Long-term outcome by risk factors using conformal high-dose-rate brachytherapy (HDR-BT) boost with or without neoadjuvant androgen suppression for localized prostate cancer

The Journey of Radiotherapy Dose Escalation in High Risk Prostate Cancer; Conventional Dose Escalation to Stereotactic Body Radiotherapy (SBRT) Boost Treatments

High risk prostate cancer (HR-PrCa) is a subset of localized PrCa with significant potential for morbidity and mortality associated with disease recurrence and metastasis. Radiotherapy combined with Androgen Deprivation Therapy has been the standard of care for many years in HR-PrCa. In recent years, dose escalation, hypo-fractionation and high precision delivery with immobilization and image-guidance have substantially changed the face of modern PrCa radiotherapy, improving treatment convenience and outcomes. Ultra-hypo-fractionated radiotherapy delivered with high precision in the form of stereotactic body radiation therapy (SBRT) combines delivery of high biologically equivalent dose radiotherapy with the convenience of a shorter treatment schedule, as well as the promise of similar efficacy and reduced toxicity compared to conventional radiotherapy. However, rigorous investigation of SBRT in HR-PrCa remains limited. Here, we review the changes in HR-PrCa radiotherapy through dose escalation, hypo- and ultra-hypo-fractionated radiotherapy boost treatments, and the radiobiological basis of these treatments. We focus on completed and on-going trials in this disease utilizing SBRT as a sole radiation modality or as boost therapy following pelvic radiation.

High rate of local control and cure at 10 years after treatment of prostate cancer with external beam radiotherapy and high-dose-rate brachytherapy: a single centre experience

BACKGROUND AND PURPOSE

To analyse the cumulative incidence of any failure (AF), prostate cancer-specific failure (PCSF), any death (AD), prostate cancer-specific death (PCSD), and local control in 2387 men with prostate cancer (PC), consecutively treated with combined high-dose-rate brachytherapy (HDRBT) and external beam radiotherapy (EBRT) from 1998 to 2010.

MATERIAL AND METHODS

A retrospective, single-institution study of men with localised PC. The mean age was 66 years and 54.7% had high-risk PC according to the Cambridge prognostic group (CPG) classification. The treatment was delivered as EBRT (2 Gy × 25) and HDRBT (10 Gy × 2) with combined androgen blockade (CAB). The median follow-up was 10.2 years.

RESULTS

The cumulative incidence of PCSD at 10 years was 5% [CI 95% 0.04-0.06]. The 10 years PCSD per risk group were: low (L) 0.4%, intermediate favourable (IF) 1%, intermediate unfavourable (IU) 4.3%, high-risk favourable (HF) 5.8%, and high-risk unfavourable (HU) 13.9%. The PCSF rate at 10 years was 16.5% [CI 95% 0.15-0.18]. The PCSF per risk group at 10 years were: L 2.5%, IF 5.5%, IU 15.9%, HF 15.6%, and HU 38.99%. PCSF occurred in 399 men, of whom 15% were found to have local failure. The estimated frequency of local failure in the entire cohort was 1.2%.

CONCLUSIONS

HDRBT combined with EBRT is an effective treatment with long-term overall survival and excellent local control for patients with PC. The low rate of local recurrence among men with relapse suggests that these patients were micro metastasised at time of treatment, which calls for improved methods to detect disseminated disease.

High-dose-rate brachytherapy for prostate cancer: Rationale, current applications, and clinical outcome

Background

High‐dose‐rate brachytherapy (HDR BRT) has been enjoying rapid acceptance as a treatment modality offered to selected prostate cancer patients devoid of risk group, employed either in monotherapy setting or combined with external beam radiation therapy (EBRT) and is currently one of the most active clinical research areas.

Recent findings

This review encompasses all the current evidence to support the use of HDR BRT in various clinical scenario and shines light to the HDR BRT rationale, as an ultimately conformal dose delivery method enabling safe dose escalation to the prostate.

Conclusion

Valid long‐term data, both in regard to the oncologic outcomes and toxicity profile, support the current clinical indication spectrum of HDR BRT. At the same time, this serves as solid, rigid ground for emerging therapeutic applications, allowing the technique to remain in the spotlight alongside stereotactic radiosurgery.

Lost in application: Measuring hypoxia for radiotherapy optimisation

The history of radiotherapy is intertwined with research on hypoxia. There is level 1a evidence that giving hypoxia-targeting treatments with radiotherapy improves locoregional control and survival without compromising late side-effects. Despite coming in and out of vogue over decades, there is now an established role for hypoxia in driving molecular alterations promoting tumour progression and metastases. While tumour genomic complexity and immune profiling offer promise, there is a stronger evidence base for personalising radiotherapy based on hypoxia status. Despite this, there is only one phase III trial targeting hypoxia modification with full transcriptomic data available. There are no biomarkers in routine use for patients undergoing radiotherapy to aid management decisions, and a roadmap is needed to ensure consistency and provide a benchmark for progression to application. Gene expression signatures address past limitations of hypoxia biomarkers and could progress biologically optimised radiotherapy. Here, we review recent developments in generating hypoxia gene expression signatures and highlight progress addressing the challenges that must be overcome to pave the way for their clinical application.

The one hundred most cited publications in prostate brachytherapy

PURPOSE

The aim of this study is to identify the leaders in research on prostate brachytherapy through a bibliometric analysis of the top 100 most cited publications in the field.

METHODS AND MATERIALS

A broad search was performed with the term "prostate brachytherapy" using the Web of Science database to generate wide-ranging results that were reviewed by reading the abstracts and, if necessary, the articles to select the top 100 most cited publications.

RESULTS

The median of the total citation count was 187 (range 132-1464). The median citation per year index (citations/year since publication) was 13.5 (range 6.3-379.0). In all publications, the first author was also the corresponding author. The top publishing countries of the first author included the United States (n = 78), Canada (n = 6), the UK (n = 5), and Germany (n = 4). The journal with the most publications was the International Journal of Radiation Oncology Biology Physics (n = 38). There were 27 more publications on low-dose-rate (LDR) than on high-dose-rate (HDR) (43 vs 16) among the top 100. HDR publications had only one first author that had three articles in comparison to LDR publications, which had four first authors, each with three articles on LDR. The United States was the leading country in 43.8% of HDR publications (n = 7) and 88.4% of LDR publications (n = 38).

CONCLUSIONS

Our bibliometric analysis of the top 100 most cited publications clearly demonstrates the North American dominance in the publications of prostate brachytherapy, especially in LDR. However, European first authors were more frequent in HDR publications.

Brachytherapy boost (BT-boost) or stereotactic body radiation therapy boost (SBRT-boost) for high-risk prostate cancer (HR-PCa)

Systematic review for the treatment of high-risk prostate cancer (HR-PCa, D'Amico classification risk system) with external body radiation therapy (EBRT)+brachytherapy-boost (BT-boost) or with EBRT+stereotactic body RT-boost (SBRT-boost). In March 2020, 391 English citations on PubMed matched with search terms "high risk prostate cancer boost". Respectively 9 and 48 prospective and retrospective studies were on BT-boost and 7 retrospective studies were on SBRT-boost. Two SBRT-boost trials were prospective. Only one study (ASCENDE-RT) directly compared the gold standard treatment [dose-escalation (DE)-EBRT+androgen deprivation treatment (ADT)] versus EBRT+ADT+BT-boost. Biochemical control rates at 9 years were 83% in the experimental arm versus 63% in the standard arm. Cumulative incidence of late grade 3 urinary toxicity in the experimental arm and in the standard arm was respectively 18% and 5%. Two recent studies with HR-PCa (National Cancer Database) demonstrated better overall survival with BT-boost (low dose rate LDR or high dose rate HDR) compared with DE-EBRT. These recent findings demonstrate the superiority of EBRT+BT-boost+ADT versus DE-EBRT+ADT for HR-PCa. It seems that EBRT+BT-boost+ADT could now be considered as a gold standard treatment for HR-PCa. HDR or LDR are options. SBRT-boost represents an attractive alternative, but the absence of randomised trials does not allow us to conclude for HR-PCa. Prospective randomised international phase III trials or meta-analyses could improve the level of evidence of SBRT-boost for HR-PCa.

