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

Interdisciplinary consensus statement on indication and application of a hydrogel spacer for prostate radiotherapy based on experience in more than 250 patients

Background

The aim of the study was to reach a consensus on indication and application of a hydrogel spacer based on multicentre experience and give new users important information to shorten the learning curve for this innovative technique.

Methods

The interdisciplinary meeting was attended by radiation oncologists and urologists, each with experience of 23 – 138 hydrogel injections (SpaceOAR®) in prostate cancer patients before dose-escalated radiotherapy. User experience was discussed and questions were defined to comprise practical information relevant for successful hydrogel injection and treatment. Answers to the defined key questions were generated. Hydrogel-associated side effects were collected to estimate the percentage, treatment and prognosis of potential risks.

Results

The main indication for hydrogel application was dose-escalated radiotherapy for histologically confirmed low or intermediate risk prostate cancer. It was not recommended in locally advanced prostate cancer. The injection or implantation was performed under transrectal ultrasound guidance via the transperineal approach after prior hydrodissection. The rate of injection-related G2-toxicity was 2% (n = 5) in a total of 258 hydrogel applications. The most frequent complication (n = 4) was rectal wall penetration, diagnosed at different intervals after hydrogel injection and treated conservatively.

Conclusions

A consensus was reached on the application of a hydrogel spacer. Current experience demonstrated feasibility, which could promote initiation of this method in more centres to reduce radiation-related gastrointestinal toxicity of dose-escalated IGRT. However, a very low rate of a potential serious adverse event could not be excluded. Therefore, the application should carefully be discussed with the patient and be balanced against potential benefits.

Clinical validation and benchmarking of knowledge-based IMRT and VMAT treatment planning in pelvic anatomy

PURPOSE

The aim of this work was to determine whether a commercial knowledge-based treatment planning (KBP) module can efficiently produce IMRT and VMAT plans in the pelvic region (prostate & cervical cancer), and to assess sensitivity of plan quality to training data and model parameters.

METHODS

Initial benchmarking of KBP was performed using prostate cancer cases. Structures and dose distributions from 40 patients previously treated using a 5-field IMRT technique were used for model training. Two types of model were created: one excluded statistical outliers (as identified by RapidPlan guidelines) and the other had no exclusions. A separate model for cervix uteri cancer cases was subsequently developed using 37 clinical patients treated for cervical cancer using RapidArc™ VMAT, with no exclusions. The resulting models were then used to generate plans for ten patients from each patient group who had not been included in the modelling process. Comparisons of generated RapidPlans with the corresponding clinical plans were carried out to indicate the required modifications to the models. Model parameters were then iteratively adjusted until plan quality converged with that obtained by experienced planners without KBP.

RESULTS

Initial automated model generation settings led to poor conformity, coverage and efficiency compared to clinical plans. Therefore a number of changes to the initial KBP models were required. Before model optimisation, it was found that the PTV coverage was slightly reduced in the superior and inferior directions for RapidPlan compared with clinical plans and therefore PTV parameters were adjusted to improve coverage. OAR doses were similar for both RapidPlan and clinical plans (p>0.05). Excluding outliers had little effect on plan quality (p≫0.05). Manually fixing key optimisation objectives enabled production of clinically acceptable treatment plans without further planner intervention for 9 of 10 prostate test patients and all 10 cervix test patients.

CONCLUSIONS

The Varian RapidPlan™ system was able to produce IMRT & VMAT treatment plans in the pelvis, in a single optimisation, that had comparable sparing and comparable or better conformity than the original clinically acceptable plans. The system allows for better consistency and efficiency in the treatment planning process and has therefore been adopted clinically within our institute with over 100 patients treated.

Radiotherapy for Prostate Cancer: is it 'what you do' or 'the way that you do it'? A UK Perspective on Technique and Quality Assurance

AIMS

The treatment of prostate cancer has evolved markedly over the last 40 years, including radiotherapy, notably with escalated dose and targeting. However, the optimal treatment for localised disease has not been established in comparative randomised trials. The aim of this article is to describe the history of prostate radiotherapy trials, including their quality assurance processes, and to compare these with the ProtecT trial.

MATERIALS AND METHODS

The UK ProtecT randomised trial compares external beam conformal radiotherapy, surgery and active monitoring for clinically localised prostate cancer and will report on the primary outcome (disease-specific mortality) in 2016 following recruitment between 1999 and 2009. The embedded quality assurance programme consists of on-site machine dosimetry at the nine trial centres, a retrospective review of outlining and adherence to dose constraints based on the trial protocol in 54 participants (randomly selected, around 10% of the total randomised to radiotherapy, n = 545). These quality assurance processes and results were compared with prostate radiotherapy trials of a comparable era.

RESULTS

There has been an increasingly sophisticated quality assurance programme in UK prostate radiotherapy trials over the last 15 years, reflecting dose escalation and treatment complexity. In ProtecT, machine dosimetry results were comparable between trial centres and with the UK RT01 trial. The outlining review showed that most deviations were clinically acceptable, although three (1.4%) may have been of clinical significance and were related to outlining of the prostate. Seminal vesicle outlining varied, possibly due to several prostate trials running concurrently with different protocols. Adherence to dose constraints in ProtecT was considered acceptable, with 80% of randomised participants having two or less deviations and planning target volume coverage was excellent.

CONCLUSION

The ProtecT trial quality assurance results were satisfactory and comparable with trials of its era. Future trials should aim to standardise treatment protocols and quality assurance programmes where possible to reduce complexities for centres involved in multiple trials.

Common genetic variation associated with increased susceptibility to prostate cancer does not increase risk of radiotherapy toxicity

BACKGROUND

Numerous germline single-nucleotide polymorphisms increase susceptibility to prostate cancer, some lying near genes involved in cellular radiation response. This study investigated whether prostate cancer patients with a high genetic risk have increased toxicity following radiotherapy.

METHODS

The study included 1560 prostate cancer patients from four radiotherapy cohorts: RAPPER (n=533), RADIOGEN (n=597), GenePARE (n=290) and CCI (n=150). Data from genome-wide association studies were imputed with the 1000 Genomes reference panel. Individuals were genetically similar with a European ancestry based on principal component analysis. Genetic risks were quantified using polygenic risk scores. Regression models tested associations between risk scores and 2-year toxicity (overall, urinary frequency, decreased stream, rectal bleeding). Results were combined across studies using standard inverse-variance fixed effects meta-analysis methods.

RESULTS

A total of 75 variants were genotyped/imputed successfully. Neither non-weighted nor weighted polygenic risk scores were associated with late radiation toxicity in individual studies (P>0.11) or after meta-analysis (P>0.24). No individual variant was associated with 2-year toxicity.

CONCLUSION

Patients with a high polygenic susceptibility for prostate cancer have no increased risk for developing late radiotherapy toxicity. These findings suggest that patients with a genetic predisposition for prostate cancer, inferred by common variants, can be safely treated using current standard radiotherapy regimens.

