The 15-year outcomes of high-dose-rate brachytherapy for radical dose escalation in patients with prostate cancer—A benchmark for high-tech external beam radiotherapy alone?

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

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

Two-Weekly High-Dose-Rate Brachytherapy Boost After External Beam Radiotherapy for Localized Prostate Cancer: Long-Term Outcome and Toxicity Analysis

Purpose

Evaluation of clinical outcome of two-weekly high-dose-rate brachytherapy boost after external beam radiotherapy (EBRT) for localized prostate cancer.

Methods

338 patients with localized prostate cancer receiving definitive EBRT followed by a two-weekly high-dose-rate brachytherapy boost (HDR-BT boost) in the period of 2002 to 2019 were analyzed. EBRT, delivered in 46 Gy (D_Mean) in conventional fractionation, was followed by two fractions HDR-BT boost with 9 Gy (D_90%) two and four weeks after EBRT. Androgen deprivation therapy (ADT) was added in 176 (52.1%) patients. Genitourinary (GU)/gastrointestinal (GI) toxicity was evaluated utilizing the Common Toxicity Criteria for Adverse Events (version 5.0) and biochemical failure was defined according to the Phoenix definition.

Results

Median follow-up was 101.8 months. 15 (4.4%)/115 (34.0%)/208 (61.5%) patients had low-/intermediate-/high-risk cancer according to the D`Amico risk classification. Estimated 5-year and 10-year biochemical relapse-free survival (bRFS) was 84.7% and 75.9% for all patients. The estimated 5-year bRFS was 93.3%, 93.4% and 79.5% for low-, intermediate- and high-risk disease, respectively. The estimated 10-year freedom from distant metastasis (FFM) and overall survival (OS) rates were 86.5% and 70.0%. Cumulative 5-year late GU toxicity and late GI toxicity grade ≥ 2 was observed in 19.3% and 5.0% of the patients, respectively. Cumulative 5-year late grade 3 GU/GI toxicity occurred in 3.6%/0.3%.

Conclusions

Two-weekly HDR-BT boost after EBRT for localized prostate cancer showed an excellent toxicity profile with low GU/GI toxicity rates and effective long-term biochemical control.

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.

ACR-ABS-ASTRO practice parameter for the performance of radionuclide-based high-dose-rate brachytherapy

PURPOSE

This practice parameter aims to detail the processes, qualifications of personnel, patient selection, equipment, patient and personnel safety, documentation, and quality control and improvement necessary for an HDR brachytherapy program.

METHODS AND MATERIALS

This practice parameter was revised collaboratively by the American College of Radiology (ACR), the American Brachytherapy Society (ABS), and the American Society for Radiation Oncology (ASTRO).

RESULTS

Brachytherapy is a radiotherapeutic modality in which radionuclide or electronic sources are used to deliver a radiation dose at a distance of up to a few centimeters by surface, intracavitary, intraluminal, or interstitial application. Brachytherapy alone or combined with external beam radiotherapy plays an important role in the management and treatment of patients with cancer. High-dose-rate (HDR) brachytherapy uses radionuclides, such as iridium-192, at dose rates of ≥12 Gy/hr to a designated target point or volume, and it is an important treatment for a variety of malignant and benign conditions. Its use allows for application of high doses of radiation to defined target volumes with relative sparing of adjacent critical structures.

CONCLUSIONS

HDR brachytherapy requires detailed attention to personnel, equipment, patient and personnel safety, and continuing staff education. Coordination between the radiation oncologist and treatment planning staff and effective quality assurance procedures are important components of successful HDR brachytherapy programs.

Reduction of toxicity in brachytherapy using a new technique

PURPOSE

The purpose of the study was to elucidate the usefulness of a dose evaluation method for reducing late genitourinary (GU) toxicity in high-dose-rate brachytherapy (HDR-BT) of prostate cancer.

METHODS AND MATERIALS

GU toxicity was scored in accordance with the Common Terminology Criteria for Adverse Events version 4.0. The prostatic urethra was divided into three segments (base = B, midgland = M, apex = A), which were subclassified into seven subgroups (B, M, A, BM, BA, MA, BMA) using a D_10% color map of the urethra. Significance testing was conducted on urethral D_0.1% and D_10% among the seven subgroups. Grade < 2 GU toxicity was also implemented.

RESULTS

Data of 174 patients with localized prostate cancer treated with HDR-BT combined with external beam radiotherapy between November 2011 and July 2014 were analyzed retrospectively. Median age was 74 (53-84) years, and median followup period was 44 (6-69) months. The number of Grade < 2 and Grade ≥ 2 toxicity was significantly different in the M subgroup than in the other subgroups (p < 0.05), suggesting increased radioresistance in the midgland urethra.

