the body, most commonly to the pulmonary vasculature.

Case presentation

A 78-year-old Japanese man received iodine-125 low-dose-rate prostate brachytherapy. Computed tomography revealed that one seed had migrated to the right kidney. No seed was observed in the ureter upon ureteroscopy. Transesophageal echocardiography confirmed a right-to-left shunt due to a patent foramen ovale, suggesting that the seed had migrated into the right renal artery. Three years after treatment, no recurrence of prostate cancer and no adverse events due to seed migration or due to the patent foramen ovale occurred.

Conclusion

Arteriovenous malformations and a right-to-left shunt should be suspected if a brachytherapy seed has migrated to an artery of the systemic circulatory system.

Trimodality Therapy With Iodine-125 Brachytherapy, External Beam Radiation Therapy, and Short- or Long-Term Androgen Deprivation Therapy for High-Risk Localized Prostate Cancer: Results of a Multicenter, Randomized Phase 3 Trial (TRIP/TRIGU0907)

PURPOSE

This phase 3 randomized investigation was designed to determine whether 30 months of androgen deprivation therapy (ADT) was superior to 6 months of ADT when combined with brachytherapy and external beam radiation therapy (EBRT) for localized high-risk prostate cancer.

METHODS AND MATERIALS

This study was conducted at 37 hospitals on men aged 40 to 79 years, with stage T2c-3a, prostate-specific antigen >20 ng/mL, or Gleason score >7, who received 6 months of ADT combined with iodine-125 brachytherapy followed by EBRT. After stratification, patients were randomly assigned to either no further treatment (short arm) or 24 months of adjuvant ADT (long arm). According to the Phoenix definition of failure, the primary endpoint was the cumulative incidence of biochemical progression. Secondary endpoints included clinical progression, metastasis, salvage treatment, disease-specific mortality, overall survival, and grade 3+ adverse events. An intention-to-treat analysis was conducted using survival estimates determined using competing risk analyses.

RESULTS

Of 332 patients, 165 and 167 were randomly assigned to the short and long arms, respectively. The median follow-up period was 9.2 years. The cumulative incidence of biochemical progression at 7 years was 9.0% (95% CI, 5.5-14.5) and 8.0% (4.7-13.5) in the short and long arms, respectively (P = .65). The outcomes of secondary endpoints did not differ significantly between the arms. Incidence rates of endocrine- and radiation-related grade 3+ adverse events for the short versus long arms were 0.6 versus 1.8% (P = .62) and 1.2 versus 0.6% (P = .62), respectively.

CONCLUSIONS

Both treatment arms showed similar efficacy among selected populations with high-risk features. The toxicity of the trimodal therapy was acceptable. The present investigation, designed as a superiority trial, failed to demonstrate that 30-month ADT yielded better biochemical control than 6-month ADT when combined with brachytherapy and EBRT. Therefore, a noninferiority study is warranted to obtain further evidence supporting these preliminary results.

Current status and issues with the dosimetric assay of iodine-125 seed sources at medical facilities in Japan: a questionnaire-based survey†

In conducting dosimetric assays of seed sources containing iodine-125 (125I), several major guidelines require the medical physicist to verify the source strength before patient treatment. Japanese guidelines do not mandate dosimetric assays at medical facilities, but since 2017, three incidents have occurred in Japan wherein seeds with incorrect strengths were delivered to medical facilities. Therefore, this study aimed to survey the current situation and any barriers to conducting the dosimetric assay of iodine-125 seeds at medical facilities in Japan. We conducted a questionnaire-based survey from December 2020 to April 2021, to examine whether seed assay and verification of the number of seeds delivered were being performed. We found that only 9 facilities (16%) performed seed assay and 28 (52%) verified the number of seeds. None of the facilities used an assay method that ensured traceability. The reasons for not performing an assay were divided into two categories: lack of resources and legal issues. Lack of resources included lack of instruments, lack of knowledge of assay methods, shorthand, or all of the above, whereas legal issues included the inability to resterilize iodine-125 seeds distributed in Japan and/or purchase seeds dedicated to the assay. Dosimetric assays, including simple methods, are effective in detecting calibration date errors and non-radioactive seeds. The study findings suggest that familiarization of medical personnel with these assay methods and investigation of the associated costs of labor and equipment should be recommended, as these measures will lead to medical reimbursement for quality assurance.