Implementation of high-dose-rate brachytherapy for prostatic carcinoma in an unshielded operating room facility

PURPOSE

The purpose of the study was to describe our approach towards safe delivery of single-fraction high-dose-rate (HDR) brachytherapy (BT) boost in patients with prostate cancer in the setting of an unshielded operating room (OR).

METHODS AND MATERIALS

A total of 95 patients received 15 Gy HDR BT boost. The procedure involved transrectal ultrasound-based catheter insertion and planning in the OR, after which the patient was moved to a shielded treatment room for radiation. This required three vital components: (1) an OR table capable of transporting the patient in lithotomy position, (2) robust motion management checks to ensure reproducibility of prostate and catheter positions in the treatment room before radiation delivery, (3) remote monitoring of patient vitals while under anesthesia, during the radiation. Initial viability of this approach was confirmed by assessing acute toxicities using the Common Terminology Criteria for Adverse Events v4.0 and American Urologic Association symptom scores.

RESULTS

We found good stability in prostate and catheter position, with less than 1 mm shifts in each direction due to patient transfer. The median baseline American Urologic Association score was 7 (3-11), which increased to 12 (7-17) at 4 weeks and 9 (5-14) at 3 months (p = 0.003). Common Terminology Criteria for Adverse Events ≥ grade 2 genitourinary and gastrointestinal toxicities were experienced by 7% and 0% patients, respectively, at 3 months posttreatment completion.

CONCLUSIONS

Single-fraction HDR prostate BT can be delivered safely in an unshielded OR facility with a distant shielded treatment room using rigorous motion management checks and supplementary procedural equipment.

Stereotactic body radiotherapy for localized prostate cancer - 5-year efficacy results

BACKGROUND

The use of stereotactic body radiotherapy (SBRT) as the primary treatment modality in clinically localized prostate cancer (PCa) is emerging. The aim of the study was to analyze the long-term results of PCa patients treated with SBRT.

METHODS

This non-selected, real-life patient cohort included 213 patients with localized PCa treated with a robotic SBRT device during 2012-2015.

RESULTS

The median follow-up was 64 months (range, 10-85 months), and all risk-groups were represented as 47 (22.1%), 56 (26.3%) and 110 (51.6%) patients were classified into D'Amico risk stratification of low, intermediate and high-risk groups, respectively. Androgen deprivation therapy (ADT) was administered to 64.3% of the patients. At cut-off, the biochemical relapse-free survival (bRFS) was 100, 87.5 and 80.0% for patients at low, intermediate and high-risk (p = 0.004), and 92.5, 84.2 and 66.7% for patients with Gleason score ≤ 6, 7 and ≥ 8, respectively (p = 0.001). The actuarial 5-year overall survival (OS) rates were 97.9, 96.4 and 88.6% in the low, intermediate and high-risk groups, respectively, and at the cut-off, the disease-specific survival (DSS) rate of the whole cohort was high (99.1%), as only two high-risk patients died due to PCa.

CONCLUSION

Our present results of SBRT delivered with CyberKnife produced excellent long-term bRFS, OS and DSS outcomes among patients with localized PCa. We conclude that SBRT provides an efficient and convenient treatment option for patients with localized PCa, irrespective of the risk-group.

MRI targeted single fraction HDR Brachytherapy for localized Prostate Carcinoma: a feasibility study of focal radiation therapy (ProFocAL)

OBJECTIVES

The aim of the study was to establish the setup and workflow for delivering focal MRI-guided high-dose-rate (HDR) brachytherapy for prostate cancer (PCA) and to assess patient comfort and safety aspects of MRI-guided single-fraction HDR.

METHODS

Patients with histologically proven focal low- to intermediate-risk PCA with a single PIRADS 4/5 lesion were treated with percutaneous interstitial HDR brachytherapy in a single fraction with a minimum dose for the gross tumor volume of 20 Gy while sparing the organ at risk (OAR). Using a 3T-MRI, brachytherapy catheters were placed transgluteal in freehand technique. No antibiotic therapy or general analgesics were administered. Patient data, procedure time, patient discomfort, and complications were recorded. Quarterly PSA controls, biannual follow-up imaging, and annual re-biopsy were planned.

RESULTS

So far, 9 patients were successfully treated and followed for 6 months. Mean intervention time was 34 min. Using the VAS scale, the pain reported for the intervention ranged from 2 to 3. Short-term follow-up showed no acute genitourinary or gastrointestinal toxicity so far. None of the patients displayed signs of infection. PSA levels in all patients decreased significantly. On follow up no residual PCA was detected treated region so far. PSA levels in all patients decreased significantly. On follow-up, no residual PCA was detected so far.

CONCLUSIONS

MR-guided single-fraction focal HDR brachytherapy for localized PCA is feasible as well as safe for the individual patient. Catheters can be placed accurately and maximum therapeutic dose distribution can be restricted to the tumor. Countersigning the minimally invasive character of the procedure, no general anesthesia or antibiosis is necessary.

KEY POINTS

• MR-guided focal HDR brachytherapy allows an accurate placement of catheters with maximum therapeutic dose distribution restricted to the tumor. • No major anesthesia or antibiosis is necessary emphasizing the minimal invasive character of the procedure. • Patients with low- and intermediate-risk prostate carcinoma in particular may benefit to halt disease progression whereas treatment-related morbidity is reduced compared with radical therapy.

Single fraction high-dose-rate brachytherapy as monotherapy for low and intermediate risk prostate cancer: toxicities and early outcomes from a single institutional experience

Purpose

High-dose-rate brachytherapy (HDR-BT) delivered in a single fraction as monotherapy is a potential treatment modality for low- and intermediate-risk prostate cancer (LIR-PC); however, outcome data with this technique remain limited. Here we describe our institutional HDR monotherapy experience and report the efficacy and toxicity of this treatment.

Material and methods

LIR-PC patients who received a definitive single fraction HDR-BT during 2013-2017 were retrospectively identified. The intended HDR monotherapy dose was 19 Gy in one fraction. Acute (< 90 days) and late (≥ 90 days) toxicity was assessed using CTCAE version 4.03. Trends in prostate-specific antigen (PSA) and American Urological Association (AUA) symptom scores after treatment were assessed using Bayesian linear mixed models. The Kaplan-Meier method was used to evaluate biochemical failure-free survival (BFFS).

Results

28 patients with median follow-up of 23.6 months were identified. The median age at treatment was 65 years (48-83). The NCCN risk groups were low in 14, favorable intermediate in 10, and unfavorable intermediate in 4 patients. There were 5 (18%) and 0 (0%) acute grade 2 genitourinary (GU) and gastrointestinal (GI) toxicities, respectively, and one (4%) acute grade 3 GU toxicity. There were no late grade 3 toxicities, and 5 (18%) and 0 (0%) late grade 2 GU and GI toxicities respectively. PSA values and AUA symptom scores decreased significantly after treatment. There were 3 biochemical failures with the two- and three-year BFFS of 90.7% and 80.6%, respectively.