CONCLUSIONS

A high-dose-area evaluation method using a urethral D_10% color map may be helpful in reducing late GU toxicity in HDR-BT for prostate cancer.

High-dose-rate brachytherapy as monotherapy for localized prostate cancer using three different doses - 14 years of single-centre experience

Purpose

To evaluate clinical outcomes in patients with localized prostate cancer (LPC) treated with 3D conformal high-dose-rate (HDR) brachytherapy (BT) as monotherapy.

Material and methods

From March 2004 to November 2017, 277 men with LPC underwent 3D conformal HDR-BT as monotherapy, with a temporary implant. The dose prescription was: 38 Gy in 4 fractions (149 patients), 27 Gy in 2 fractions (41 patients), and 19-20 Gy in a single fraction (87 patients). Biochemical progression-free survival (bPFS), progression-free survival (PFS), and cancer-specific survival (CSS) were calculated. Acute and late genitourinary (GU) and gastrointestinal (GI) toxicity assessment were performed using Common Terminology Criteria for Adverse Events v5.0.

Results

The mean age was 67 (range, 47-81) years. Overall, 145 patients were low-risk, 116 intermediate-risk, and 16 high-risk prostate cancer. After a median follow-up of six years (range, 6-160 months), bPFS, PFS, and CSS were 81%, 96%, and 97%, respectively. Dose prescription, initial prostate specific antigen (iPSA) ≥ 9,5 ng/ml, and high-risk disease resulted in prognostic factors regarding bPFS. Only G2-G3 acute or late GI and GU toxicities were observed.

Conclusions

HDR-BT as monotherapy is a valid and safe treatment modality for localized prostate cancer. After a long follow-up, patients receiving 19-20 Gy in a single fraction had a lower biochemical control rate compared to patients receiving 38 Gy in 4 fractions or 27 Gy in 2 fractions. Randomized prospective trials with a longer follow-up are necessary to confirm our results, and define total doses and dose per fraction for HDR-BT in patients with LPC.

Brachytherapy in Belgium in 2018. A national survey of the brachytherapy study group of the Belgian SocieTy for Radiotherapy and Oncology (BeSTRO)

PURPOSE

To explore the current practices patterns and evaluate the actual brachytherapy (BT) resources in Belgium.

MATERIAL AND METHODS

In 2019, the Brachytherapy Study Group proposed to conduct a survey on behalf of the Belgian SocieTy of Radiation Oncology (BeSTRO) in order to identify current BT practice patterns. An electronic questionnaire was sent to all primary radiotherapy centers in Belgium. This questionnaire was based on the questionnaire that was used by the Italian Association of Radiation Oncology (AIRO) in 2016, asking for: (a) General information on the Radiation Oncology Centre; (b) BT equipment and human resources; (c) BT procedures; (d) BT assessment (number of patients treated annually, treated sites, and different modalities of treatments).

RESULTS

All 24 radiation oncology centers (100% response rate) answered the questionnaire and gave also information on the performance of brachytherapy in their (eventual) satellite centers. Eighteen (18) BT afterloader units were installed and operational in 2018. Thirteen centers mentioned a prostate seed implant program, one center a prostate and eye plaque program and one center only an eye plaque program. Less than 50% of centers have the infrastructure to offer the full-range of BT in their own department. In 2018, 1486 patients received a BT-treatment, 28% of them were treated by prostate seed implant, 8% were treated by eye-(seed) BT and 64% by high dose rate (HDR)/pulsed dose rate (PDR) BT. Forty-five percent of HDR/PDR patients were treated by vaginal dome BT, 22% by intra-uterine BT, 11% by skin BT, 10% by breast BT (almost exclusively in one centre), 8% for benign pathology (keloid) and the remaining 4% were treated for prostate (as a boost or as salvage in one centre), anal, penile, lung or oesophageal cancer.

CONCLUSIONS

Belgian radiotherapy departments often perform BT only in a (highly) selected group of pathologies, resulting in a limited number of patients treated by this technique despite the sufficient availability of BT equipment. Modern indications are often not covered, hence patients do not have regular access to recognized treatment options, possibly leading to inferior oncological outcome. BeSTRO will use the results of this survey to stimulate improvements in training, awareness, education, implementation, collaboration and cooperation in the field of brachytherapy.