The prognosis of patients with prostate cancer receiving permanent seed implantation stratified by prostate volume: Should we be reluctant to treat with brachytherapy because of a very small prostate (<15 cc)?

PURPOSE

We evaluated the treatment outcomes of different prostate volumes (PVs), <15 cc, 15-20 cc, and > 20 cc, in patients with prostate cancer who underwent permanent seed implantation (PI) ± external beam radiation therapy ± hormone therapy in a national Japanese prospective cohort study (J-POPS).

METHODS AND MATERIALS

Of the 6721 patients in J-POPS from 2005 to 2011, 6652 were included in the analysis population. We categorized the patients into the following three PV groups: <15 cc, 15-20 cc, and > 20 cc. We evaluated the effect of PV on biochemical freedom from failure (bFFF), prostate cancer-specific mortality (PCSM), and all-cause mortality (ACM) using the Phoenix definition and Cox proportional hazard models.

RESULTS

The median follow-up period was 60.0 months. Patients in each PV group was 491 (7.4%), 1118 (16.8%), and 5043 (75.8%), respectively. No difference was observed in bFFF (94.7%, 96.2%, and 95.7%, p = 0.407), PCSM (99.8%, 99.7%, and 99.8%, p = 0.682), and ACM (98.2%, 96.7%, and 97.2%, p = 0.119) at 5 years for each PV group. In univariate and multivariate analyses, PV was not associated with bFFF, PCSM, ACM, or grade 2 toxicity. The percentage of positive biopsies was the single most significant predictor for all treatment outcomes.

CONCLUSIONS

Our results obtained by analyzing a very large Japanese prospective database showed no difference in treatment outcomes according to PV (<15 cc, 15-20 cc, and ˃20 cc). Our study confirmed that PI in small prostates (even < 15 cc) remains an effective treatment option.

Direct Comparison of Two Different Definitions with Biochemical Recurrence after Low-Dose-Rate Brachytherapy for Prostate Cancer

We aimed to determine whether biochemical recurrence-free survival (BRFS) of patients with prostate cancer (PCa) who received low-dose-rate brachytherapy (LDR-BT) differed according to the definition of biochemical recurrence (BCR) after radical prostatectomy (RP) and the definition given by the Japanese Prostate Cancer Outcome Study of Permanent Iodine-125 Seed Implantation (J-POPS). We reviewed the clinical records of 476 consecutive patients with PCa who received LDR-BT at the Gifu University Hospital. The primary endpoint of this study was the difference in BRFS between the two aforementioned definitions. When the follow-up period ended, 74 (15.5%) and 20 (4.2%) patients had BCR according to the RP and J-POPS definitions, respectively. The 5-year BRFS rates were 85.0% and 96.9% for the RP and J-POPS definitions, respectively (p < 0.005). According to the RP definition, the 5-year BRFS rates were 80.6% in the group aged <63 years and 86.6% in those aged ≥63 years (p = 0.050). According to the J-POPS definition, the 5-year BRFS rates were 94.1% and 97.8% in the groups aged <63 years and ≥63 years, respectively (p = 0.005). The definition of recurrence in LDR-BT may need to be reconsidered.

Biochemical outcomes and toxicities in young men with prostate cancer after permanent iodine-125 seed implantation: Prospective cohort study in 6662 patients

PURPOSE

We evaluated the effect of age, <60 and ≥60 years, on biochemical outcomes and toxicities in patients with prostate cancer who underwent permanent seed implantation (PI) ± external beam radiation therapy ± hormone therapy in a national Japanese prospective cohort study (J-POPS).