Conclusions

Early results from a single institution suggest that single fraction HDR-BT with 19 Gy has limited toxicity, although with suboptimal biochemical control.

Effect of Androgen Deprivation Therapy on Other-Cause of Mortality in Elderly Patients with Clinically Localized Prostate Cancer Treated with Modern Radiotherapy: Is There a Negative Impact?

The influence of androgen deprivation therapy (ADT) on other-cause of mortality (OCM) was investigated in patients with localized prostate cancer treated with modern high-dose radiotherapy. A retrospective review was conducted on 1125 patients with localized prostate cancer treated with high-dose radiotherapy, including image-guided, intensity-modulated radiotherapy or brachytherapy with a median follow-up of 80.7 months. Overall survival rate was no different between ADT (+) and ADT (−) group in high-, intermediate-, and low-risk groups. OCM was found in 71 patients, consisting of 4% (10/258) in the ADT (−) group and 7% (61/858) in the ADT (+) group (p = 0.0422). The 10-year OCM-free survival rate (OCMFS), if divided by the duration of ADT (ADT naïve (ADT (−)), ADT <2-year, and ADT ≥2-year groups), showed statistical significance, and was 90.7%, 88.2%, and 78.6% (p = 0.0039) for the ADT (−), ADT <2-year, and ADT ≥2-year groups, respectively. In patients aged ≥75 years, 10-year OCMFS for ADT (−), ADT <2-, and ADT ≥2-year groups was 93.5% (at 115.6 months), 85.6%, and 60.7% (p = 0.0189), respectively, whereas it was 90.7%, 89.9%, and 89.0% (p = 0.4716), respectively, in their younger counterparts. In localized prostate cancer patients, treatment with longer ADT for ≥2 years potentially increases the risk of OCM, especially in patients aged ≥75 years.

Development and dosimetric assessment of a patient-specific elastic skin applicator for high-dose-rate brachytherapy

PURPOSE

The purpose of this study was to develop a patient-specific elastic skin applicator and to evaluate its dosimetric characteristics for high-dose-rate (HDR) brachytherapy.

METHODS AND MATERIALS

We simulated the treatment of a nonmelanoma skin cancer on the nose. An elastic skin applicator was manufactured by pouring the Dragon Skin (Smooth-On Inc., Easton, PA) with a shore hardness of 10A into an applicator mold. The rigid skin applicator was printed using high-impact polystyrene with a shore hardness of 73D. HDR plans were generated using a Freiburg Flap (FF) applicator and patient-specific rigid and elastic applicators. For dosimetric assessment, dose-volumetric parameters for target volume and normal organs were evaluated. Global gamma evaluations were performed, comparing film measurements and treatment planning system calculations with various gamma criteria. The 10% low-dose threshold was applied.

RESULTS

The V_120% values of the target volume were 56.9%, 70.3%, and 70.2% for HDR plans using FF, rigid, and elastic applicators, respectively. The maximum doses of the right eyeball were 21.7 Gy, 20.5 Gy, and 20.5 Gy for the HDR plans using FF, rigid, and elastic applicators, respectively. The average gamma passing rates were 82.5% ± 1.5%, 91.6% ± 0.8%, and 94.8% ± 0.2% for FF, rigid, and elastic applicators, respectively, with 3%/3 mm criterion.

CONCLUSIONS

Patient-specific elastic skin applicator showed better adhesion to irregular or curved body surfaces, resulting in better agreement between planned and delivered dose distributions. The applicator suggested in this study can be effectively implemented clinically.

Lack of Apparent Survival Benefit With Use of Androgen Deprivation Therapy in Patients With High-risk Prostate Cancer Receiving Combined External Beam Radiation Therapy and Brachytherapy

PURPOSE

Although level 1 evidence has demonstrated a survival benefit from the addition of androgen deprivation therapy (ADT) to external beam radiation therapy (EBRT) for patients with high-risk prostate cancer, the benefits of ADT with combined EBRT and brachytherapy for high-risk patients are unclear. We examined the association between ADT and overall survival in a national cohort of high-risk patients treated with EBRT with or without brachytherapy.

METHODS AND MATERIALS

We identified 46,325 men in the National Cancer Database with a diagnosis of high-risk prostate cancer (Gleason score 8-10, clinical stage T3-T4, or prostate-specific antigen >20 ng/mL) who were treated with EBRT with or without brachytherapy and ADT from 2004 through 2011. Multivariable Cox regression analysis adjusting for sociodemographic and clinicopathologic factors was used to identify the association between ADT and overall survival.

RESULTS

The median follow-up period was 48.6 and 59.2 months for patients treated with EBRT only and combined modality RT, respectively. ADT was associated with an improvement in overall survival for the 85.0% (39,361) of the study cohort who underwent EBRT alone (adjusted hazard ratio 0.91, P=.001) but not for patients treated with combined modality RT (adjusted hazard ratio 1.05, P=.496), with a significant interaction (P_interaction=.036).

CONCLUSIONS

In contrast to the known survival benefit when ADT is given with EBRT, our results suggest that ADT might not improve survival for high-risk patients who undergo combined EBRT and brachytherapy. Given the significant adverse effects of ADT, in particular, with long-term therapy, a randomized controlled trial of combined EBRT and brachytherapy with or without ADT for select high-risk patients using a noninferiority design should be undertaken.

Combined high-dose rate brachytherapy (HDR-BT) and whole pelvic radiation therapy (WPRT) in node negative, intermediate- to high-risk localised prostate cancer: clinical outcomes and patient behaviours across ethnicities

Background

This retrospective study aimed to report clinical outcomes of high-dose rate brachytherapy (HDR-BT) and whole pelvic radiation therapy (WPRT) in intermediate- to high-risk localised prostate cancer and to gain a better understanding of how behavioural variability of patients from various ethnic origins affects clinical practice.

Materials and methods

In total, 116 localised intermediate- to high-risk prostate cancer patients who were treated during 2004–12 were enroled into the study. WPRT was delivered to the full pelvis (50 Gy per conventional fractionation) and two fractions (15 Gy per fraction) of high-dose rate brachytherapy were designed for all patients to the peripheral zone of McNeal. The reported results were biochemical control rate, toxicity profiles and behavioural variations of patients.

Results

The median follow-up time was 51 months. The 4-year biochemical control rates, according to the American Society for Therapeutic Radiology and Oncology was 93·1%. T stage was the prognostic factor for biochemical control. No significant differences in biochemical control could be identified across ethnic groups (p>0·05). Five patients developed grade 3–4 gastrointestinal toxicity. Prior knowledge was commonly found among Caucasian patients and urinary functions seemed to be more concerned among Caucasian and Middle East patients than those from other ethnic origins.

Conclusions

Clinical outcomes of intermediate- to high-risk prostate cancer patients from various ethnic origins were comparable with that of the Caucasian-only population reported previously. A number of detected ethnic-related factors might be beneficial for treatment decision-making for patients with different cultural background and could be utilised to better personalise/optimise cancer care and aftercare.

Intensity-Modulated Radiation Therapy with Stereotactic Body Radiation Therapy Boost for Unfavorable Prostate Cancer: A Report on 3-Year Toxicity

Background

Recent data suggest that intensity-modulated radiation therapy (IMRT) plus brachytherapy boost for unfavorable prostate cancer provides improved biochemical relapse-free survival over IMRT alone. Stereotactic body radiation therapy (SBRT) may be a less invasive alternative to brachytherapy boost. Here, we report the 3-year gastrointestinal (GI) and genitourinary (GU) toxicities of IMRT plus SBRT boost.

