Implementing the UK Medical Research Council (MRC) RT01 trial (ISRCTN 47772397): methods and practicalities of a randomised controlled trial of conformal radiotherapy in men with localised prostate cancer

Dose-escalated radiotherapy for clinically localized and locally advanced prostate cancer

BACKGROUND

Treatments for clinically localized prostate cancer include radical prostatectomy, external beam radiation therapy, brachytherapy, active surveillance, hormonal therapy, and watchful waiting. For external beam radiation therapy, oncological outcomes may be expected to improve as the dose of radiotherapy (RT) increases. However, radiation-mediated side effects on surrounding critical organs may also increase.

OBJECTIVES

To assess the effects of dose-escalated RT in comparison with conventional dose RT for curative treatment of clinically localized and locally advanced prostate cancer.

SEARCH METHODS

We performed a comprehensive search using multiple databases including trial registries and other sources of grey literature, up until 20 July 2022. We applied no restrictions on publication language or status.

SELECTION CRITERIA

We included parallel-arm randomized controlled trials (RCTs) of definitive RT in men with clinically localized and locally advanced prostate adenocarcinoma. RT was dose-escalated RT (equivalent dose in 2 Gy [EQD2] ≥ 74 Gy, lesser than 2.5 Gy per fraction) versus conventional RT (EQD2 < 74 Gy, 1.8 Gy or 2.0 Gy per fraction). Two review authors independently classified studies for inclusion or exclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently abstracted data from the included studies. We performed statistical analyses by using a random-effects model and interpreted them according to the Cochrane Handbook for Systematic Reviews of Interventions. We used GRADE guidance to rate the certainty of the evidence of RCTs.

MAIN RESULTS

We included nine studies with 5437 men in an analysis comparing dose-escalated RT versus conventional dose RT for the treatment of prostate cancer. The mean participant age ranged from 67 to 71 years. Almost all men had localized prostate cancer (cT1-3N0M0). Primary outcomes Dose-escalated RT probably results in little to no difference in time to death from prostate cancer (hazard ratio [HR] 0.83, 95% CI 0.66 to 1.04; I2 = 0%; 8 studies; 5231 participants; moderate-certainty evidence). Assuming a risk of death from prostate cancer of 4 per 1000 at 10 years in the conventional dose RT group, this corresponds to 1 fewer men per 1000 (1 fewer to 0 more) dying of prostate cancer in the dose-escalated RT group. Dose-escalated RT probably results in little to no difference in severe RT toxicity of grade 3 or higher late gastrointestinal (GI) toxicity (RR 1.72, 95% CI 1.32 to 2.25; I2 = 0%; 8 studies; 4992 participants; moderate-certainty evidence); 23 more men per 1000 (10 more to 40 more) in the dose-escalated RT group assuming severe late GI toxicity as 32 per 1000 in the conventional dose RT group. Dose-escalated RT probably results in little to no difference in severe late genitourinary (GU) toxicity (RR 1.25, 95% CI 0.95 to 1.63; I2 = 0%; 8 studies; 4962 participants; moderate-certainty evidence); 9 more men per 1000 (2 fewer to 23 more) in the dose-escalated RT group assuming severe late GU toxicity as 37 per 1000 in the conventional dose RT group. Secondary outcomes Dose-escalated RT probably results in little to no difference in time to death from any cause (HR 0.98, 95% CI 0.89 to 1.09; I2 = 0%; 9 studies; 5437 participants; moderate-certainty evidence). Assuming a risk of death from any cause of 101 per 1000 at 10 years in the conventional dose RT group, this corresponds to 2 fewer men per 1000 (11 fewer to 9 more) in the dose-escalated RT group dying of any cause. Dose-escalated RT probably results in little to no difference in time to distant metastasis (HR 0.83, 95% CI 0.57 to 1.22; I2 = 45%; 7 studies; 3499 participants; moderate-certainty evidence). Assuming a risk of distant metastasis of 29 per 1000 in the conventional dose RT group at 10 years, this corresponds to 5 fewer men per 1000 (12 fewer to 6 more) in the dose-escalated RT group developing distant metastases. Dose-escalated RT may increase overall late GI toxicity (RR 1.27, 95% CI 1.04 to 1.55; I2 = 85%; 7 studies; 4328 participants; low-certainty evidence); 92 more men per 1000 (14 more to 188 more) in the dose-escalated RT group assuming overall late GI toxicity as 342 per 1000 in the conventional dose RT group. However, dose-escalated RT may result in little to no difference in overall late GU toxicity (RR 1.12, 95% CI 0.97 to 1.29; I2 = 51%; 7 studies; 4298 participants; low-certainty evidence); 34 more men per 1000 (9 fewer to 82 more) in the dose-escalated RT group assuming overall late GU toxicity as 283 per 1000 in the conventional dose RT group. Based on long-term follow-up (up to 36 months), dose-escalated RT may result or probably results in little to no difference in the quality of life using 36-Item Short Form Survey; physical health (MD -3.9, 95% CI -12.78 to 4.98; 1 study; 300 participants; moderate-certainty evidence) and mental health (MD -3.6, 95% CI -83.85 to 76.65; 1 study; 300 participants; low-certainty evidence), respectively.

AUTHORS' CONCLUSIONS

Compared to conventional dose RT, dose-escalated RT probably results in little to no difference in time to death from prostate cancer, time to death from any cause, time to distant metastasis, and RT toxicities (except overall late GI toxicity). While dose-escalated RT may increase overall late GI toxicity, it may result, or probably results, in little to no difference in physical and mental quality of life, respectively.

Reduced Dose Posterior to Prostate Correlates With Increased PSA Progression in Voxel-Based Analysis of 3 Randomized Phase 3 Trials

PURPOSE

Reducing margins during treatment planning to decrease dose to healthy organs surrounding the prostate can risk inadequate treatment of subclinical disease. This study aimed to investigate whether lack of dose to subclinical disease is associated with increased disease progression by using high-quality prostate radiation therapy clinical trial data to identify anatomically localized regions where dose variation is associated with prostate-specific antigen progression (PSAP).

METHODS AND MATERIALS

Planned dose distributions for 683 patients of the Trans-Tasman Radiation Oncology Group 03.04 Randomized Androgen Deprivation and Radiotherapy (RADAR) trial were deformably registered onto a single exemplar computed tomography data set. These were divided into high-risk and intermediate-risk subgroups for analysis. Three independent voxel-based statistical tests, using permutation testing, Cox regression modeling, and least absolute shrinkage selection operator feature selection, were applied to identify regions where dose variation was associated with PSAP. Results from the intermediate-risk RADAR subgroup were externally validated by registering dose distributions from the RT01 (n = 388) and Conventional or Hypofractionated High Dose Intensity Modulated Radiotherapy for Prostate Cancer Trial (CHHiP) (n = 253) trials onto the same exemplar and repeating the tests on each of these data sets.

RESULTS

Voxel-based Cox regression revealed regions where reduced dose was correlated with increased prostate-specific androgen progression. Reduced dose in regions associated with coverage at the posterior prostate, in the immediate periphery of the posterior prostate, and in regions corresponding to the posterior oblique beams or posterior lateral beam boundary, was associated with increased PSAP for RADAR and RT01 patients, but not for CHHiP patients. Reduced dose to the seminal vesicle region was also associated with increased PSAP for RADAR intermediate-risk patients.

CONCLUSIONS

Ensuring adequate dose coverage at the posterior prostate and immediately surrounding posterior region (including the seminal vesicles), where aggressive cancer spread may be occurring, may improve tumor control. It is recommended that particular care be taken when defining margins at the prostate posterior, acknowledging the trade-off between quality of life due to rectal dose and the preferences of clinicians and patients.

Relationships between rectal and perirectal doses and rectal bleeding or tenesmus in pooled voxel-based analysis of 3 randomised phase III trials

BACKGROUND AND PURPOSE

This study aimed to identify anatomically-localised regions where planned radiotherapy dose is associated with gastrointestinal toxicities in healthy tissues throughout the pelvic anatomy.

MATERIALS AND METHODS

Planned dose distributions for up to 657 patients of the Trans Tasman Radiation Oncology Group 03.04 RADAR trial were deformably registered onto a single exemplar computed tomography dataset. Voxel-based multiple comparison permutation dose difference testing, Cox regression modelling and LASSO feature selection were used to identify regions where dose-increase was associated with grade ≥2 rectal bleeding (RB) or tenesmus, according to the LENT/SOMA scale. This was externally validated by registering dose distributions from the RT01 (n = 388) and CHHiP (n = 241) trials onto the same exemplar and repeating the tests on each of these data sets, and on all three datasets combined.

RESULTS

Voxel-based Cox regression and permutation dose difference testing revealed regions where increased dose was correlated with gastrointestinal toxicity. Grade ≥2 RB was associated with posteriorly extended lateral beams that manifested high doses (>55 Gy) in a small rectal volume adjacent to the clinical target volume. A correlation was found between grade ≥2 tenesmus and increased low-intermediate dose (∼25 Gy) at the posterior beam region, including the posterior rectum and perirectal fat space (PRFS).

CONCLUSIONS

The serial response of the rectum with respect to RB has been demonstrated in patients with posteriorly extended lateral beams. Similarly, the parallel response of the PRFS with respect to tenesmus has been demonstrated in patients treated with the posterior beam.

Active monitoring, radical prostatectomy and radical radiotherapy in PSA-detected clinically localised prostate cancer: the ProtecT three-arm RCT

BACKGROUND

Prostate cancer is the most common cancer among men in the UK. Prostate-specific antigen testing followed by biopsy leads to overdetection, overtreatment as well as undertreatment of the disease. Evidence of treatment effectiveness has lacked because of the paucity of randomised controlled trials comparing conventional treatments.