METHODS AND MATERIALS

The safety and efficacy analyses included 6721 and 6662 patients, respectively. We categorized patients into two age groups: <60 (n = 716) and ≥60 (n = 6,005) years. We used propensity score matching (PSM) to estimate the marginal effect of age on biochemical freedom from failure (bFFF) using a Phoenix definition and Cox proportional hazard models.

RESULTS

The median followup period was 60.0 months. Without PSM, men <60 years demonstrated similar 5-year bFFF (96.3%) compared with men ≥60 years (95.6%; p = 0.576); percent positive biopsies, biologically effective dose, Gleason score, risk classification, and supplemental external beam radiation therapy (p <0.001, <0.001, <0.001, 0.008, and <0.001) were significantly associated with bFFF while age was not (p = 0.576). With PSM, bFFF was not significantly different between age groups (p = 0.664); however, men <60 years showed a significantly lower incidence of declining erectile function, grade ≥2 all urinary toxicities, urinary frequency/urgency, and rectal bleeding (p <0.001, 0.024, 0.031, and 0.010) than men ≥60 years.

CONCLUSIONS

After PI, men <60 years achieved a comparable 5-year biochemical control rate and showed a lower incidence of several toxicities compared to men ≥60 years. This suggests that PI should be an excellent treatment option for men <60 years with prostate cancer.

Patient age as a predictive factor in biochemical recurrence following brachytherapy: Oncological outcomes at a single center

Background

Iodine-125 low-dose-rate brachytherapy (LDR-BT) is a treatment modality utilized in both localized and advanced prostate cancer (PCa). We aimed to evaluate the long-term oncological outcomes in patients with PCa who underwent LDR-BT, at a single institution in Japan.

Methods

We retrospectively reviewed the clinical records of 340 consecutive patients with localized PCa who underwent LDR-BT between August 2004 and December 2014 at our institution. Patients with low-risk PCa who had a pretreatment prostate volume >50 mL received neoadjuvant androgen deprivation therapy (ADT) for at least 3 months before LDR-BT. Patients with intermediate-risk PCa were treated with a combination of LDR-BT and/or external beam radiation therapy (EBRT) and/or ADT for 9 months. Patients with high-risk PCa underwent LDR-BT, EBRT, and ADT for 24 months. The endpoints of this study were biochemical recurrence-free survival (BRFS) and overall survival (OS). Additionally, the association between biochemical recurrence (BCR) and clinical/pathological covariates was analyzed.

Results

At the end of the follow-up period, nine patients (2.6%) showed BCR, and six patients (1.8%) developed secondary cancers after LDR-BT. The 5-year and 10-year BRFS rates were 99.4% and 95.3%, respectively. Factoring in the patients' ages, the 5-year and 10-year BRFS rates were 99.1% and 99.1%, respectively, in patients aged >63 years. The rates were 100% and 89.4% in those aged ≤63 years, respectively. In the multivariate analysis, age ≤63 years was identified as a significant independent predictor of BCR after LDR-BT.

Conclusion

Age ≤63 years was a significant predictor of BCR following LDR-BT. Although the risk of secondary malignant neoplasms should be considered when opting for LDR-BT in younger patients with PCa, the prevalence of them in these patients is relatively low. Therefore, clinicians should weigh the risks and benefits of definitive therapy in PCa, particularly in younger patients.

Ischemic proctitis after low-dose-rate brachytherapy using hydrogel spacer for prostate cancer

INTRODUCTION

Recently, an absorbable hydrogel spacer is becoming more widespread to reduce rectal radiation dose for radiation therapy for localized prostate cancer.

CASE PRESENTATION

A 79-year-old male patient was referred to our hospital for radical treatment of organ-confined prostate cancer. Low-dose-rate brachytherapy was performed, and the hydrogel spacer injection was added. The spacer was properly injected between the prostate and the rectum, causing no acute complications during hospitalization. Two months after low-dose-rate brachytherapy, the patient visited our hospital with constipation and melena, without fever. He was diagnosed with ischemic proctitis based on clinical courses and examinations. He was hospitalized for 19 days and made a complete recovery with conservative treatment.