Materials and methods

Between March 2008 and September 2012, patients with prostate cancer were treated with robotic SBRT (19.5 Gy in three fractions) followed by fiducial-guided IMRT (45–50.4 Gy) on an institutional protocol. Toxicity was prospectively graded using the common terminology criteria for adverse events version 4.0 (CTCAEv.4) at the start of and at 1- to 6-month intervals after therapy. Rectal telangiectasias were graded using the Vienna Rectoscopy Score (VRS).

Results

At a median follow-up of 4.2 years (2.4–7.5), 108 patients (4 low-, 45 intermediate-, and 59 high-risk) with a median age of 74 years (55–92) were treated with SBRT plus IMRT, with 8% on anticoagulation and an additional 48% on antiplatelet therapy at the start of therapy. The cumulative incidence of late ≥grade 2 GI toxicity was 12%. Of these, 7% were due to late rectal bleeding, with six patients requiring up to two coagulation procedures. One patient with rectal telangiectasias was treated with hyperbaric oxygen (grade 3 toxicity). No rectal fistulas or stenoses were observed. Ten patients had multiple non-confluent telangiectasias (VRS grade 2), and three patients had multiple confluent telangiectasias (VRS grade 3). The cumulative incidence of late grade 3 GU toxicity was 6%. Most late toxicities were due to hematuria requiring bladder fulguration. There were no late ≥grade 4 GU toxicities.

Conclusion

Rates of clinically significant GI and GU toxicities are modest following IMRT plus SBRT boost. Future studies should compare cancer control, quality of life, and toxicity with other treatment modalities for patients with high-risk prostate cancer.

American Brachytherapy Society Task Group Report: Use of androgen deprivation therapy with prostate brachytherapy-A systematic literature review

PURPOSE

Prostate brachytherapy (PB) has well-documented excellent long-term outcomes in all risk groups. There are significant uncertainties regarding the role of androgen deprivation therapy (ADT) with brachytherapy. The purpose of this report was to review systemically the published literature and summarize present knowledge regarding the impact of ADT on biochemical progression-free survival (bPFS), cause-specific survival (CSS), and overall survival (OS).

METHODS AND MATERIALS

A literature search was conducted in Medline and Embase covering the years 1996-2016. Selected were articles with >100 patients, minimum followup 3 years, defined risk stratification, and directly examining the role and impact of ADT on bPFS, CSS, and OS. The studies were grouped to reflect disease risk stratification. We also reviewed the impact of ADT on OS, cardiovascular morbidity, mortality, and on-going brachytherapy randomized controlled trials (RCTs).

RESULTS

Fifty-two selected studies (43,303 patients) were included in this review; 7 high-dose rate and 45 low-dose rate; 25 studies were multi-institutional and 27 single institution (retrospective review or prospective data collection) and 2 were RCTs. The studies were heterogeneous in patient population, risk categories, risk factors, followup time, and treatment administered, including ADT administration and duration (median, 3-12 months);71% of the studies reported a lack of benefit, whereas 28% showed improvement in bPFS with addition of ADT to PB. The lack of benefit was seen in low-risk and favorable intermediate-risk (IR) disease and most high-dose rate studies. A bPFS benefit of up to 15% was seen with ADT use in patients with suboptimal dosimetry, those with multiple adverse risk factors (unfavorable IR [uIR]), and most high-risk (HR) studies. Four studies reported very small benefit to CSS (2%). None of the studies showed OS advantage; however, three studies reported an absolute 5-20% OS detriment with ADT. Literature suggests that OS detriment is more likely in older patients or those with pre-existing cardiovascular disease. Four RCTs with an adequate number of patients and well-defined risk stratification are in progress. One RCT will answer the question regarding the role of ADT with PB in favorable IR patients and the other three RCTs will focus on optimal duration of ADT in the uIR and favorable HR population.

CONCLUSIONS

Patients treated with brachytherapy have excellent long-term disease outcomes. Existing evidence shows no benefit of adding ADT to PB in low-risk and favorable IR patients. UIR and HR patients and those with suboptimal dosimetry may have up to 15% improvement in bPFS with addition of 3-12 months of ADT, with uncertain impact on CSS and a potential detriment on OS. To minimize morbidity, one should exercise caution in prescribing ADT together with PB, in particular to older men and those with existing cardiovascular disease. Due to the retrospective nature of this evidence, significant selection, and treatment bias, no definitive conclusions are possible. RCT is urgently needed to define the potential role and optimal duration of ADT in uIR and favorable HR disease.

American Brachytherapy Society Task Group Report: Combination of brachytherapy and external beam radiation for high-risk prostate cancer

PURPOSE

To review outcomes for high-risk prostate cancer treated with combined modality radiation therapy (CMRT) utilizing external beam radiation therapy (EBRT) with a brachytherapy boost.

METHODS AND MATERIALS

The available literature for high-risk prostate cancer treated with combined modality radiation therapy was reviewed and summarized.

RESULTS

At this time, the literature suggests that the majority of high-risk cancers are curable with multimodal treatment. Several large retrospective studies and three prospective randomized trials comparing CMRT to dose-escalated EBRT have demonstrated superior biochemical control with CMRT. Longer followup of the randomized trials will be required to determine if this will translate to a benefit in metastasis-free survival, disease-specific survival, and overall survival. Although greater toxicity has been associated with CMRT compared to EBRT, recent studies suggest that technological advances that allow better definition and sparing of critical adjacent structures as well as increasing experience with brachytherapy have improved implant quality and the toxicity profile of brachytherapy. The role of androgen deprivation therapy is well established in the external beam literature for high-risk disease, but there is controversy regarding the applicability of these data in the setting of dose escalation. At this time, there is not sufficient evidence for the omission of androgen deprivation therapy with dose escalation in this population. Comparisons with surgery remain limited by differences in patient selection, but the evidence would suggest better disease control with CMRT compared to surgery alone.

CONCLUSIONS

Due to a series of technological advances, modern combination series have demonstrated unparalleled rates of disease control in the high-risk population. Given the evidence from recent randomized trials, combination therapy may become the standard of care for high-risk cancers.

Two-fraction high-dose-rate brachytherapy within a single day combined with external beam radiotherapy for prostate cancer: single institution experience and outcomes

We investigated the outcomes of treatment for patients with localized prostate cancer (PCa) treated with 3D conformal radiation therapy (3D-CRT) followed by two-fraction high-dose-rate brachytherapy within a single day (2-fr.-HDR-BT/day) at a single institution. A total of 156 consecutive Asian males (median age, 67 years) were enrolled. To compare our findings with those of other studies, we analyzed our results using the D'Amico classification, assigning the patients to low- ( N =: 5; 3.2%), intermediate- ( N =: 36; 23.1%) and high-risk ( N =: 115; 73.7%) groups (Stage T3 PCa patients were classified as high-risk). One patient in the D'Amico low-risk group (20%), 13 intermediate-risk patients (36.1%) and 99 high-risk patients (86.1%) underwent androgen deprivation therapy. We administered a prescription dose of 39 Gy in 13 fractions of 3D-CRT combined with 18 Gy of HDR-BT in two 9-Gy fractions delivered within a single day. We did not distinguish between risk groups in determining the prescription dose. The median follow-up period was 38 months. Of the 156 patients, one died from primary disease and five died from other diseases. The 3-year overall survival (OS) rates were 100%, 100% and 93.7%, and the 3-year 'biochemical no evidence of disease (bNED)' rates were 100%, 100% and 96.9% for the D'Amico low-, intermediate- and high-risk groups, respectively. No patient developed ≥ Grade 3 early toxicity. The Grade 3 late genitourinary toxicity rate was 2.6%, and no ≥ Grade 3 late gastrointestinal toxicity occurred. The efficacy and safety of this study were satisfactory, and longer-term follow-up is necessary.