OBJECTIVES

To evaluate the effectiveness of conventional treatments for localised prostate cancer (active monitoring, radical prostatectomy and radical radiotherapy) in men aged 50-69 years.

DESIGN

A prospective, multicentre prostate-specific antigen testing programme followed by a randomised trial of treatment, with a comprehensive cohort follow-up.

SETTING

Prostate-specific antigen testing in primary care and treatment in nine urology departments in the UK.

PARTICIPANTS

Between 2001 and 2009, 228,966 men aged 50-69 years received an invitation to attend an appointment for information about the Prostate testing for cancer and Treatment (ProtecT) study and a prostate-specific antigen test; 82,429 men were tested, 2664 were diagnosed with localised prostate cancer, 1643 agreed to randomisation to active monitoring (n = 545), radical prostatectomy (n = 553) or radical radiotherapy (n = 545) and 997 chose a treatment.

INTERVENTIONS

The interventions were active monitoring, radical prostatectomy and radical radiotherapy.

TRIAL PRIMARY OUTCOME MEASURE

Definite or probable disease-specific mortality at the 10-year median follow-up in randomised participants.

SECONDARY OUTCOME MEASURES

Overall mortality, metastases, disease progression, treatment complications, resource utilisation and patient-reported outcomes.

RESULTS

There were no statistically significant differences between the groups for 17 prostate cancer-specific (p = 0.48) and 169 all-cause (p = 0.87) deaths. Eight men died of prostate cancer in the active monitoring group (1.5 per 1000 person-years, 95% confidence interval 0.7 to 3.0); five died of prostate cancer in the radical prostatectomy group (0.9 per 1000 person-years, 95% confidence interval 0.4 to 2.2 per 1000 person years) and four died of prostate cancer in the radical radiotherapy group (0.7 per 1000 person-years, 95% confidence interval 0.3 to 2.0 per 1000 person years). More men developed metastases in the active monitoring group than in the radical prostatectomy and radical radiotherapy groups: active monitoring, n = 33 (6.3 per 1000 person-years, 95% confidence interval 4.5 to 8.8); radical prostatectomy, n = 13 (2.4 per 1000 person-years, 95% confidence interval 1.4 to 4.2 per 1000 person years); and radical radiotherapy, n = 16 (3.0 per 1000 person-years, 95% confidence interval 1.9 to 4.9 per 1000 person-years; p = 0.004). There were higher rates of disease progression in the active monitoring group than in the radical prostatectomy and radical radiotherapy groups: active monitoring (n = 112; 22.9 per 1000 person-years, 95% confidence interval 19.0 to 27.5 per 1000 person years); radical prostatectomy (n = 46; 8.9 per 1000 person-years, 95% confidence interval 6.7 to 11.9 per 1000 person-years); and radical radiotherapy (n = 46; 9.0 per 1000 person-years, 95% confidence interval 6.7 to 12.0 per 1000 person years; p < 0.001). Radical prostatectomy had the greatest impact on sexual function/urinary continence and remained worse than radical radiotherapy and active monitoring. Radical radiotherapy's impact on sexual function was greatest at 6 months, but recovered somewhat in the majority of participants. Sexual and urinary function gradually declined in the active monitoring group. Bowel function was worse with radical radiotherapy at 6 months, but it recovered with the exception of bloody stools. Urinary voiding and nocturia worsened in the radical radiotherapy group at 6 months but recovered. Condition-specific quality-of-life effects mirrored functional changes. No differences in anxiety/depression or generic or cancer-related quality of life were found. At the National Institute for Health and Care Excellence threshold of £20,000 per quality-adjusted life-year, the probabilities that each arm was the most cost-effective option were 58% (radical radiotherapy), 32% (active monitoring) and 10% (radical prostatectomy).

LIMITATIONS

A single prostate-specific antigen test and transrectal ultrasound biopsies were used. There were very few non-white men in the trial. The majority of men had low- and intermediate-risk disease. Longer follow-up is needed.

CONCLUSIONS

At a median follow-up point of 10 years, prostate cancer-specific mortality was low, irrespective of the assigned treatment. Radical prostatectomy and radical radiotherapy reduced disease progression and metastases, but with side effects. Further work is needed to follow up participants at a median of 15 years.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN20141297.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 37. See the National Institute for Health Research Journals Library website for further project information.

Increased Dose to Organs in Urinary Tract Associates With Measures of Genitourinary Toxicity in Pooled Voxel-Based Analysis of 3 Randomized Phase III Trials

Purpose: Dose information from organ sub-regions has been shown to be more predictive of genitourinary toxicity than whole organ dose volume histogram information. This study aimed to identify anatomically-localized regions where 3D dose is associated with genitourinary toxicities in healthy tissues throughout the pelvic anatomy. Methods and Materials: Dose distributions for up to 656 patients of the Trans-Tasman Radiation Oncology Group 03.04 RADAR trial were deformably registered onto a single exemplar CT dataset. Voxel- based multiple comparison permutation dose difference testing, Cox regression modeling and LASSO feature selection were used to identify regions where 3D dose-increase was associated with late grade ≥ 2 genitourinary dysuria, incontinence and frequency, and late grade ≥ 1 haematuria. This was externally validated by registering dose distributions from the RT01 (up to n = 388) and CHHiP (up to n = 247) trials onto the same exemplar and repeating the voxel-based tests on each of these data sets. All three datasets were then combined, and the tests repeated. Results: Voxel-based Cox regression and multiple comparison permutation dose difference testing revealed regions where increased dose was correlated with genitourinary toxicity. Increased dose in the vicinity of the membranous and spongy urethra was associated with dysuria for all datasets. Haematuria was similarly correlated with increased dose at the membranous and spongy urethra, for the RADAR, CHHiP, and combined datasets. Some evidence was found for the association between incontinence and increased dose at the internal and external urethral sphincter for RADAR and the internal sphincter alone for the combined dataset. Incontinence was also strongly correlated with dose from posterior oblique beams. Patients with fields extending inferiorly and posteriorly to the CTV, adjacent to the membranous and spongy urethra, were found to experience increased frequency. Conclusions: Anatomically-localized dose-toxicity relationships were determined for late genitourinary symptoms in the urethra and urinary sphincters. Low-intermediate doses to the extraprostatic urethra were associated with risk of late dysuria and haematuria, while dose to the urinary sphincters was associated with incontinence.

Recurrent cerebellar infarction associated with hereditary heterozygous protein C deficiency in a 35-year-old woman: A case report and genetic study on the pedigree

Deficiency of protein C may cause deep venous thrombosis and pulmonary embolism, leading to ischemic stroke. The present study reports on a case of a young adult with recurrent cerebellar infarction due to hereditary heterozygous protein C deficiency and performs a literature review. A 35-year-old Asian woman was admitted t o the Department of Neurology of The First Affiliated Hospital of Guangxi Medical University (Nanning, China) due to right limb paralysis and vomiting. The diagnosis of stroke was confirmed by computed tomography and magnetic resonance imaging, which indicated acute cerebral infarction of the right cerebellar hemisphere and cerebellar vermis, as well as a previous cerebral infarction on the left cerebellar hemisphere. This patient had taken aspirin orally for 4 years following surgical therapy for small intestine thrombosis and was regularly taking hydroxychloroquine sulfate to treat systemic lupus erythematosus. The protein C (PROC) levels were 57.6%, while protein S and antithrombin levels were normal. Gene sequencing analysis of the patient and the patient's pedigree revealed a heterozygous mutation, c.565C>T, on the PROC gene in the patient and the patient's father. In conclusion, the clinical manifestations of hereditary PROC deficiency may vary between individuals. The heterozygous mutation locus c.565C>T on the PROC gene is associated with thrombophilia. Awareness of the association between natural anticoagulants and thrombophilia may promote the prevention and therapy of stroke.

Older Age, Early Symptoms and Physical Function are Associated with the Severity of Late Symptom Clusters for Men Undergoing Radiotherapy for Prostate Cancer

AIMS

To identify symptom clusters and predisposing factors associated with long-term symptoms and health-related quality of life after radiotherapy in men with prostate cancer.

MATERIALS AND METHODS

Patient-reported outcomes (PROs) data from the Medical Research Council RT01 radiotherapy with neoadjuvant androgen deprivation therapy trial of 843 patients were used. PROs were collected over 5 years with the University of California, Los Angeles Prostate Cancer Index (UCLA-PCI) and the 36 item Short-Form Health Survey (SF-36). Symptom clusters were explored using hierarchical cluster analysis. The association of treatment dose, baseline patient characteristics and early symptom clusters with the change in severity of PROs over 3 years was investigated with multivariate linear mixed effects models.

RESULTS

Seven symptom clusters of three or more symptoms were identified. The clusters were stable over time. The longitudinal profiles of symptom clusters showed the onset of acute symptoms during treatment for all symptom clusters and significant recovery by 6 months. Some clusters, such as physical health and sexual function, were adversely affected more than others by androgen deprivation therapy, and were less likely to return to pretreatment levels over time. Older age was significantly associated with decreased long-term physical function, physical health and sexual function (P < 0.001). Both baseline and acute symptom clusters were significant antecedents for impaired function and health-related quality of life at 3 years.

CONCLUSIONS

Men with poorer physical function and health before or during treatment were more likely to report poorer PROs at year 3. Early assessment using PROs and lifestyle interventions should be used to identify those with higher needs and provide targeted rehabilitation and symptom management.

Two-years Postradiotherapy Biopsies: Lessons from MRC RT01 Trial

BACKGROUND

The importance of 2-yr postradiotherapy prostate biopsy status remains uncertain.