Predicting toxicity in radiotherapy for prostate cancer

This comprehensive review addresses most organs at risk involved in planning optimization for prostate cancer. It can be considered an update of a previous educational review that was published in 2009 (Fiorino et al., 2009). The literature was reviewed based on PubMed and MEDLINE database searches (from January 2009 up to September 2015), including papers in press; for each section/subsection, key title words were used and possibly combined with other more general key-words (such as radiotherapy, dose-volume effects, NTCP, DVH, and predictive model). Publications generally dealing with toxicity without any association with dose-volume effects or correlations with clinical risk factors were disregarded, being outside the aim of the review. A focus was on external beam radiotherapy, including post-prostatectomy, with conventional fractionation or moderate hypofractionation (<4Gy/fraction); extreme hypofractionation is the topic of another paper in this special issue. Gastrointestinal and urinary toxicity are the most investigated endpoints, with quantitative data published in the last 5years suggesting both a dose-response relationship and the existence of a number of clinical/patient related risk factors acting as dose-response modifiers. Some results on erectile dysfunction, bowel toxicity and hematological toxicity are also presented.

Randomized Phase III Noninferiority Study Comparing Two Radiotherapy Fractionation Schedules in Patients With Low-Risk Prostate Cancer

PURPOSE

Conventional radiotherapy (C-RT) treatment schedules for patients with prostate cancer typically require 40 to 45 treatments that take place from > 8 to 9 weeks. Preclinical and clinical research suggest that hypofractionation-fewer treatments but at a higher dose per treatment-may produce similar outcomes. This trial was designed to assess whether the efficacy of a hypofractionated radiotherapy (H-RT) treatment schedule is no worse than a C-RT schedule in men with low-risk prostate cancer.

PATIENTS AND METHODS

A total of 1,115 men with low-risk prostate cancer were randomly assigned 1:1 to C-RT (73.8 Gy in 41 fractions over 8.2 weeks) or to H-RT (70 Gy in 28 fractions over 5.6 weeks). This trial was designed to establish (with 90% power and an α of .05) that treatment with H-RT results in 5-year disease-free survival (DFS) that is not worse than C-RT by more than 7.65% (H-RT/C-RT hazard ratio [HR] < 1.52).

RESULTS

A total of 1,092 men were protocol eligible and had follow-up information; 542 patients were assigned to C-RT and 550 to H-RT. Median follow-up was 5.8 years. Baseline characteristics were not different according to treatment assignment. The estimated 5-year DFS was 85.3% (95% CI, 81.9 to 88.1) in the C-RT arm and 86.3% (95% CI, 83.1 to 89.0) in the H-RT arm. The DFS HR was 0.85 (95% CI, 0.64 to 1.14), and the predefined noninferiority criterion that required that DFS outcomes be consistent with HR < 1.52 was met (P < .001). Late grade 2 and 3 GI and genitourinary adverse events were increased (HR, 1.31 to 1.59) in patients who were treated with H-RT.

CONCLUSION

In men with low-risk prostate cancer, the efficacy of 70 Gy in 28 fractions over 5.6 weeks is not inferior to 73.8 Gy in 41 fractions over 8.2 weeks, although an increase in late GI/genitourinary adverse events was observed in patients treated with H-RT.

Prospective Study Delivering Simultaneous Integrated High-dose Tumor Boost (≤70 Gy) With Image Guided Adaptive Radiation Therapy for Radical Treatment of Localized Muscle-Invasive Bladder Cancer

PURPOSE

Image guided adaptive radiation therapy offers individualized solutions to improve target coverage and reduce normal tissue irradiation, allowing the opportunity to increase the radiation tumor dose and spare normal bladder tissue.

METHODS AND MATERIALS

A library of 3 intensity modulated radiation therapy plans were created (small, medium, and large) from planning computed tomography (CT) scans performed at 30 and 60 minutes; treating the whole bladder to 52 Gy and the tumor to 70 Gy in 32 fractions. A "plan of the day" approach was used for treatment delivery. A post-treatment cone beam CT (CBCT) scan was acquired weekly to assess intrafraction filling and coverage.

RESULTS

A total of 18 patients completed treatment to 70 Gy. The plan and treatment for 1 patient was to 68 Gy. Also, 1 patient's plan was to 70 Gy but the patient was treated to a total dose of 65.6 Gy because dose-limiting toxicity occurred before dose escalation. A total of 734 CBCT scans were evaluated. Small, medium, and large plans were used in 36%, 48%, and 16% of cases, respectively. The mean ± standard deviation rate of intrafraction filling at the start of treatment (ie, week 1) was 4.0 ± 4.8 mL/min (range 0.1-19.4) and at end of radiation therapy (ie, week 5 or 6) was 1.1 ± 1.6 mL/min (range 0.01-7.5; P=.002). The mean D98 (dose received by 98% volume) of the tumor boost and bladder as assessed on the post-treatment CBCT scan was 97.07% ± 2.10% (range 89.0%-104%) and 99.97% ± 2.62% (range 96.4%-112.0%). At a median follow-up period of 19 months (range 4-33), no muscle-invasive recurrences had developed. Two patients experienced late toxicity (both grade 3 cystitis) at 5.3 months (now resolved) and 18 months after radiation therapy.

CONCLUSIONS

Image guided adaptive radiation therapy using intensity modulated radiation therapy to deliver a simultaneous integrated tumor boost to 70 Gy is feasible, with acceptable toxicity, and will be evaluated in a randomized trial.

Intensity-modulated radiotherapy reduces toxicity with similar biochemical control compared with 3-dimensional conformal radiotherapy for prostate cancer: A randomized clinical trial

BACKGROUND

The objective of this article was to report the results from a randomized clinical trial comparing intensity-modulated radiotherapy (IMRT) with 3-dimensonal conformal radiotherapy (3DCRT) for the treatment of prostate cancer on a hypofractionated schedule.

METHODS

The authors randomly assigned 215 men who had localized prostate cancer to receive hypofractionated radiotherapy to a total dose of 70 grays (Gy) in 25 fractions (at 2.8 Gy per fraction) using either IMRT or 3DCRT. Acute and late gastrointestinal (GI) and genitourinary (GU) toxicity were prospectively evaluated according to modified Radiation Therapy Oncology Group criteria. Biochemical control was defined according to the Phoenix criteria (prostate-specific antigen nadir + 2 ng/mL).

RESULTS

In total, 215 patients were enrolled in the IMRT group (n = 109) or the 3DCRT group (n = 106). The 3DCRT arm had a 27% rate of grade ≥ 2 acute GU toxicity compared with a 9% rate in the IMRT arm (P = .001) and a 24% rate of grade ≥ 2 acute GI toxicity compared with a 7% rate in the IMRT arm (P = .001). The maximal rate of grade ≥2 late GU toxicity during the entire period of follow-up was 3.7% in the IMRT group versus 12.3% in the 3DCRT group (P = .02). The maximal rate of grade ≥2 late GI toxicity during the entire follow-up was 6.4% in the IMRT group versus 21.7% in the 3DCRT group (P = .001). The 5-year rate of freedom from biochemical failure was 95.4% in the IMRT arm and 94.3% in the 3DCRT arm (P = .678).

