Focal partial salvage low-dose-rate brachytherapy for local recurrent prostate cancer after permanent prostate brachytherapy with a review of the literature

Salvage high-intensity focused ultrasound (S-HIFU) for recurrence after primary radiotherapy of prostate cancer

OBJECTIVES

To evaluate functional and oncological outcomes of salvage high-intensity focal ultrasound (S-HIFU) after external beam radiotherapy (EBRT) failure in prostate cancer (PCa) patients.

METHODS

This single-center study included patients who underwent S-HIFU for local recurrence after EBRT between 2006 and 2023. Cancer-specific survival, metastasis-free survival and progression-free survival were illustrated using Kaplan-Meier curves. Disease progression was defined by one of the following criteria: increase of 2ng/mL or more above the PSA nadir, positive post-S-HIFU biopsy or initiation of androgen deprivation therapy (ADT). Multivariable Cox proportional hazards model was used to identify predictors of disease progression after S-HIFU.

RESULTS

A total of 52 S-HIFU sessions for 48 patients were performed. Median time between EBRT and S-HIFU was 6.5 years. Median PSA before S-HIFU was 3.2ng/mL and median PSA nadir after S-HIFU was 0.58ng/mL. A total of 39 (81.3%) complications was recorded, including 3 (6.3%) high grade complications according to the Clavien-Dindo classification. After a median follow-up period of 6 years, 14 (29.2%) patients developed metastatic disease. Eighteen (37.5%) patients had no recurrence, whereas 30 (62.5%) patients received ADT for disease progression. The estimated 5-yr cancer-specific survival (CSS), metastasis-free survival (MFS) and progression-free survival rates (PFSR) were 100%, 79.9% (95% CI 67-92) and 41.2% (95% CI 74-96), respectively. The estimated 10-yr CSS, MFS and PFSR were 80% (95% CI 45-100), 50.7% (95% CI 19.4-82.1) and 14% (95% CI 10.8-45), respectively. The hazard of progression increased with the intermediate (HR 3.8; 95% CI 0.99 to 15; p=0.049) and high pre-EBRT d'Amico-s risk group (HR 4.1; 95% CI 0.98 to 16.2; p=0.050). Also, the time between EBRT and S-HIFU was significantly associated with risk of progression (HR 0.61; 95% CI 0.43 to 0.86; p=0.004). No significant difference linked to the disease progression (DP) risk was found between focal vs whole-gland treatment (p=0.70).

CONCLUSION

Physicians should consider HIFU as a local salvage treatment after failed EBRT, thus avoiding or delaying palliative androgen deprivation therapy. Further studies are needed to improve patient selection for this therapy.

LEVEL OF EVIDENCE: 4

Re-salvage focal low-dose rate brachytherapy for local recurrence of prostate cancer after salvage focal low-dose rate brachytherapy

Introduction

Salvage brachytherapy represents an effective treatment for local recurrence of prostate cancer after prior external beam radiotherapy. However, the optimal therapeutic strategies for local recurrence after salvage brachytherapy have not yet been determined.

Case presentation

We describe the case of a 77-year-old man who underwent re-salvage focal low-dose rate brachytherapy for local recurrence after carbon ion radiotherapy and salvage focal low-dose rate brachytherapy. We performed re-salvage focal low-dose rate brachytherapy for the recurrence with a different type of seed, which resulted in a significant reduction in the prostate-specific antigen level. During the 35-month follow-up after re-salvage focal low-dose rate brachytherapy, no recurrence of prostate cancer and no severe radiation-related toxicities were observed.

Conclusion

Our patient was successfully treated with re-salvage focal low-dose rate brachytherapy for local recurrence after salvage focal low-dose rate brachytherapy. This treatment strategy might be effective for such patients and is not associated with sexual dysfunction or severe adverse events.