CONCLUSIONS

Herein, we report the first case of ischemic proctitis after low-dose-rate brachytherapy using hydrogel spacer for prostate cancer.

Comparison of the clinicopathologic features of prostate cancer in US and Chinese populations

BACKGROUND

Prostate cancer (PCa) is the most common malignant tumor found among men in the United States. Incidence rates of PCa have recently grown in Asian countries, partially due to the comprehensive implementation of early detection systems. Interestingly, a prospective cohort study showed that adopting a westernized dietary pattern was associated with a higher risk of being diagnosed with PCa among Korean and Japanese men. However, a comparison of current clinicopathological features of PCa between American and Chinese men is lacking. In this study, we report the current clinicopathological features of PCa in Chinese men and compare them to those of patients in the USA.

MATERIALS AND METHODS

Case cohorts included, in total, 871 PCa cases with prostatectomy sequentially treated since 2017, including 299 cases from USA and 572 cases from two different academic hospitals in China. The parameters, including patient's age, preoperative Prostate-Specific Antigen (PSA) level, Gleason score, Grade Group, stage and tumor focality, were collected, analyzed and compared using two sample t-test, Wilcoxon rank sum test, Pearson's Chi-squared test and Fisher's exact test.

RESULTS

Significant differences were demonstrated in the mean age of patients, preoperative PSA levels, extra-prostatic extension, Gleason scores, and Grade Groups (p < 0.05). PCa patients in the Chinese group were older than patients in the USA group (67.81 vs. 63.53, p < 0.01). The preoperative PSA levels in the Chinese group were higher than those in the USA group (11.69 v.s 6.30, p < 0.01). A higher percentage of high Grade Groups (Groups 4 and 5) was observed in the Chinese group (25.7%) compared to the USA cohort (17.11%), while Grade Group 2 was more common in the USA group than in the Chinese group (51.68% vs. 32.52%, p < 0.01).

CONCLUSIONS

All these data suggest that the clinicopathologic features of PCa are different between the USA and Chinese populations, which may be influenced by treatment strategies (including surgical case selection criteria).

Stereotactic Radiation Therapy versus Brachytherapy: Relative Strengths of Two Highly Efficient Options for the Treatment of Localized Prostate Cancer

Stereotactic body radiation therapy (SBRT) has become a valid option for the treatment of low- and intermediate-risk prostate cancer. In randomized trials, it was found not inferior to conventionally fractionated external beam radiation therapy (EBRT). It also compares favorably to brachytherapy (BT) even if level 1 evidence is lacking. However, BT remains a strong competitor, especially for young patients, as series with 10-15 years of median follow-up have proven its efficacy over time. SBRT will thus have to confirm its effectiveness over the long-term as well. SBRT has the advantage over BT of less acute urinary toxicity and, more hypothetically, less sexual impairment. Data are limited regarding SBRT for high-risk disease while BT, as a boost after EBRT, has demonstrated superiority against EBRT alone in randomized trials. However, patients should be informed of significant urinary toxicity. SBRT is under investigation in strategies of treatment intensification such as combination of EBRT plus SBRT boost or focal dose escalation to the tumor site within the prostate. Our goal was to examine respective levels of evidence of SBRT and BT for the treatment of localized prostate cancer in terms of oncologic outcomes, toxicity and quality of life, and to discuss strategies of treatment intensification.

Low dose rate brachytherapy for primary treatment of localized prostate cancer: A systemic review and executive summary of an evidence-based consensus statement

PURPOSE

The purpose of this guideline is to present evidence-based consensus recommendations for low dose rate (LDR) permanent seed brachytherapy for the primary treatment of prostate cancer.