CONCLUSIONS

IMRT reduced the delivery of significant radiation doses to the bladder and rectum using a similar target volume. This dosimetric advantage resulted in a lower rate of acute/late grade ≥ 2 GI and GU toxicity for IMRT compared with 3DCRT. Cancer 2016;122:2004-11. © 2016 American Cancer Society.

Prostate Radiotherapy in the Era of Advanced Imaging and Precision Medicine

Tremendous technological advancements in prostate radiotherapy have decreased treatment toxicity and improved clinical outcomes for men with prostate cancer. While these advances have allowed for significant treatment volume reduction and whole-organ dose escalation, further improvement in prostate radiotherapy has been limited by classic techniques for diagnosis and risk stratification. Developments in prostate imaging, image-guided targeted biopsy, next-generation gene expression profiling, and targeted molecular therapies now provide information to stratify patients and select treatments based on tumor biology. Image-guided targeted biopsy improves detection of clinically significant cases of prostate cancer and provides important information about the biological behavior of intraprostatic lesions which can further guide treatment decisions. We review the evolution of prostate magnetic resonance imaging (MRI) and MRI-ultrasound fusion-guided prostate biopsy. Recent advancements in radiation therapy including dose escalation, moderate and extreme hypofractionation, partial prostate radiation therapy, and finally dose escalation by simultaneous integrated boost are discussed. We also review next-generation sequencing and discuss developments in targeted molecular therapies. Last, we review ongoing clinical trials and future treatment paradigms that integrate targeted biopsy, molecular profiling and therapy, and prostate radiotherapy.

Propensity score matched comparison of SBRT versus IMRT for the treatment of localized prostate cancer

Objective

Stereotactic body radiation therapy (SBRT) is an attractive option for prostate cancer due to its short treatment duration and cost. In this report, we compare the efficacy and toxicity outcomes of prostate cancer patients treated with SBRT to those who received intensity-modulated radiation therapy (IMRT).

Methods

Two hundred sixty-three patients with localized prostate adenocarcinoma were included, ranging from clinically very low- to high-risk groups. We retrospectively compare consecutive patients treated with SBRT with consecutive patients treated with conventionally fractionated IMRT. For most patients, SBRT was delivered to a total dose of 36.25 Gy in five fractions and IMRT to 75.6 Gy in 42 fractions. To minimize selection bias, we perform propensity score analyses.

Results

The treatment groups became similar after propensity matching with absolute standard bias reduced to ≤0.19. For the first analysis, 5-year actuarial survival was 90.8 and 88.1 % in SBRT and IMRT groups, respectively (p = 0.7260), while FFBF was 88.7 and 95.5 %, respectively (p = 0.1720). For the second analysis (accounting for risk group), actuarial 5-year survival was 96.7 and 87.1 % in the SBRT and IMRT groups, respectively (p = 0.3025), while FFBF was 89.7 and 90.3 %, respectively (p = 0.6446). Toxicity did not exceed grade 3 in any of the studied patients. The highest recorded genitourinary toxicity at the time of latest follow-up was grade 2.

Conclusion

Our data support the hypothesis that SBRT has non-inferior efficacy and toxicity rates as IMRT. Given the lower cost and convenience for patients, SBRT may be considered as an alternative treatment for localized prostate cancer.

Cost-effectiveness analysis of intensity-modulated radiation therapy with normal and hypofractionated schemes for the treatment of localised prostate cancer

The aim of our analysis was to compare the cost-effectiveness of high-dose intensity-modulated radiation therapy (IMRT) and hypofractionated intensity-modulated radiation therapy (HF-IMRT) versus conventional dose three-dimensional radiation therapy (3DCRT) for the treatment of localised prostate cancer. A Markov model was constructed to calculate the incremental quality-adjusted life years and costs. Transition probabilities, adverse events and utilities were derived from relevant systematic reviews. Microcosting in a large university hospital was applied to calculate cost vectors. The expected mean lifetime cost of patients undergoing 3DCRT, IMRT and HF-IMRT were 7,160 euros, 6,831 euros and 6,019 euros respectively. The expected quality-adjusted life years (QALYs) were 5.753 for 3DCRT, 5.956 for IMRT and 5.957 for HF-IMRT. Compared to 3DCRT, both IMRT and HF-IMRT resulted in more health gains at a lower cost. It can be concluded that high-dose IMRT is not only cost-effective compared to the conventional dose 3DCRT but, when used with a hypofractionation scheme, it has great cost-saving potential for the public payer and may improve access to radiation therapy for patients.

Quality of life outcomes from a dose-per-fraction escalation trial of hypofractionation in prostate cancer

OBJECTIVE

This multi-institutional phase I/II trial explored patient-assessed tolerance of increasingly hypofractionated (HPFX) radiation for low/intermediate risk prostate cancer.

METHODS

347 patients enrolled from 2002 to 2010. Three increasing dose-per-fraction schedules of 64.7 Gy/22 fx, 58.08 Gy/16 fx and 51.6 Gy/12 fx were each designed to yield equivalent predicted late toxicity. Three quality of life (QoL) surveys were administered prior to treatment and annually upto 3 years.

RESULTS

Bowel QoL data at 3years revealed no significant difference among regimens (p=0.469). Bowel QoL for all regimens declined transiently, largely recovering by three years, with only the 22 fraction decrement reaching significance. Bladder outcomes at 3 years were comparable (p=0.343) although, for all patients combined, a significant decline was observed from the baseline (p=0.008). Spitzer quality of life data revealed similarly excellent, 3-year means (p=0.188). International erectile function data also revealed no significant differences at 3 years although all measures except intercourse satisfaction worsened post-treatment.

CONCLUSIONS

Three-year QoL changes for bowel, bladder and SQLI were modest and similar for 3 HPFX regimens spanning 2.94-4.3 Gy per fraction. These favorable patient-scored outcomes demonstrate the safety and tolerability of such regimens and may be leveraged to support further implementation of mild to moderately hypofractionated radiotherapy in the setting of low and intermediate-risk prostate cancer.

Hypofractionated radiotherapy versus conventionally fractionated radiotherapy for patients with intermediate-risk localised prostate cancer: 2-year patient-reported outcomes of the randomised, non-inferiority, phase 3 CHHiP trial

BACKGROUND

Patient-reported outcomes (PROs) might detect more toxic effects of radiotherapy than do clinician-reported outcomes. We did a quality of life (QoL) substudy to assess PROs up to 24 months after conventionally fractionated or hypofractionated radiotherapy in the Conventional or Hypofractionated High Dose Intensity Modulated Radiotherapy in Prostate Cancer (CHHiP) trial.