Locally recurrent prostate cancer with RB1/TP53 alterations successfully treated by salvage focal brachytherapy: a case report

Retinoblastoma transcriptional corepressor 1 (RB1) and tumor protein p53 (TP53) are well-known tumor suppressor genes; their alterations are associated with poor prognosis in human malignancies and quite rare in locally recurrent cases. The patient was a 58-year-old man who was diagnosed with cT1cN0M0 prostate cancer with Gleason score of 3+3=6 and underwent brachytherapy as the initial treatment. Local recurrence was detected in the left lobe of the prostate 154 months later and whole-exome sequencing that was performed at the request of the patient revealed RB1 loss-of-heterozygosity and TP53 p.I162Rfs*27 mutations. He underwent salvage focal brachytherapy with 125I seeds and serum prostate-specific antigen levels has been stabilized without any genitourinary or gastrointestinal toxicity.

Salvage stereotactic body radiation therapy for locally recurrent prostate cancer following primary radiation therapy, are benefits worth toxicity risks?: A systematic review

INTRODUCTION

Salvage stereotactic body radiation therapy (SBRT) for localized prostate cancer recurrence following radiation therapy remains controversial. We performed a systematic review to assess the efficacy and side effect profile of salvage SBRT for locally recurrent prostate cancer to define the role of salvage SBRT in clinical practice.

METHODS

A systematic review was carried out using Pubmed (MEDLINE) and Scopus databases. Inclusion and exclusion criteria were satisfied if studies reported on patients with prior radiation therapy for prostate cancer who had subsequently had a local recurrence. Those studies included were quality assessed using the ROBINS-I checklist.

RESULTS

Five studies in total met criteria for inclusion and included all reportable outcomes. A total of 265 participants are reported on in total. Median doses for SBRT ranged from 30 to 36 Gy delivered over 5-6 fractions. Recurrence free survival ranged from 40% to 76% at 2 years. Genitourinary toxicity was more prevalent than gastrointestinal toxicities. Grade 2 and 3 genitourinary complication rates ranged from 5% to 22% and 0% to 9%, respectively. Gastrointestinal grade 2 complication rates ranged from 0% to 11% and no grade 3 complications were recorded.

DISCUSSION

Salvage SBRT appears to be comparable and potentially superior in some aspects to other salvage therapies, taking into account the limitations in cross-study comparisons. This systematic review serves as one of the first to characterize SBRT as a salvage option for locally recurrent prostate cancer.

Dosimetric outcomes of preoperative treatment planning with intraoperative optimization using stranded seeds in prostate brachytherapy

This study aimed to evaluate the quality of low-dose-rate (LDR) prostate brachytherapy (BT) based on treatment-related dosimetric outcomes. Data of 100 patients treated using LDR BT with stranded seeds from November 2012 to November 2017 were collected. The prescription dose for the prostate was 145 Gy. The dose constraints for the preoperative plan were: V100% ≥ 95%, V150% ≤ 60%, V200% ≤ 20% for the prostate; V100% for rectum, ≤ 1 cc; and V200 Gy for urethra, 0.0 cc. Intraoperative real-time dose calculation and postoperative dose distribution analysis on days 0 and 30 were performed. Median dosimetric outcomes on days 0 and 30 respective were: V100% 92.28% and 92.23%, V200% 18.63% and 25.02%, and D90% 150.88 Gy and 151.46 Gy for the prostate; V100% for the rectum, 0.11 cc and 0.22 cc; and V200 Gy for the urethra, 0.00 cc and 0.00 cc, respectively. Twenty patients underwent additional seed implantation to compensate for insufficient dose coverage of the prostate. No loss or substantial migration of seeds or severe toxicity was reported. With stranded seed implantation and intraoperative optimization, appropriate dose delivery to the prostate without excessive dose to the organs at risk could be achieved.

