Conventional versus hypofractionated high-dose intensity-modulated radiotherapy for prostate cancer: preliminary safety results from the CHHiP randomised controlled trial

Validation of a Metastatic Assay using biopsies to improve risk stratification in patients with prostate cancer treated with radical radiation therapy

Background

Radiotherapy is an effective treatment of intermediate/high-risk locally advanced prostate cancer, however, >30% of patients relapse within 5 years. Clinicopathological parameters currently fail to identify patients prone to systemic relapse and those whom treatment intensification may be beneficial. The purpose of this study was to independently validate the performance of a 70-gene Metastatic Assay in a cohort of diagnostic biopsies from patients treated with radical radiotherapy and androgen deprivation therapy.

Patients and methods

A bridging cohort of prostate cancer diagnostic biopsy specimens was profiled to enable optimization of the Metastatic Assay threshold before further independent clinical validation in a cohort of diagnostic biopsies from patients treated with radical radiotherapy and androgen deprivation therapy. Multivariable Cox proportional hazard regression analysis was used to assess assay performance in predicting biochemical failure-free survival (BFFS) and metastasis-free survival (MFS).

Results

Gene expression analysis was carried out in 248 patients from the independent validation cohort and the Metastatic Assay applied. Ten-year MFS was 72% for Metastatic Assay positive patients and 94% for Metastatic Assay negative patients [HR = 3.21 (1.35–7.67); P = 0.003]. On multivariable analysis the Metastatic Assay remained predictive for development of distant metastases [HR = 2.71 (1.11–6.63); P = 0.030]. The assay retained independent prognostic performance for MFS when assessed with the Cancer of the Prostate Assessment Score (CAPRA) [HR = 3.23 (1.22–8.59); P = 0.019] whilst CAPRA itself was not significant [HR = 1.88, (0.52–6.77); P = 0.332]. A high concordance [100% (61.5–100)] for the assay result was noted between two separate foci taken from 11 tumours, whilst Gleason score had low concordance.

Conclusions

The Metastatic Assay demonstrated significant prognostic performance in patients treated with radical radiotherapy both alone and independent of standard clinical and pathological variables. The Metastatic Assay could have clinical utility when deciding upon treatment intensification in high-risk patients. Genomic and clinical data are available as a public resource.

Linac-based stereotactic body radiation therapy vs moderate hypofractionated radiotherapy in prostate cancer: propensity-score based comparison of outcome and toxicity

OBJECTIVE

Prostate cancer represents the second most common malignancy in the world and majority of patients have diagnosis of localized disease. The aim of the present study was to compare two cohorts of patients treated with moderate hypofractionation (MHRT) or stereotactic body radiation therapy (SBRT).

METHODS

We included patients treated between 2010 and 2015. Inclusion criteria were: adenocarcinoma of the prostate; class risks low or intermediate; WHO performance status 0-2. We evaluated rectal, gastrointestinal toxicity and genitourinary. Measures of outcome were biochemical disease-free survival and overall survival. Propensity score was used to approximate the balance in covariates.

RESULTS

209 patients were included, treated with MHRT (n = 109) or SBRT (n = 100). Median follow-up time was 37.4 months. Rates of biochemical disease-free survival at 1- and 3 years were 100 and 95%, respectively. There was no significant difference between the two groups (p = 0.868). Rates of overall survival at 1- and 3 years were 100 and 97.1%, respectively with no differences between the two groups (p = 0.312). After propensity scoring matching, no differences were observed in terms of acute and late rectal and gastrointestinal toxicity. While mild genitourinary side-effects were more common in SBRT group (45.5% vs 19.5 %), Grade 2 and 3 toxicity was increased after MHRT (11.7% vs 2.6 %; p = 0.029).

CONCLUSIONS

Moderate hypofractionation and SBRT are two effective and safe options for the treatment of low- and intermediate-risk prostate cancer. The analysis showed no difference in terms of disease's control and survival but increased moderate and severe toxicity after MHRT.

ADVANCES IN KNOWLEDGE

Moderate hypofractionation and SBRT are comparable in terms of efficacy while moderate and severe toxicity is more common in the first one.

Toxicity and Patient-Reported Outcomes of a Phase 2 Randomized Trial of Prostate and Pelvic Lymph Node Versus Prostate only Radiotherapy in Advanced Localised Prostate Cancer (PIVOTAL)

PURPOSE

To establish the toxicity profile of high-dose pelvic lymph node intensity-modulated radiation therapy (IMRT) and to assess whether it is safely deliverable at multiple centers.

METHODS AND MATERIALS

In this phase 2 noncomparative multicenter trial, 124 patients with locally advanced, high-risk prostate cancer were randomized between prostate-only IMRT (PO) (74 Gy/37 fractions) and prostate and pelvic lymph node IMRT (P&P; 74 Gy/37 fractions to prostate, 60 Gy/37 fractions to pelvis). The primary endpoint was acute lower gastrointestinal (GI) Radiation Therapy Oncology Group (RTOG) toxicity at week 18, aiming to exclude a grade 2 or greater (G2+) toxicity-free rate of 80% in the P&P group. Key secondary endpoints included patient-reported outcomes and late toxicity.

RESULTS

One hundred twenty-four participants were randomized (62 PO, 62 P&P) from May 2011 to March 2013. Median follow-up was 37.6 months (interquartile range [IQR], 35.4-38.9 months). Participants had a median age of 69 years (IQR, 64-74 years) and median diagnostic prostate-specific androgen level of 21.6 ng/mL (IQR, 11.8-35.1 ng/mL). At week 18, G2+ lower GI toxicity-free rates were 59 of 61 (96.7%; 90% confidence interval [CI], 90.0-99.4) for the PO group and 59 of 62 (95.2%; 90% CI, 88.0-98.7) for the P&P group. Patients in both groups reported similarly low Inflammatory Bowel Disease Questionnaire symptoms and Vaizey incontinence scores. The largest difference occurred at week 6 with 4 of 61 (7%) and 16 of 61 (26%) PO and P&P patients, respectively, experiencing G2+ toxicity. At 2 years, the cumulative proportion of RTOG G2+ GI toxicity was 16.9% (95% CI, 8.9%-30.9%) for the PO group and 24.0% (95% CI, 8.4%-57.9%) for the P&P group; in addition, RTOG G2+ bladder toxicity was 5.1% (95% CI, 1.7%-14.9%) for the PO group and 5.6% (95% CI, 1.8%-16.7%) for the P&P group.

CONCLUSIONS

PIVOTAL demonstrated that high-dose pelvic lymph node IMRT can be delivered at multiple centers with a modest side effect profile. Although safety data from the present study are encouraging, the impact of P&P IMRT on disease control remains to be established.

Localization accuracy of two electromagnetic tracking systems in prostate cancer radiotherapy: A comparison with fiducial marker based kilovoltage imaging

The aim of this study was to evaluate the localization accuracy of electromagnetic (EM) tracking systems RayPilot (Micropos Medical AB) and Calypso (Varian Medical Systems) in prostate cancer radiotherapy. The accuracy was assessed by comparing couch shifts obtained with the EM methods to the couch shifts determined by simultaneous fiducial marker (FM) based orthogonal kilovoltage (kV) imaging. Agreement between the methods was compared using Bland-Altman analysis. Interfractional positional stability of the FMs, RayPilot transmitters and Calypso transponders was investigated. 582 fractions from 22 RayPilot patients and 335 fractions from 26 Calypso patients were analyzed. Mean (± standard deviation (SD)) differences between RayPilot and kV imaging were 0.3 ± 2.2, -2.2 ± 2.4 and -0.0 ± 1.0 mm in anterior-posterior (AP), superior-inferior (SI) and left-right (LR) directions, respectively. Corresponding 95% limits of agreement (LOA) were ±4.3, ±4.7 and ±2.1 mm around the mean. Mean (±SD) differences between Calypso and kV imaging were -0.2 ± 0.6, 0.1 ± 0.5 and -0.1 ± 0.4 mm in AP, SI and LR directions, respectively, and corresponding LOAs were ±1.3, ±1.0 and ±0.8 mm around the mean. FMs and transponders were stable: SD of intermarker and intertransponder distances was 0.5 mm. Transmitters were unstable: mean caudal transmitter shift of 1.8 ± 2.0 mm was observed. Results indicate that the localization accuracy of the Calypso is comparable to kV imaging of fiducials and the methods could be used interchangeably. The localization accuracy of the RayPilot is affected by transmitter instability and the positioning of the patient should be verified by other setup techniques. The study is part of clinical trial NCT02319239.