OBJECTIVE

To assess the value of 2 year post treatment biopsies in a randomised trial of radiotherapy dose escalation.

DESIGN, SETTING, AND PARTICIPANTS

Between 1998 and 2001, 843 men with localised prostate cancer were randomised to receive either control-64Gy or escalated-74Gy conformal radiotherapy (CFRT) in the MRC RT01 trial in combination with 3-6-mo neoadjuvant androgen deprivation therapy. Prostate biopsies were planned at 2 yr from start of CFRT in suitable men.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Prostate biopsy results and prostate-specific antigen (PSA) levels performed at 2 yr post-CFRT were evaluated with long-term biochemical progression free survival (bPFS) and overall survival. Outcome measures were timed from the 2-yr biopsy using a landmark approach.

RESULTS AND LIMITATIONS

A 2-yr biopsy was performed in 312/843 patients. One hundred and seventy-seven patients were included in the per-protocol group with median follow-up of 7.8 yr from biopsy. Median PSA at biopsy was 0.5ng/ml. Sixty-four bPFS events were reported: 46/145 (32%) in patients with negative, 6/18 (33%) suspicious, and 12/14 (86%) positive biopsies. A positive biopsy was prognostic of worse bPFS, going forward, compared with negative and suspicious biopsies, hazard ratio (HR)=4.81 (95% confidence interval [CI]: 2.50-9.26, p<0.001). The estimate for survival was HR=1.58 (95% CI: 0.52-4.78, p=0.42). PSA values at 2 yr between 1.01ng/ml and 2.09ng/ml were also associated with subsequent PSA failures (HR=2.71, 95% CI: 1.98-3.71), bPFS events (HR=2.45, 95% CI: 1.81-3.32), and prostate cancer-specific survival (HR=2.87, 95% CI: 1.08-7.64) compared with PSA ≤1.0ng/ml.

CONCLUSIONS

Two-year postradiotherapy prostate biopsies have limited value in patients with PSA control but both positive biopsy and higher PSA status are strongly associated with future bPFS events. A policy of selected biopsy may provide an opportunity for early salvage interventions.

PATIENT SUMMARY

Routine 2-yr postradiotherapy biopsy is not recommended but can be considered in selected patients with unfavourable post-treatment prostate-specific antigen levels who are suitable for early salvage treatments.

Symptom clusters for revising scale membership in the analysis of prostate cancer patient reported outcome measures: a secondary data analysis of the Medical Research Council RT01 trial (ISCRTN47772397)

PURPOSE

To investigate the role of symptom clusters in the analysis and utilisation of patient reported outcome measures (PROMs) for data modelling and clinical practice. To compare symptom clusters with scales, and to explore their value in PROMs interpretation and symptom management.

METHODS

A dataset called RT01 (ISCRTN47772397) of 843 prostate cancer patients was used. PROMs were reported with the University of California, Los Angeles Prostate Cancer Index (UCLA-PCI). Symptom clusters were explored with hierarchical cluster analysis (HCA) and average linkage method (correlation > 0.6). The reliability of the Urinary Function Scale was evaluated with Cronbach's Alpha. The strength of the relationship between the items was investigated with Spearman's correlation. Predictive accuracy of the clusters was compared to the scales by receiver operating characteristic (ROC) analysis. Presence of urinary symptoms at 3 years measured with the late effects on normal tissue: subjective, objective, management tool (LENT/SOM) was an endpoint.

RESULTS

Two symptom clusters were identified (urinary cluster and sexual cluster). The grouping of symptom clusters was different than UCLA-PCI Scales. Two items of the urinary function scales ("number of pads" and "urinary leak interfering with sex") were excluded from the urinary cluster. The correlation with the other items in the scale ranged from 0.20 to 0.21 and 0.31 to 0.39, respectively. Cronbach's Alpha showed low correlation of those items with the Urinary Function Scale (0.14-0.36 and 0.33-0.44, respectively). All urinary function scale items were subject to a ceiling effect. Clusters had better predictive accuracy, AUC = 0.70 -0.65, while scales AUC = 0.67-0.61.

CONCLUSION

This study adds to the knowledge on how cluster analysis can be applied for the interpretation and utilisation of PROMs. We conclude that multiple-item scales should be evaluated and that symptom clusters provide a study-specific approach for modelling and interpretation of PROMs.

10-Year Outcomes after Monitoring, Surgery, or Radiotherapy for Localized Prostate Cancer

BACKGROUND

The comparative effectiveness of treatments for prostate cancer that is detected by prostate-specific antigen (PSA) testing remains uncertain.

METHODS

We compared active monitoring, radical prostatectomy, and external-beam radiotherapy for the treatment of clinically localized prostate cancer. Between 1999 and 2009, a total of 82,429 men 50 to 69 years of age received a PSA test; 2664 received a diagnosis of localized prostate cancer, and 1643 agreed to undergo randomization to active monitoring (545 men), surgery (553), or radiotherapy (545). The primary outcome was prostate-cancer mortality at a median of 10 years of follow-up. Secondary outcomes included the rates of disease progression, metastases, and all-cause deaths.

RESULTS

There were 17 prostate-cancer-specific deaths overall: 8 in the active-monitoring group (1.5 deaths per 1000 person-years; 95% confidence interval [CI], 0.7 to 3.0), 5 in the surgery group (0.9 per 1000 person-years; 95% CI, 0.4 to 2.2), and 4 in the radiotherapy group (0.7 per 1000 person-years; 95% CI, 0.3 to 2.0); the difference among the groups was not significant (P=0.48 for the overall comparison). In addition, no significant difference was seen among the groups in the number of deaths from any cause (169 deaths overall; P=0.87 for the comparison among the three groups). Metastases developed in more men in the active-monitoring group (33 men; 6.3 events per 1000 person-years; 95% CI, 4.5 to 8.8) than in the surgery group (13 men; 2.4 per 1000 person-years; 95% CI, 1.4 to 4.2) or the radiotherapy group (16 men; 3.0 per 1000 person-years; 95% CI, 1.9 to 4.9) (P=0.004 for the overall comparison). Higher rates of disease progression were seen in the active-monitoring group (112 men; 22.9 events per 1000 person-years; 95% CI, 19.0 to 27.5) than in the surgery group (46 men; 8.9 events per 1000 person-years; 95% CI, 6.7 to 11.9) or the radiotherapy group (46 men; 9.0 events per 1000 person-years; 95% CI, 6.7 to 12.0) (P<0.001 for the overall comparison).

CONCLUSIONS

At a median of 10 years, prostate-cancer-specific mortality was low irrespective of the treatment assigned, with no significant difference among treatments. Surgery and radiotherapy were associated with lower incidences of disease progression and metastases than was active monitoring. (Funded by the National Institute for Health Research; ProtecT Current Controlled Trials number, ISRCTN20141297 ; ClinicalTrials.gov number, NCT02044172 .).

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.

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.

Inter-departmental dosimetry audits - development of methods and lessons learned

External dosimetry audits give confidence in the safe and accurate delivery of radiotherapy. In the United Kingdom, such audits have been performed for almost 30 years. From the start, they included clinically relevant conditions, as well as reference machine output. Recently, national audits have tested new or complex techniques, but these methods are then used in regional audits by a peer-to-peer approach. This local approach builds up the radiotherapy community, facilitates communication, and brings synergy to medical physics.

Radiotherapy dosimetry audit: three decades of improving standards and accuracy in UK clinical practice and trials

Dosimetry audit plays an important role in the development and safety of radiotherapy. National and large scale audits are able to set, maintain and improve standards, as well as having the potential to identify issues which may cause harm to patients. They can support implementation of complex techniques and can facilitate awareness and understanding of any issues which may exist by benchmarking centres with similar equipment. This review examines the development of dosimetry audit in the UK over the past 30 years, including the involvement of the UK in international audits. A summary of audit results is given, with an overview of methodologies employed and lessons learnt. Recent and forthcoming more complex audits are considered, with a focus on future needs including the arrival of proton therapy in the UK and other advanced techniques such as four-dimensional radiotherapy delivery and verification, stereotactic radiotherapy and MR linear accelerators. The work of the main quality assurance and auditing bodies is discussed, including how they are working together to streamline audit and to ensure that all radiotherapy centres are involved. Undertaking regular external audit motivates centres to modernize and develop techniques and provides assurance, not only that radiotherapy is planned and delivered accurately but also that the patient dose delivered is as prescribed.

Active monitoring, radical prostatectomy, or radiotherapy for localised prostate cancer: study design and diagnostic and baseline results of the ProtecT randomised phase 3 trial

BACKGROUND

Prostate cancer is a major public health problem with considerable uncertainties about the effectiveness of population screening and treatment options. We report the study design, participant sociodemographic and clinical characteristics, and the initial results of the testing and diagnostic phase of the Prostate testing for cancer and Treatment (ProtecT) trial, which aims to investigate the effectiveness of treatments for localised prostate cancer.

METHODS

In this randomised phase 3 trial, men aged 50-69 years registered at 337 primary care centres in nine UK cities were invited to attend a specialist nurse appointment for a serum prostate-specific antigen (PSA) test. Prostate biopsies were offered to men with a PSA concentration of 3·0 μg/L or higher. Consenting participants with clinically localised prostate cancer were randomly assigned to active monitoring (surveillance strategy), radical prostatectomy, or three-dimensional conformal external-beam radiotherapy by a computer-generated allocation system. Randomisation was stratified by site (minimised for differences in participant age, PSA results, and Gleason score). The primary endpoint is prostate cancer mortality at a median 10-year follow-up, ascertained by an independent committee, which will be analysed by intention to treat in 2016. This trial is registered with ClinicalTrials.gov, number NCT02044172, and as an International Standard Randomised Controlled Trial, number ISRCTN20141297.