GEC-ESTRO ACROP prostate brachytherapy guidelines

This is an evidence-based guideline for prostate brachytherapy. Throughout levels of evidence quoted are those from the Oxford Centre for Evidence based Medicine (https://www.cebm.ox.ac.uk/resources/levels-of-evidence/oxford-centre-for-evidence-based-medicine-levels-of-evidence-march-2009). Prostate interstitial brachytherapy using either permanent or temporary implantation is an established and evolving treatment technique for non-metastatic prostate cancer. Permanent brachytherapy uses Low Dose Rate (LDR) sources, most commonly I-125, emitting photon radiation over months. Temporary brachytherapy involves first placing catheters within the prostate and, on confirmation of accurate positioning, temporarily introducing the radioactive source, generally High Dose Rate (HDR) radioactive sources of Ir-192 or less commonly Co-60. Pulsed dose rate (PDR) brachytherapy has also been used for prostate cancer [1] but few centres have adopted this approach. Previous GEC ESTRO recommendations have considered LDR and HDR separately [2-4] but as there is considerable overlap, this paper provides updated guidance for both treatment techniques. Prostate brachytherapy allows safe radiation dose escalation beyond that achieved using external beam radiotherapy alone as it has greater conformity around the prostate, sparing surrounding rectum, bladder, and penile bulb. In addition there are fewer issues with changes in prostate position during treatment delivery. Systematic review and randomised trials using both techniques as boost treatments demonstrate improved PSA control when compared to external beam radiotherapy alone [5-7].

Focal low-dose-rate prostate brachytherapy for low- and intermediate-risk prostate cancer

Purpose

To prospectively investigate the efficacy and feasibility of focal low-dose-rate (LDR) prostate brachytherapy for low- and intermediate-risk prostate cancer.

Material and methods

Between October 2014 and May 2019, nineteen low- and intermediate-risk prostate cancer patients who presented with abnormality on both diffusion-weighted and T2-weighted magnetic resonance imaging (MRI) underwent focal LDR brachytherapy at our institution. Focal gross tumor volume (F-GTV) was delineated on transrectal ultrasound, based on abnormality seen on fused T2-weighted MRI. F-GTV was expanded by 5 mm, as a safety margin, to create focal clinical target volume (F-CTV). Prescribed dose to F-CTV was 145 Gy. Biochemical recurrence (BCR) was determined using Phoenix criterion (prostate specific antigen nadir + 2 ng/ml). Pre- and post-implant dosimetry data were compared using non-parametric Wilcoxon’s rank sum test. Treatment-related toxicities were evaluated using common terminology criteria for adverse events.

Results

Mean F-CTV D_90% was significantly lower in the post-implant evaluation than in intraoperative planning (p = 0.004). On post-implant dosimetry, the mean D_90% for F-GTV and mean V_100% for the entire prostate were 222 Gy and 35%, respectively. Median follow-up time for all patients was 31 months. BCR occurred in one patient after 23 months. Kaplan-Meier 2-year BCR-free rate was 92.9% (95% confidence interval [CI]: 79.4-100%). No patients had grade 1 or greater gastrointestinal toxicity. Three patients who were taking α-blockers to treat benign prostatic hyperplasia (present before brachytherapy), experienced no treatment-related genitourinary toxicities. Two patients suffered from temporary grade 2 urinary frequency. None of the remaining patients experienced grade 2 or higher genitourinary toxicity.

Conclusions

Focal LDR prostate brachytherapy appears acceptable for MRI-based index tumors, with a low cumulative incidence of BCR. Such brachytherapy might offer a feasible minimally invasive therapeutic option for localized prostate cancer.

Salvage low dose rate brachytherapy for prostate cancer recurrence following definitive external beam radiation therapy

PURPOSE

We sought to describe the safety and efficacy of salvage low dose rate (LDR) brachytherapy for local prostate cancer recurrence following definitive RT.

MATERIALS AND METHODS

We included patients from two prospectively maintained institutional databases who underwent salvage LDR brachytherapy for biopsy confirmed intra-prostatic recurrence following primary RT. All patients were without evidence of metastatic disease. Freedom from biochemical failure (FFbF), prostate cancer specific survival (PCaSS), and overall survival (OS) were determined using the Kaplan-Meier estimates. Cox proportional hazard models were used to identify factors predictive of FFbF. Toxicity was graded by Common Terminology Criteria for Adverse Events (CTCAE) v5.0.

RESULTS

108 patients were included. Median follow-up was 6.3 years. The 5- and 10-year actuarial survival outcomes were as follows: FFbF, 63.1% and 52.0%; PCaSS, 90.5% and 77.8%; OS, 80.9% and 56.7%. On multivariate modeling, increasing grade group (HR 1.41, 95% CI 1.02-1.95, p = 0.036) and initial PSA at diagnosis (HR 1.02, 95% CI 1.004-1.05, p = 0.022) were associated with worse FFbF. Grade 3 toxicity occurred in 16.7% of patients; including genitourinary events in 15.7% and gastrointestinal events in 2.8% of patients. IPSS scores increased following implant, peaking at 2 months (median IPSS 20, p = 0.002) and thereafter remaining elevated throughout follow-up.