METHODS

The CHHiP trial is a randomised, non-inferiority phase 3 trial done in 71 centres, of which 57 UK hospitals took part in the QoL substudy. Men with localised prostate cancer who were undergoing radiotherapy were eligible for trial entry if they had histologically confirmed T1b-T3aN0M0 prostate cancer, an estimated risk of seminal vesicle involvement less than 30%, prostate-specific antigen concentration less than 30 ng/mL, and a WHO performance status of 0 or 1. Participants were randomly assigned (1:1:1) to receive a standard fractionation schedule of 74 Gy in 37 fractions or one of two hypofractionated schedules: 60 Gy in 20 fractions or 57 Gy in 19 fractions. Randomisation was done with computer-generated permuted block sizes of six and nine, stratified by centre and National Comprehensive Cancer Network (NCCN) risk group. Treatment allocation was not masked. UCLA Prostate Cancer Index (UCLA-PCI), including Short Form (SF)-36 and Functional Assessment of Cancer Therapy-Prostate (FACT-P), or Expanded Prostate Cancer Index Composite (EPIC) and SF-12 quality-of-life questionnaires were completed at baseline, pre-radiotherapy, 10 weeks post-radiotherapy, and 6, 12, 18, and 24 months post-radiotherapy. The CHHiP trial completed accrual on June 16, 2011, and the QoL substudy was closed to further recruitment on Nov 1, 2009. Analysis was on an intention-to-treat basis. The primary endpoint of the QoL substudy was overall bowel bother and comparisons between fractionation groups were done at 24 months post-radiotherapy. The CHHiP trial is registered with ISRCTN registry, number ISRCTN97182923.

FINDINGS

2100 participants in the CHHiP trial consented to be included in the QoL substudy: 696 assigned to the 74 Gy schedule, 698 assigned to the 60 Gy schedule, and 706 assigned to the 57 Gy schedule. Of these individuals, 1659 (79%) provided data pre-radiotherapy and 1444 (69%) provided data at 24 months after radiotherapy. Median follow-up was 50·0 months (IQR 38·4-64·2) on April 9, 2014, which was the most recent follow-up measurement of all data collected before the QoL data were analysed in September, 2014. Comparison of 74 Gy in 37 fractions, 60 Gy in 20 fractions, and 57 Gy in 19 fractions groups at 2 years showed no overall bowel bother in 269 (66%), 266 (65%), and 282 (65%) men; very small bother in 92 (22%), 91 (22%), and 93 (21%) men; small bother in 26 (6%), 28 (7%), and 38 (9%) men; moderate bother in 19 (5%), 23 (6%), and 21 (5%) men, and severe bother in four (<1%), three (<1%) and three (<1%) men respectively (74 Gy vs 60 Gy, ptrend=0.64, 74 Gy vs 57 Gy, ptrend=0·59). We saw no differences between treatment groups in change of bowel bother score from baseline or pre-radiotherapy to 24 months.

INTERPRETATION

The incidence of patient-reported bowel symptoms was low and similar between patients in the 74 Gy control group and the hypofractionated groups up to 24 months after radiotherapy. If efficacy outcomes from CHHiP show non-inferiority for hypofractionated treatments, these findings will add to the growing evidence for moderately hypofractionated radiotherapy schedules becoming the standard treatment for localised prostate cancer.

FUNDING

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

Rationale and development of image-guided intensity-modulated radiotherapy post-prostatectomy: the present standard of care?

The indications for post-prostatectomy radiotherapy have evolved over the last decade, although the optimal timing, dose, and target volume remain to be well defined. The target volume is susceptible to anatomical variations with its borders interfacing with the rectum and bladder. Image-guided intensity-modulated radiotherapy has become the gold standard for radical prostate radiotherapy. Here we review the current evidence for image-guided techniques with intensity-modulated radiotherapy to the prostate bed and describe current strategies to reduce or account for interfraction and intrafraction motion.

Minimizing metastatic risk in radiotherapy fractionation schedules

Metastasis is the process by which cells from a primary tumor disperse and form new tumors at distant anatomical locations. The treatment and prevention of metastatic cancer remains an extremely challenging problem. This work introduces a novel biologically motivated objective function to the radiation optimization community that takes into account metastatic risk instead of the status of the primary tumor. In this work, we consider the problem of developing fractionated irradiation schedules that minimize production of metastatic cancer cells while keeping normal tissue damage below an acceptable level. A dynamic programming framework is utilized to determine the optimal fractionation scheme. We evaluated our approach on a breast cancer case using the heart and the lung as organs-at-risk (OAR). For small tumor [Formula: see text] values, hypo-fractionated schedules were optimal, which is consistent with standard models. However, for relatively larger [Formula: see text] values, we found the type of schedule depended on various parameters such as the time when metastatic risk was evaluated, the [Formula: see text] values of the OARs, and the normal tissue sparing factors. Interestingly, in contrast to standard models, hypo-fractionated and semi-hypo-fractionated schedules (large initial doses with doses tapering off with time) were suggested even with large tumor α/β values. Numerical results indicate the potential for significant reduction in metastatic risk.

Prostate Dose-painting Radiotherapy and Radiobiological Guided Optimisation Enhances the Therapeutic Ratio

AIMS

To describe the treatment of 11 patients with radiobiologically guided dose-painting radiotherapy and report on toxicity.

MATERIALS AND METHODS

Boost volumes were identified with functional magnetic resonance imaging scans in 11 patients with high-risk prostate cancer. Patients were treated using a dose-painting approach; the boost dose was limited to 86 Gy in 37 fractions, while keeping the rectal normal tissue complication probability to 5-6%. Rotational intensity-modulated radiotherapy was used with daily image guidance and fiducial markers.

RESULTS

The median dose to the prostate (outside the boost volume) and urethra was 75.4 Gy/37 fractions (range 75.1-75.8 Gy), whereas the median boost dose was 83.4 Gy (range 79.0-87.4 Gy). The tumour control probability (TCP) (Marsden model) increased from 71% for the standard plans to 83.6% [76.6-86.8%] for the dose-painting boost plans. The mean (Lyman-Kutcher-Burman) normal tissue complication probability for rectal bleeding was 5.2% (range 3.3-6.2%) and 5.2% for faecal incontinence (range 3.6-7.8%). All patients tolerated the treatment well, with a low acute toxicity profile. At a median follow-up of 36 months (range 24-50) there was no grade 3 late toxicity. Two patients had grade 2 late urinary toxicity (urethral stricture, urinary frequency and urgency), one patient had grade 1 and one grade 2 late rectal toxicity. The mean prostate-specific antigen at follow-up was 0.81 ng/ml after stopping hormone therapy; one patient relapsed biochemically at 32 months (2.70 ng/ml).

CONCLUSIONS

The toxicity for this radiobiological guided dose-painting protocol was low, but we have only treated a small cohort with limited follow-up time. The advantages of this treatment approach should be established in a clinical trial.

Genomic and Histopathological Tissue Biomarkers That Predict Radiotherapy Response in Localised Prostate Cancer

Localised prostate cancer, in particular, intermediate risk disease, has varied survival outcomes that cannot be predicted accurately using current clinical risk factors. External beam radiotherapy (EBRT) is one of the standard curative treatment options for localised disease and its efficacy is related to wide ranging aspects of tumour biology. Histopathological techniques including immunohistochemistry and a variety of genomic assays have been used to identify biomarkers of tumour proliferation, cell cycle checkpoints, hypoxia, DNA repair, apoptosis, and androgen synthesis, which predict response to radiotherapy. Global measures of genomic instability also show exciting capacity to predict survival outcomes following EBRT. There is also an urgent clinical need for biomarkers to predict the radiotherapy fraction sensitivity of different prostate tumours and preclinical studies point to possible candidates. Finally, the increased resolution of next generation sequencing (NGS) is likely to enable yet more precise molecular predictions of radiotherapy response and fraction sensitivity.