Intensity-Modulated Radiation Therapy with Stereotactic Body Radiation Therapy Boost for Unfavorable Prostate Cancer: The Georgetown University Experience

Purpose/objective(s)

Stereotactic body radiation therapy (SBRT) is emerging as a minimally invasive alternative to brachytherapy to deliver highly conformal, dose-­escalated radiation therapy (RT) to the prostate. SBRT alone may not adequately cover the tumor extensions outside the prostate commonly seen in unfavorable prostate cancer. External beam radiation therapy (EBRT) with high dose rate brachytherapy boost is a proven effective therapy for unfavorable prostate cancer. This study reports on early prostate-specific antigen and prostate cancer-specific quality of life (QOL) outcomes in a cohort of unfavorable patients treated with intensity-modulated radiation therapy (IMRT) and SBRT boost.

Materials/methods

Prostate cancer patients treated with SBRT (19.5 Gy in three fractions) followed by fiducial-guided IMRT (45–50.4 Gy) from March 2008 to September 2012 were included in this retrospective review of prospectively collected data. Biochemical failure was assessed using the Phoenix definition. Patients completed the expanded prostate cancer index composite (EPIC)-26 at baseline, 1 month after the completion of RT, every 3 months for the first year, then every 6 months for a minimum of 2 years.

Results

One hundred eight patients (4 low-, 45 intermediate-, and 59 high-risk) with median age of 74 years completed treatment, with median follow-up of 4.4 years. Sixty-four percent of the patients received androgen deprivation therapy prior to the initiation of RT. The 3-year actuarial biochemical control rates were 100 and 89.8% for intermediate- and high-risk patients, respectively. At the initiation of RT, 9 and 5% of men felt their urinary and bowel function was a moderate to big problem, respectively. Mean EPIC urinary and bowel function and bother scores exhibited transient declines, with subsequent return to near baseline. At 2 years posttreatment, 13.7 and 5% of men felt their urinary and bowel function was a moderate to big problem, respectively.

Conclusion

At 3-year follow-up, biochemical control was favorable. Acute urinary and bowel symptoms were comparable to conventionally fractionated IMRT and brachytherapy. Patients recovered to near their baseline urinary and bowel function by 2 years posttreatment. A combination of IMRT with SBRT boost is well tolerated with minimal impact on prostate cancer-specific QOL.

Prostate-specific antigen nadir after high-dose-rate brachytherapy predicts long-term survival outcomes in high-risk prostate cancer

PURPOSE

To evaluate the prognostic value of prostate-specific antigen nadir (nPSA) after high-dose-rate (HDR) brachytherapy in clinically non-metastatic high-risk prostate cancer patients.

MATERIAL AND METHODS

Data from 216 patients with high-risk or locally advanced prostate cancer who underwent HDR brachytherapy and external beam radiation therapy with long-term androgen deprivation therapy (ADT) between 2003 and 2008 were analyzed. The median prostate-specific antigen (PSA) level at diagnosis was 24 ng/ml (range: 3-338 ng/ml). The clinical stage was T1c-2a in 55 cases (26%), T2b-2c in 48 (22%), T3a in 75 (35%), and T3b-4 in 38 (17%). The mean dose to 90% of the planning target volume was 6.3 Gy/fraction of HDR brachytherapy. After 5 fractions, external beam radiation therapy with 10 fractions of 3 Gy was administered. All patients initially underwent neoadjuvant ADT for at least 6 months, and adjuvant ADT was continued for 36 months. The median follow-up was 7 years from the start of radiotherapy.

RESULTS

The 7-year PSA relapse-free rate among patients with a post-radiotherapy nPSA level of ≤ 0.02 ng/ml was 94%, compared with 23% for patients with higher nPSA values (HR = 28.57; 95% CI: 12.04-66.66; p < 0.001). Multivariate analysis revealed that the nPSA value after radiotherapy was a significant independent predictor of biochemical failure, whereas pretreatment predictive values for worse biochemical control including higher level of initial PSA, Gleason score ≥ 8, positive biopsy core rate ≥ 67%, and T3b-T4, failed to reach independent predictor status. The 7-year cancer-specific survival rate among patients with a post-radiotherapy nPSA level of ≤ 0.02 ng/ml was 99%, compared with 82% for patients with higher nPSA values (HR = 32.25; 95% CI: 3.401-333.3; p = 0.002).

CONCLUSIONS

A post-radiotherapy nPSA value of ≤ 0.02 ng/ml was associated with better long-term biochemical tumor control even if patients had pretreatment predictive values for worse control.

Portfolio of prospective clinical trials including brachytherapy: an analysis of the ClinicalTrials.gov database

Background

To evaluate the current status of prospective interventional clinical trials that includes brachytherapy (BT) procedures.

Methods

The records of 175,538 (100 %) clinical trials registered at ClinicalTrials.gov were downloaded on September 2014 and a database was established. Trials using BT as an intervention were identified for further analyses. The selected trials were manually categorized according to indication(s), BT source, applied dose rate, primary sponsor type, location, protocol initiator and funding source. We analyzed trials across 8 available trial protocol elements registered within the database.

Results

In total 245 clinical trials were identified, 147 with BT as primary investigated treatment modality and 98 that included BT as an optional treatment component or as part of the standard treatment. Academic centers were the most frequent protocol initiators in trials where BT was the primary investigational treatment modality (p < 0.01). High dose rate (HDR) BT was the most frequently investigated type of BT dose rate (46.3 %) followed by low dose rate (LDR) (42.0 %). Prostate was the most frequently investigated tumor entity in trials with BT as the primary treatment modality (40.1 %) followed by breast cancer (17.0 %). BT was rarely the primary investigated treatment modality for cervical cancer (6.8 %).

Conclusion

Most clinical trials using BT are predominantly in early phases, investigator-initiated and with low accrual numbers. Current investigational activities that include BT mainly focus on prostate and breast cancers. Important questions concerning the optimal usage of BT will not be answered in the near future.

Electronic supplementary material

The online version of this article (doi:10.1186/s13014-016-0624-8) contains supplementary material, which is available to authorized users.

High-dose-rate brachytherapy boost in prostate cancer: a New Zealand case series

Aim

The aim of the present study was to report the survival outcomes and late toxicity of high-dose-rate brachytherapy (HDRBT) boost for dose escalation in patients with intermediate-to-high-risk prostate cancer.

Materials and methods

Retrospective data were collected from 137 patients who had undergone definitive radiotherapy for prostate cancer between 2006 and 2010. All patients had external-beam radiotherapy (median dose 46Gy) and HDRBT. Brachytherapy dose was 19Gy in two fractions (6 hours apart) with one implant using Ir-192.

Results

There were 94 high-risk and 43 intermediate-risk patients (NCCN classification). The median follow-up period was 60 months. The 5-year biochemical progression-free survival was 92 and 76% for intermediate- and high-risk groups, respectively. Prostate cancer-specific survival for the intermediate-risk group was 100% and for the high-risk group it was 92% at 5 years. For the entire cohort, the 5-year rate of urethral stricture formation was 13%, and the 5-year rate of late grade 2 and grade 3 gastrointestinal toxicity was 4·7 and 4·6%, respectively. There was no grade 3 or greater genitourinary toxicity.

Findings

Our data add to the growing body of literature supporting the use of HDRBT in prostate cancer. Late toxicity rates were marginally higher than that expected.