Building a High-Dose-Rate Prostate Brachytherapy Program With Real-Time Ultrasound-Based Planning: Initial Safety, Quality, and Outcome Results

Purpose

Growing evidence supports the efficacy and safety of high-dose-rate (HDR) brachytherapy as a boost or monotherapy in prostate cancer treatment. We initiated a new HDR prostate brachytherapy practice in April 2014. Here, we report the learning experiences, short-term safety, quality, and outcome.

Methods and Materials

From April 2014 to December 2017, 164 men were treated with HDR brachytherapy with curative intent. Twenty-eight men (17.1%) underwent HDR brachytherapy as monotherapy, receiving 25 to 27 Gy in 2 fractions. Men treated with HDR brachytherapy as a boost received 19 to 21 Gy in 2 fractions. Fifty-two men (31.7%) had high-risk disease. HDR procedure times, dosimetry, and response were recorded and analyzed. Genitourinary (GU) and gastrointestinal (GI) toxicities were recorded according to the toxicity criteria of the Radiation Therapy Oncology Group.

Results

Mean HDR procedure times decreased yearly from 179 minutes in 2014 to 115 minutes in 2017. Median follow-up was 18.6 months (range, 3-55 months). At last review, 79% of patients reported returning to baseline GU status, and 100% of patients noted no change in GI status from their baseline. Four patients experienced acute urinary retention. Treatment planning target volume (PTV) was defined as prostate with margins. Dosimetrically, 97.5% of all HDR implants had PTV D90 ≥100%, 81.5% had PTV V100 ≥95%, 73.6% had maximal urethral doses ≤120%, and 77.5% had rectal 1 mL dose ≤70% (all but one ≤10.8 Gy). The estimated 3-year overall survival was 98.7% (95% confidence interval, 91.4%-99.8%), and disease-free survival was 96.2% (95% confidence interval, 89.5%-98.7%).

Conclusions

The low incidence of GU and GI complications in our cohort demonstrates that a HDR brachytherapy program can be successfully developed as a treatment option for patients with localized prostate cancer.

Health-related quality of life and rates of toxicity after high-dose-rate brachytherapy in combination with external beam radiation therapy for high-risk prostate cancer

Purpose

High-dose-rate brachytherapy (HDR-BT) with external beam radiation therapy (EBRT) is a common treatment option for locally advanced prostate cancer. Quality of life is an important factor when discussing therapy options for high-risk prostate cancer. This study evaluated adverse effects and health-related quality of life (HRQOL).

Materials and Methods

Ninety male patients (median age, 71 years; range, 50 to 79 years) with high-risk prostate cancer underwent HDR-BT after EBRT between December 2009 and January 2017 with a median follow-up of 43 months. A total of 57 patients (69.5%) answered the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life of Cancer Patients questionnaire (QLQ-C30; ver. 3.0), and 8 patients died during follow-up. In order to put the results of this study in context, we compared the results with reference data from the EORTC QLQ-C30 Scoring Manual. Correlations of prostate-specific antigen (PSA) values, International Prostate Symptom Score, and HRQOL measures were calculated.

Results

The study participants reported better physical functioning and better global health compared with the reference data, but worse social, role, and cognitive functioning. We found negative statistically significant correlations between the last-measured PSA value and social functioning (p>0.01), cognitive functioning, pain, and constipation (all p<0.05). Toxicity rates were 10.0% for gastrointestinal and 12.2% for genitourinary adverse effects. All reported complications for toxicity were Grade I.

Conclusions

The described therapy results in high biochemical control rates with minimal adverse effects. Compared with reference groups, the HRQOL of this study cohort was acceptable. PSA values during follow-up seem to be a possible indicator to influence HRQOL.

High Dose Rate Brachytherapy in High-Risk Localised Disease - Why Do Anything Else?

The management of high-risk prostate cancer is challenging, as patients have a high risk of both local and distant relapse. Although adjuvant systemic treatment remains an important component of management, for those receiving radiotherapy, optimal local treatment should include a brachytherapy boost. This may be given by low dose rate (LDR) or high dose rate (HDR) techniques, but HDR has several advantages over LDR by virtue of more consistent dose optimisation, ability to treat outside the prostate and lower toxicity. A significant body of evidence now supports the use of HDR brachytherapy in addition to supplementary pelvic external beam radiotherapy for men with high-risk disease. Consistent evidence has emerged from randomised clinical trials, meta-analyses, and from institutional and multicentre cohort studies. It has been shown to improve local disease control and possibly reduce metastases and improve cancer-specific survival compared with external beam radiotherapy alone. It should be considered as standard treatment.