Identifying the dominant prostate cancer focal lesion using image analysis and planning of a simultaneous integrated stereotactic boost

BACKGROUND

Prostate cancer is now the only solid organ cancer in which therapy is commonly applied to the whole gland. One of the main challenges in adopting focal boost or true focal therapy is in the accurate mapping of cancer foci defined on magnetic resonance (MR) images onto the computerised tomography (CT) images used for radiotherapy planning.

MATERIAL AND METHODS

Prostate cancer patients (n = 14) previously treated at the Edinburgh Cancer Centre (ECC) were selected for this study. All patients underwent MR scanning for the purpose of diagnosis and staging. Patients received three months of androgen deprivation hormone therapy followed by a radiotherapy planning CT scan. The dominant focal prostate lesions were identified on MR scans by a radiologist and a novel image analysis approach was used to map the location of the dominant focal lesion from MR to CT. An offline planning study was undertaken on suitable patients (n = 7) to investigate boosting of the radiation dose to the tumour using a stereotactic ablative body radiotherapy (SABR) technique.

RESULTS

The non-rigid registration algorithm showed clinically acceptable estimates of the location of the dominant focal disease on all CT image data of patients suitable for a boost treatment. Standard rigid registration was found to produce unacceptable estimates of the dominant focal lesion on CT. A SABR boost dose of 47.5 Gy was delivered to the dominant focal lesion of all patients whilst meeting all dose-volume histogram (DVH) constraints. Normal tissue complication probability (NTCP) for the rectum decreased from 1.28% to 0.73% with this method.

CONCLUSIONS

These preliminary results demonstrate the potential of this image analysis method for reliably mapping dominant focal disease within the prostate from MR images onto planning CT images. Significant dose escalation using a simultaneous integrated SABR boost was achieved in all patients.

Sexual, irritative, and voiding outcomes, following stereotactic body radiation therapy for prostate cancer

BACKGROUND

Urinary symptoms and sexual dysfunction are the two most common complaints following prostate radiotherapy. The impact of hypofractionated treatment on sexual function, irritative symptoms, and voiding symptoms has not been determined within the same patient population. Here we present our institutional data on sexual function, voiding function, irritative symptoms, and treatment response following SBRT.

METHODS

This retrospective analysis includes 102 non-metastatic patients treated with SBRT at a single institution between May 2008 and September 2014. The course of radiotherapy consisted of 36.25 Gy (range 35-40) over five daily fractions. International Prostate Symptom Score (IPSS), Sexual Health Inventory for Men (SHIM), and PSA were recorded at baseline, 1, 3, 6, 9, 12, 18, 24, and 36 months after treatment.

RESULTS

Median patient age was 72 years old with a median follow-up of 4.3 years. Pretreatment IPSS-I score was 5.21, increasing to 6.97 (p < .001) after 1 month. The mean IPSS-I score returned close to baseline after 3 months to 5.86 and decreased to below baseline after 2 years to 5.09. At 3 months, 9 months, and 2 years, 47.5, 76.2, and 91.1% of patients had reached IPSS-I resolution. The mean IPSS-O score prior to treatment was 5.31 and there was an increase in the score to 6.45 (p = 0.344) at 1 month. The score remained close to baseline and decreased to 4.00 at 2 years and significantly decreased to 3.74 (p = 0.035) at 3 years. 64.4, 82.1, and 96.0% of patients had IPSS-O resolution by 3 months, 9 months, and 2 years. The mean SHIM score prior to treatment was 13.52 and continually decreased to below baseline a year after treatment to 10.56 (p < .001). SHIM score began to improve at 18 months, but was still significantly less than baseline at 12.12 (p = .01).

CONCLUSIONS

While an increase in AUA/IPSS score initially occurred, all patients resume normal activities immediately following treatment and the AUA/IPSS symptoms improved from baseline. Irittative symptoms take longer to resolve when compared to obstructive voiding symptoms in patients treated with SBRT. Three year PSA response, reported toxicity, erectile function preservation, and urinary function improvement, shows favorable results.

[Which rules apply to hypofractionated radiotherapy?]

Hypofractionated radiotherapy is now more widely prescribed due to improved targeting techniques (intensity modulated radiotherapy, image-guided radiotherapy and stereotactic radiotherapy). Low dose hypofractionated radiotherapy is routinely administered mostly for palliative purposes. High or very high dose hypofractionated irradiation must be delivered according to very strict procedures since every minor deviation can lead to major changes in dose delivery to the tumor volume and organs at risk. Thus, each stage of the processing must be carefully monitored starting from the limitations and the choice of the hypofractionation technique, tumour contouring and dose constraints prescription, planning and finally dose calculation and patient positioning verification.

Accumulated dose to the rectum, measured using dose-volume histograms and dose-surface maps, is different from planned dose in all patients treated with radiotherapy for prostate cancer

OBJECTIVE

We sought to calculate accumulated dose (DA) to the rectum in patients treated with radiotherapy for prostate cancer. We were particularly interested in whether dose-surface maps (DSMs) provide additional information to dose-volume histograms (DVHs).

METHODS

Manual rectal contours were obtained for kilovoltage and daily megavoltage CT scans for 10 participants from the VoxTox study (380 scans). Daily delivered dose recalculation was performed using a ray-tracing algorithm. Delivered DVHs were summated to create accumulated DVHs. The rectum was considered as a cylinder, cut and unfolded to produce daily delivered DSMs; these were summated to produce accumulated DSMs.

RESULTS

Accumulated dose-volumes were different from planned in all participants. For one participant, all DA levels were higher and all volumes were larger than planned. For four participants, all DA levels were lower and all volumes were smaller than planned. For each of these four participants, ≥1% of pixels on the accumulated DSM received ≥5 Gy more than had been planned.

CONCLUSION

Differences between accumulated and planned dose-volumes were seen in all participants. DSMs were able to identify differences between DA and planned dose that could not be appreciated from the DVHs. Further work is needed to extract the dose data embedded in the DSMs. These will be correlated with toxicity as part of the VoxTox Programme.

ADVANCES IN KNOWLEDGE

DSMs are able to identify differences between DA and planned dose that cannot be appreciated from DVHs alone and should be incorporated into future studies investigating links between DA and toxicity.