FINDINGS

Between Oct 1, 2001, and Jan 20, 2009, 228,966 men were invited to attend an appointment with a specialist nurse. Of the invited men, 100,444 (44%) attended their initial appointment and 82,429 (82%) of attenders had a PSA test. PSA concentration was below the biopsy threshold in 73,538 (89%) men. Of the 8566 men with a PSA concentration of 3·0-19·9 μg/L, 7414 (87%) underwent biopsies. 2896 men were diagnosed with prostate cancer (4% of tested men and 39% of those who had a biopsy), of whom 2417 (83%) had clinically localised disease (mostly T1c, Gleason score 6). With the addition of 247 pilot study participants recruited between 1999 and 2001, 2664 men were eligible for the treatment trial and 1643 (62%) agreed to be randomly assigned (545 to active monitoring, 545 to radiotherapy, and 553 to radical prostatectomy). Clinical and sociodemographic characteristics of randomly assigned participants were balanced across treatment groups.

INTERPRETATION

The ProtecT trial randomly assigned 1643 men with localised prostate cancer to active monitoring, radiotherapy, or surgery. Participant clinicopathological features are more consistent with contemporary patient characteristics than in previous prostate cancer treatment trials.

FUNDING

UK National Institute for Health Research Health Technology Assessment Programme.

Escalated-dose versus control-dose conformal radiotherapy for prostate cancer: long-term results from the MRC RT01 randomised controlled trial

BACKGROUND

The aim of this trial was to compare dose-escalated conformal radiotherapy with control-dose conformal radiotherapy in patients with localised prostate cancer. Preliminary findings reported after 5 years of follow-up showed that escalated-dose conformal radiotherapy improved biochemical progression-free survival. Based on the sample size calculation, we planned to analyse overall survival when 190 deaths occurred; this target has now been reached, after a median 10 years of follow-up.

METHODS

RT01 was a phase 3, open-label, international, randomised controlled trial enrolling men with histologically confirmed T1b-T3a, N0, M0 prostate cancer with prostate specific antigen of less than 50 ng/mL. Patients were randomly assigned centrally in a 1:1 ratio, using a computer-based minimisation algorithm stratifying by risk of seminal vesicle invasion and centre to either the control group (64 Gy in 32 fractions, the standard dose at the time the trial was designed) or the escalated-dose group (74 Gy in 37 fractions). Neither patients nor investigators were masked to assignment. All patients received neoadjuvant androgen deprivation therapy for 3-6 months before the start of conformal radiotherapy, which continued until the end of conformal radiotherapy. The coprimary outcome measures were biochemical progression-free survival and overall survival. All analyses were done on an intention-to-treat basis. Treatment-related side-effects have been reported previously. This trial is registered, number ISRCTN47772397.

FINDINGS

Between Jan 7, 1998, and Dec 20, 2001, 862 men were registered and 843 subsequently randomly assigned: 422 to the escalated-dose group and 421 to the control group. As of Aug 2, 2011, 236 deaths had occurred: 118 in each group. Median follow-up was 10·0 years (IQR 9·1-10·8). Overall survival at 10 years was 71% (95% CI 66-75) in each group (hazard ratio [HR] 0·99, 95% CI 0·77-1·28; p=0·96). Biochemical progression or progressive disease occurred in 391 patients (221 [57%] in the control group and 170 [43%] in the escalated-dose group). At 10 years, biochemical progression-free survival was 43% (95% CI 38-48) in the control group and 55% (50-61) in the escalated-dose group (HR 0·69, 95% CI 0·56-0·84; p=0·0003).

INTERPRETATION

At a median follow-up of 10 years, escalated-dose conformal radiotherapy with neoadjuvant androgen deprivation therapy showed an advantage in biochemical progression-free survival, but this advantage did not translate into an improvement in overall survival. These efficacy data for escalated-dose treatment must be weighed against the increase in acute and late toxicities associated with the escalated dose and emphasise the importance of use of appropriate modern radiotherapy methods to reduce side-effects.

FUNDING

UK Medical Research Council.

Quality assurance for clinical trials

Cooperative groups, of which the Radiation Therapy Oncology Group is one example, conduct national clinical trials that often involve the use of radiation therapy. In preparation for such a trial, the cooperative group prepares a protocol to define the goals of the trial, the rationale for its design, and the details of the treatment procedure to be followed. The Radiological Physics Center (RPC) is one of several quality assurance (QA) offices that is charged with assuring that participating institutions deliver doses that are clinically consistent and comparable. The RPC does this by conducting a variety of independent audits and credentialing processes. The RPC has compiled data showing that credentialing can help institutions comply with the requirements of a cooperative group clinical protocol. Phantom irradiations have been demonstrated to exercise an institution's procedures for planning and delivering advanced external beam techniques (1-3). Similarly, RPC data indicate that a rapid review of patient treatment records or planning procedures can improve compliance with clinical trials (4). The experiences of the RPC are presented as examples of the contributions that a national clinical trials QA center can make to cooperative group trials. These experiences illustrate the critical need for comprehensive QA to assure that clinical trials are successful and cost-effective. The RPC is supported by grants CA 10953 and CA 81647 from the National Cancer Institute, NIH, DHHS.

The dose-response of the anal sphincter region--an analysis of data from the MRC RT01 trial

PURPOSE

Most studies investigating the dose-response of the rectum focus on rectal bleeding. However, it has been reported that other symptoms such as urgency or sphincter control have a large impact on quality-of-life and that different symptoms are related to the dose to different parts of the anorectal wall. In this study correlations between the 3D dose distribution to the anal-sphincter region and radiation-induced side-effects were quantified.

MATERIALS AND METHODS

Dose-surface maps of the anal canal were generated. Next, longitudinal and lateral extent and eccentricity were calculated at different dose levels; DSHs and DVHs were also determined. Correlations between these dosimetric measures and seven clinically relevant endpoints were determined by assessing dosimetric constraints. Furthermore, an LKB model was generated. The study was performed using the data of 388 prostate patients from the RT01 trial (ISRCTN 47772397).

RESULTS

Subjective sphincter control was significantly correlated with the dose to the anal surface. The strongest correlations were found for lateral extent at 53 Gy (p=0.01). Outcome was also significantly correlated with the DSH and the mean dose to the anal surface.

CONCLUSIONS

The dose to the anal sphincter region should be taken into account when generating treatment-plans. This could be done using shape-based tools, DSH/DVH-based tools or an NTCP model.

EORTC Radiation Oncology Group quality assurance platform: establishment of a digital central review facility

OBJECTIVE

Quality assurance (QA) in clinical trials is essential to ensure treatment is safely and effectively delivered. As QA requirements have increased in complexity in parallel with evolution of radiation therapy (RT) delivery, a need to facilitate digital data exchange emerged. Our objective is to present the platform developed for the integration and standardization of QART activities across all EORTC trials involving RT.

METHODS

The following essential requirements were identified: secure and easy access without on-site software installation; integration within the existing EORTC clinical remote data capture system; and the ability to both customize the platform to specific studies and adapt to future needs. After retrospective testing within several clinical trials, the platform was introduced in phases to participating sites and QART study reviewers.

RESULTS

The resulting QA platform, integrating RT analysis software installed at EORTC Headquarters, permits timely, secure, and fully digital central DICOM-RT based data review. Participating sites submit data through a standard secure upload webpage. Supplemental information is submitted in parallel through web-based forms. An internal quality check by the QART office verifies data consistency, formatting, and anonymization. QART reviewers have remote access through a terminal server. Reviewers evaluate submissions for protocol compliance through an online evaluation matrix. Comments are collected by the coordinating centre and institutions are informed of the results.

CONCLUSIONS

This web-based central review platform facilitates rapid, extensive, and prospective QART review. This reduces the risk that trial outcomes are compromised through inadequate radiotherapy and facilitates correlation of results with clinical outcomes.

Parameters for the Lyman Kutcher Burman (LKB) model of Normal Tissue Complication Probability (NTCP) for specific rectal complications observed in clinical practise

BACKGROUND AND PURPOSE

The Normal Tissue Complication Probability (NTCP) for rectum is usually defined for late rectal bleeding. This study calculates NTCP parameter values for additional rectal toxicity endpoints observed in clinical practise.

MATERIALS AND METHODS

388 patients from the multicentre MRC-RT01 prostate conformal radiotherapy trial (ISRCTN 47772397) were used to derive independent Lyman Kutcher Burman model (LKB) parameters for five late rectal toxicity endpoints: rectal bleeding, proctitis, stool frequency, loose stools and rectal urgency. The parameters were derived using maximum likelihood estimation. Bootstrap and leave-one-out methods were employed to test the generalisability of the results for use in a general population.

RESULTS

A consistent pattern of increasing value of TD50(1) for Grade 2 toxicity only compared to Grades 1 and 2 toxicity was observed for all endpoints. Parameter values varied between endpoints (particularly for the volume parameter n). TD50(1), m and n were 68.5 Gy (95% CI)(66.8-70.8), 0.15 (0.13-0.17) and 0.13 (0.10-0.17), respectively, for G2 rectal bleeding. Bootstrap and leave-one-out results showed that the rectal bleeding and proctitis parameter fits were extremely robust.

CONCLUSIONS

The variation between the values derived for different endpoints may indicate different patho-physiological responses of the rectum to radiation. Therefore different parameter sets would be required to predict specific rectal toxicity endpoints.

Independent validation of genes and polymorphisms reported to be associated with radiation toxicity: a prospective analysis study

BACKGROUND

Several studies have reported associations between radiation toxicity and single nucleotide polymorphisms (SNPs) in candidate genes. Few associations have been tested in independent validation studies. This prospective study aimed to validate reported associations between genotype and radiation toxicity in a large independent dataset.