CONCLUSIONS

Salvage LDR brachytherapy is safe and efficacious, with acceptable grade 3+ toxicity and good biochemical control on long-term follow-up. Patients with higher grade group and higher PSA at initial diagnosis may be at increased risk for biochemical failure.

Salvage I-125 brachytherapy for locally-recurrent prostate cancer after radiotherapy

Purpose

Retrospective, single-institution analysis of clinical outcomes and treatment-related toxicity in patients treated with salvage I-125 low-dose rate (LDR) brachytherapy (BT) for locally-recurrent prostate cancer after radiotherapy.

Materials and methods

Between 2008 and 2018, 30 patients with biopsy-confirmed prostate cancer recurrence underwent salvage treatment with I-125 LDR-BT. Of these 30 patients, 14 were previously treated with primary external beam radiotherapy (EBRT; median dose, 73 Gy) and 16 with primary I-125 LDR-BT (145 Gy and 160 Gy in 14 and 2 cases, respectively). At seed implantation, the mean age was 75.8 years, with a median Gleason score of 7 and pre-salvage PSA of <10 ng/mL. Six patients received androgen deprivation therapy for six months after relapse diagnosis. The prescribed salvage I-125 BT dose to the gland was 120-130 Gy, with dose restrictions of Dmax <135% (urethra) and <100% (rectum). Toxicity was evaluated according to the CTCAE scale (v4.0).

Results

At a median follow-up of 45 months, the biochemical recurrence-free survival rates at 1, 3 and 5 years were 86.7%, 56.7% and 53.3%, respectively. Overall survival at 5 years was 87%. On the multivariate analysis, two variables were significant predictors of recurrence: PSA at relapse and nadir PSA post-salvage. Grade 3 genitourinary toxicity was observed in 5 patients (radiation-induced cystitis in 3 cases and urethral stenosis in 2) and G3 gastrointestinal toxicity in 3 patients (rectal bleeding).

Conclusion

Salvage therapy with I-125 brachytherapy is a safe and effective treatment option for locally-recurrent prostate cancer in previously-irradiated patients. High pre-salvage PSA and post-salvage nadir PSA values were significantly associated with a worse disease control after salvage I-125 LDR-BT. In well-selected patients, I-125 LDR-BT is comparable to other salvage therapies in terms of disease control and toxicity. However, more research is needed to determine the optimal management of locally-recurrent prostate cancer.

Interim Results of a Prospective Prostate-Specific Membrane Antigen-Directed Focal Stereotactic Reirradiation Trial for Locally Recurrent Prostate Cancer

PURPOSE

To report the feasibility, toxicity, and preliminary outcomes (metabolic and biochemical) of ⁶⁸Ga-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT)-directed focal prostate reirradiation using linear accelerator (LINAC)-based stereotactic body radiation treatment (SBRT).

METHODS AND MATERIALS

From March 2016 to March 2019, 25 patients were enrolled in a prospective single institution trial (ACTRN12617000035325). Eligibility criteria included patients with biopsy proven isolated prostate recurrence after definitive irradiation, with concordant multiparametric MRI and ⁶⁸Ga-PSMA PET/CT findings, and a prostate-specific antigen of less than 15 ng/mL at the time of recurrence. The study included a sequential dose escalation component with the first 18 patients receiving 36 Gy in 6 fractions on alternate days with subsequent patients receiving 38 Gy in 6 fractions assuming acceptable toxicity.

RESULTS

Median age was 72 years (range, 62-83) with a median time between first radiation treatment and salvage SBRT of 8.3 years (range, 4.5- 13.6). Median prostate-specific antigen at reirradiation was 4.1 (range, 1.1-16.6). The median follow-up was 25 months (range, 13-46). Acute grade 1 and 2 genitourinary (GU) toxicity occurred in 6 (24%) and 1 (4%) men, respectively. Acute grade 1 gastrointestinal (GI) toxicity occurred in 8% with one acute grade 3 GI toxicity (4%) due to a rectal ulcer overlying the hydrogel. Late grade 1 and 2 GU toxicity occurred in 28% and 4%. Late grade 1 GI toxicity occurred in 8% with no grade 2 or greater toxicity. Twenty-four patients have undergone per-protocol 12-month ⁶⁸Ga-PSMA PET/CT, of which 23 (92%) demonstrated a complete metabolic response. Biochemical freedom from failure was 80% at 2 years with 3 out of 4 of the biochemical failures exhibiting recurrent local disease.