Changes in prostate apparent diffusion coefficient values during radiotherapy after neoadjuvant hormones

Background

Changes in prostate cancer apparent diffusion coefficient (ADC) derived from diffusion-weighted magnetic resonance imaging (MRI) provide a noninvasive method for assessing radiotherapy response. This may be attenuated by neoadjuvant hormone therapy (NA-HT). We investigate ADC values measured before, during and after external beam radiotherapy (EBRT) following NA-HT.

Methods

Patients with ⩾T2c biopsy-proven prostate cancer receiving 3 months of NA-HT plus definitive radiotherapy were prospectively identified. All underwent ADC-MRI scans in the week before EBRT, in the third week of EBRT and 8 weeks after its completion. Imaging was performed at 1.5 T. The tumour, peripheral zone (PZ) and central zone (CZ) of the prostate gland were identified and median ADC calculated for each region and time point.

Results

Between September and December 2014, 15 patients were enrolled (median age 68.3, range 57-78) with a median Gleason score of 7 (6-9) and prostate-specific antigen (PSA) at diagnosis 14 (3-197) ng/ml. Median period of NA-HT prior to first imaging was 96 days (69-115). All patients completed treatment. Median follow up was 25 months (7-34), with one patient relapsing in this time. Thirteen patients completed all imaging as intended, one withdrew after one scan and another missed the final imaging. PZ and CZ could not be identified in one patient. Median tumour ADC before, during and post radiotherapy was 1.24 × 10^-3 mm²/s (interquartile range 0.16 × 10^-3 mm²/s), 1.31 × 10^-3 mm²/s (0.22 × 10^-3 mm²/s), then 1.32 × 10^-3 mm²/s (0.13 × 10^-3 mm²/s) respectively (p > 0.05). There was no significant difference between median tumour and PZ or CZ ADC at any point. Gleason score did not correlate with ADC values.

Conclusions

Differences in ADC parameters of normal and malignant tissue during EBRT appear attenuated by prior NA-HT. The use of changes in ADC as a predictive tool in this group may have limited utility.

Phase II Trial of Pure Hypofractionated Radiotherapy in the Treatment of Localized Carcinoma of the Prostate

Purpose To evaluate acute and late genitourinary (GU) and gastrointestinal (GI) toxicity and the biochemical control of pure hypofractionated radiotherapy (without acceleration) for the treatment of prostate cancer. Methods and materials This phase II prospective trial evaluated low-risk and intermediate-risk prostate cancer patients who received hypofractionated radiotherapy. Fifty-three patients with low-risk prostate cancer received 50 Gy in 15 fractions, 156 patients with intermediate-risk prostate cancer received 60 Gy in 20 fractions over eight weeks. Acute toxicity and late toxicity were graded per the Radiation Therapy Oncology Group (RTOG) toxicity scales and the Phoenix Definition (nadir plus two) defined biochemical failure. Results Median follow-up was 6.5 years. Acute phase grade 2/3 toxicity was 6%/0 and 8%/2% for GI and GU symptoms, respectively, and one grade 4 acute GU toxicity (0.5%). Late grade 2/3 GI and GU toxicity were 7%/0 and 8%/0.5%, respectively. There were no late grade 4 toxicities. The five-year freedom-from-biochemical-failure (FFBF) rates were 85% for low-risk patients and 80% for intermediate-risk patients. Conclusions Pure hypofractionation seems to be associated with low toxicity rates and biochemical control rates that are similar or better than those observed with accelerated hypofractionated or conventionally fractionated therapy.

Genitourinary and gastrointestinal toxicity among patients with localized prostate cancer treated with conventional versus moderately hypofractionated radiation therapy: systematic review and meta-analysis

BACKGROUND

Hypofractionated (HRT) prostate radiation therapy has the potential to deliver a higher biologically effective dose over a shorter time compared with conventional fractionation (CRT). HRT, giving fewer fractions each with higher dose, might improve the therapeutic ratio, resource use and patient convenience but the toxicity is still controversial. Our objective was to compare the gastroinstestinal (GI) and genitourinary (GU) toxicity of HRT versus CRT.

METHODS

Systematic review and meta-analysis of randomized clinical trials studies in PubMed, Cochrane and EMBASE databases published through December 2016 was done. Only randomized trials that evaluated patients with localized prostate cancer (PCa) undergoing CRT or HRT were included. In these studies, the daily dose was 1.8 Gy or 2 Gy per day for CRT and 2.4 to 3.4 Gy for HRT.

RESULTS

7317 patients in nine studies were analyzed. Six studies included acute GU toxicity data which showed similar rates for both HRT and CRT (32.6vs. 31.9%; RD 0.00; 95% CI; -0.03,0.03; p = .81; I² = 0%). Similarly, seven studies showed no difference in late GU toxicity based on treatment schedule (28.7 vs. 28.0%; RD -0.01; 95% CI; -0.04,0.03; p = .67; I² = 52%). GI toxicity at three months after radiotherapy was higher in patients treated with HRT in six studies (27.5 vs. 21.9%; RD 0.06; 95% CI; 0.02,0.10; p = .004; I² = 39%); however, eight studies showed GI toxicity 12 months or more after radiotherapy that was statistically the same (12.9 HRT vs. 16.2% CRT; RD -0.01; 95% CI; -0.04,0.02; p = .41; I² = 58%).

CONCLUSION

In meta-analysis of the available randomized trials on moderate HRT versus CRT for prostate cancer, acute and late GU toxicity were similar for both treatment schemes. While HRT was associated with higher acute GI toxicity, late toxicity was similar.

Acute toxicity and quality of life in high risk prostate cancer patients: Updated results of randomized hypofractionation trial

Purpose

The aim of our study was to perform the final analysis of acute toxicity and quality of life data obtained from 221 consecutive patients who suffered from intermediate-to-high risk prostate cancer.

Methods

In this trial, 221 patients were randomized to receive either hypofractionated (63 Gy in 20 fractions, 4 fractions/week) or conventionally fractionated (76 Gy in 38 fractions, 5 fractions/week) radiotherapy to the prostate and seminal vesicles. Elective pelvic lymph node irradiation with 46 Gy in 23 fractions sequentially and 44 Gy in 20 fractions simultaneously was also applied.

Results

There was no statistically significant difference in acute GU and GI toxicity in men treated with hypofractionated (SIB) (Arm 2) in comparison with patients who had conventional fractionation (Arm 1) radiation therapy. Multivariate analysis using logistic regression showed statistical significant association between acute GU ≥ 1 and PTV(LN) (p = 0.008) only. We found out that clinically relevant decrease (CRD) was significantly higher only in the urinary domain of Arm 1 at month 3 (p = 0.02).

Conclusion

Our study demonstrated that hypofractionated radiotherapy was associated with a small but insignificant increase of acute toxicity. The reduction of overall treatment time has no significant influence on patients' QOL in any domain.