METHODS

92 (of 98 attempted) SNPs in 46 genes were successfully genotyped in 1613 patients: 976 received adjuvant breast radiotherapy in the Cambridge breast IMRT trial (ISRCTN21474421, n=942) or in a prospective study of breast toxicity at the Christie Hospital, Manchester, UK (n=34). A further 637 received radical prostate radiotherapy in the MRC RT01 multicentre trial (ISRCTN47772397, n=224) or in the Conventional or Hypofractionated High Dose Intensity Modulated Radiotherapy for Prostate Cancer (CHHiP) trial (ISRCTN97182923, n=413). Late toxicity was assessed 2 years after radiotherapy with a validated photographic technique (patients with breast cancer only), clinical assessment, and patient questionnaires. Association tests of genotype with overall radiation toxicity score and individual endpoints were undertaken in univariate and multivariable analyses. At a type I error rate adjusted for multiple testing, this study had 99% power to detect a SNP, with minor allele frequency of 0·35, associated with a per allele odds ratio of 2·2.

FINDINGS

None of the previously reported associations were confirmed by this study, after adjustment for multiple comparisons. The p value distribution of the SNPs tested against overall toxicity score was not different from that expected by chance.

INTERPRETATION

We did not replicate previously reported late toxicity associations, suggesting that we can essentially exclude the hypothesis that published SNPs individually exert a clinically relevant effect. Continued recruitment of patients into studies within the Radiogenomics Consortium is essential so that sufficiently powered studies can be done and methodological challenges addressed.

FUNDING

Cancer Research UK, The Royal College of Radiologists, Addenbrooke's Charitable Trust, Breast Cancer Campaign, Cambridge National Institute of Health Research (NIHR) Biomedical Research Centre, Experimental Cancer Medicine Centre, East Midlands Innovation, the National Cancer Institute, Joseph Mitchell Trust, Royal Marsden NHS Foundation Trust, Institute of Cancer Research NIHR Biomedical Research Centre for Cancer.

Modeling late rectal toxicities based on a parameterized representation of the 3D dose distribution

Many models exist for predicting toxicities based on dose-volume histograms (DVHs) or dose-surface histograms (DSHs). This approach has several drawbacks as firstly the reduction of the dose distribution to a histogram results in the loss of spatial information and secondly the bins of the histograms are highly correlated with each other. Furthermore, some of the complex nonlinear models proposed in the past lack a direct physical interpretation and the ability to predict probabilities rather than binary outcomes. We propose a parameterized representation of the 3D distribution of the dose to the rectal wall which explicitly includes geometrical information in the form of the eccentricity of the dose distribution as well as its lateral and longitudinal extent. We use a nonlinear kernel-based probabilistic model to predict late rectal toxicity based on the parameterized dose distribution and assessed its predictive power using data from the MRC RT01 trial (ISCTRN 47772397). The endpoints under consideration were rectal bleeding, loose stools, and a global toxicity score. We extract simple rules identifying 3D dose patterns related to a specifically low risk of complication. Normal tissue complication probability (NTCP) models based on parameterized representations of geometrical and volumetric measures resulted in areas under the curve (AUCs) of 0.66, 0.63 and 0.67 for predicting rectal bleeding, loose stools and global toxicity, respectively. In comparison, NTCP models based on standard DVHs performed worse and resulted in AUCs of 0.59 for all three endpoints. In conclusion, we have presented low-dimensional, interpretable and nonlinear NTCP models based on the parameterized representation of the dose to the rectal wall. These models had a higher predictive power than models based on standard DVHs and their low dimensionality allowed for the identification of 3D dose patterns related to a low risk of complication.

Using Bayesian logistic regression to evaluate a new type of dosimetric constraint for prostate radiotherapy treatment planning

PURPOSE

Modern radiotherapy treatments can be optimized using dose-volume constraints which specify the volume of tumor and organs-at-risk receiving a given threshold dose. Careful derivation and evaluation of rectal constraints is essential to allow safe dose escalation in radiotherapy of prostate cancer. The authors present a new type of hybrid dosimetric constraint which comprises both volumetric and spatial factors of the dose-distribution. The authors also propose a framework to evaluate these constraints.

METHODS

The authors used data from the RT01 prostate radiotherapy trial (ISRCTN 47772397) to derive this set of hybrid constraints for the rectum based on measures extracted from dose-surface maps. For comparison, the authors also derive a set of dose-volume constraints. In order to evaluate these dosimetric constraints, the authors propose a new framework for predicting radiation-induced toxicities using Bayesian logistic regression with high-order interactions. The predictive power of the new RT01-based constraints, as well as of two sets of rectal dose-volume constraints proposed in the recent literature-The constraints proposed by other researchers [C. Fiorino, G. Fellin, T. Rancati, V. Vavassori, C. Bianchi, V. C. Borca, G. Girelli, M. Mapelli, L. Menegotti, S. Nava, and R. Valdagni, "Clinical and dosimetric predictors of late rectal syndrome after 3D-CRT for localized prostate cancer: Preliminary results of a multicenter prospective study," Int. J. Radiat. Oncol., Biol., Phys. 70, 1130-1137 (2008)] and the constraints used in the conventional or hypofractionated high dose intensity modulated radiotherapy for prostate cancer (CHHiP) trial [C. P. South, V. S. Khoo, O. Naismith, A. Norman, and D. P. Dearnaley, "A comparison of treatment planning techniques used in two randomised UK external beam radiotherapy trials for localised prostate cancer," Clin. Oncol. (R Coll. Radiol) 20, 15-21 (2008)]--were evaluated using a tenfold cross-validation with follow-up data from the RT01 trial. The predictive power was quantified using receiver-operator characteristic (ROC) curves. Toxicities considered were rectal bleeding, loose stools, and a global toxicity score.

RESULTS

Dose-volume constraints had less predictive power than the new type of hybrid constraints. A probabilistic model for predicting rectal bleeding based on the dose-volume constraints proposed by other researchers [C. Fiorino, G. Fellin, T. Rancati, V. Vavassori, C. Bianchi, V. C. Borca, G. Girelli, M. Mapelli, L. Menegotti, S. Nava, and R. Valdagni, "Clinical and dosimetric predictors of late rectal syndrome after 3D-CRT for localized prostate cancer: Preliminary results of a multicenter prospective study," Int. J. Radiat. Oncol., Biol., Phys. 70, 1130-1137 (2008)], the CHHiP dose-volume constraints, the RT01-based dose-volume constraints, and the hybrid constraints resulted in average areas under the ROC curves of 0.56, 0.58, 0.62, and 0.67, respectively. For predicting loose stools, the corresponding values were 0.57, 0.53, 0.66, and 0.71, respectively. The areas under the respective ROC curves for predicting the global toxicity score were 0.58, 0.55, 0.61, and 0.63.

CONCLUSIONS

Thus, imposing the new type of hybrid constraints when generating a treatment plan should result in a reduction in the incidence of radiation-induced late rectal toxicity.

Dose-volume constraints to reduce rectal side effects from prostate radiotherapy: evidence from MRC RT01 Trial ISRCTN 47772397

PURPOSE

Radical radiotherapy for prostate cancer is effective but dose limited because of the proximity of normal tissues. Comprehensive dose-volume analysis of the incidence of clinically relevant late rectal toxicities could indicate how the dose to the rectum should be constrained. Previous emphasis has been on constraining the mid-to-high dose range (>/=50 Gy). Evidence is emerging that lower doses could also be important.

METHODS AND MATERIALS

Data from a large multicenter randomized trial were used to investigate the correlation between seven clinically relevant rectal toxicity endpoints (including patient- and clinician-reported outcomes) and an absolute 5% increase in the volume of rectum receiving the specified doses. The results were quantified using odds ratios. Rectal dose-volume constraints were applied retrospectively to investigate the association of constraints with the incidence of late rectal toxicity.

RESULTS

A statistically significant dose-volume response was observed for six of the seven endpoints for at least one of the dose levels tested in the range of 30-70 Gy. Statistically significant reductions in the incidence of these late rectal toxicities were observed for the group of patients whose treatment plans met specific proposed dose-volume constraints. The incidence of moderate/severe toxicity (any endpoint) decreased incrementally for patients whose treatment plans met increasing numbers of dose-volume constraints from the set of V30

CONCLUSION

Considering the entire dose distribution to the rectum by applying dose-volume constraints such as those tested here in the present will reduce the incidence of late rectal toxicity.

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Key Words Collapse

MESH Headings

• Dose-Response Relationship, Radiation
• Gastrointestinal Hemorrhage/etiology
• Humans
• Male
• Odds Ratio
• Prostatic Neoplasms/radiotherapy
• Radiation Injuries/complications
• Radiation Injuries/prevention & control
• Radiotherapy Dosage
• Rectal Diseases/etiology
• Rectum/pathology
• Rectum/radiation effects

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Grants

• G0501019 Medical Research Council
• MC_U122861330 Medical Research Council
• C46/A2131 Cancer Research UK

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Affiliation(s)

Sarah L Gulliford Joint Department of Physics, Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton, United Kingdom
Kerwyn Foo
Rachel C Morgan
Edwin G Aird
A Margaret Bidmead
Helen Critchley
Philip M Evans
Stefano Gianolini
W Philip Mayles
A Rollo Moore
Beatriz Sánchez-Nieto
Mike Partridge
Matthew R Sydes
Steve Webb
David P Dearnaley

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Expression of Bcl-2, p53, and MDM2 in localized prostate cancer with respect to the outcome of radical radiotherapy dose escalation

PURPOSE

Established prognostic factors in localized prostate cancer explain only a moderate proportion of variation in outcome. We analyzed tumor expression of apoptotic markers with respect to outcome in men with localized prostate cancer in two randomized controlled trials of radiotherapy dose escalation.