METHODS AND MATERIALS

The American Brachytherapy Society convened a task force for addressing key questions concerning ultrasound-based LDR prostate brachytherapy for the primary treatment of prostate cancer. A comprehensive literature search was conducted to identify prospective and multi-institutional retrospective studies involving LDR brachytherapy as monotherapy or boost in combination with external beam radiation therapy with or without adjuvant androgen deprivation therapy. Outcomes included disease control, toxicity, and quality of life.

RESULTS

LDR prostate brachytherapy monotherapy is an appropriate treatment option for low risk and favorable intermediate risk disease. LDR brachytherapy boost in combination with external beam radiation therapy is appropriate for unfavorable intermediate risk and high-risk disease. Androgen deprivation therapy is recommended in unfavorable intermediate risk and high-risk disease. Acceptable radionuclides for LDR brachytherapy include iodine-125, palladium-103, and cesium-131. Although brachytherapy monotherapy is associated with increased urinary obstructive and irritative symptoms that peak within the first 3 months after treatment, the median time toward symptom resolution is approximately 1 year for iodine-125 and 6 months for palladium-103. Such symptoms can be mitigated with short-term use of alpha blockers. Combination therapy is associated with worse urinary, bowel, and sexual symptoms than monotherapy. A prostate specific antigen <= 0.2 ng/mL at 4 years after LDR brachytherapy may be considered a biochemical definition of cure.

CONCLUSIONS

LDR brachytherapy is a convenient, effective, and well-tolerated treatment for prostate cancer.

Prognostic value of PSA bounce in prostate cancer following definitive radiation therapy: a systematic review and meta-analysis

BACKGROUND

The prognostic significance of PSA bounce following definitive radiation therapy remains controversial. To develop a sense of current opinion in this area, we performed a systematic search of the literature based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

METHODS

In January 2021, we systematically searched PubMed, the Cochrane library, and Scopus for studies that compared patients who had localized prostate cancer with or without PSA bounce after definitive radiation therapy. Our objective was to evaluate the association of PSA bounce with biochemical recurrence-free survival, metastatic-free survival, cancer-specific survival, and overall survival, using multivariate Cox regression analysis.

RESULTS

A total of 8881 patients in 10 studies matched the selection criteria for the systematic review and meta-analysis. The number of patients with PSA bounce accounted for 2706 of all 8881 patients (30.5%). PSA bounce was associated with better biochemical recurrence-free survival after definitive radiation therapy (pooled HR: 0.62, 95% CI: 0.54-0.71). Subgroup analyses also showed that PSA bounce was independently associated with decreased risk for biochemical recurrence-free survival in prostate cancer patients treated with low dose rate brachytherapy alone (pooled HR: 0.38, 95% CI: 0.27-0.55) and external beam radiotherapy alone (pooled HR: 0.71, 95% CI: 0.57-0.87).

CONCLUSIONS

This meta-analysis indicated that PSA bounce after definitive radiation therapy is related to improved outcome in terms of biochemical failure in prostate cancer patients.

Low-dose-rate brachytherapy for prostate cancer: A 15-year experience in Japan

The history of prostate brachytherapy has passed one century. In 1983, modern low-dose-rate prostate brachytherapy using a transrectal ultrasound-guided procedure was introduced. In the early 1990s, low-dose-rate brachytherapy was introduced and rapidly spread across the USA due to its excellent oncological control, cost-effectiveness and technically easy procedure. Since low-dose-rate brachytherapy was introduced in Japan (2003), over 15 years have passed. More than 43 000 patients have undergone low-dose-rate brachytherapy. Japanese urologists and radiation oncologists are on course with leading brachytherapists in the USA. A nationwide prospective cohort study, J-POPS, was initiated in 2005. The J-POPS group also provides educational programs including an annual novel training course in low-dose-rate brachytherapy to familiarize urologists, radiation oncologists and pathologists with the procedure. Important information on Japanese patients has accumulated, especially by the J-POPS study group. The Japanese investigators reported excellent oncological outcomes of low-dose-rate brachytherapy, showing equivalent or superior efficacy to surgery in low- to intermediate-risk patients, and superior efficacy in high-risk patients using the surgery biochemical recurrence definition (prostate-specific antigen cut-off value of 0.2 ng/mL). Two randomized controlled studies (SHIP study: intermediate risk, and TRIP study: high risk) carried out by the J-POPS group are ongoing, and an additional follow-up study (J-POPS 2 study) has been started to evaluate survival outcomes over longer follow-up periods. Low-dose-rate brachytherapy is expected to provide a survival benefit, which must be confirmed by further studies with longer follow-up periods in the future.