Clinical outcomes of whole pelvis radiotherapy and stereotactic body radiotherapy boost for intermediate- and high-risk prostate cancer

AIM

We report our experience with Cyberknife to deliver hypofractionated stereotactic body radiotherapy (SBRT) boost combined with whole pelvis radiotherapy (WPRT) to patients with intermediate- to high-risk prostate cancer.

METHODS

From March 2008 to July 2014, 39 patients with newly diagnosed, intermediate- and high-risk (National Comprehensive Cancer Network definition) localized prostate cancer were treated with WPRT and SBRT boost. The whole pelvis dose was 45 Gy (25 fractions of 1.8 Gy) and the SBRT boost dose was 21 Gy (3 fractions of 7 Gy). No one received androgen deprivation therapy before biochemical relapse. The acute and late toxicities were recorded using the Radiation Therapy Oncology Group scale. Prostate-specific antigen (PSA) response was monitored.

RESULTS

Thirty-nine patients with a median 53.6 months (range 14-74 months) follow-up were analyzed. The median pretreatment PSA was 15.97 ng/mL. The estimated 5-year biochemical failure (BCF)-free survival was 94.7%. Two BCFs were observed in only high-risk group. The median PSA nadir was 0.30 ng/mL at median 36 months and PSA bounce occurred in 15.4% (n = 6) of patients at median 12 months. No grade 3 acute toxicity was noted. A total of 23% of the patients had grade 2 acute genitourinary (GU) toxicities and 21% had grade 2 acute gastrointestinal (GI) toxicities. At 2 months, most complications had returned to baseline. GU and GI toxicities were observed.

CONCLUSIONS

WPRT followed by SBRT boost using Cyberknife in intermediate- and high-risk prostate cancer is feasible with minimal toxicity and encouraging BCF-free survival.

Dose escalation with external beam radiation therapy and high-dose-rate brachytherapy combined with long-term androgen deprivation therapy in high and very high risk prostate cancer: Comparison of two consecutive high-dose-rate schemes

PURPOSE

To compare rectal toxicity, urinary toxicity, and nadir+2 PSA relapse-free survival (bRFS) in two consecutive Phase II protocols of high-dose-rate (HDR) brachytherapy used at the authors institution from 2001 to 2012.

METHODS AND MATERIALS

Patients with National Comprehensive Cancer Network high risk and very high risk prostate cancer enrolled in studies HDR4 (2001-2007, n = 183) and HDR2 (2007-2012, n = 56) were analyzed. Patients received minipelvis external beam radiation therapy/intensity-modulated external radiotherapy to 54 Gy and 2 years of androgen blockade along with HDR brachytherapy. HDR4 protocol consisted of four 4.75 Gy fractions delivered in 48 hours; the HDR2 protocol delivered two 9.5 Gy fractions in 24 hours. Average 2-Gy equivalent dose (α/β = 1.2) prostate D90 doses for the HDR4 and HDR2 groups were 89.8 Gy and 110.5 Gy, respectively (p = 0.0001). Both groups were well balanced regarding risk factors. Prior transurethral resection of the prostate was more frequent in the HDR2 group (p = 0.001).

RESULTS

After a median followup of 7.4 years (range, 2-11.2), there was no difference in adverse grade ≥ 2 rectal events (HDR4 = 10.4% vs. HDR2 = 12.5%; p = ns) or grade ≥3 (HDR4 = 2.2% vs. HDR2 = 3.6%; p = ns). No differences in urinary grade ≥2 adverse events (HDR4 = 23% vs. HDR2 = 26.8%; p = ns) or grade ≥3 (HDR4 = 7.7% vs. HDR2 = 8.9%; p = ns) were detected. The 7-year bRFS for HDR4 and HDR2 protocols was 88.7% and 87.8%, respectively (p = ns).

CONCLUSIONS

HDR4 and HDR2 protocols produce similar results in terms of toxicity and bRFS at the intermediate time point of 7 years.

High dose rate brachytherapy for prostate cancer: Standard of care and future direction

High dose rate brachytherapy is a highly conformal method of radiation dose escalation for prostate cancer and one of several treatment options for men with localised disease. The large doses per fraction exploit the low alpha/beta ratio of prostate cancer cells so that biological radiation dose delivered is substantially greater than that achieved with conventional external beam delivery. This review article presents contemporary data on the rationale for high dose rate brachytherapy including treatment technique and future directions.

Outcomes of hypofractionated stereotactic body radiotherapy boost for intermediate and high-risk prostate cancer

BACKGROUND AND PURPOSE

Treatment of intermediate and high-risk prostate cancer with a high BED has been shown to increase recurrence free survival (RFS). While high dose rate (HDR) brachytherapy, given as a boost is effective in delivering a high BED, many patients are not candidates for the procedure or wish to avoid an invasive procedure. We evaluated the use of stereotactic body radiotherapy (SBRT) as a boost, with dosimetry modeled after HDR-boost.

MATERIAL AND METHODS

Fifty patients were treated with two fractions of SBRT (9.5-10.5 Gy/fraction) after 45 Gy external-beam radiotherapy, with 48 eligible for analysis at a median follow-up of 42.7 months.

RESULTS

The Kaplan-Meier estimates of biochemical control post-radiation therapy (95 % Confidence Interval) at 3, 4 and 5 years were 95 % (81-99 %), 90 % (72-97 %) and 90 % (72-97 %), respectively (not counting 2 patients with a PSA bounce as failures). RFS (defined as disease recurrence or death) estimates at 3, 4 and 5 years were 92 % (77-97 %), 88 % (69-95 %) and 83 % (62-93 %) if patients with PSA bounces are not counted as failures, and were 90 % (75-96 %), 85 % (67-94 %) and 75 % (53-88 %) if they were. The median time to PSA nadir was 26.2 months (range 5.8-82.9 months), with a median PSA nadir of 0.05 ng/mL (range <0.01-1.99 ng/mL). 2 patients had a "benign PSA bounce", and 4 patients recurred with radiographic evidence of recurrence beyond the RT fields. Treatment was well tolerated with no acute G3 or higher GI or GU toxicity and only a single G3 late GU toxicity of urinary obstruction.

CONCLUSIONS

SBRT boost is well-tolerated for intermediate and high-risk prostate cancer patients with good biochemical outcomes and low toxicity.

Outcomes of T3a Prostate Cancer with Unfavorable Prognostic Factors Treated with Brachytherapy Combined with External Radiotherapy and Hormone Therapy

OBJECTIVE

To evaluate the outcomes of T3a prostate cancer with unfavorable prognostic factors treated with permanent interstitial brachytherapy combined with external radiotherapy and hormone therapy.

METHODS

From January 2003 to December 2008, 38 patients classified as T3a prostate cancer with unfavorable prognostic factors were treated with trimodality therapy (brachytherapy + external radiotherapy + hormone therapy). The prescription dose of brachytherapy and external radiotherapy were 110 Gy and 45 Gy, respectively. The duration of hormone therapy was 2-3 years. The endpoints of this study included biochemical failure-free survival (BFFS), distant metastasis-free survival (DMFS), cancer-specific survival (CSS), and overall survival (OS). Survival curves were calculated using the Kaplan-Meier method. The Log-rank test was used to identify the prognostic predictors for univariate analysis.