Hypofractionated Helical Tomotherapy for Older Aged Patients With Prostate Cancer: Preliminary Results of a Phase I-II Trial

In our center, the feasibility and related acute toxicities of hypofractionated helical tomotherapy have been evaluated in older aged patients with prostate cancer . Between February 2009 and February 2014, 67 patients (older than 65 years) were enrolled in a prospective phase I-II study (registered number, ChiCTR-ONC-13004037). Patients in cohort 1 (n = 33) and cohort 2 (n = 34) received 76 Gy in 34 fractions (2.25 Gy/F) and 71.6 Gy in 28 fractions (2.65 Gy/F), respectively, to the prostate and seminal vesicles, while 25 patients in cohort 2 also received integrated elective lymph node irradiation (50.4 Gy). All patients were treated with helical tomotherapy, and daily image guidance was performed before each treatment. Acute toxicities were assessed with Radiation Therapy Oncology Group (RTOG)/European Organization for Research on Treatment of Cancer (EORTC) criteria. No significant difference was detected between the 2 cohorts in the incidence of acute toxicities. In cohort 1, the incidences of grade 1 and 2 genitourinary and gastrointestinal toxicities were 45.5% and 45.4%, respectively, and without grade 3 and 4 toxicities. In cohort 2, the incidences of acute grade 1 and 2 genitourinary and gastrointestinal toxicities were 47.1% and 55.9%, respectively, and grade 3 genitourinary toxicity (hematuria) was noted only in 1 patient. No significant difference was detected in the incidence of acute toxicities between the patients receiving integrated elective lymph node irradiation and those receiving irradiation to prostate and seminal vesicle in cohort 2. Univariate and multivariate analyses were performed with clinical parameters. Only the baseline weight was found negatively correlated with genitourinary toxicities at a weak level (relative risk = 0.946, 95% confidence interval 0.896-0.998], P = .043). This study shows that 2 hypofractionation regimens (76 Gy/34F and 71.6 Gy/28F) delivered with HT are well tolerated in older aged patients having prostate cancer without significant difference for acute toxicities between the 2 cohorts. Late toxicities and treatment outcomes for these patients are under investigation.

Initial UK Experience of Stereotactic Body Radiotherapy for Extracranial Oligometastases: Can We Change the Therapeutic Paradigm?

AIMS

To retrospectively review the toxicity and early outcome data from patients who have received stereotactic body radiotherapy (SBRT) for extracranial oligometastases at a single UK institution.

MATERIALS AND METHODS

Eligible patients had ≤3 extracranial metastases and performance status ≤2. Prior systemic therapy and radical treatment of oligometastastic relapse with any standard treatment modality was permitted. Patients with synchronous metastatic disease were excluded unless they had evidence of controlled primary disease after radical therapy. Follow-up consisted of clinical examination, biochemical and radiological assessments in accordance with standard clinical care. Progression events were defined using RECIST. Toxicity was evaluated using CTCAE v4.0. Local control, progression-free survival (PFS), freedom from widespread distant metastasis (defined as disease not amenable to further radical salvage therapy) and overall survival were calculated.

RESULTS

Between July 2011 and April 2014, 73 patients with 87 metastases received SBRT (range 1-3 per patient). The median follow-up was 14.5 months (range 0-26.4). The median PFS was 14.5 months (1 year PFS 57%, 2 year 28%); 1 year overall survival 96%, 2 year 79.8%; 2 year local control 88%. At 2 years, 46% of patients were free from widespread distant metastases. No ≥ grade 3 acute or late toxicity was observed.

CONCLUSION

At this time point, observed toxicity is minimal with excellent local control rates. This promising treatment paradigm requires further investigation in the context of a randomised controlled trial to establish if the addition of SBRT to standard care improves survival outcomes.

Treatment of Breast and Prostate Cancer by Hypofractionated Radiotherapy: Potential Risks and Benefits

Breast cancer and prostate cancer are the most common cancers diagnosed in women and men, respectively, in the UK, and radiotherapy is used extensively in the treatment of both. In vitro data suggest that tumours in the breast and prostate have unique properties that make a hypofractionated radiotherapy treatment schedule advantageous in terms of therapeutic index. Many clinical trials of hypofractionated radiotherapy treatment schedules have been completed to establish the extent to which hypofractionation can improve patient outcome. Here we present a concise description of hypofractionation, the mathematical description of converting between conventional and hypofractionated schedules, and the motivation for using hypofractionation in the treatment of breast and prostate cancer. Furthermore, we summarise the results of important recent hypofractionation trials and highlight the limitations of a hypofractionated treatment regimen.

Moderate hypofractionation and simultaneous integrated boost by helical tomotherapy in prostate cancer: monoinstitutional report of acute tolerability assessment with different toxicity scales

INTRODUCTION

Based on radiobiology evidence, hypofractionated radiotherapy has the potential of improving treatment outcome in prostate cancer patients. In this study, we evaluated the safety, in terms of acutetoxicity, of using moderate hypofractionated radiotherapy delivered with Helical Tomotherapy (HT) to treat prostate cancer patients.

MATERIALS AND METHODS

Between December 2012 and April 2014, 42 consecutive patients were treated with hypofractionated radiotherapy using HT. All patients received 70 Gy in 28 fractions to PTV1, which included the prostate. In the intermediate risk group, 61.6 Gy were delivered to PTV2, which included the seminal vesicles. In high risk patients, the pelvic nodes were added (PTV3) and received 50.4 Gy. Acute toxicity was recorded prospectively with RTOG and Common Terminology Criteria for Adverse Events 3.0, retrospectively with CTCAE 4.0. Expanded Prostate Cancer Index Composite (EPIC) was measured at baseline and 3 months after end of treatment, to investigate health related quality of life with regards to bladder and gastrointestinal function.

RESULTS

Acute toxicity was acceptable, independently from the system used to score side effects. Moderate genitourinary toxicity was more frequent than gastrointestinal toxicity. No correlation between acute side effects and patients' characteristics or physical dose parameters was registered. EPIC evaluation showed a negligible difference in urinary and bowel function post-treatment, that did not reach statistical significance.

CONCLUSIONS

Our experience confirms the safety of moderate hypofractionation delivered with HT in prostate cancer patients with low, intermediate and high risk.

Using routinely collected data to stratify prostate cancer patients into phases of care in the United Kingdom: implications for resource allocation and the cancer survivorship programme

BACKGROUND

Prostate cancer is the most commonly diagnosed malignancy in British men. The increasing use of PSA screening test has resulted in many more patients being diagnosed with this condition. Advances in its treatment have improved the survival rate among these patients. By 2040, the prevalence of prostate cancer survivors is expected to reach 830 000. Many of them will require medical support for the management of their progressive disease or long-term toxicities from previous treatments. Successful implementation of the cancer survivorship programme among these patients depends on a good understanding of their demand on the health care system. The aim of this study is to segment the population of prostate cancer survivors into different needs groups and to quantify them with respect to their phase of care.

METHODS

Incidence, survival, prevalence and mortality data collected and reported by cancer registries across the United Kingdom have been used for the current study to provide indicative estimates as to the number of prostate cancer patients in each phase of the care pathway in a year.

RESULTS

The majority of prostate cancer patients are in the post-treatment monitoring phase. Around a fifth of the patients are either receiving treatment or in the recovery and readjustment phase having completed their treatment in the preceding year. Thirteen percent have not received any anticancer treatment, a further 12% (32 000) have developed metastatic disease and 4% are in the final stage of their lives.

CONCLUSION

On the basis of our estimates, patients undergoing post-treatment monitoring phase will constitute the biggest group among prostate cancer survivors. The pressure to provide adequate follow-up care to these patients will be a challenge. There is limited data available to definitively quantify the number of prostate cancer patients who follow different pathways of care, and we hope this study has highlighted the importance of collecting and reporting of such data to help future health care planning for these patients.