Quality of life outcomes after low dose-rate brachytherapy for localized prostate cancer: Current status and future perspectives

The present review summarizes data from studies reporting on health-related quality of life after brachytherapy and competing modalities. There are various therapeutic modalities for localized prostate cancer, including radical surgery, external beam radiotherapy and active surveillance. Advances in surgical and radiation treatment have entered clinical practice in the form of robot-assisted surgery or intensity-modulated radiotherapy. Brachytherapy remains the main treatment option for patients with localized prostate cancer, with 10-year survival data showing favorable outcomes. Because each treatment modality has achieved favorable survival outcomes, focus in determining appropriate treatment has shifted toward health-related quality of life, where each treatment has a different profile and/or adverse symptoms. The development of health-related quality of life assessment tools has allowed the creation of a pool of specific health-related quality of life data across many studies. The present article reviews the impact of brachytherapy and other modalities on quality of life, as well as future directions.

Whole-gland salvage treatment for recurrent prostate cancer after initial definitive radiotherapy: A case series of 125I brachytherapy and robot-assisted radical prostatectomy

Purpose

To analyze outcomes following whole-gland salvage treatments applied to patients with pathology-proven, locally recurrent prostate cancer following primary definitive radiotherapy.

Material and methods

Eighteen consecutive patients who received whole-gland salvage treatments at our institution were retrospectively reviewed. All patients underwent transperineal template-guided mapping biopsy (TTMB) using the standard iodine-125 (¹²⁵I) brachytherapy (BT) setup. Twelve patients received ¹²⁵I BT, and six patients underwent robot-assisted laparoscopic prostatectomy (RARP). Prostate-specific antigen (PSA) failure was determined using the Phoenix definition (nadir + 2 ng/ml) following BT and a PSA level of > 0.2 ng/ml following RARP. Toxicities were graded according to CTCAE version 4.0.

Results

The median follow-up times were 71 and 11 months for the BT and RARP groups, respectively. In the BT group, the median dose to 90% of the prostate was 131 Gy. The median time to biochemical failure was 47 months, and the biochemical relapse-free survival (BRFS) rates were 56% (95% confidence interval [CI]: 33-94%) and 46% (95% CI: 25-88%) at 3 years and 5 years, respectively. Four patients (33%) developed grade 2 genitourinary (GU) toxicity, and two (17%) developed grade 3 GU toxicity. No patients developed grade ≥ 2 gastrointestinal (GI) toxicity. In the RARP group, three out of six patients (50%) had PSA failure, and four patients (67%) developed grade 2 GU toxicity. No patients developed grade 3 GU toxicity or grade ≥ 2 GI toxicity. On pre-salvage magnetic resonance imaging (MRI), no patients were suspected of having T3 or higher stage lesions. However, three patients (50%) had pT3a and two patients (33%) had pT3b (i.e., seminal vesicle invasion) stage lesions.

Conclusions

Whole-gland salvage BT is an effective treatment with an acceptable toxicity profile. The pathology findings from RARP imply that there is a room for improvement in diagnoses made by MRI in the pre-salvage setting.

Biochemical outcomes and predictive factors by risk group after permanent iodine-125 seed implantation: Prospective cohort study in 2,316 patients

PURPOSE

To evaluate the biochemical freedom from failure (bFFF) by risk group and treatment modality and the predictive factors of bFFF by risk group in patients with prostate cancer undergoing permanent seed implantation (PI) with or without external beam radiation therapy (EBRT) in a nationwide prospective cohort study (Japanese Prostate Cancer Outcome Study of Permanent Iodine-125 [I-125] Seed Implantation) in Japan during the first 2 years.