METHODS AND MATERIALS

Between 1995 and 2001, 308 patients with localized prostate cancer received neoadjuvant androgen deprivation and radical radiotherapy at our institution in one of two dose-escalation trials. The biopsy specimens in 201 cases were used to make a biopsy tissue microarray. We evaluated tumor expression of Bcl-2, p53, and MDM2 by immunohistochemistry with respect to outcome.

RESULTS

Median follow-up was 7 years, and 5-year freedom from biochemical failure (FFBF) was 70.4% (95% CI, 63.5-76.3%). On univariate analysis, expression of Bcl-2 (p < 0.001) and p53 (p = 0.017), but not MDM2 (p = 0.224), was significantly associated with FFBF. Expression of Bcl-2 remained significantly associated with FFBF (p = 0.001) on multivariate analysis, independently of T stage, Gleason score, initial prostate-specific antigen level, and radiotherapy dose. Seven-year biochemical control was 61% vs. 41% (p = 0.0122) for 74 Gy vs. 64 Gy, respectively, among patients with Bcl-2-positive tumors and 87% vs. 81% (p = 0.423) for 74 Gy vs. 64 Gy, respectively, among patients with Bcl-2-negative tumors. There was no statistically significant interaction between dose and Bcl-2 expression.

CONCLUSIONS

Bcl-2 expression was a significant, independent determinant of biochemical control after neoadjuvant androgen deprivation and radical radiotherapy for prostate cancer. These data generate the hypothesis that Bcl-2 expression could be used to inform the choice of radiotherapy dose in individual patients.

Assessing correlations between the spatial distribution of the dose to the rectal wall and late rectal toxicity after prostate radiotherapy: an analysis of data from the MRC RT01 trial (ISRCTN 47772397)

Many studies have been performed to assess correlations between measures derived from dose-volume histograms and late rectal toxicities for radiotherapy of prostate cancer. The purpose of this study was to quantify correlations between measures describing the shape and location of the dose distribution and different outcomes. The dose to the rectal wall was projected on a two-dimensional map. In order to characterize the dose distribution, its centre of mass, longitudinal and lateral extent, and eccentricity were calculated at different dose levels. Furthermore, the dose-surface histogram (DSH) was determined. Correlations between these measures and seven clinically relevant rectal-toxicity endpoints were quantified by maximally selected standardized Wilcoxon rank statistics. The analysis was performed using data from the RT01 prostate radiotherapy trial. For some endpoints, the shape of the dose distribution is more strongly correlated with the outcome than simple DSHs. Rectal bleeding was most strongly correlated with the lateral extent of the dose distribution. For loose stools, the strongest correlations were found for longitudinal extent; proctitis was most strongly correlated with DSH. For the other endpoints no statistically significant correlations could be found. The strengths of the correlations between the shape of the dose distribution and outcome differed considerably between the different endpoints. Due to these significant correlations, it is desirable to use shape-based tools in order to assess the quality of a dose distribution.

Late gastrointestinal toxicity after dose-escalated conformal radiotherapy for early prostate cancer: results from the UK Medical Research Council RT01 trial (ISRCTN47772397)

Purpose

In men with localized prostate cancer, dose-escalated conformal radiotherapy (CFRT) improves efficacy outcomes at the cost of increased toxicity. We present a detailed analysis to provide further information about the incidence and prevalence of late gastrointestinal side effects.

Methods and Materials

The UK Medical Research Council RT01 trial included 843 men with localized prostate cancer, who were treated for 6 months with neoadjuvant radiotherapy and were randomly assigned to either 64-Gy or 74-Gy CFRT. Toxicity was evaluated before CFRT and during long-term follow-up using Radiation Therapy Oncology Group (RTOG) grading, the Late Effects on Normal Tissue: Subjective, Objective, Management (LENT/SOM) scale, and Royal Marsden Hospital assessment scores. Patients regularly completed Functional Assessment of Cancer Therapy--Prostate (FACT-P) and University of California, Los Angeles, Prostate Cancer Index (UCLA-PCI) questionnaires.

Results

In the dose-escalated group, the hazard ratio (HR) for rectal bleeding (LENT/SOM grade ≥2) was 1.55 (95% CI, 1.17–2.04); for diarrhea (LENT/SOM grade ≥2), the HR was 1.79 (95% CI, 1.10–2.94); and for proctitis (RTOG grade ≥2), the HR was 1.64 (95% CI, 1.20–2.25). Compared to baseline scores, the prevalence of moderate and severe toxicities generally increased up to 3 years and than lessened. At 5 years, the cumulative incidence of patient-reported severe bowel problems was 6% vs. 8% (standard vs. escalated, respectively) and severe distress was 4% vs. 5%, respectively.

Conclusions

There is a statistically significant increased risk of various adverse gastrointestinal events with dose-escalated CFRT. This remains at clinically acceptable levels, and overall prevalence ultimately decreases with duration of follow-up.

Accuracy and reproducibility of conformal radiotherapy using data from a randomised controlled trial of conformal radiotherapy in prostate cancer (MRC RT01, ISRCTN47772397)

Aims

The MRC RT01 trial used conformal radiotherapy to the prostate, a method that reduces the volume of normal tissue treated by 40–50%. Because of the risk of geographical miss, the trial used portal imaging to examine whether treatment delivery was within the required accuracy.

Material and methods

In total, 843 patients were randomly assigned to receive 64 Gy in 32 fractions over 6.5 weeks or 74 Gy in 37 fractions over 7.5 weeks. Field displacements and corrections were recorded for all imaged fractions. Displacement trends and their association with time, disease and treatment set-up characteristics were examined using univariate and multivariate analyses. A Radiographer Trial Implementation Group (RTIG) was set up to inform the quality assurance process and to promote the development of best practice.

Results

Treatment isocentre positioning was within 5 mm in every direction on 6238 (83%) of the 7535 fractions imaged. In total, 532 (81%) of 695 included patients had at least one ≥ 3mm displacement and 415 (63%) had at least one ≥ 5mm displacement. Univariate, multivariate and stepwise models of ≥ 5mm displacements showed an increased likelihood of displacement in weeks 1 and 2 with low melting point alloy (LMPA) blocks compared with multileaf collimators, film verification compared with electronic portal imaging (EPI) and increased number of fractions imaged. Except for LMPA, this was also seen for ≥ 5mm displacements in weeks 3–6.

Conclusions

Accurate conformal treatment was delivered. The use of EPI was associated with increased reported accuracy. The RTIG was a crucial part of the quality assurance process.

Quality assurance of dosimetry and the impact on sample size in randomized clinical trials

BACKGROUND AND PURPOSE

The aim of this study was to investigate the impact of appropriate dosimetry quality assurance (QA) on patient number required in radiotherapy randomized control trials (RCT).

MATERIALS AND METHODS

The steepness of clinical dose-response curves, gamma(clin.), was calculated by a convoluting a biological dose-response distribution and the distribution of technical and dosimetrical factors. Population size calculation was performed taking into account gamma(clin.) and expected difference in outcome between two arms of an RCT, for different levels of variation in dose to the patient population.

RESULTS

Uncertainties in dose reduces gamma(clin.) to the largest extent when the initial gamma-value is high and less so for low gamma-value. Reduced uncertainty in dose led to a significant reduction in the number of patients required in an RCT if the expected difference between the experimental and conventional arm is small. The reduction in patient numbers is less when the differences between the conventional and experimental arm is larger.

CONCLUSION

The number of patients required in an RCT may be reduced by introducing appropriate dosimetry QA as the risk of under-powering the study is minimized. Dosimetry QA in clinical studies is therefore cost-effective.

Secular trends in prostate cancer mortality, incidence and treatment: England and Wales, 1975-2004

OBJECTIVE

To aid the interpretation of the trends in prostate cancer mortality, which declined in the UK in the early 1990 s for unknown reasons, by investigating prostate cancer death rates, incidence and treatments in England and Wales in 1975-2004.

METHODS

Join-point regression was used to assess secular trends in mortality and incidence (source: Office of National Statistics), radical prostatectomy and orchidectomy (source: Hospital Episode Statistics database) and androgen-suppression drugs (source: Intercontinental Medical Statistics).

RESULTS

Prostate cancer mortality declined from 1992 (95% confidence interval, CI, 1990-94). The relative decline in mortality to 2004 was greater and more sustained amongst men aged 55-74 years (annual percentage mortality reduction 2.75%; 95% CI 2.33-3.18%) than amongst those aged >or=75 years (0.71%, 0.26-1.15%). The use of radical prostatectomy increased between 1991 (89 operations) and 2004 (2788) amongst men aged 55-74 years. The prescribing of androgen suppression increased between 1987 (33,000 prescriptions) and 2004 (470,000).

CONCLUSIONS

The decrease in prostate cancer mortality was greater amongst men aged 55-74 years than in those aged >or=75 years, but pre-dated the substantial use of prostate-specific antigen screening and radical prostatectomy in the UK. An increase in radical therapy amongst younger groups with localized cancers and screen-detected low-volume locally advanced disease as a result of stage migration, as well as prolonged survival from increased medical androgen suppression therapy, might partly explain recent trends.