CONCLUSIONS

PSMA-directed salvage focal reirradiation to the prostate using linear accelerator-based SBRT is feasible and safe. Toxicity was low, with very favorable short term local and biochemical control in a carefully selected cohort of patients.

A systematic review of salvage focal therapies for localised non-metastatic radiorecurrent prostate cancer

Although radiotherapy to the prostate for cancer is effective, recurrence occurs in 10–15% within 5 years. Traditional salvage treatments for men with radiorecurrent prostate cancer comprise of watchful waiting (WW) with or without androgen deprivation therapy (ADT) or radical prostatectomy (RP). Neither strategy provides ideal therapeutic ratios. Salvage focal ablation is an emerging option. We performed a systematic review of the Medline and Embase databases for studies reporting outcomes of focal salvage brachytherapy (sBT), cryotherapy (sCT) or high-intensity focused ultrasound (sHIFU) for radiorecurrent prostate cancer (conception to April 2019). Results were screened for inclusion against predetermined eligibility criteria. Certain data were extracted, including rates of biochemical disease-free survival (BDFS), metastasis, conversion to second-line therapies and adverse events. Of a total 134 articles returned from the search, 15 studies (14 case series and 1 comparative study) reported outcomes after focal sBT [5], sCT [7] and sHIFU [3]. Cohort size varied depending on intervention, with eligible studies of sBT being small case series. Median follow-up ranged from 10 to 56 months. Although pre-salvage demographics were similar [median age range, 61–75 years; prostate-specific antigen (PSA) range, 2.8–5.5 ng/mL], there was heterogeneity in patient selection, individual treatment protocols and outcome reporting. At 3 years, BDFS ranged from 61% to 71.4% after sBT, 48.1–72.4% after sCT and 48% after sHIFU. Only studies of sCT reported 5-year BDFS, which ranged from 46.5% to 54.4%. Rates of metastasis were low after all salvage modalities, as were conversion to second-line therapies (although this was poorly reported). Grade 3 adverse events were rare. This systematic review indicates that salvage focal ablation of radiorecurrent prostate cancer provides acceptable oncological outcomes and is well tolerated. Unfortunately, there is heterogeneity in the study design of existing evidence. Level 1 research comparing salvage focal therapies to existing whole-gland strategies is needed to further establish the role of these promising treatments.

Brachytherapy for the urologist: A multidisciplinary team update for 2019

Brachytherapy is a well-established treatment for localised prostate cancer. Urologists are often tasked with discussing all available treatment options with the newly diagnosed patient. Unlike radical prostatectomy and external beam radiotherapy, knowledge of brachytherapy may be limited. The aim of this article is to provide an up-to-date guide on patient selection, modern brachytherapy techniques and the management of side effects, such that the core urologist can be more confident in both discussing initial treatment options and the long-term management of brachytherapy patients.

Level of Evidence: Level 5 - review article

Focal Salvage Treatment of Radiorecurrent Prostate Cancer: A Narrative Review of Current Strategies and Future Perspectives

Over the last decades, primary prostate cancer radiotherapy saw improving developments, such as more conformal dose administration and hypofractionated treatment regimens. Still, prostate cancer recurrences after whole-gland radiotherapy remain common, especially in patients with intermediate- to high-risk disease. The vast majority of these patients are treated palliatively with androgen deprivation therapy (ADT), which exposes them to harmful side-effects and is only effective for a limited amount of time. For patients with a localized recurrent tumor and no signs of metastatic disease, local treatment with curative intent seems more rational. However, whole-gland salvage treatments such as salvage radiotherapy or salvage prostatectomy are associated with significant toxicity and are, therefore, uncommonly performed. Treatments that are solely aimed at the recurrent tumor itself, thereby better sparing the surrounding organs at risk, potentially provide a safer salvage treatment option in terms of toxicity. To achieve such tumor-targeted treatment, imaging developments have made it possible to better exclude metastatic disease and accurately discriminate the tumor. Currently, focal salvage treatment is being performed with different modalities, including brachytherapy, cryotherapy, high-intensity focused ultrasound (HIFU), and stereotactic body radiation therapy (SBRT). Oncologic outcomes seem comparable to whole-gland salvage series, but with much lower toxicity rates. In terms of oncologic control, these results will improve further with better understanding of patient selection. Other developments, such as high-field diagnostic MRI and live adaptive MRI-guided radiotherapy, will further improve precision of the treatment.