METHODS AND MATERIALS

The analyses included 2,316 participants in 42 institutions; bFFF was evaluated using the Phoenix definition and calculated using the Kaplan-Meier method, and the Cox proportional hazards model was used to identify the factors associated with bFFF.

RESULTS

Median followup period was 60.0 months. The 5-year bFFF rates in all patients, 1,028 low-risk patients, 1,114 intermediate-risk patients, and 133 high-risk patients were 93.6%, 94.9%, 92.7%, and 91.1%, respectively. The 5-year bFFF rates in the PI group and EBRT combination therapy group were 93.7% and 93.3%, respectively. In a multivariate analysis, younger age, higher Gleason score (GS), higher percent positive biopsies (%PB), and lower prostate V₁₀₀ (p = 0.0012, 0.0030, 0.0026, and 0.0368) in all patients; younger age, higher pretreatment prostate-specific antigen, and lower prostate V₁₀₀ (p = 0.0002, 0.0048, and 0.0012) in low-risk patients; higher GS, higher %PB, and no hormonal treatment (p = 0.0005, 0.0120, and 0.0022) in intermediate-risk patients; and higher GS and higher %PB (p = 0.0329 and 0.0120) in high-risk patients were significantly associated with bFFF.

CONCLUSIONS

PI with or without EBRT resulted in excellent short-term biochemical outcomes in all risk groups, especially in high-risk patients. Age, pretreatment prostate-specific antigen, and prostate V₁₀₀ in low-risk patients; GS, %PB, and hormonal treatment in intermediate-risk patients; and GS and %PB in high-risk patients were independently affected bFFF.

Five-year effectiveness of low-dose-rate brachytherapy: comparisons with nomogram predictions in patients with non-metastatic prostate cancer presenting significant control of intra- and periprostatic disease

PURPOSE

To assess the effectiveness of low-dose-rate (LDR) brachytherapy in patients with localized prostate cancer and to compare the outcome with predictions from Kattan and Partin nomograms at 60 months after seed implantation.

MATERIAL AND METHODS

One thousand, one hundred and eighty-seven patients with localized prostate cancer at low-, intermediate-, or high-risk of progression received LDR brachytherapy using iodine-125 seeds with curative intent, applied as monotherapy or in combination with external beam radiation therapy (EBRT), and/or androgen deprivation therapy (ADT). At 60 months after seed implantation, data of 1,064 patients (1,058 alive + 6 who died of prostate cancer) were analyzed for biochemical progression-free survival (bPFS) based on prostate-specific antigen (PSA) levels using the Phoenix definition. Five-year bPFS probabilities were determined for various risk group classifications (d'Amico, Mt. Sinai, MSKCC/Seattle, NCCN). Outcomes were also compared to patient-individualized nomogram predictions of 5-year bPFS (Kattan 2002) and probability of organ-confined disease (Kattan 2002, Partin 2007).

RESULTS

Overall, 93.3% (993/1,064) of the patients were free of biochemical progression within 5 years, while the average 5-year bPFS probability according to the Kattan nomogram was significantly lower (85%, p < 0.001). Outcomes were significantly better than Kattan nomogram predictions in the subgroup of patients with monotherapy as well as in patients additionally treated with EBRT. Comparison of the overall outcome with nomogram predictions for organ-confined disease (Kattan nomogram: 50%; Partin nomogram: 65%) revealed a significant probability of LDR brachytherapy to destroy periprostatic tumor spread (p < 0.001) in all risk group constellations, even in high-risk patients.

CONCLUSIONS

The results indicate high effectiveness of LDR brachytherapy in all risk groups, significantly better than predicted with the Kattan nomogram in most subgroups. The significant superiority of LDR brachytherapy compared to nomogram predictions of organ-confined disease suggests that LDR brachytherapy effectively controls both intra- and periprostatic disease.