Acute toxicity of hypofractionated intensity-modulated radiotherapy for prostate cancer

BACKGROUND

Dose-escalated hypofractionated radiotherapy (hfrt) using intensity-modulated radiotherapy (imrt), with inclusion of the pelvic lymph nodes (plns), plus androgen suppression therapy (ast) in high-risk prostate cancer patients should improve patient outcomes, but acute toxicity could limit its feasibility.

METHODS

Our single-centre phase ii prospective study enrolled 40 high-risk prostate cancer patients. All patients received hfrt using imrt with daily mega-voltage computed tomography imaging guidance, with 95% of planning target volumes (ptv68 and ptv50) receiving 68 Gy and 50 Gy (respectively) in 25 daily fractions. The boost volume was targeted to the involved plns and the prostate (minus the urethra plus 3 mm and minus 3 mm from adjacent rectal wall) and totalled up to 75 Gy in 25 fractions. Acute toxicity scores were recorded weekly during and 3 months after radiotherapy (rt) administration.

RESULTS

For the 37 patients who completed rt and the 3-month follow-up, median age was 65.5 years (range: 50-76 years). Disease was organ-confined (T1c-T2c) in 23 patients (62.1%), and node-positive in 5 patients (13.5%). All patients received long-term ast. Maximum acute genitourinary (gu) and gastrointestinal (gi) toxicity peaked at grade 2 in 6 of 36 evaluated patients (16.6%) and in 4 of 31 evaluated patients (12.9%) respectively. Diarrhea and urinary frequency were the chief complaints. Dose-volume parameters demonstrated no correlation with toxicity. The ptv treatment objectives were met in 36 of the 37 patients.

CONCLUSIONS

This hfrt dose-escalation trial in high-risk prostate cancer has demonstrated the feasibility of administering 75 Gy in 25 fractions with minimal acute gi and gu toxicities. Further follow-up will report late toxicities and outcomes.

Long-term results of a study using individualized planning target volumes for hypofractionated intensity-modulated radiotherapy boost for prostate cancer

Background

This is the final report of a prospective phase I study which evaluated the feasibility, toxicities, and biochemical control in prostate cancer patients treated with a hypofractionated boost utilizing a fiducial marker-based daily image guidance strategy and small patient-specific PTV margins.

Methods

Low- and intermediate-risk prostate cancer patients underwent transperineal ultrasound-guided implantation of three gold fiducial markers and were treated with three-dimensional conformal radiotherapy to 42 Gy (2 Gy/day). During the first nine fractions of treatment, pre- and post-treatment electronic portal imaging was performed to calculate intrafraction prostate motion. Patient-specific PTV margins were derived and a 30 Gy (3 Gy/day) intensity modulated radiotherapy boost was delivered (Total dose = 72 Gy in 31 fractions; EQD2 = 81 Gy, α/β = 1.4).

Results

Thirty-three patients completed treatment and were followed for a median of 7.2 years (range, 1.2 – 9.5). Seven patients (21%) developed Radiation Therapy Oncology Group (RTOG) late grade 2 GI toxicity and 1 patient (3%) developed late grade 2 GU toxicity. No patients developed late grade 3 GI or GU toxicity. To date, nine patients developed PSA relapse according to the Phoenix criteria. The actuarial five, seven and nine year biochemical control (BC) rates were 87% (95% confidence interval: 69–95), 77% (95% confidence interval: 56–89) and 66% (95% confidence interval: 42–82).

Conclusions

Our study demonstrates that the use of prostate fiducial markers in combination with a daily online image guidance protocol permits reduced, patient-specific PTV margins in a hypofractionated treatment scheme. This treatment planning and delivery strategy was well tolerated in the intermediate time frame. The use of very small PTV margins did not result in excessive failures when compared to other radiation regimens of similar radiobiological intensity.

Volumetric modulated arc therapy in prostate cancer patients with metallic hip prostheses in a UK centre

AIM

This study aimed to investigate whether IMRT using VMAT is a viable and safe solution in dose escalated RT in these patients.

BACKGROUND

An increasing number of prostate cancer patients are elderly and have hip prostheses. These implants pose challenges in radiotherapy treatment planning. Although intensity modulated radiotherapy (IMRT) is commonly used, there is a lack of clinical studies documenting its efficacy and toxicities in this subgroup of patients.

MATERIALS AND METHODS

The data from 23 patients with hip prostheses and non-metastatic prostate cancer treated with VMAT (volumetric modulated arc therapy) between 2009 and 2011, were retrospectively analyzed. Baseline characteristics, treatment details and outcome data were collected on all patients. The median follow up was 40.9 months. MRI-CT image fusion was performed and the treatment plans were created using RapidArc™ (RA) techniques utilizing 1 or 2 arcs and 10 MV photon beams.

RESULTS

96% of patients were treated with a dose of 72 Gy/32 fractions over 44 days. 21/23 plans met the PTV targets. The mean homogeneity index was 1.07. 20/23 plans met all OAR constraints (rectum, bladder). Two plans deviated from rectal constraints, four from bladder constraints; all were classed as minor deviations. One patient experienced late grade 3 genitourinary toxicity. Three other patients experienced late grade 2 or lower gastrointestinal toxicity. One patient had biochemical failure and one had a non-prostate cancer related death.

CONCLUSIONS

VMAT provides an elegant solution to deliver dose escalated RT in patients with unilateral and bilateral hip replacements with minimal acute and late toxicities.

[Elderly patients and radiotherapy: A short review]

The ageing of French population imposes to radiotherapists the challenge to treat older patients and to adjust their treatment. Unthinkable 30 years ago, radiation therapy concerns nowadays patients aged more than 90 years old. Oncogeriatric scales have been improved those last years without necessarily making sure that the right treatment is given to the right patient: if oncogeriatric scales use influences the final therapeutic decision, it does not define new target volumes, new doses, or new fractionation protocols. Except for some organs, there is not, for the moment, any consensus concerning geriatric population adapted treatments. This makes any therapeutic decision difficult. The present review has for objective to realise a report of the studies about favorable and unfavorable effects of radiation therapy amongst aged (>70 years old) or very aged (>90years old) population.

Ion therapy of prostate cancer: daily rectal dose reduction by application of spacer gel

Background

Ion beam therapy represents a promising approach to treat prostate cancer, mainly due to its high conformity and radiobiological effectiveness. However, the presence of prostate motion, patient positioning and range uncertainties may deteriorate target dose and increase exposure of organs at risk. Spacer gel injected between prostate and rectum may increase the safety of prostate cancer (PC) radiation therapy by separating the rectum from the target dose field. The dosimetric impact of the application of spacer gel for scanned carbon ion therapy of PC has been analyzed at Heidelberg Ion-Beam Therapy Center (HIT).

Materials and methods

The robustness of ion therapy treatment plans was investigated by comparison of two data sets of patients treated with and without spacer gel. A research treatment planning system for ion therapy was used for treatment plan optimization and calculation of daily dose distributions on 2 to 9 Computed Tomography (CT) studies available for each of the 19 patients. Planning and daily dose distributions were analyzed with respect to target coverage, maximal dose to the rectum (excluding 1 ml of the greatest dose; Dmax-1 ml) and the rectal volume receiving dose greater than 90% of prescribed target dose (V90_Rectum), respectively.