Intensity-modulated radiotherapy for prostate cancer

Radiation therapy (RT) is a curative treatment modality for localized prostate cancer. Over the past two decades, advances in technology and imaging have considerably changed RT in prostate cancer treatment. Treatment has evolved from 2-dimensional (2D) planning using X-ray fields based on pelvic bony landmarks to 3-dimensional (3D) conformal RT (CRT) which uses computed tomography (CT) based planning. Despite improvements with 3D-CRT, dose distributions often remained suboptimal with portions of the rectum and bladder receiving unacceptably high doses. In more recent years, intensity-modulated radiation therapy (IMRT) has become the standard of care to deliver external beam RT. IMRT uses multiple radiation beams of different shapes and intensities delivered from a wide range of angles to ‘paint’ the radiation dose onto the tumor. IMRT allows for a higher dose of radiation to be delivered to the prostate while reducing dose to surrounding organs. Multiple clinical trials have demonstrated improved cancer outcomes with dose escalation, but toxicities using 3D-CRT and escalated doses have been problematic. IMRT is a method to deliver dose escalated RT with more conformal dose distributions than 3D-CRT and has been associated with improved toxicity profiles. IMRT also appears to be the safest method to deliver hypofractionated RT and pelvic lymph node radiation. The purpose of this review is to summarize the technical aspects of IMRT planning and delivery, and to review the literature supporting the use of IMRT for prostate cancer.

Moderate hypofractionated radiotherapy is more effective and safe for localized prostate cancer patients: a meta-analysis

To compare the efficacy and safety of moderate hypofractionated radiotherapy (H-RT) with those of conventional radiotherapy (C-RT) in patients with localized prostate cancer, we conducted extensive literature searches of The Web of Science, Embase, Pubmed and Cochrane Library databases. We identified nine studies with 5969 patients for a meta-analysis. We calculated pooled risk ratios (RRs) and the 95% confidence intervals (CIs) for multiple parameters and performed statistical analysis using RevMan 5.3 software. Our analysis showed that the H-RT group obtained greater improvements in the 5-year biochemical or clinical failure-free survival (RR = 1.04, 95% CI:1.01–1.08; P = 0.01) and 5-year disease-free survival(RR = 1.04, 95% CI: 1.01–1.07, P = 0.02)than the C-RT group. However, the 5-year overall survival rates were comparable in the two groups (RR = 1.02, 95% CI: 0.99–1.04; P = 0.18). Comparison of multiple secondary parameters, including grade 2-4 acute/late gastrointestinal toxicity, grade 2–4 acute/late genitourinary toxicity, biochemical failure, local failure, distant failure and prostate cancer-specific mortality between the H-RT and the C-RT groups showed no statistical differences. This meta-analysis thus indicates that in patients with localized prostate cancer, moderate H-RT exerts a great beneficial effect on the primary parameters than C-RT without enhancing adverse events.

Prostate cancer as a paradigm of multidisciplinary approach? Highlights from the Italian young radiation oncologist meeting

Aims and background

The diagnostic and therapeutic approach to prostate cancer has evolved rapidly in last decades. Young professionals need an update about these recent developments in order to improve the care of patients treated in their daily clinical practice.

Methods

On May 18, 2013, AIRO Giovani (the young section of the Italian Association of Radiation Oncology) organized a multidisciplinary meeting involving, as speakers, several young physicians from many parts of Italy actively involved in the diagnostic and therapeutic approach to prostate cancer. The meeting was specifically addressed to young physicians (radio-oncologists, urologists, medical oncologists) and presented the state-of-the-art of the diagnostic/therapeutic approach based on the latest evidence on the issue. Highlights of the congress are summarized and presented in this report.

Results

The large participation in the meeting (more than 120 participants were present) confirmed the interest of young radiation oncologists in improving their skills in prostate cancer management. The contributions of the speakers confirmed the need for regular updates, considering the promising results of recently published studies and the many new ongoing trials, on the diagnostic and therapeutic approaches to prostate cancer.

Conclusions

Multidisciplinary meetings are helpful to improve the skills of young professionals.

A Noninvasive Body Setup Method for Radiotherapy by Using a Multimodal Image Fusion Technique

Purpose:

To minimize the mismatch error between patient surface and immobilization system for tumor location by a noninvasive patient setup method.

Materials and Methods:

The method, based on a point set registration, proposes a shift for patient positioning by integrating information of the computed tomography scans and that of optical surface landmarks. An evaluation of the method included 3 areas: (1) a validation on a phantom by estimating 100 known mismatch errors between patient surface and immobilization system. (2) Five patients with pelvic tumors were considered. The tumor location errors of the method were measured using the difference between the proposal shift of cone-beam computed tomography and that of our method. (3) The collected setup data from the evaluation of patients were compared with the published performance data of other 2 similar systems.

Results:

The phantom verification results showed that the method was capable of estimating mismatch error between patient surface and immobilization system in a precision of <0.22 mm. For the pelvic tumor, the method had an average tumor location error of 1.303, 2.602, and 1.684 mm in left–right, anterior–posterior, and superior–inferior directions, respectively. The performance comparison with other 2 similar systems suggested that the method had a better positioning accuracy for pelvic tumor location.

Conclusion:

By effectively decreasing an interfraction uncertainty source (mismatch error between patient surface and immobilization system) in radiotherapy, the method can improve patient positioning precision for pelvic tumor.

Standard whole prostate gland radiotherapy with and without lesion boost in prostate cancer: Toxicity in the FLAME randomized controlled trial

PURPOSE

To compare toxicity rates in patients with localized prostate cancer treated with standard fractionated external beam radiotherapy (EBRT) with or without an additional integrated boost to the macroscopically visible tumour.

MATERIAL AND METHODS

FLAME is a phase 3 multicentre RCT (NCT01168479) of patients with pathologically confirmed localized intermediate or high-risk prostate cancer. The standard treatment arm (n = 287) received a dose to the entire prostate of 77 Gy in 35 fractions. The dose-escalated treatment arm (n = 284) received 77 Gy in 35 fractions to the entire prostate, with an integrated boost up to 95 Gy to the multi-parametric MRI-defined (macroscopic) tumour within the prostate. Treatment related toxicity was measured using the CTCAE version 3.0. Grade 2 or worse GU or GI events up to two years were compared between groups by presenting proportions and by Generalized Estimating Equations (GEE) analyses for repeated measures.

RESULTS

Ninety percent of the 571 men randomly assigned between September 2009 and January 2015 had high-risk disease (Ash 2000), of whom nearly 66% were prescribed hormonal therapy up to three years. Median follow-up was 55 months at the time of this analysis. Toxicity prevalence rates for both GI and GU increased until the end of treatment and regressed thereafter, with no obvious differences across treatment groups. Late cumulative GI toxicity rates were 11.1% and 10.2% for the standard and dose-escalated group, respectively. These rates were 22.6% and 27.1% for GU toxicity. GEE analyses showed that both GU toxicity and GI toxicity (≥grade 2) up to two years after treatment were similar between arms (OR 1.02 95%CI 0.78-1.33p = 0.81 and (OR 1.19 95%CI 0.82-1.73p = 0.38), respectively.

CONCLUSIONS

In intermediate- and high-risk prostate cancer patients, focal dose escalation integrated with standard EBRT did not result in an increase in GU and GI toxicity when compared to the standard treatment up to two years after treatment. This suggests that the described focal dose escalation technique is safe and feasible.

Comparison of forward- and back-projection in vivo EPID dosimetry for VMAT treatment of the prostate

In the forward-projection method of portal dosimetry for volumetric modulated arc therapy (VMAT), the integrated signal at the electronic portal imaging device (EPID) is predicted at the time of treatment planning, against which the measured integrated image is compared. In the back-projection method, the measured signal at each gantry angle is back-projected through the patient CT scan to give a measure of total dose to the patient. This study aims to investigate the practical agreement between the two types of EPID dosimetry for prostate radiotherapy. The AutoBeam treatment planning system produced VMAT plans together with corresponding predicted portal images, and a total of 46 sets of gantry-resolved portal images were acquired in 13 patients using an iViewGT portal imager. For the forward-projection method, each acquisition of gantry-resolved images was combined into a single integrated image and compared with the predicted image. For the back-projection method, iViewDose was used to calculate the dose distribution in the patient for comparison with the planned dose. A gamma index for 3% and 3 mm was used for both methods. The results were investigated by delivering the same plans to a phantom and repeating some of the deliveries with deliberately introduced errors. The strongest agreement between forward- and back-projection methods is seen in the isocentric intensity/dose difference, with moderate agreement in the mean gamma. The strongest correlation is observed within a given patient, with less correlation between patients, the latter representing the accuracy of prediction of the two methods. The error study shows that each of the two methods has its own distinct sensitivity to errors, but that overall the response is similar. The forward- and back-projection EPID dosimetry methods show moderate agreement in this series of prostate VMAT patients, indicating that both methods can contribute to the verification of dose delivered to the patient.