Evidence-based radiation oncology: Definitive, adjuvant and salvage radiotherapy for non-metastatic prostate cancer

The standard treatment options based on the risk category (stage, Gleason score, PSA) for localized prostate cancer include surgery, radiotherapy and watchful waiting. The literature does not provide clear-cut evidence for the superiority of surgery over radiotherapy, whereas both approaches differ in their side effects. The definitive external beam irradiation is frequently employed in stage T1b-T1c, T2 and T3 tumors. There is a pretty strong evidence that intermediate- and high-risk patients benefit from dose escalation. The latter requires reduction of the irradiated normal tissue (using 3-dimensional conformal approach, intensity modulated radiotherapy, image-guided radiotherapy, etc.). Recent data suggest that prostate cancer may benefit from hypofractionation due to relatively low alpha/beta ratio; these findings warrant confirmation though. The role of whole pelvis irradiation is still controversial. Numerous randomized trials demonstrated a clinical benefit in terms of biochemical control, local and distant control, and overall survival from the addition of androgen suppression to external beam radiotherapy in intermediate- and high-risk patients. These studies typically included locally advanced (T3-T4) and poor-prognosis (Gleason score >7 and/or PSA >20 ng/mL) tumors and employed neoadjuvant/concomitant/adjuvant androgen suppression rather than only adjuvant setting. The ongoing trials will hopefully further define the role of endocrine treatment in more favorable risk patients and in the setting of the dose escalated radiotherapy. Brachytherapy (BRT) with permanent implants may be offered to low-risk patients (cT1-T2a, Gleason score <7, or 3+4, PSA <or=10 ng/mL), with prostate volume of <or=50 ml, no previous transurethral prostate resection and a good urinary function. Some recent data suggest a benefit from combining external beam irradiation and BRT for intermediate-risk patients. EBRT after radical prostatectomy improves disease-free survival and biochemical and local control rates in patients with positive surgical margins or pT3 tumors. Salvage radiotherapy may be considered at the time of biochemical failure in previously non-irradiated patients.

Escalated-dose versus standard-dose conformal radiotherapy in prostate cancer: first results from the MRC RT01 randomised controlled trial

BACKGROUND

In men with localised prostate cancer, conformal radiotherapy (CFRT) could deliver higher doses of radiation than does standard-dose conventional radical external-beam radiotherapy, and could improve long-term efficacy, potentially at the cost of increased toxicity. We aimed to present the first analyses of effectiveness from the MRC RT01 randomised controlled trial.

METHODS

The MRC RT01 trial included 843 men with localised prostate cancer who were randomly assigned to standard-dose CFRT or escalated-dose CFRT, both administered with neoadjuvant androgen suppression. Primary endpoints were biochemical-progression-free survival (bPFS), freedom from local progression, metastases-free survival, overall survival, and late toxicity scores. The toxicity scores were measured with questionnaires for physicians and patients that included the Radiation Therapy Oncology Group (RTOG), the Late Effects on Normal Tissue: Subjective/Objective/Management (LENT/SOM) scales, and the University of California, Los Angeles Prostate Cancer Index (UCLA PCI) scales. Analysis was done by intention to treat. This trial is registered at the Current Controlled Trials website http://www.controlled-trials.com/ISRCTN47772397.

FINDINGS

Between January, 1998, and December, 2002, 843 men were randomly assigned to escalated-dose CFRT (n=422) or standard-dose CFRT (n=421). In the escalated group, the hazard ratio (HR) for bPFS was 0.67 (95% CI 0.53-0.85, p=0.0007). We noted 71% bPFS (108 cumulative events) and 60% bPFS (149 cumulative events) by 5 years in the escalated and standard groups, respectively. HR for clinical progression-free survival was 0.69 (0.47-1.02; p=0.064); local control was 0.65 (0.36-1.18; p=0.16); freedom from salvage androgen suppression was 0.78 (0.57-1.07; p=0.12); and metastases-free survival was 0.74 (0.47-1.18; p=0.21). HR for late bowel toxicity in the escalated group was 1.47 (1.12-1.92) according to the RTOG (grade >/=2) scale; 1.44 (1.16-1.80) according to the LENT/SOM (grade >/=2) scales; and 1.28 (1.03-1.60) according to the UCLA PCI (score >/=30) scale. 33% of the escalated and 24% of the standard group reported late bowel toxicity within 5 years of starting treatment. HR for late bladder toxicity according to the RTOG (grade >/=2) scale was 1.36 (0.90-2.06), but this finding was not supported by the LENT/SOM (grade >/=2) scales (HR 1.07 [0.90-1.29]), nor the UCLA PCI (score >/=30) scale (HR 1.05 [0.81-1.36]).

INTERPRETATION

Escalated-dose CFRT with neoadjuvant androgen suppression seems clinically worthwhile in terms of bPFS, progression-free survival, and decreased use of salvage androgen suppression. This additional efficacy is offset by an increased incidence of longer term adverse events.

The early toxicity of escalated versus standard dose conformal radiotherapy with neo-adjuvant androgen suppression for patients with localised prostate cancer: Results from the MRC RT01 trial (ISRCTN47772397)

BACKGROUND

Five-year disease-free survival rates for localised prostate cancer following standard doses of conventional radical external beam radiotherapy are around 80%. Conformal radiotherapy (CFRT) raises the possibility that radiotherapy doses can be increased and long-term efficacy outcomes improved, with safety an important consideration.

METHODS

MRC RT01 is a randomised controlled trial of 862 men with localised prostate cancer comparing Standard CFRT (64Gy/32f) versus Escalated CFRT (74Gy/37f), both administered with neo-adjuvant androgen suppression. Early toxicity was measured using physician-reported instruments (RTOG, LENT/SOM, Royal Marsden Scales) and patient-reported questionnaires (MOS SF-36, UCLA Prostate Cancer Index, FACT-P).

RESULTS

Overall early radiotherapy toxicity was similar, apart from increased bladder, bowel and sexual toxicity, in the Escalated Group during a short immediate post-radiotherapy period. Toxicity in both groups had abated by week 12. Using RTOG Acute Toxicity scores, cumulative Grade 2 bladder and bowel toxicity was 38% and 30% for Standard Group and 39% and 33% in Escalated Group, respectively. Urinary frequency (Royal Marsden Scale) improved in both groups from pre-androgen suppression to 6 months post-radiotherapy (p<0.001), but bowel and sexual functioning deteriorated. This pattern was supported by patient-completed assessments. Six months after starting radiotherapy the incidence of RTOG Grade > or = 2 side-effects was low (<1%); but there were six reports of rectal ulceration (6 Escalated Group), six haematuria (5 Escalated Group) and eight urethral stricture (6 Escalated Group).

CONCLUSIONS

The two CFRT schedules with neo-adjuvant androgen suppression have broadly similar early toxicity profiles except for the immediate post-RT period. At 6 months and compared to before hormone therapy, bladder symptoms improved, whereas bowel and sexual symptoms worsened. These assessments of early treatment safety will be complemented by further follow-up to document late side-effects and efficacy.

The quality of life of men with locally advanced prostate cancer during neoadjuvant hormone therapy: data from the Medical Research Council RT01 trial (ISRCTN 47772397)

OBJECTIVE

To explore patients' quality of life (QoL) during neoadjuvant hormone therapy (HT) using data from the Medical Research Council RT01 trial of standard- (64 Gy/32-fraction) and high- (74 Gy/37-fraction) dose radiotherapy (RT, both given conformally).

PATIENTS AND METHODS

Of the 843 patients randomized to the RT01 trial, 316 completed the Functional Assessment Of Cancer Therapy core questionnaire with its additional prostate subscale, and the Short Form-36 Health Survey questionnaire with the University of California-Los Angeles Prostate Cancer Index before HT and again before starting RT. Three predefined QoL hypotheses were generated to focus the analyses.

RESULTS

For the three primary QoL analyses there was evidence that sexual functioning deteriorated, urinary function did not change, and there was a slight decline in physical well-being after > or = 3 months of HT. Sensitivity analyses confirmed these findings. Exploratory analyses also suggested that role functioning deteriorated, sleep was more disturbed, and there was an increase in fatigue. However, overall QoL was not reported to be affected and patients indicated an improvement in attitude and satisfaction with treatment.

CONCLUSIONS

In this group of men, many of whom reported reduced sexual functioning before treatment, the additional decline during HT seemed to be generally accepted as the price to pay for an appropriate cancer treatment. Nevertheless, these changes need to be discussed with patients before HT is commenced.

Evaluating the relationship between erectile dysfunction and dose received by the penile bulb: Using data from a randomised controlled trial of conformal radiotherapy in prostate cancer (MRC RT01, ISRCTN47772397)

AIM

To evaluate the relationship between erectile function and the radiation dose to the penile bulb and other proximal penile structures in men receiving conformal radiotherapy (CFRT) for prostate cancer (PCa).

METHODS

The Medical Research Council (MRC) RT01 trial randomised 843 men who had localised PCa to receive either 64 or 74 Gy after 3 - 6 months neoadjuvant hormonal treatment. Fifty-one men were selected who were potent prior to hormonal treatment, having completed both pre-hormone and 2-year post-CFRT Quality of Life assessments, and on whom dose volume data were available for analysis. The men were divided into three groups according to 2-year follow-up: potent, reduced potency, and impotent. The bulb of the penis together with the crura, were outlined on restored treatment plans. Dose - volume histograms were generated and compared between the three groups. An ordered logistic regression model was used to calculate the odds ratio of a range of dose - volume parameters to the penile bulb and effect on erectile dysfunction. The dose to the penile bulb was correlated to the dose received by the crura.

RESULTS

Of the 51 patients, 12 remained potent, 22 had reduced potency, and 17 were impotent at 2 years. No differences were seen in mean dose to the penile bulb by allocated treatment (t test = 1.61, p = 0.11). The mean doses to the penile bulb received by the potent, reduced potency, and impotent groups were 45.5 Gy (SD 17.1), 48 Gy (SD 16.1), and 59.2 Gy (SD 13.8), respectively. There was a strong correlation between the mean dose received by the penile bulb and dose to the crura (r = 0.82, p < 0.0001). 83.3% of impotent patients received a D90 > or = 50 Gy to the penile bulb compared with 29.4% of patients who maintained potency at 2 years (p = 0.006).