Current status and progress of focal therapy in Asia

PURPOSE OF REVIEW

With the increasing incidence of low-to-intermediate risk of prostate cancer (PCa) by the introduction of prostate-specific antigen (PSA) screening, focal therapy has become one of the promising treatment options in the world. In Asia, same movement are occurring using several technologies including cryoablation, high-intensity focused ultrasound, brachytherapy and irreversible electroporation. However, these are still not common strategies to treat organ-confined PCa. The purpose of this review is to summarize the most updated experience and future direction of focal therapy in Asian countries.

RECENT FINDINGS

The prevalence and diagnosis of PCa are increasing in Asian countries. This increase is related to various factors including the widespread implementation of PSA testing and lifestyle changes to more Westernized diets. With the increasing detection rate of early stage PCa, overdetection and overtreatment are recognized even in Asia. In this setting, accumulating data on multiparametric MRI and MRI-targeted biopsy as well as MRI-transrectal ultrasound (TRUS) fusion biopsy suggest the potential in improving the detection of clinically significant PCa in Asia. Furthermore, targeted focal therapy has emerged as a promising treatment strategy aiming for both providing oncological outcome and maintaining functional preservation in many Asian countries.

SUMMARY

At present, focal therapy is not a current standard choice for the treatment of localized PCa in Asian countries. However, with the increase of localized PCa and patient's preference for less invasive treatment with preservation of organ-function, focal therapy should become a definite treatment option for localized PCa in Asia.

Multiparametric MRI for the detection of local recurrence of prostate cancer in the setting of biochemical recurrence after low dose rate brachytherapy

PURPOSE

Prostate multiparametric magnetic resonance imaging (mpMRI) has utility in detecting post-radiotherapy local recurrence. We conducted a multireader study to evaluate the diagnostic performance of mpMRI for local recurrence after low dose rate (LDR) brachytherapy.

METHODS

A total of 19 patients with biochemical recurrence after LDR brachytherapy underwent 3T endorectal coil mpMRI with T2-weighted imaging, dynamic contrast-enhanced imaging (DCE) and diffusion-weighted imaging (DWI) with pathologic confirmation. Prospective reads by an experienced prostate radiologist were compared with reads from 4 radiologists of varying experience. Readers identified suspicious lesions and rated each MRI detection parameter. MRI-detected lesions were considered true-positive with ipsilateral pathologic confirmation. Inferences for sensitivity, specificity, positive predictive value (PPV), kappa, and index of specific agreement were made with the use of bootstrap resampling.

RESULTS

Pathologically confirmed recurrence was found in 15 of 19 patients. True positive recurrences identified by mpMRI were frequently located in the transition zone (46.7%) and seminal vesicles (30%). On patient-based analysis, average sensitivity of mpMRI was 88% (standard error [SE], 3.5%). For highly suspicious lesions, specificity of mpMRI was 75% (SE, 16.5%). On lesion-based analysis, the average PPV was 62% (SE, 6.7%) for all lesions and 78.7% (SE, 10.3%) for highly suspicious lesions. The average PPV for lesions invading the seminal vesicles was 88.8% (n=13). The average PPV was 66.6% (SE, 5.8%) for lesions identified with T2-weighted imaging, 64.9% (SE, 7.3%) for DCE, and 70% (SE, 7.3%) for DWI.

CONCLUSION

This series provides evidence that mpMRI after LDR brachytherapy is feasible with a high patient-based cancer detection rate. Radiologists of varying experience demonstrated moderate agreement in detecting recurrence.