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.

Radical dose escalation by high-dose-rate brachytherapy for localized prostate cancer-Significance of prostate-specific antigen nadir level within 18 months as correlation for long-term biochemical control

PURPOSE

High-dose-rate brachytherapy (HDR-BT) for dose escalation in localized prostate cancer has been established as one standard treatment option. However, long-term results at followup (FU) ≥5 years are usually needed to ensure robustness of reported outcomes. Potential benefit of salvage therapy is, nevertheless, higher when relapse is diagnosed early. This study aimed to solve this dilemma by evaluating the prostate-specific antigen (PSA) nadir for early prediction of long-term biochemical control.

METHODS AND MATERIALS

Combined pelvis-external beam radiation/HDR-BT boost to EQD2 >100 Gy (α/β = 3) was performed in 459 consecutively treated patients. These patients with an FU ≥ 24 months were analyzed and stratified in PSA nadir (nPSA)-groups by PSA nadir within 18 months after radiotherapy (nPSA18). Kaplan-Meier/log-rank tests and Cox-regression models were used to compare the study endpoints.

RESULTS

The mean FU was 77 months. A PSA nadir within 18 months (nPSA18) <0.5 ng/mL was achieved in 222 patients with median time to reach nPSA18 of 7 months. The 5-year American Society of Therapeutic Radiology and Oncology (ASTRO) biochemical control (prostate-specific antigen disease-free survival) for the nPSA18 group <0.5 ng/mL was 89% and for the group ≥ 0.5 ng/mL, it was 78.6% (p = 0.011). nPSA18 was an independent predictor of cancer-specific survival, distant metastasis-free survival, and biochemical control (ASTRO) (p = 0.026, p = 0.020, and p = 0.01, respectively).

CONCLUSIONS

The present results suggest that the PSA nadir level within 18 months after radiotherapy may serve as an early parameter for long-term biochemical control according to ASTRO definitions following radical dose escalation by HDR-BT for prostate cancer. Excellent outcomes were associated with nPSA18 < 0.5 ng/mL.

High dose-rate brachytherapy in the treatment of prostate cancer

High dose-rate (HDR) brachytherapy involves delivery of a high dose of radiation to the cancer with great sparing of surrounding organs at risk. Prostate cancer is thought to be particularly sensitive to radiation delivered at high dose-rate or at high dose per fraction. The rapid delivery and high conformality of dose results in lower toxicity than that seen with low dose-rate (LDR) implants. HDR combined with external beam radiotherapy results in higher cancer control rate than external beam only, and should be offered to eligible high and intermediate risk patients. While a variety of dose and fractionations have been used, a single 15 Gy HDR combined with 40-50 Gy external beam radiotherapy results in a disease-free survival of over 90% for intermediate risk and 80% for high risk. HDR monotherapy in two or more fractions (e.g., 27 Gy in 2 fractions or 34.5 Gy in 3) is emerging as a viable alternative to LDR brachytherapy for low and low-intermediate risk patients, and has less toxicity. The role of single fraction monotherapy to a dose of 19-20 Gy is evolving, with some conflicting data to date. HDR should also be considered as a salvage approach for recurrent disease following previous external beam radiotherapy. A particular advantage of HDR in this setting is the ease of delivering focal treatments, which combined with modern imaging allows focal dose escalation with minimal toxicity. Trans-rectal ultrasound (TRUS) based planning is replacing CT-based planning as the technique of choice as it minimizes or eliminates the need to move the patient between insertion, planning and treatment delivery, thus ensuring high accuracy and reproducibility of treatment.

Salvage high-dose-rate brachytherapy for prostate cancer persistence after brachytherapy: repeated use of a polyethylene glycol hydrogel spacer

Purpose

The aim of this study is to determine if a repeated hydrogel injection in a previously irradiated patient prior to salvage high-dose-rate brachytherapy (HDR-BT) is feasible.

Material and methods

A 61-year-old man with an organ confined (cT1c cN0 cM0, Gleason score 3 + 3 = 6, initial prostate-specific antigen [PSA] 7.9 ng/ml) prostate cancer was previously treated with HDR-BT (3 fractions of 11.5 Gy every 2^nd week) after hydrogel injection to reduce the rectal dose. Ten months after, an isolated local persistence was seen on a PSMA PET-CT. Nadir PSA was 2.0 ng/ml, 3 months after treatment and was 3.95 ng/ml by the re-treatment. Salvage therapy consisted of HDR-BT (3 fractions of 9 Gy every 2^nd week) with a simultaneous integrated boost to the residual region. Again, a hydrogel injection (10 ml) was applied to reduce the rectal dose prior to the treatment.

