When should factorial designs be used for late-phase randomised controlled trials?

BACKGROUND

A 2×2 factorial design evaluates two interventions (A versus control and B versus control) by randomising to control, A-only, B-only or both A and B together. Extended factorial designs are also possible (e.g. 3×3 or 2×2×2). Factorial designs often require fewer resources and participants than alternative randomised controlled trials, but they are not widely used. We identified several issues that investigators considering this design need to address, before they use it in a late-phase setting.

METHODS

We surveyed journal articles published in 2000-2022 relating to designing factorial randomised controlled trials. We identified issues to consider based on these and our personal experiences.

RESULTS

We identified clinical, practical, statistical and external issues that make factorial randomised controlled trials more desirable. Clinical issues are (1) interventions can be easily co-administered; (2) risk of safety issues from co-administration above individual risks of the separate interventions is low; (3) safety or efficacy data are wanted on the combination intervention; (4) potential for interaction (e.g. effect of A differing when B administered) is low; (5) it is important to compare interventions with other interventions balanced, rather than allowing randomised interventions to affect the choice of other interventions; (6) eligibility criteria for different interventions are similar. Practical issues are (7) recruitment is not harmed by testing many interventions; (8) each intervention and associated toxicities is unlikely to reduce either adherence to the other intervention or overall follow-up; (9) blinding is easy to implement or not required. Statistical issues are (10) a suitable scale of analysis can be identified; (11) adjustment for multiplicity is not required; (12) early stopping for efficacy or lack of benefit can be done effectively. External issues are (13) adequate funding is available and (14) the trial is not intended for licensing purposes. An overarching issue (15) is that factorial design should give a lower sample size requirement than alternative designs. Across designs with varying non-adherence, retention, intervention effects and interaction effects, 2×2 factorial designs require lower sample size than a three-arm alternative when one intervention effect is reduced by no more than 24%-48% in the presence of the other intervention compared with in the absence of the other intervention.

CONCLUSIONS

Factorial designs are not widely used and should be considered more often using our issues to consider. Low potential for at most small to modest interaction is key, for example, where the interventions have different mechanisms of action or target different aspects of the disease being studied.

A comparison of different population-level summary measures for randomised trials with time-to-event outcomes, with a focus on non-inferiority trials

BACKGROUND

The population-level summary measure is a key component of the estimand for clinical trials with time-to-event outcomes. This is particularly the case for non-inferiority trials, because different summary measures imply different null hypotheses. Most trials are designed using the hazard ratio as summary measure, but recent studies suggested that the difference in restricted mean survival time might be more powerful, at least in certain situations. In a recent letter, we conjectured that differences between summary measures can be explained using the concept of the non-inferiority frontier and that for a fair simulation comparison of summary measures, the same analysis methods, making the same assumptions, should be used to estimate different summary measures. The aim of this article is to make such a comparison between three commonly used summary measures: hazard ratio, difference in restricted mean survival time and difference in survival at a fixed time point. In addition, we aim to investigate the impact of using an analysis method that assumes proportional hazards on the operating characteristics of a trial designed with any of the three summary measures.

METHODS

We conduct a simulation study in the proportional hazards setting. We estimate difference in restricted mean survival time and difference in survival non-parametrically, without assuming proportional hazards. We also estimate all three measures parametrically, using flexible survival regression, under the proportional hazards assumption.

RESULTS

Comparing the hazard ratio assuming proportional hazards with the other summary measures not assuming proportional hazards, relative performance varies substantially depending on the specific scenario. Fixing the summary measure, assuming proportional hazards always leads to substantial power gains compared to using non-parametric methods. Fixing the modelling approach to flexible parametric regression assuming proportional hazards, difference in restricted mean survival time is most often the most powerful summary measure among those considered.

CONCLUSION

When the hazards are likely to be approximately proportional, reflecting this in the analysis can lead to large gains in power for difference in restricted mean survival time and difference in survival. The choice of summary measure for a non-inferiority trial with time-to-event outcomes should be made on clinical grounds; when any of the three summary measures discussed here is equally justifiable, difference in restricted mean survival time is most often associated with the most powerful test, on the condition that it is estimated under proportional hazards.