Oncological outcome, complications, lower urinary tract symptoms, and health-related quality of life after low-dose-rate salvage brachytherapy for recurrent prostate cancer following primary radiotherapy: a report of 8 cases

Purpose

We evaluated our experience with low-dose-rate salvage brachytherapy for local recurrence after primary prostate radiotherapy, and described the changes in lower urinary tract symptoms and health-related quality of life.

Material and methods

Between 2011 and 2016, eight men with local recurrence after primary prostate radiotherapy underwent iodine-125 salvage brachytherapy with a prescribed dose of 110 or 145 Gy. Recurrence-free survival was evaluated with a post-treatment prostate-specific antigen profile. The toxicity and changes in lower urinary tract symptoms and health-related quality of life during the follow-up were evaluated on the Common Terminology Criteria for Adverse Events version 4.0, International Prostate Symptom Score, Short Form-8, and Expanded Prostate Cancer Index Composite, respectively.

Results

The median follow-up was 12.2 months (range, 8.3-71.9) after salvage brachytherapy. Of all eight patients, two (25%) experienced treatment failure, one of whom developed left seminal vesicle recurrence 36 months after salvage brachytherapy for the right seminal vesicle recurrence, while the other developed bone metastases after 6 months. The International Prostate Symptom Scores peaked at 3 months, and returned to baseline by 6 months. The scores of all domains of health-related quality of life remained unchanged during the 12-month follow-up after salvage brachytherapy. Early grade ≤ 2 genitourinary toxicity was observed in five patients (63%), and late grade 2 gastrointestinal toxicity in one patient (13%) having persistent diarrhea. No patient required intermittent catheterization and no grade 3 or greater toxicity occurred during follow-up.

Conclusions

The present study is our experiment of eight patients undergoing salvage brachytherapy, suggesting that this modality is noninvasive, safe, and an effective salvage local treatment in selected patients. To our knowledge, this is the first study to evaluate lower urinary tract symptoms and health-related quality of life in the post-treatment period in prostate cancer patients.

Focal therapy for prostate cancer: the technical challenges

Focal therapy for prostate cancer has been proposed as an alternative treatment to whole gland therapy, offering the opportunity for tumor dose escalation and/or reduced toxicity. Brachytherapy, either low-dose-rate or high-dose-rate, provides an ideal approach, offering both precision in dose delivery and opportunity for a highly conformal, non-uniform dose distribution. Whilst multiple consensus documents have published clinical guidelines for patient selection, there are insufficient data to provide clear guidelines on target volume delineation, treatment planning margins, treatment planning approaches, and many other technical issues that should be considered before implementing a focal brachytherapy program. Without consensus guidelines, there is the potential for a diversity of practices to develop, leading to challenges in interpreting outcome data from multiple centers. This article provides an overview of the technical considerations for the implementation of a clinical service, and discusses related topics that should be considered in the design of clinical trials to ensure precise and accurate methods are applied for focal brachytherapy treatments.

Focal application of low-dose-rate brachytherapy for prostate cancer: a pilot study

Purpose

To evaluate the feasibility and to report the early outcomes of focal treatment of prostate cancer using low-dose-rate brachytherapy (LDR-PB).

Material and methods

Seventeen patients were screened with multi-parametric magnetic resonance imaging (mpMRI), 14 of whom proceeded to receive trans-perineal template mapping biopsy (TTMB). Focal LDR-PB was performed on five eligible patients using dual air kerma strength treatment plans based on planning target volumes derived from cancer locations and determined by TTMB. Patient follow-up includes prostate specific antigen (PSA) measurements, urinary and sexual function questionnaires, repeated imaging and TTMB at specific intervals post-treatment.

Results

Feasibility of focal LDR-PB was shown and short-term outcomes are promising. While the detection rate of tumors, a majority of which were low grade GS 3 + 3, was found to be low on mpMRI (sensitivity of 37.5%), our results suggest the potential of mpMRI in detecting the presence of higher grade (GS ≥ 3 + 4), and bilateral disease indicating its usefulness as a screening tool for focal LDR-PB.