Outcomes and toxicity from a prospective study of moderately hypofractionated radiation therapy for prostate cancer

Purpose

The purpose of this study is to report the long-term outcomes and toxicity results of a prospective trial of moderately hypofractionated, image guided radiation therapy (RT) for localized prostate cancer.

Methods and materials

Patients were enrolled between December 2006 and February 2012. Patients in group 1 were stage T1-T2b, had a Gleason score (GS) of 2 to 6 or 7 (3 + 4) with only 1 lobe involved, and had prostate-specific antigen levels ≤10 ng/mL. Group 2 patients were stage ≥T2c, had a GS ≥7 (4 + 3), a GS 7 (3 + 4) involving both lobes, or a PSA >10 ng/mL and ≤30 ng/mL. All patients underwent transrectal ultrasound guided fiducial (Visicoil) placement prior to computed tomography/magnetic resonance imaging simulation. Daily cone beam computed tomography with online correction was used. The prescribed dose was 64 Gy in 20 fractions. The primary endpoint was acute and late toxicity. The secondary endpoint was biochemical control.

Results

A total of 40 patients with a median age of 70 years were recruited for the study. Twenty-two patients (55%) were in group 1, and 18 patients (45%) were in group 2. Thirteen patients (32.5%) were classified as low, 26 patients (65%) as intermediate, and 1 patient (2.5%) as high risk per the National Comprehensive Cancer Network criteria. The median follow-up time was 59 months. Five-year biochemical control was 100% and 94.4% for groups 1 and 2, respectively. Thirteen patients (32.5%) developed acute gastrointestinal (GI) toxicities grade ≥2 and 3 (7.5%) developed acute grade 3 GI toxicity. A total of 17 patients (42.5%) developed grade ≥2 acute genitourinary toxicities and 1 (2.5%) developed acute grade 3 dysuria. Two patients (5%) developed late GI toxicities grade ≥2. There was 1 case (2.5%) of grade 4 fistula requiring sigmoid resection. Seven patients (17.5%) developed grade ≥2 late genitourinary toxicities; 2 patients (5%) late grade 3 urinary frequency/urgency.

Conclusions

Moderately hypofractionated RT is effective with favorable toxicity and biochemical control, providing further evidence that increasing daily fractional dose can be safely and effectively delivered with contemporary RT techniques.

4 Weeks Versus 5 Weeks of Hypofractionated High-dose Radiation Therapy as Primary Therapy for Prostate Cancer: Interim Safety Analysis of a Randomized Phase 3 Trial

PURPOSE

Hypofractionated radiation therapy (HFRT) for localized prostate cancer is safe and effective. The question that remains is which hypofractionation schedule to implement. We compared 2 different HFRT regimens in the present study.

METHODS AND MATERIALS

From June 2013 to July 2016, 160 patients with prostate cancer were randomly assigned (1:1), within this single-center phase III trial, to 56 Gy (16 fractions of 3.5 Gy; arm A) or 67 Gy (25 fractions of 2.68 Gy; arm B). Randomization was performed using computer-generated permuted blocks, stratified by previous transurethral resection of the prostate and the presence of a dominant intraprostatic lesion. Treatment allocation was not masked, and the clinicians were not blinded. The primary endpoint was acute gastrointestinal (GI) toxicity, assessed using the Common Terminology Criteria for Adverse Events, version 4.0, and Radiation Therapy Oncology Group toxicity scale. An interim analysis of acute toxicity was planned at 160 patients to prove the safety of both treatment regimens. If ≥22 of 72 patients had grade ≥2 GI toxicity, the study arm would be rejected. The study is registered at ClinicalTrials.gov (NCT01921803).

RESULTS

In arm A, 20 patients (26%) and 1 patient (1%) developed acute grade 2 and grade 3 GI toxicity. In arm B, 16 patients (20%) reported acute grade 2 GI toxicity. In arm A, 42 (55%) and 5 (6%) patients developed acute grade 2 and grade 3 urinary toxicity. In arm B, 40 (49%) and 7 (9%) patients reported acute grade 2 and grade 3 urinary toxicity. Toxicity peaked during radiation therapy and resolved in the months after radiation therapy.

CONCLUSIONS

With acute grade ≥2 GI toxicity reported in 21 of 77 patients in arm A and 16 of 82 patients in arm B, both treatment arms can be considered safe.

Stereotactic Body Radiation Therapy for Localized Prostate Cancer

Stereotactic body radiation therapy (SBRT) has become a viable treatment option for the many patients who receive a diagnosis of localized prostate cancer each year. Technological advancements have led to tight target conformality, allowing for high-dose-per-fraction delivery without untoward normal tissue toxicity. Biochemical control, now reported up to 5 years, appears to compare favorably with dose-escalated conventionally fractionated radiotherapy. Moreover, toxicity and quality of life follow-up data indicate genitourinary and gastrointestinal toxicities are likewise comparable to conventional radiation therapy. Nevertheless, because of the long natural history of prostate cancer, extended follow-up will be necessary to confirm these impressive initial results. Within this prostate SBRT review, we explore the detailed rationale for SBRT treatment, the diverse SBRT techniques utilized and their unique technical considerations, and finally data for SBRT clinical efficacy and treatment-related toxicity.

Hypo-fractionated SBRT for localized prostate cancer: a German bi-center single treatment group feasibility trial

BACKGROUND

For prostate cancer treatment, treatment options with minimal side effects are desired. External beam radiation therapy (EBRT) is non-invasive, standard of care and delivered in either conventional fractionation over 8 weeks or with moderate hypo-fractionation over about 5 weeks. Recent advances in radiotherapy technology have made extreme hypo-fractionated stereotactic body radiation therapy (SBRT) of prostate cancer feasible, which has not yet been introduced as a standard treatment method in Germany. Initial results from other countries are promising, but long-term results are not yet available. The aim of this study is to investigate feasibility and effectiveness of SBRT for prostate cancer in Germany.

METHODS/DESIGN

This German bi-center single group trial (HYPOSTAT) is designed to evaluate feasibility and effectiveness, as measured by toxicity and PSA-response, respectively, of an extreme hypo-fractionated SBRT regimen with five fractions of 7 Gy in treatment of localized low and intermediate risk prostate cancer. The target volume includes the prostate with or without the base of seminal vesicles depending on risk stratification and uncertainty margins that are kept at 3-5 mm. SBRT treatment is delivered with the robotic CyberKnife system, which was recently introduced in Germany. Acute and late toxicity after one year will be evaluated according to Common Terminology Criteria for Adverse Events (CTCAE v. 4.0), Radiation Therapy Oncology Group (RTOG) and International Prostate Symptom Score (IPSS) Scores. The quality of life will be assessed before and after treatment with the EORTC QLQ C30 questionnaire. Hypothesizing that the proportion of patients with grade 2 side effects or higher is less or equal than 2.8%, thus markedly lower than the standard EBRT percentage (17.5%), the recruitment target is 85 patients.

DISCUSSION

The HYPOSTAT trial aims at demonstrating short term feasibility of extreme hypo-fractioned SBRT for the treatment of prostate cancer and might be used as the pilot study for a multi-center multi-platform or for randomized-controlled trials comparing conventional radiotherapy with SBRT for localized prostate cancer in the future. The study concept of patient enrollment, follow up and evaluation by multiple public university clinics and actual patient treatment in dedicated private radiosurgery practices with high-tech radiation equipment is unique for clinical trials.