RESULTS

The median follow-up was 71 months. The serum pre-treatment prostate-specific antigen (PSA) level ranged from 10.0 to 99.8 ng/ml (mean 56.3 ng/ml), the Gleason score ranged from 5 to 9 (median 8), and the percentage of positive biopsy cores ranged from 10% to 100% (mean 65%). The 5-year BFFS, DMFS, CSS, and OS rates were 44%, 69%, 82%, and 76%, respectively. All biochemical failures occurred within 40 months. The percentage of positive biopsy cores was significantly correlated with BFFS, DMFS, and OS (all P=0.000), and the Gleason score with DMFS (P=0.000) and OS (P=0.001).

CONCLUSIONS

T3a prostate cancer with unfavorable prognostic factors presents not so optimistic outcome. Hormone therapy should be applied to prolong the biochemical progression-free or metastasis-free survival. The percentage of positive biopsy cores and the Gleason score are significant prognostic factors.

Dose-Escalated Robotic SBRT for Stage I-II Prostate Cancer

Stereotactic body radiotherapy (SBRT) is the precise external delivery of very high-dose radiotherapy to targets in the body, with treatment completed in one to five fractions. SBRT should be an ideal approach for organ-confined prostate cancer because (I) dose-escalation should yield improved rates of cancer control; (II) the unique radiobiology of prostate cancer favors hypofractionation; and (III) the conformal nature of SBRT minimizes high-dose radiation delivery to immediately adjacent organs, potentially reducing complications. This approach is also more convenient for patients, and is cheaper than intensity-modulated radiotherapy (IMRT). Several external beam platforms are capable of delivering SBRT for early-stage prostate cancer, although most of the mature reported series have employed a robotic non-coplanar platform (i.e., CyberKnife). Several large studies report 5-year biochemical relapse rates which compare favorably to IMRT. Rates of late GU toxicity are similar to those seen with IMRT, and rates of late rectal toxicity may be less than with IMRT and low-dose rate brachytherapy. Patient-reported quality of life (QOL) outcomes appear similar to IMRT in the urinary domain. Bowel QOL may be less adversely affected by SBRT than with other radiation modalities. After 5 years of follow-up, SBRT delivered on a robotic platform is yielding outcomes at least as favorable as IMRT, and may be considered appropriate therapy for stage I–II prostate cancer.

Systematic review and meta-analysis of the survival outcomes of first-line treatment options in high-risk prostate cancer

Prostate cancer (PCa) is the most common non-dermatologic cancer in the western countries in western countries. High-risk PCa accounts for 15% of the diagnosed cases. In this study, we compare the long-term survival outcomes of radical prostatectomy (RP), radiation therapy (RT), brachytherapy (BT), androgen- deprivation therapy (ADT), and watchful waiting (WW) in high-risk prostate cancer (PCa). Overall, RP/(RT plus ADT) gave the best survival outcome in patients with high-risk PCa, whereas ADT/WW had the worst outcome. The overall priority for treatment strategy could be ranked as follows: RP/(RT plus ADT), RT, and ADT/WW. RP had significant better overall survival (OS) than RT or BT, and RP had significant lower cancer-specific mortality (CSM) than RT (0.51 [95% CI 0.30–0.73], P<0.001). ADT improved the cancer-specific survival (CSS) of RP based on a case-controlled study; added ADT to RT failed to challenge the position of RP but could improve the outcome of RT. In conclusions,RP/(RT plus adjuvant ADT) could both be used for the first-line therapy of high-risk PCa. When encountering an individual patient, urologists should consider various factors like tumors themselves, preferences of individuals, and so on.

Clinical management and burden of prostate cancer: a Markov Monte Carlo model

Background

Prostate cancer (PCa) is the most common non-skin cancer among men in developed countries. Several novel treatments have been adopted by healthcare systems to manage PCa. Most of the observational studies and randomized trials on PCa have concurrently evaluated fewer treatments over short follow-up. Further, preceding decision analytic models on PCa management have not evaluated various contemporary management options. Therefore, a contemporary decision analytic model was necessary to address limitations to the literature by synthesizing the evidence on novel treatments thereby forecasting short and long-term clinical outcomes.

Objectives

To develop and validate a Markov Monte Carlo model for the contemporary clinical management of PCa, and to assess the clinical burden of the disease from diagnosis to end-of-life.

Methods

A Markov Monte Carlo model was developed to simulate the management of PCa in men 65 years and older from diagnosis to end-of-life. Health states modeled were: risk at diagnosis, active surveillance, active treatment, PCa recurrence, PCa recurrence free, metastatic castrate resistant prostate cancer, overall and PCa death. Treatment trajectories were based on state transition probabilities derived from the literature. Validation and sensitivity analyses assessed the accuracy and robustness of model predicted outcomes.

Results

Validation indicated model predicted rates were comparable to observed rates in the published literature. The simulated distribution of clinical outcomes for the base case was consistent with sensitivity analyses. Predicted rate of clinical outcomes and mortality varied across risk groups. Life expectancy and health adjusted life expectancy predicted for the simulated cohort was 20.9 years (95%CI 20.5–21.3) and 18.2 years (95% CI 17.9–18.5), respectively.

Conclusion

Study findings indicated contemporary management strategies improved survival and quality of life in patients with PCa. This model could be used to compare long-term outcomes and life expectancy conferred of PCa management paradigms.

Dosimetric analysis of urethral strictures following HDR (192)Ir brachytherapy as monotherapy for intermediate- and high-risk prostate cancer

BACKGROUND AND PURPOSE

To evaluate dosimetric parameters related to urethral strictures following high dose-rate brachytherapy (HDRBT) alone for prostate cancer.

MATERIAL AND METHODS

Ten strictures were identified in 213 patients treated with HDRBT alone receiving 34Gy in four fractions, 36Gy in four fractions, 31.5Gy in 3 fractions or 26Gy in 2 fractions. A matched-pair analysis used 2 controls for each case matched for dose fractionation schedule, pre-treatment IPSS score, number of needles used and clinical target volume. The urethra was divided into membranous urethra and inferior, mid and superior thirds of the prostatic urethra.

RESULTS

Stricture rates were 3% in the 34Gy group, 4% in the 36Gy group, 6% in the 31.5Gy group and 4% in the 26Gy group. The median time to stricture formation was 26months (range 8-40). The dosimetric parameters investigated were not statistically different between cases and controls. No correlation was seen between stricture rate and fractionation schedule.

CONCLUSIONS

Urethral stricture is an infrequent complication of prostate HDRBT when used to deliver high doses as sole treatment, with an overall incidence in this cohort of 10/213 (4.7%). In a matched pair analysis no association with dose schedule or urethral dosimetry was identified, but the small number of events limits definitive conclusions.

Comparison of IPSA and HIPO inverse planning optimization algorithms for prostate HDR brachytherapy

Publications have reported the benefits of using high‐dose‐rate brachytherapy (HDRB) for the treatment of prostate cancer, since it provides similar biochemical control as other treatments while showing lowest long‐term complications to the organs at risk (OAR). With the inclusion of anatomy‐based inverse planning optimizers, HDRB has the advantage of potentially allowing dose escalation. Among the algorithms used, the Inverse Planning Simulated Annealing (IPSA) optimizer is widely employed since it provides adequate dose coverage, minimizing dose to the OAR, but it is known to generate large dwell times in particular positions of the catheter. As an alternative, the Hybrid Inverse treatment Planning Optimization (HIPO) algorithm was recently implemented in Oncentra Brachytherapy V. 4.3. The aim of this work was to compare, with the aid of radiobiological models, plans obtained with IPSA and HIPO to assess their use in our clinical practice. Thirty patients were calculated with IPSA and HIPO to achieve our department's clinical constraints. To evaluate their performance, dosimetric data were collected: Prostate PTV D90(%),V100(%),V150(%), and V200(%), Urethra D10(%), Rectum D2cc(%), and conformity indices. Additionally tumor control probability (TCP) and normal tissue complication probability (NTCP) were calculated with the BioSuite software. The HIPO optimization was performed firstly with Prostate PTV (HIPOPTV) and then with Urethra as priority 1 (HIPOurethra). Initial optimization constraints were then modified to see the effects on dosimetric parameters, TCPs, and NTCPs. HIPO optimizations could reduce TCPs up to 10%–20% for all PTVs lower than 74 cm³. For the urethra, IPSA and HIPOurethra provided similar NTCPs for the majority of volume sizes, whereas HIPOPTV resulted in large NTCP values. These findings were in agreement with dosimetric values. By increasing the PTV maximum dose constraints for HIPOurethra plans, TCPs were found to be in agreement with IPSA without affecting the urethral NTCPs.