Conclusions

Low-dose-rate brachytherapy is a favorable ablation option for focal treatment of prostate cancer, requiring minimal modification to the standard (whole gland) LDR-PB treatment, and appears to have a more favorable side effect profile. Further investigation, in the form of a larger study, is needed to assess the methods used and the long-term outcomes of focal LDR-PB.

Salvage high-dose-rate brachytherapy for histologically confirmed macroscopic local relapsed prostate cancer after radical prostatectomy

Purpose

To evaluate the feasibility of the use of real-time magnetic resonance imaging (MRI)-transrectal ultrasound (TRUS) fusion guided high-dose-rate brachytherapy (HDR-BT) +/– external beam radiation therapy (EBRT) in patients with histologically-proven local relapse after radical prostatectomy.

Material and methods

We retrospectively reviewed 13 patients treated with real-time MRI-TRUS fusion HDR-BT for a local relapse of prostate cancer after radical surgery. All patients underwent multiparametric magnetic resonance imaging (mpMRI) to confirm the presence of macroscopic lesions in prostate bed, and choline positron emission tomography/computed tomography (PET/CT) to rule out nodal or distant metastases. Local failure was confirmed by transrectal biopsy. Patients without previous EBRT received 1 fraction of 15 Gy with HDR-BT plus hypofractionated EBRT (37.5 Gy in 15 fractions). Two patients received 2 fractions of 12 Gy with HDR-BT without EBRT. Follow-up visits were at 1, 3, 6 months, and every 6 months thereafter.

Results

After a median follow-up of 7 months, all patients showed an appropriate biochemical response. Median prostate-specific antigen (PSA) levels before treatment, 1 month, and 6 months after HDR-BT were 2.62 ng/ml (range: 1.55-9.61), 0.97 ng/ml (range: 0.12-3.14), 0.23 ng/ml (range: 0.1-0.74), respectively. Five patients (42%) experienced acute grade 1 GU toxicity and 1 patient (8%) suffered from grade 2 GU toxicity. Regarding gastrointestinal (GI) toxicity, 5 patients referred grade 1 acute toxicity and 1 grade 2 (proctitis). No late toxicity has been observed so far.

Conclusions

MRI-TRUS fusion guided salvage HDR-BT +/– EBRT is a feasible procedure for patients with local macroscopic relapse in tumor bed after radical prostatectomy. Exquisite selection of patients through mpMRI and choline PET/CT is crucial to avoid overtreatment. A larger number of patients and longer follow-up are required in order to draw more solid conclusions regarding the effectiveness of this strategy.

Comparative cost-effectiveness of focal and total salvage 125I brachytherapy for recurrent prostate cancer after primary radiotherapy

PURPOSE

Focal salvage (FS) iodine 125 (125I) brachytherapy could be an effective treatment for locally radiorecurrent prostate cancer (PCa). Toxicity is often reduced compared to total salvage (TS) while cancer control can be maintained, which could increase cost-effectiveness. The current study estimates the incremental cost per quality-adjusted life year (QALY) of FS compared to TS.

MATERIAL AND METHODS

A decision analytic Markov model was developed, which compares costs and QALYs associated with FS and TS. A 3-year time horizon was adopted with six month cycles, with a hospital perspective on costs. Probabilities for genitourinary (GU) and gastrointestinal (GI) toxicity and their impact on health-related quality of life (SF-36) were derived from clinical studies in the University Medical Center Utrecht (UMCU). Probabilistic sensitivity analysis, using 10,000 Monte Carlo simulations, was performed to quantify the joint decision uncertainty up to the recommended maximum willingness-to-pay threshold of €80,000/QALY.

RESULTS

Focal salvage dominates TS as it results in less severe toxicity and lower treatment costs. Decision uncertainty is small, with a 97-100% probability for FS to be cost-effective compared to TS (€0-€80,000/QALY). Half of the difference in costs between FS and TS was explained by higher treatment costs of TS, the other half by higher incidence of severe toxicity. One-way sensitivity analyses show that model outcomes are most sensitive to utilities and probabilities for severe toxicity.

CONCLUSIONS

Focal salvage 125I brachytherapy dominates TS, as it has lower treatment costs and leads to less toxicity in our center. Larger comparative studies with longer follow-up are necessary to assess the exact influence on (biochemical disease free) survival and toxicity.