STUDY STATUS

The study is ongoing and currently recruiting patients.

TRIAL REGISTRATION

Registration number: NCT02635256 ( clinicaltrials.gov ). Registered 8 December 2015.

Assessment and management of radiotherapy induced toxicity in older patients

Radiotherapy is an attractive treatment option for older adults, especially where surgery and chemotherapy pose too great a risk. Radiotherapy toxicity may be divided into acute/early and late effects of treatment. The latter may have limited relevance to an older patient with competing causes of mortality due to significant comorbidity. Altered fractionation regimes have been employed in numerous sites, with no significant toxicity impact. These offer greater convenience in the elderly, especially those with limited social support or in active caregiving roles. As radiotherapy toxicity is site specific, it's important to assess baseline function via Comprehensive Geriatric Assessment (CGA), and any pre-existing comorbidities that may influence toxicity. With modern radiotherapy technology and capabilities, these are less of an issue and radiotherapy is a very suitable treatment option for the older adult. When evaluating the literature on toxicity in older patients, it's important to recognise that older studies do not represent modern day radiotherapy techniques and capabilities. Advanced technology may simultaneously deliver enhanced target coverage and reduced toxicity. More research is required related to the predictive power of CGA in linking radiotherapy toxicity to frailty. What little evidence exists shows that CGA has a role in treatment of older patients with radiotherapy and that, in general, radiotherapy appears to be well tolerated in older adults. The purpose of this review is to provide a broad overview of the mechanisms of normal tissue reactions to radiotherapy and how radiation induced toxicity may affect older patients.

Nomogram to predict rectal toxicity following prostate cancer radiotherapy

BACKGROUND

To identify predictors of acute and late rectal toxicity following prostate cancer radiotherapy (RT), while integrating the potential impact of RT technique, dose escalation, and moderate hypofractionation, thus enabling us to generate a nomogram for individual prediction.

METHODS

In total, 972 patients underwent RT for localized prostate cancer, to a total dose of 70 Gy or 80 Gy, using two different fractionations (2 Gy or 2.5 Gy/day), by means of several RT techniques (3D conformal RT [3DCRT], intensity-modulated RT [IMRT], or image-guided RT [IGRT]). Multivariate analyses were performed to identify predictors of acute and late rectal toxicity. A nomogram was generated based on the logistic regression model used to predict the 3-year rectal toxicity risk, with its accuracy assessed by dividing the cohort into training and validation subgroups.

RESULTS

Mean follow-up for the entire cohort was 62 months, ranging from 6 to 235. The rate of acute Grade ≥2 rectal toxicity was 22.2%, decreasing when combining IMRT and IGRT, compared to 3DCRT (RR = 0.4, 95%CI: 0.3-0.6, p<0.01). The 5-year Grade ≥2 risks for rectal bleeding, urgency/tenesmus, diarrhea, and fecal incontinence were 9.9%, 4.5%, 2.8%, and 0.4%, respectively. The 3-year Grade ≥2 risk for overall rectal toxicity increased with total dose (p<0.01, RR = 1.1, 95%CI: 1.0-1.1) and dose per fraction (2Gy vs. 2.5Gy) (p = 0.03, RR = 3.3, 95%CI: 1.1-10.0), and decreased when combining IMRT and IGRT (RR = 0.50, 95% CI: 0.3-0.8, p<0.01). Based on these three parameters, a nomogram was generated.

CONCLUSIONS

Dose escalation and moderate hypofractionation increase late rectal toxicity. IMRT combined with IGRT markedly decreases acute and late rectal toxicity. Performing combined IMRT and IGRT can thus be envisaged for dose escalation and moderate hypofractionation. Our nomogram predicts the 3-year rectal toxicity risk by integrating total dose, fraction dose, and RT technique.

Adoption of Radiation Technology Among Privately Insured Nonelderly Patients With Cancer in the United States, 2008 to 2014: A Claims-Based Analysis

Despite enthusiasm for advanced radiation technologies, understanding of their adoption in recent years is limited. The aim of this study was to elucidate utilization trends of conventional radiation, intensity-modulated radiotherapy (IMRT), brachytherapy, proton radiotherapy, stereotactic body radiotherapy (SBRT), and stereotactic radiosurgery (SRS) using a large convenience sample of irradiated patients with cancer identified from private insurance claims in the United States. The unit of analysis was a claim corresponding to a fraction of delivered radiotherapy from 2008 to 2014. Each claim was assigned a disease site on the basis of the diagnosis code and a radiation technology on the basis of the procedure code. In 2014, conventional radiation and IMRT constituted 56% and 39% of all radiation treatment claims, respectively, while brachytherapy constituted 2%, proton radiotherapy 1%, SBRT 1%, and SRS <1%. Compared with the first quarter of 2008, the proportional contribution of conventional radiation and brachytherapy to all radiation claims each decreased by 16% in the fourth quarter of 2014. In contrast, proportional contribution increased by 32% for IMRT, 83% for proton radiotherapy, 124% for SRS, and 309% for SBRT. Prostate cancer constituted 60% of all proton claims in 2008 but declined to 37% by 2014. SBRT was used to treat a variety of disease sites, most commonly primary lung (25%), prostate (12%), secondary bone (9%), and secondary lung (9%), in 2014. In this claims-based analysis of younger patients with private insurance, conventional radiation and IMRT were the most commonly used technologies from 2008 to 2014, while SBRT showed the most robust growth over the study period.

The Role of Hypofractionated Radiotherapy in Prostate Cancer

PURPOSE OF REVIEW

It is now accepted that prostate cancer has a low alpha/beta ratio, establishing a strong basis for hypofractionation of prostate radiotherapy. This review focuses on the rationale for hypofractionation and presents the evidence base for establishing moderate hypofractionation for localised disease as the new standard of care. The emerging evidence for extreme hypofractionation in managing localized and oligometastatic prostate cancer is reviewed.

RECENT FINDINGS

The 5-year efficacy and toxicity outcomes from four phase III studies have been published within the last 12 months. These studies randomizing over 6000 patients to conventional fractionation (1.8-2.0 Gy per fraction) or moderate hypofractionation (3.0-3.4 Gy per fraction). They demonstrate hypofractionation to be non-inferior to conventional fractionation. Moderate hypofractionation for localized prostate cancer is safe and effective. There is a growing body of evidence in support of extreme hypofractionation for localized prostate cancer. Extreme hypofractionation may have a role in managing prostate oligometastases, but further studies are needed.

Acute and late complications after hypofractionated intensity modulated radiotherapy in prostate cancer

PURPOSE

The present study compared the complications associated with hypofractionated intensity-modulated radiation therapy (Hypo-IMRT) of prostate cancer to conventionally fractionated IMRT (Conv-IMRT).

MATERIALS AND METHODS

Hypo-IMRT delivered 70 Gy in 28 fractions, whereas Conv-IMRT delivered 78 Gy in 39 fractions. Toxicity was graded with the Common Terminology Criteria for Adverse Events, version 4.0, weekly during radiotherapy, 1 month after radiotherapy, and annually in both patient groups.

RESULTS

The median follow-ups were 39.1 and 38.7 months for patients in the Hypo- and Conv-IMRT groups, respectively. There was no significant difference in rates of acute and late adverse events. The proportions of grade 2 acute genitourinary complications were 48.4 and 51.2% in the Hypo- and Conv-IMRT groups, respectively. The presence of a baseline International Prostate Symptom Score (IPSS) of ten or more was the only significant prognostic factor for grade 2 acute genitourinary toxicity. The incidence of grade 2 late rectal hemorrhage at 3 years was 3.2 and 3.5% in the Hypo- and Conv-IMRT groups, respectively. Small rectal volume was significantly associated with grade 2 late rectal hemorrhage.

CONCLUSION

Regarding acute and late adverse events, hypofractionated IMRT for prostate cancer was well tolerated and comparable with conventionally fractionated IMRT. Clinical trial registration no. UMIN000003218.