Results

The application of spacer gel did substantially diminish rectum dose. Dmax-1 ml on the treatment planning CT was on average reduced from 100.0 ± 1.0% to 90.2 ± 4.8%, when spacer gel was applied. The robustness analysis performed with daily CT studies demonstrated for all analyzed patient cases that application of spacer gel results in a decrease of the daily V90_Rectum index, which calculated over all patient cases and CT studies was 10.2 ± 10.4 [ml] and 1.1 ± 2.1 [ml] for patients without and with spacer gel, respectively.

Conclusions

The dosimetric benefit of increasing the distance between prostate and rectum using spacer gel for PC treatment with carbon ion beams has been quantified. Application of spacer gel substantially reduced rectal exposure to high treatment dose and, therefore, can reduce the hazard of rectal toxicity in ion beam therapy of PC. The results of this study enable modifications of the PC ion therapy protocol such as dose escalation or hypofractionation.

Electronic supplementary material

The online version of this article (doi:10.1186/s13014-015-0348-1) contains supplementary material, which is available to authorized users.

Radiotherapy for high-risk prostate cancer

The combination of radiation treatment and long-term androgen deprivation therapy (ADT) has been shown in multiple clinical trials to prolong overall survival in men with high-risk prostate cancer compared with either treatment alone. New radiation technologies enable the safe delivery of high radiation doses that improve cancer control compared with lower radiation doses. Based on the results of multiple randomized trials, clinical practice guidelines for high-risk prostate cancer recommend total radiation doses of at least 75.6 Gy, with long-term (2-3 years) ADT. Ongoing research into hypofractionated radiation treatment, whole-pelvic radiation, and combinations of radiation with novel hormonal agents could further improve cancer control and survival outcomes for patients with high-risk prostate cancer.

Hypofractionated versus conventionally fractionated radiotherapy for patients with prostate cancer (HYPRO): acute toxicity results from a randomised non-inferiority phase 3 trial

BACKGROUND

In 2007, we began the randomised phase 3 multicentre HYPRO trial to investigate the effect of hypofractionated radiotherapy compared with conventionally fractionated radiotherapy on relapse-free survival in patients with prostate cancer. Here, we examine whether patients experience differences in acute gastrointestinal and genitourinary adverse effects.

METHODS

In this randomised non-inferiority phase 3 trial, done in seven radiotherapy centres in the Netherlands, we enrolled intermediate-risk or high-risk patients aged between 44 and 85 years with histologically confirmed stage T1b-T4 NX-0MX-0 prostate cancer, a PSA concentration of 60 ng/mL or lower, and WHO performance status of 0-2. A web-based application was used to randomly assign (1:1) patients to receive either standard fractionation with 39 fractions of 2 Gy in 8 weeks (five fractions per week) or hypofractionation with 19 fractions of 3·4 Gy in 6·5 weeks (three fractions per week). Randomisation was done with minimisation procedure, stratified by treatment centre and risk group. The primary endpoint is 5-year relapse-free survival. Here we report data for the acute toxicity outcomes: the cumulative incidence of grade 2 or worse acute and late genitourinary and gastrointestinal toxicity. Non-inferiority of hypofractionation was tested separately for genitourinary and gastrointestinal acute toxic effects, with a null hypothesis that cumulative incidences of each type of adverse event were not more than 8% higher in the hypofractionation group than in the standard fractionation group. We scored acute genitourinary and gastrointestinal toxic effects according to RTOG-EORTC criteria from both case report forms and patients' self-assessment questionnaires, at baseline, twice during radiotherapy, and 3 months after completion of radiotherapy. Analyses were done in the intention-to-treat population. Patient recruitment has been completed. This study is registered with www.controlled-trials.com, number ISRCTN85138529.

FINDINGS

Between March 19, 2007, and Dec 3, 2010, 820 patients were randomly assigned to treatment with standard fractionation (n=410) or hypofractionation (n=410). 3 months after radiotherapy, 73 (22%) patients in the standard fractionation group and 75 (23%) patients in the hypofractionation group reported grade 2 or worse genitourinary toxicity; grade 2 or worse gastrointestinal toxicity was noted in 43 (13%) patients in the standard fractionation group and in 42 (13%) in the hypofractionation group. Grade 4 acute genitourinary toxicity was reported for two patients, one (<1%) in each group. No grade 4 acute gastrointestinal toxicities were observed. We noted no significant difference in cumulative incidence by 120 days after radiotherapy of grade 2 or worse acute genitourinary toxicity (57·8% [95% CI 52·9-62·7] in the standard fractionation group vs 60·5% (55·8-65·3) in the hypofractionation group; difference 2·7%, 90% CI -2·99 to 8·48; odds ratio [OR] 1·12, 95% CI 0·84-1·49; p=0·43). The cumulative incidence of grade 2 or worse acute gastrointestinal toxicity by 120 days after radiotherapy was higher in patients given hypofractionation (31·2% [95% CI 26·6-35·8] in the standard fractionation group vs 42·0% [37·2-46·9] in the hypofractionation group; difference 10·8%, 90% CI 5·25-16·43; OR 1·6; p=0·0015; non-inferiority not confirmed).

INTERPRETATION

Hypofractionated radiotherapy was not non-inferior to standard fractionated radiotherapy in terms of acute genitourinary and gastrointestinal toxicity for men with intermediate-risk and high-risk prostate cancer. In fact, the cumulative incidence of grade 2 or worse acute gastrointestinal toxicity was significantly higher in patients given hypofractionation than in those given standard fractionated radiotherapy. Patients remain in follow-up for efficacy endpoints.

FUNDING

The Dutch Cancer Society.

Accelerated hypofractioned postoperative radiotherapy for prostate cancer: a prospective phase I/II study

AIMS

To present the initial findings of a single institution, phase I/II study investigating hypofractionated radiotherapy in patients undergoing post-prostatectomy treatment.

MATERIALS AND METHODS

Patients requiring postoperative radiotherapy were prospectively enrolled. Dose was prescribed to the prostate bed with 51 Gy in 17 daily fractions. Androgen deprivation was optional. Acute and late gastrointestinal/genitourinary toxicity were assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0 and quality of life was assessed using the Expanded Prostate Cancer Index Composite evaluation tool. Prostate-specific antigen (PSA) was evaluated at every follow-up.

RESULTS

Thirty patients were enrolled between 2009 and 2011. The median age was 65 years and most had Gleason 7 disease (86%) with pT2c or pT3a (82%). Positive margins were documented in 67% of the patients. The median pre-treatment PSA was 0.12 ng/ml. The median follow-up was 24 months. Overall toxicity was low, with >80% of patients having ≤ grade 1 acute toxicity in both genitourinary and gastrointestinal realms. Similarly, only two patients (6%) experienced grade 2/3 late gastrointestinal/genitourinary toxicity. Quality of life scores were also indicative of a well-tolerated treatment. PSA failure was seen in five patients (17%).

CONCLUSIONS

We present a hypofractionated schedule of postoperative prostate radiotherapy that is both well tolerated in terms of both toxicity and quality of life measures. Initial PSA control is encouraging. Further evaluation with a longer follow-up and a larger cohort is warranted.