Results

Both hydrogel injection and salvage HDR-BT could be applied without any significant complications or toxicity. A good PSA response was observed with a nadir of 0.42 ng/ml, twelve months after salvage therapy. Acute toxicity (max grade II) resolved within 2 days after treatment.

Conclusions

The use of a hydrogel prior to salvage HDR-BT in a patient previously treated with HDR-BT is feasible and could help reduce the rectal exposure in the salvage setting.

The American College of Radiology and the American Brachytherapy Society practice parameter for the performance of radionuclide-based high-dose-rate brachytherapy

Brachytherapy is a radiation therapy method in which radionuclide sources are used to deliver a radiation dose at a distance of up to a few centimeters by surface, intracavitary, intraluminal, or interstitial application. This practice parameter refers only to the use of radionuclides for brachytherapy. Brachytherapy alone or combined with external beam therapy plays an important role in the management and treatment of patients with cancer. High-dose-rate (HDR) brachytherapy uses radionuclides such as iridium-192 at dose rates of 20 cGy per minute (12 Gy per hour) or more to a designated target point or volume. High-dose-rate (HDR) brachytherapy is indicated for treating malignant or benign tumors where the treatment volume or targeted points are defined and accessible.

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.

Prostate Specific Antigen (PSA) as Predicting Marker for Clinical Outcome and Evaluation of Early Toxicity Rate after High-Dose Rate Brachytherapy (HDR-BT) in Combination with Additional External Beam Radiation Therapy (EBRT) for High Risk Prostate Cancer

High-dose-rate brachytherapy (HDR-BT) with external beam radiation therapy (EBRT) is a common treatment option for locally advanced prostate cancer (PCa). Seventy-nine male patients (median age 71 years, range 50 to 79) with high-risk PCa underwent HDR-BT following EBRT between December 2009 and January 2016 with a median follow-up of 21 months. HDR-BT was administered in two treatment sessions (one week interval) with 9 Gy per fraction using a planning system and the Ir192 treatment unit GammaMed Plus iX. EBRT was performed with CT-based 3D-conformal treatment planning with a total dose administration of 50.4 Gy with 1.8 Gy per fraction and five fractions per week. Follow-up for all patients was organized one, three, and five years after radiation therapy to evaluate early and late toxicity side effects, metastases, local recurrence, and prostate-specific antigen (PSA) value measured in ng/mL. The evaluated data included age, PSA at time of diagnosis, PSA density, BMI (body mass index), Gleason score, D'Amico risk classification for PCa, digital rectal examination (DRE), PSA value after one/three/five year(s) follow-up (FU), time of follow-up, TNM classification, prostate volume, and early toxicity rates. Early toxicity rates were 8.86% for gastrointestinal, and 6.33% for genitourinary side effects. Of all treated patients, 84.81% had no side effects. All reported complications in early toxicity were grade 1. PSA density at time of diagnosis (p = 0.009), PSA on date of first HDR-BT (p = 0.033), and PSA on date of first follow-up after one year (p = 0.025) have statistical significance on a higher risk to get a local recurrence during follow-up. HDR-BT in combination with additional EBRT in the presented design for high-risk PCa results in high biochemical control rates with minimal side-effects. PSA is a negative predictive biomarker for local recurrence during follow-up. A longer follow-up is needed to assess long-term outcome and toxicities.

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.

High-dose-rate brachytherapy boost for prostate cancer: rationale and technique

High-dose-rate brachytherapy (HDR) is a method of conformal dose escalation to the prostate. It can be used as a local boost in combination with external beam radiotherapy, with a high degree of efficacy and low rate of long term toxicity. Data consistently reports relapse free survival rates of greater than 90% for intermediate risk patients and greater than 80% for high risk. Results are superior to those achieved with external beam radiotherapy alone. A wide range of dose and fractionation is reported, however, we have found that a single 15 Gy HDR combined with hypofractionated radiotherapy to a dose of 37.5 Gy in 15 fractions is well tolerated and is associated with a long term relapse-free survival of over 90%. Either CT-based or trans-rectal ultrasound-based planning may be used. The latter enables treatment delivery without having to move the patient with risk of catheter displacement. We have found it to be an efficient and quick method of treatment, allowing catheter insertion, planning, and treatment delivery to be completed in less than 90 minutes. High-dose-rate boost should be considered the treatment of choice for many men with high and intermediate risk prostate cancer.