Acute toxicity and its dosimetric correlates for high-risk prostate cancer treated with moderately hypofractionated radiotherapy

AIMS

To report the acute toxicity and the dosimetric correlates after moderately hypofractionated radiotherapy for localized prostate cancer.

METHODS

A total of 101 patients with localized prostate cancer were treated with image-guided intensity-modulated radiation therapy. Patients were treated to 65Gy/25Fr/5 weeks (n = 18), or 60Gy/20Fr/4 weeks (n = 83). Most (82.2%) had high-risk or pelvic node-positive disease. Acute toxicity was assessed using Radiation Therapy Oncology Group (RTOG) acute morbidity scoring criteria. Dose thresholds for acute rectal and bladder toxicity were identified.

RESULTS

The incidence of acute grade 2 GI toxicity was 20.8%, and grade 2 genitourinary (GU) toxicity was 6.9%. No Grade 3 to 4 toxicity occurred. Small bowel toxicity was uncommon (Gr 2 = 4%). The 2Gy equivalent doses (EQD2) to the rectum and bladder (α/β = 3) calculated showed that the absolute doses were more consistent predictors of acute toxicities than the relative volumes. Those with grade 2 or more GI symptoms had significantly higher V_EQD2-60Gy (13.2 vs 9.9cc, p = 0.007) and V_EQD2-50Gy (20.6 vs 15.4cc, p = 0.005). Those with grade 2 or more GU symptoms had significantly higher V_EQD2-70Gy (30.4 vs 18.4cc, p = 0.001) and V_EQD2-65Gy (44.0 vs 28.8cc, p = 0.001). The optimal cutoff value for predicting grade 2 acute proctitis, for V_EQD2-60Gy was 9.7cc and for V_EQD2-50Gy was 15.9cc. For grade 2 GU symptoms, the threshold values were 23.6cc for V_EQD2-70Gy and 38.1cc for V_EQD2-65Gy.

CONCLUSIONS

Hypofractionated radiotherapy for prostate cancer is well tolerated and associated with manageable acute side effects. The absolute dose-volume parameters of rectum and bladder predict for acute toxicities.

Long-Term Patient-Reported Outcomes From a Phase 3 Randomized Prospective Trial of Conventional Versus Hypofractionated Radiation Therapy for Localized Prostate Cancer

PURPOSE

To assess the long-term quality of life (QoL) outcomes from a phase 3 trial comparing 2 modes of intensity modulated radiation therapy (IMRT): conventional IMRT (CIMRT) versus hypofractionated IMRT (HIMRT) in patients with localized prostate cancer.

METHODS AND MATERIALS

Between 2002 and 2006, 303 men with low-risk to high-risk prostate cancer were randomized to 76 Gy in 38 fractions (CIMRT) versus 70.2 Gy in 26 fractions (HIMRT). QoL was compared by use of the Expanded Prostate Cancer Index Composite (EPIC), the International Prostate Symptom Score (IPSS), and EuroQoL (EQ5D) questionnaires. The primary outcome of the QoL analysis was a minimum clinically important difference defined as a 0.5 standard deviation change from baseline for each respective QoL parameter. Treatment effects were evaluated with the use of logistic mixed effects regression models.

RESULTS

A total of 286, 299, and 218 patients had baseline EPIC, IPSS, or EQ5D data available and were included in the analysis. Overall, there was no statistically significant difference between the 2 treatment arms in terms of EPIC, IPSS, or EQ5D scores over time, although there was a trend toward lower EPIC urinary incontinence scores in the HIMRT arm. More patients in the HIMRT arm had a lower EPIC urinary incontinence score relative to baseline versus patients in the CIMRT arm with long-term follow-up. On multivariable analysis, there was no association between radiation fractionation scheme and any QoL parameter. When other clinical factors were examined, lymph node radiation was associated with worse EPIC hormonal scores versus patients receiving no lymph node radiation. In general, QoL outcomes were generally stable over time, with the exception of EPIC hormonal and EQ5D scores.

CONCLUSIONS

In this randomized prospective study, there were stable QoL changes in patients receiving HIMRT or CIMRT. Our results add to the growing body of literature suggesting that HIMRT may be an acceptable treatment modality in clinically localized prostate cancer.

Comparison of prostate positioning guided by three-dimensional transperineal ultrasound and cone beam CT

OBJECTIVE

The accuracy of a transperineal three-dimensional ultrasound system (3DUS) was assessed for prostate positioning and compared to fiducial- and bone-based positioning in kV cone beam computed tomography (CBCT) during definitive radiotherapy of prostate cancer.

METHODS

Each of the 7 patients had three fiducial markers implanted into the prostate before treatment. Prostate positioning was simultaneously measured by 3DUS and CBCT before each fraction. In total, 177 pairs of 3DUS and CBCT scans were collected. Bone-match and seed-match were performed for each CBCT. Using seed-match as a reference, the accuracy of 3DUS and bone-match was evaluated. Systematic and random errors as well as optimal setup margins were calculated for 3DUS and bone-match.

RESULTS

The discrepancy between 3DUS and seed-match in CBCT (average ± standard deviation) was 0.0 ± 1.7 mm laterally, 0.2 ± 2.0 mm longitudinally, and 0.3 ± 1.7 mm vertically. Using seed-match as a reference, systematic errors for 3DUS were 1.2 mm, 1.1 mm, and 0.9 mm; and random errors were 1.4 mm, 1.8 mm, and 1.6 mm, on lateral, longitudinal, and vertical axes, respectively. By analogy, the difference of bone-match to seed-match was 0.1 ± 1.1 mm laterally, 1.3 ± 3.8 mm longitudinally, and 1.3 ± 4.5 mm vertically. Systematic errors were 0.5 mm, 2.2 mm, and 2.6 mm; and random errors were 1.0 mm, 3.1 mm, and 3.9 mm on lateral, longitudinal, and vertical axes, respectively. The accuracy of 3DUS was significantly higher than that of bone-match on longitudinal and vertical axes, but not on the lateral axis.

CONCLUSION

Image-guided radiotherapy of prostate cancer based on transperineal 3DUS was feasible, with overall small discrepancy to seed-match in CBCT in this retrospective study. Compared to bone-match, transperineal 3DUS achieved higher accuracy on longitudinal and vertical axes.

Acute and Late Adverse Events Associated With Radical Radiation Therapy Prostate Cancer Treatment: A Systematic Review of Clinician and Patient Toxicity Reporting in Randomized Controlled Trials

PURPOSE

This review aimed to determine the clinician and patient reported outcome (PRO) instruments currently usedin randomized controlled trials (RCTs) of radical radiation therapy for nonmetastatic prostate cancer to report acute and late adverse events (AEs), review the quality of methodology and PRO reporting, and report the prevalence of acute and late AEs.

METHODS AND MATERIALS

The MEDLINE, EMBASE, and Cochrane databases were searched between April and August 2014 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. Identified reports were reviewed according to the PRO Consolidated Standards of Reporting Trials (CONSORT) guidelines and the Cochrane Risk of Bias tool. In all, 1149 records were screened, and 21 articles were included in the final review.

RESULTS

We determined the acute and late AEs for 9040 patients enrolled in 15 different RCTs. Only clinician reported instruments were used to report acute AEs <3 months (eg, Radiation Therapy Oncology Group [RTOG] and Common Terminology Criteria for Adverse Events [CTCAE]). For late clinician reporting, the Late Effects on Normal Tissues-Subjective, Objective, Management and Analytic scale and RTOG were used and were often augmented with additional items to provide comprehensive coverage of sexual functioning and anorectal symptoms. Some late AEs were reported (48% articles) using PROs (eg, ULCA-PCI [University of California, Los Angeles Prostate Cancer Index], FACT-G and P [Functional Assessment of Cancer Therapy General & Prostate Module], EORTC QLQC-30 + PR25 [European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire & Prostate Module]); however, a definitive "preferred" instrument was not evident.