CONCLUSION

There is evidence from this study to suggest a dose volume effect on the penile bulb and erectile dysfunction. A D90 > or = 50 Gy is associated with a significant risk of erectile dysfunction and this should form a basis for selecting dose constraints in future dose escalation studies.

A versatile phantom for quality assurance in the UK Medical Research Council (MRC) RT01 trial (ISRCTN47772397) in conformal radiotherapy for prostate cancer

Within the UK RT01 trial the MRC also funded a quality assurance (QA) programme. This included a planning and dosimetry audit at participating centres using a purpose built phantom. Geometrical setup was visually assessed via field shaping around the phantom GTV (to within the order of 1 mm). Within the phantom, ion chamber positional uncertainties were estimated as 0.6 mm (95% CL, k=2). This was the basis for ion chamber measurements in a variety of dose gradients around the PTV closely simulating a patient case. The design provides a representative but reproducible system for QA in the prostate radiotherapy process, from CT scan to treatment. Setup errors are not eliminated, but minimised and estimated.

Radiotherapy Treatment Verification in the UK: An Audit of Practice in 2004

AIMS

To audit current practice related to treatment verification undertaken in radiotherapy departments throughout the UK.

MATERIALS AND METHODS

A questionnaire was circulated to the radiotherapy service managers of 62 radiotherapy centres in the UK. This looked in detail at the department demographics, imaging equipment, site-specific verification protocols, and training and competency assessment of staff responsible for verification.

RESULTS

The response rate was 48% (30/62). All departments were using megavoltage imaging equipment in routine clinical practice. Twenty-four out of 29 (83%) departments that had electronic portal imaging capability were using image analysis software for verification. Twenty-nine out of 30 (97%) departments had site-specific written verification protocols. Twenty out of 30 (67%) treatment centres audited set-up errors within their department. Forty-three per cent of centres were using simulator image as the reference image of choice across all sites. Electronic portal imaging, alone or in combination with portal film, was being used for verification in 75% of the centres. Fifty-three per cent of centres used off-line correction strategies for measuring set-up errors across all sites. Radiographer-led interventions were primarily in the pelvis.

CONCLUSION

Presently in the UK, verification strategies vary widely at individual treatment sites and between departments. Dedicated departmental verification teams, with input from radiographers, physicists and clinicians, may assist in the effective implementation of evidence-based verification. The inclusion of comprehensive verification protocols within multicentre radiotherapy trials encourages standardisation across treatment centres.

Radiotherapeutic techniques for prostate cancer, dose escalation and brachytherapy

There is evidence to confirm a dose-response relationship in prostate cancer. The relative benefit is dependent on the clinical prognostic risk factors (T stage, Gleason score and presenting prostate-specific antigen [PSA]) being more favourable for intermediate-risk patients. Refinement of prognostic groups and clinical threshold parameters is ongoing. Escalation of dose in prostate radiotherapy using conventional techniques is limited by rectal tolerance. Substantial advances have been made in radiotherapy practice, such as the development of conformal radiotherapy (CFRT) and intensity-modulated radiotherapy (IMRT). Randomised data support the value of CFRT in reducing rectal toxicity. IMRT can permit higher-dose escalation while still respecting known rectal tolerance thresholds. Brachytherapy is a recognised alternative for low-risk prostate cancer subgroups. New radiotherapeutic strategies for prostate cancer include pelvic nodal irradiation, exploiting the presumed low alpha/beta ratio in prostate cancer for hypofractionation and combining external beam with high-dose-rate brachytherapy boosts. New image-guided methodologies will enhance the therapeutic ratio of any radiotherapy technique or dose escalation programme by enabling more reliable and accurate treatment delivery for improved patient outcomes.

The alpha/beta ratio for prostate cancer: what is it, really?

Two recent studies of fractionated external beam radiotherapy in early prostate cancer provide outcome data that allow a statistical estimation of the alpha/beta-ratio of the linear-quadratic model when combined with clinical data on the steepness of the dose-response curve. Results of the large randomized PR5 trial by the Ontario Clinical Oncology Group/National Cancer Institute of Canada yield an estimate of alpha/beta at 1.12 Gy with 95% confidence interval (-3.3, 5.6) Gy. A non-randomized study by Valdagni and colleagues of hyper-fractionation delivered BID versus conventional fractionation yields an alpha/beta-estimate of 8.3 Gy with 95% confidence interval (0.7, 16) Gy. Thus, the confidence interval of this latter study cannot exclude even very low values of alpha/beta. Furthermore, this point estimate may be an over-estimate if incomplete repair plays a role in the BID group of the Italian study. Taken together, the outcomes of these two studies still favor a high fractionation sensitivity of prostate cancer.

Phase III pilot study of dose escalation using conformal radiotherapy in prostate cancer: PSA control and side effects

Radical radiotherapy is a standard form of management of localised prostate cancer. Conformal treatment planning spares adjacent normal tissues reducing treatment-related side effects and may permit safe dose escalation. We have tested the effects on tumour control and side effects of escalating radiotherapy dose and investigated the appropriate target volume margin. After an initial 3-6 month period of androgen suppression, 126 men were randomised and treated with radiotherapy using a 2 by 2 factorial trial design. The initial radiotherapy tumour target volume included the prostate and base of seminal vesicles (SV) or complete SV depending on SV involvement risk. Treatments were randomised to deliver a dose of 64 Gy with either a 1.0 or 1.5 cm margin around the tumour volume (1.0 and 1.5 cm margin groups) and also to treat either with or without a 10 Gy boost to the prostate alone with no additional margin (64 and 74 Gy groups). Tumour control was monitored by prostate-specific antigen (PSA) testing and clinical examination with additional tests as appropriate. Acute and late side effects of treatment were measured using the Radiation Treatment and Oncology Groups (RTOG) and LENT SOM systems. The results showed that freedom from PSA failure was higher in the 74 Gy group compared to the 64 Gy group, but this did not reach conventional levels of statistical significance with 5-year actuarial control rates of 71% (95% CI 58-81%) in the 74 Gy group vs 59% (95% CI 45-70%) in the 64 Gy group. There were 23 failures in the 74 Gy group and 33 in the 64 Gy group (Hazard ratio 0.64, 95% CI 0.38-1.10, P=0.10). No difference in disease control was seen between the 1.0 and 1.5 cm margin groups (5-year actuarial control rates 67%, 95% CI 53-77% vs 63%, 95% CI 50-74%) with 28 events in each group (Hazard ratio 0.97, 95% CI 0.50-1.86, P=0.94). Acute side effects were generally mild and 18 weeks after treatment, only four and five of the 126 men had persistent > or =Grade 1 bowel or bladder side effects, respectively. Statistically significant increases in acute bladder side effects were seen after treatment in the men receiving 74 Gy (P=0.006), and increases in both acute bowel side effects during treatment (P=0.05) and acute bladder sequelae (P=0.002) were recorded for men in the 1.5 cm margin group. While statistically significant, these differences were of short duration and of doubtful clinical importance. Late bowel side effects (RTOG> or =2) were seen more commonly in the 74 Gy and 1.5 cm margin groups (P=0.02 and P=0.05, respectively) in the first 2 years after randomisation. Similar results were found using the LENT SOM assessments. No significant differences in late bladder side effects were seen between the randomised groups using the RTOG scoring system. Using the LENT SOM instrument, a higher proportion of men treated in the 74 Gy group had Grade > or =3 urinary frequency at 6 and 12 months. Compared to baseline scores, bladder symptoms improved after 6 months or more follow-up in all groups. Sexual function deteriorated after treatment with the number of men reporting some sexual dysfunction (Grade> or =1) increasing from 38% at baseline to 66% at 6 months and 1 year and 81% by year 5. However, no consistent differences were seen between the randomised groups. In conclusion, dose escalation from 64 to 74 Gy using conformal radiotherapy may improve long-term PSA control, but a treatment margin of 1.5 cm is unnecessary and is associated with increased acute bowel and bladder reactions and more late rectal side effects. Data from this randomised pilot study informed the Data Monitoring Committee of the Medical Research Council RT 01 Trial and the two studies will be combined in subsequent meta-analysis.

Questionnaire based quality assurance for the RT01 trial of dose escalation in conformal radiotherapy for prostate cancer (ISRCTN 47772397)

BACKGROUND AND PURPOSE

In order to ensure the validity of the outcome of the Medical Research Council's 'RTO1 trial' of dose escalation in conformal radiotherapy for prostate cancer it was considered important that the quality of treatment delivery should meet an adequate standard across all contributing centres. A questionnaire was therefore devised to ensure that all aspects of the planning and delivery process were adequately covered.

PATIENTS AND METHODS

The questionnaire considered each step in the planning and delivery process and drew the attention of the participants to the specific requirements of the trial. Before entering patients into the trial each participating centre had to complete the questionnaire and an outlining exercise (reported elsewhere).

RESULTS

It was not practicable to define a detailed universally acceptable protocol for the whole process of delivery of conformal radiotherapy, not least because of the different equipment available for planning and treatment in different centres. The questionnaire identified some areas of difference in practice between centres where there may be a need for the development of a consensus as to best practice, particularly in the area of patient set-up. Occasionally it was necessary to follow up responses to questions that had been misunderstood or inadequately answered, but in most cases these issues proved to be easily resolved.

CONCLUSIONS

The questionnaire proved to be a useful self-assessment tool as well as enabling the quality assurance group to ensure that the standards of the trial were being met. Subsequent follow-up visits confirmed the usefulness and validity of this self assessment process.