PACS numbers: 87.55.‐x, 87.55.de, 87.55.dh, 87.53.Jw

The early result of whole pelvic radiotherapy and stereotactic body radiotherapy boost for high-risk localized prostate cancer

Purpose: The rationale for hypofractionated radiotherapy in the treatment of prostate cancer is based on the modern understanding of radiobiology and advances in stereotactic body radiotherapy (SBRT) techniques. Whole-pelvis irradiation combined with SBRT boost for high-risk prostate cancer might escalate biologically effective dose without increasing toxicity. Here, we report our 4-year results of SBRT boost for high-risk localized prostate cancer.

Methods and Materials: From October 2009 to August 2012, 41 patients newly diagnosed, high-risk or very high-risk (NCCN definition) localized prostate cancer were treated with whole-pelvis irradiation and SBRT boost. The whole pelvis dose was 45 Gy (25 fractions of 1.8 Gy). The SBRT boost dose was 21 Gy (three fractions of 7 Gy). Ninety percent of these patients received hormone therapy. The toxicities of gastrointestinal (GI) and genitourinary (GU) tracts were scored by Common Toxicity Criteria Adverse Effect (CTCAE v3.0). Biochemical failure was defined by Phoenix definition.

Results: Median follow-up was 42 months. Mean PSA before treatment was 44.18 ng/ml. Mean PSA level at 3, 6, 12, 18, and 24 months was 0.94, 0.44, 0.13, 0.12, and 0.05 ng/ml, respectively. The estimated 4-year biochemical failure-free survival was 91.9%. Three biochemical failures were observed. GI and GU tract toxicities were minimal. No grade 3 acute GU or GI toxicity was noted. During radiation therapy, 27% of the patient had grade 2 acute GU toxicity and 12% had grade 2 acute GI toxicity. At 3 months, most toxicity scores had returned to baseline. At the last follow-up, there was no grade 3 late GU or GI toxicity.

Conclusions: Whole-pelvis irradiation combined with SBRT boost for high-risk localized prostate cancer is feasible with minimal toxicity and encouraging biochemical failure-free survival. Continued accrual and follow-up would be necessary to confirm the biochemical control rate and the toxicity profiles.

Stereotactic body radiotherapy as treatment for organ confined low- and intermediate-risk prostate carcinoma, a 7-year study

OBJECTIVES

Stereotactic body radiation therapy (SBRT) takes advantage of the prostate's low α/β ratio to deliver a large radiation dose in few fractions. Initial studies on small groups of low-risk patients support SBRT's potential for clinical efficacy while limiting treatment-related morbidity and maintained quality of life. This prospective study expands upon prior studies to further evaluate SBRT efficacy for a large patient population with organ confined, low- and intermediate-risk prostate cancer patients.

METHODS

Four hundred seventy-seven patients with prostate cancer received CyberKnife SBRT. The median age was 68.6 years and the median PSA was 5.3 ng/mL. Three hundred twenty-four patients were low-risk (PSA <10 ng/mL and Gleason <7), 153 were intermediate-risk (PSA 10-20 ng/mL or Gleason = 7). Androgen deprivation therapy was administered to 51 patients for up to 6 months. One hundred fifty-four patients received 35 Gy delivered in five daily fractions; the remaining patients received a total dose of 36.25 Gy in five daily fractions. Biochemical failure was assessed using the phoenix criterion.

RESULTS

Median follow-up was 72 months. The median PSA at 7 years was 0.11 ng/mL. Biochemical failures occurred for 11 low-risk patients (2 locally), 14 intermediate-risk patients (3 locally). The actuarial 7-year freedom from biochemical failure was 95.6 and 89.6% for low- and intermediate-risk groups, respectively (p < 0.012). Among patients with intermediate-risk disease, those considered to have low intermediate-risk (Gleason 6 with PSA >10, or Gleason 3 + 4 with PSA <10; n = 106) had a significantly higher bDFS than patients with high intermediate-risk (Gleason 3 + 4 with PSA 10-20 or Gleason 4 + 3; n = 47), with bDFS of 93.5 vs. 79.3%, respectively. For the low-risk and low intermediate-risk groups, there was no difference in median PSA nadir or biochemical disease control between doses of 35 and 36.25 Gy.

CONCLUSION

CyberKnife SBRT produces excellent biochemical control rates. Median PSA levels compare favorably with other radiation modalities and strongly suggest durability of response. These results also strongly suggest that 35 Gy is as effective as 36.25 Gy for low- and intermediate-risk patients.

[What is the level of evidence of new techniques in prostate cancer radiotherapy?]

Prostate cancer radiotherapy has evolved from the old 2D technique to conformal, and then to intensity-modulated radiation therapy (IMRT) and stereotactic radiotherapy. At the same time, image-guidance (IGRT) is routinely used. New techniques such as protontherapy or carbontherapy are being developed with the objective of increased efficacy, decreased treatment duration, toxicity or cost. This review summarizes the evidence-based medicine of new technologies in the treatment of prostate cancer.

High-dose-rate brachytherapy and hypofractionated external beam radiotherapy combined with long-term hormonal therapy for high-risk and very high-risk prostate cancer: outcomes after 5-year follow-up

The purpose of this study was to report the outcomes of high-dose-rate (HDR) brachytherapy and hypofractionated external beam radiotherapy (EBRT) combined with long-term androgen deprivation therapy (ADT) for National Comprehensive Cancer Network (NCCN) criteria-defined high-risk (HR) and very high-risk (VHR) prostate cancer. Data from 178 HR (n = 96, 54%) and VHR (n = 82, 46%) prostate cancer patients who underwent (192)Ir-HDR brachytherapy and hypofractionated EBRT with long-term ADT between 2003 and 2008 were retrospectively analyzed. The mean dose to 90% of the planning target volume was 6.3 Gy/fraction of HDR brachytherapy. After five fractions of HDR treatment, EBRT with 10 fractions of 3 Gy was administered. All patients initially underwent ≥ 6 months of neoadjuvant ADT, and adjuvant ADT was continued for 36 months after EBRT. The median follow-up was 61 months (range, 25-94 months) from the start of radiotherapy. The 5-year biochemical non-evidence of disease, freedom from clinical failure and overall survival rates were 90.6% (HR, 97.8%; VHR, 81.9%), 95.2% (HR, 97.7%; VHR, 92.1%), and 96.9% (HR, 100%; VHR, 93.3%), respectively. The highest Radiation Therapy Oncology Group-defined late genitourinary toxicities were Grade 2 in 7.3% of patients and Grade 3 in 9.6%. The highest late gastrointestinal toxicities were Grade 2 in 2.8% of patients and Grade 3 in 0%. Although the 5-year outcome of this tri-modality approach seems favorable, further follow-up is necessary to validate clinical and survival advantages of this intensive approach compared with the standard EBRT approach.