DISCUSSION

Our findings are at odds with recent movements toward including patient voices in reporting of AEs and patient engagement in clinical research. We recommend including PRO to evaluate radical radiation therapy before, during, and after the treatment to fully capture patient experiences, and we support the development of predictive models for late effects based on the severity of early toxicity.

CONCLUSION

Patient reporting of acute and late AEs is underrepresented in radiation therapy trials. We recommend working toward a consistent approach to PRO assessment of radiation therapy-related AEs.

Clinical development of new drug-radiotherapy combinations

In countries with the best cancer outcomes, approximately 60% of patients receive radiotherapy as part of their treatment, which is one of the most cost-effective cancer treatments. Notably, around 40% of cancer cures include the use of radiotherapy, either as a single modality or combined with other treatments. Radiotherapy can provide enormous benefit to patients with cancer. In the past decade, significant technical advances, such as image-guided radiotherapy, intensity-modulated radiotherapy, stereotactic radiotherapy, and proton therapy enable higher doses of radiotherapy to be delivered to the tumour with significantly lower doses to normal surrounding tissues. However, apart from the combination of traditional cytotoxic chemotherapy with radiotherapy, little progress has been made in identifying and defining optimal targeted therapy and radiotherapy combinations to improve the efficacy of cancer treatment. The National Cancer Research Institute Clinical and Translational Radiotherapy Research Working Group (CTRad) formed a Joint Working Group with representatives from academia, industry, patient groups and regulatory bodies to address this lack of progress and to publish recommendations for future clinical research. Herein, we highlight the Working Group's consensus recommendations to increase the number of novel drugs being successfully registered in combination with radiotherapy to improve clinical outcomes for patients with cancer.

Twenty Fraction Prostate Radiotherapy with Intra-prostatic Boost: Results of a Pilot Study

AIMS

For patients with high-risk, locally bulky prostate cancer, an intra-prostatic boost to tumour volumes (dose-painting) offers a risk-adapted dose escalation. We evaluated the feasibility of hypofractionated dose-painting radiotherapy and the associated toxicity. The possibility to streamline a radiobiologically optimised planning protocol was also investigated.

MATERIALS AND METHODS

Twenty-eight patients were treated using a dose-painting approach; boost volumes were identified with functional magnetic resonance imaging scans. The prostate dose outside the boost volume was 60 Gy in 20 fractions, and the maximum integrated boost dose was set to 68 Gy, provided that the dose constraints to the organs at risk could be fulfilled. Rotational intensity-modulated radiotherapy was used with daily image guidance and fiducial markers.

RESULTS

The boost dose was escalated to 68 Gy for 25 patients (median dose 69 Gy, range 68-70 Gy); for three patients the boost dose was 67 Gy, due to the proximity of the urethra and/or the rectum. The mean normal tissue complication probability for rectal bleeding was 4.7% (range 3.4-5.8%) and was 3.5% for faecal incontinence (range 2.3-5.0%). At a median follow-up of 38 months (range 32-45) there was no grade 3 toxicity. Two patients developed grade 2 genitourinary toxicity (7.1%) and none developed grade 2 gastrointestinal toxicity. The mean prostate-specific antigen (PSA) for 23 patients who had stopped the adjuvant hormone therapy with a normal testosterone was 0.27 ng/ml (0.02-0.72) at follow-up; two patients have suppressed PSA and testosterone after stopping 3 year adjuvant hormone and three patients have relapsed (one pelvic node, two PSA only) at 36, 12 and 42 months, respectively.

CONCLUSIONS

A hypofractionated radiotherapy schedule, 60 Gy in 20 fractions with intra-prostatic boost dose of 68 Gy, can be achieved without exceeding dose constraints for organs at risk. Hypofractionated dose-painting escalated radiotherapy has an acceptable safety profile. The same planning protocol was used in a phase II single-arm trial (BIOPROP20: ClinicalTrials.gov identifier NCT02125175) and will further be used in a large phase III randomised trial (PIVOTALboost): patients will be randomised standard radiotherapy (60 Gy in 20 fractions) with or without lymph node radiotherapy versus dose-painting radiotherapy with or without lymph node radiotherapy; the trial will be opened for recruitment in summer 2017.

Proton therapy for early stage prostate cancer: is there a case?

Proton-beam therapy (PBT) for prostate cancer has been in used for several decades, with its technique evolving significantly over this period. A growing number of centers now routinely utilize pencil-beam scanning as an advanced technique of PBT. Interest and controversy concerning its use have recently come under scrutiny. While the past decade has produced an assemblage of evidence suggesting that PBT is safe and effective for early stage prostate cancer, it is still unknown whether the theoretical dosimetric advantages of PBT translate into meaningful clinical improvements over routine intensity-modulated radiation therapy, which is commonly used for these patients. Outcomes from early trials using whole courses of PBT have shown mixed results when compared with routine intensity-modulated radiation therapy. Therefore, randomized trials comparing these two techniques should be undertaken, as this would help in defining the role of PBT for this patient group. This article aims to describe the basics of PBT, review the reasons for the growing interest in PBT, review the evidence for PBT, review the controversy surrounding PBT, and inquire about PBT's future in the treatment of prostate cancer, with attention to its physical properties, comparative clinical and cost-effectiveness, and advances in its delivery.

Treatment outcomes with hypofractionated high-dose radiation therapy for prostate cancer

AIM

To report the treatment results of a retrospective cohort of prostate cancer patients treated with Hypo-RT with a high equivalent biological effective dose (BED).

BACKGROUND

Hypofractionated radiotherapy (Hypo-RT) has gained popularity and interest in the treatment of prostate cancer. However, there are few experiences with adequate follow-up reporting treatment results using high equivalent dose with Hypo-RT.

MATERIALS AND METHODS

We assigned 149 men with low-, intermediate- and high-risk prostate cancer to receive Hypo-RT with a total dose of 69 Gy/23 fractions. Late gastrointestinal (GI) and genitourinary (GU) toxicity were prospectively evaluated according to modified RTOG criteria. Biochemical no evidence of disease (bNED) was defined as the nadir prostate-specific antigen level plus 2 ng/mL.

RESULTS

The median follow-up was 53 months. For the entire cohort, the 5-year bNED rate was 94.6%, and for low-, intermediate- and high-risk patients the 5-year bNED was 100%, 96.4%, and 86% (p = 0.007), respectively. The 5-year overall survival rate was 92%. Only 1 patient died from the disease at 48 months after treatment, giving a 5-year cancer-specific survival of 98%. The worst grade ≥2 rate GI and GU toxicity was 13.4% and 14%, respectively. No grade >3 toxicity was observed. The presence of grade ≥2 GI and GU toxicity at the last follow-up was only 1.3% and 3%, respectively.

CONCLUSIONS

Hypo-RT (69 Gy/23 fractions) with a high equivalent BED produces excellent rates of biochemical control for low, intermediate and high-risk prostate cancer. The long term GU and GI toxicity rates were considered low and acceptable.

The Comparison of Stereotactic Body Radiation Therapy and Intensity-Modulated Radiation Therapy for Prostate Cancer by NCCN Risk Groups

OBJECTIVES

The primary objective of this study is to compare freedom from biochemical failure (FFBF) between stereotactic body radiation therapy (SBRT) and intensity-modulated radiation therapy (IMRT) for patients with organ confined prostate cancer treated between 2007 through 2012 utilizing the 2015 National Comprehensive Cancer Network (NCCN) risk stratification guidelines. A secondary objective is to compare our updated toxicity at last follow-up compared with pretreatment with respect to bowel, bladder, sexual functioning, and need for invasive procedures between the two groups.

METHODS

We retrospectively reviewed 270 consecutive men treated with either SBRT (n = 150) or IMRT (n = 120) at a community hospital with two distinct radiation departments and referral patterns. Charts were reviewed for pretreatment and treatment factors including race, age, clinical T stage, initial PSA, Gleason score, use of androgen deprivation therapy, treatment with SBRT vs. IMRT, as well as stratification by 2015 NCCN guidelines. Kaplan-Meier (KM) methodology was used to estimate FFBF, with statistical comparisons accomplished using log rank tests. Multivariable Cox proportional hazard modeling was used to establish independent factors prognostic of biochemical failure. Descriptive statistics were used to describe toxicity graded by a modified Radiation Therapy Oncology Group (RTOG) late radiation morbidity scoring system.

RESULTS

Significant prognostic factors in univariate analysis for FFBF included NCCN risk groups (p = 0.0032), grade (p = 0.019), and PSA (p = 0.008). There was no significant difference in FFBF between SBRT vs. IMRT (p = 0.46) with 6-year actuarial FFBF of 91.9% for SBRT and 88.9% for IMRT. Multivariable analysis revealed only the NCCN risk stratification to be significant predictor for FFBF (p = 0.04). Four-year actuarial FFBF by NCCN risk stratification was 100% very low risk, 100% low risk, 96.5% intermediate risk, 94.5% high risk, and 72.7% very high risk. There were no grade 3 gastrointestinal or genitourinary toxicities for either SBRT or IMRT at last follow-up.

CONCLUSION

No significant difference in FFBF was found between SBRT and IMRT for organ confined prostate cancer in multivariable analysis within this retrospective data set. Overall toxicity was low. The 2015 NCCN risk stratification was validated in this population and was the only significant factor for FFBF in multivariable analysis.

Meta-analysis of Genome Wide Association Studies Identifies Genetic Markers of Late Toxicity Following Radiotherapy for Prostate Cancer

Nearly 50% of cancer patients undergo radiotherapy. Late radiotherapy toxicity affects quality-of-life in long-term cancer survivors and risk of side-effects in a minority limits doses prescribed to the majority of patients. Development of a test predicting risk of toxicity could benefit many cancer patients. We aimed to meta-analyze individual level data from four genome-wide association studies from prostate cancer radiotherapy cohorts including 1564 men to identify genetic markers of toxicity. Prospectively assessed two-year toxicity endpoints (urinary frequency, decreased urine stream, rectal bleeding, overall toxicity) and single nucleotide polymorphism (SNP) associations were tested using multivariable regression, adjusting for clinical and patient-related risk factors. A fixed-effects meta-analysis identified two SNPs: rs17599026 on 5q31.2 with urinary frequency (odds ratio [OR] 3.12, 95% confidence interval [CI] 2.08-4.69, p-value 4.16×10(-8)) and rs7720298 on 5p15.2 with decreased urine stream (OR 2.71, 95% CI 1.90-3.86, p-value=3.21×10(-8)). These SNPs lie within genes that are expressed in tissues adversely affected by pelvic radiotherapy including bladder, kidney, rectum and small intestine. The results show that heterogeneous radiotherapy cohorts can be combined to identify new moderate-penetrance genetic variants associated with radiotherapy toxicity. The work provides a basis for larger collaborative efforts to identify enough variants for a future test involving polygenic risk profiling.

Conventional versus hypofractionated high-dose intensity-modulated radiotherapy for prostate cancer: 5-year outcomes of the randomised, non-inferiority, phase 3 CHHiP trial

BACKGROUND

Prostate cancer might have high radiation-fraction sensitivity that would give a therapeutic advantage to hypofractionated treatment. We present a pre-planned analysis of the efficacy and side-effects of a randomised trial comparing conventional and hypofractionated radiotherapy after 5 years follow-up.

METHODS

CHHiP is a randomised, phase 3, non-inferiority trial that recruited men with localised prostate cancer (pT1b-T3aN0M0). Patients were randomly assigned (1:1:1) to conventional (74 Gy delivered in 37 fractions over 7·4 weeks) or one of two hypofractionated schedules (60 Gy in 20 fractions over 4 weeks or 57 Gy in 19 fractions over 3·8 weeks) all delivered with intensity-modulated techniques. Most patients were given radiotherapy with 3-6 months of neoadjuvant and concurrent androgen suppression. Randomisation was by computer-generated random permuted blocks, stratified by National Comprehensive Cancer Network (NCCN) risk group and radiotherapy treatment centre, and treatment allocation was not masked. The primary endpoint was time to biochemical or clinical failure; the critical hazard ratio (HR) for non-inferiority was 1·208. Analysis was by intention to treat. Long-term follow-up continues. The CHHiP trial is registered as an International Standard Randomised Controlled Trial, number ISRCTN97182923.

FINDINGS

Between Oct 18, 2002, and June 17, 2011, 3216 men were enrolled from 71 centres and randomly assigned (74 Gy group, 1065 patients; 60 Gy group, 1074 patients; 57 Gy group, 1077 patients). Median follow-up was 62·4 months (IQR 53·9-77·0). The proportion of patients who were biochemical or clinical failure free at 5 years was 88·3% (95% CI 86·0-90·2) in the 74 Gy group, 90·6% (88·5-92·3) in the 60 Gy group, and 85·9% (83·4-88·0) in the 57 Gy group. 60 Gy was non-inferior to 74 Gy (HR 0·84 [90% CI 0·68-1·03], pNI=0·0018) but non-inferiority could not be claimed for 57 Gy compared with 74 Gy (HR 1·20 [0·99-1·46], pNI=0·48). Long-term side-effects were similar in the hypofractionated groups compared with the conventional group. There were no significant differences in either the proportion or cumulative incidence of side-effects 5 years after treatment using three clinician-reported as well as patient-reported outcome measures. The estimated cumulative 5 year incidence of Radiation Therapy Oncology Group (RTOG) grade 2 or worse bowel and bladder adverse events was 13·7% (111 events) and 9·1% (66 events) in the 74 Gy group, 11·9% (105 events) and 11·7% (88 events) in the 60 Gy group, 11·3% (95 events) and 6·6% (57 events) in the 57 Gy group, respectively. No treatment-related deaths were reported.

INTERPRETATION

Hypofractionated radiotherapy using 60 Gy in 20 fractions is non-inferior to conventional fractionation using 74 Gy in 37 fractions and is recommended as a new standard of care for external-beam radiotherapy of localised prostate cancer.

FUNDING

Cancer Research UK, Department of Health, and the National Institute for Health Research Cancer Research Network.

Quality of treatment plans and accuracy of in vivo portal dosimetry in hybrid intensity-modulated radiation therapy and volumetric modulated arc therapy for prostate cancer

BACKGROUND AND PURPOSE

Delivering selected parts of volumetric modulated arc therapy (VMAT) plans using step-and-shoot intensity modulated radiotherapy (IMRT) beams has the potential to increase plan quality by allowing specific aperture positioning. This study investigates the quality of treatment plans and the accuracy of in vivo portal dosimetry in such a hybrid approach for the case of prostate radiotherapy.

MATERIAL AND METHODS

Conformal and limited-modulation VMAT plans were produced, together with five hybrid IMRT/VMAT plans, in which 0%, 25%, 50%, 75% or 100% of the segments were sequenced for IMRT, while the remainder were sequenced for VMAT. Integrated portal images were predicted for the plans. The plans were then delivered as a single hybrid beam using an Elekta Synergy accelerator with Agility head to a water-equivalent phantom and treatment time, isocentric dose and portal images were measured.

RESULTS

Increasing the IMRT percentage improves dose uniformity to the planning target volume (p<0.01 for 50% IMRT or more), substantially reduces the volume of rectum irradiated to 65Gy (p=0.02 for 25% IMRT) and increases the monitor units (p<0.001). Delivery time also increases substantially. All plans show accurate delivery of dose and reliable prediction of portal images.

CONCLUSIONS

Hybrid IMRT/VMAT can be efficiently planned and delivered as a single beam sequence. Beyond 25% IMRT, the delivery time becomes unacceptably long, with increased risk of intrafraction motion, but 25% IMRT is an attractive compromise. Integrated portal images can be used to perform in vivo dosimetry for this technique.