Treatment selection in multi-arm multi-stage designs: With application to a postpartum haemorrhage trial

BACKGROUND

Multi-arm multi-stage trials are an efficient, adaptive approach for testing many treatments simultaneously within one protocol. In settings where numbers of patients available to be entered into trials and resources might be limited, such as primary postpartum haemorrhage, it may be necessary to select a pre-specified subset of arms at interim stages even if they are all showing some promise against the control arm. This will put a limit on the maximum number of patients required and reduce the associated costs. Motivated by the World Health Organization Refractory HaEmorrhage Devices trial in postpartum haemorrhage, we explored the properties of such a selection design in a randomised phase III setting and compared it with other alternatives. The objectives are: (1) to investigate how the timing of treatment selection affects the operating characteristics; (2) to explore the use of an information-rich (continuous) intermediate outcome to select the best-performing arm, out of four treatment arms, compared with using the primary (binary) outcome for selection at the interim stage; and (3) to identify factors that can affect the efficiency of the design.

METHODS

We conducted simulations based on the refractory haemorrhage devices multi-arm multi-stage selection trial to investigate the impact of the timing of treatment selection and applying an adaptive allocation ratio on the probability of correct selection, overall power and familywise type I error rate. Simulations were also conducted to explore how other design parameters will affect both the maximum sample size and trial timelines.

RESULTS

The results indicate that the overall power of the trial is bounded by the probability of 'correct' selection at the selection stage. The results showed that good operating characteristics are achieved if the treatment selection is conducted at around 17% of information time. Our results also showed that although randomising more patients to research arms before selection will increase the probability of selecting correctly, this will not increase the overall efficiency of the (selection) design compared with the fixed allocation ratio of 1:1 to all arms throughout.

CONCLUSIONS

Multi-arm multi-stage selection designs are efficient and flexible with desirable operating characteristics. We give guidance on many aspects of these designs including selecting the intermediate outcome measure, the timing of treatment selection, and choosing the operating characteristics.

Postoperative radiotherapy for non-small cell lung cancer

BACKGROUND

The role of postoperative radiotherapy (PORT) in the treatment of patients with completely resected non-small cell lung cancer (NSCLC) was not clear. A systematic review and individual participant data meta-analysis was undertaken to evaluate available evidence from randomised controlled trials (RCTs). These results were first published in Lung Cancer in 2013.

OBJECTIVES

To evaluate the effects of PORT on survival and recurrence in patients with completely resected NSCLC. To investigate whether predefined patient subgroups benefit more or less from PORT.

SEARCH METHODS

We supplemented MEDLINE and CANCERLIT searches (1965 to 8 July 2016) with information from trial registers, handsearching of relevant meeting proceedings and discussion with trialists and organisations.

SELECTION CRITERIA

We included trials of surgery versus surgery plus radiotherapy, provided they randomised participants with NSCLC using a method that precluded prior knowledge of treatment assignment.

DATA COLLECTION AND ANALYSIS

We carried out a quantitative meta-analysis using updated information from individual participants from all randomised trials. We sought data on all participants from those responsible for the trial. We obtained updated individual participant data (IPD) on survival and date of last follow-up, as well as details on treatment allocation, date of randomisation, age, sex, histological cell type, stage, nodal status and performance status. To avoid potential bias, we requested information on all randomised participants, including those excluded from investigators' original analyses. We conducted all analyses on intention-to-treat on the endpoint of survival.

MAIN RESULTS

We identified 14 trials evaluating surgery versus surgery plus radiotherapy. Individual participant data were available for 11 of these trials, and our analyses are based on 2343 participants (1511 deaths). Results show a significant adverse effect of PORT on survival, with a hazard ratio of 1.18, or an 18% relative increase in risk of death. This is equivalent to an absolute detriment of 5% at two years (95% confidence interval (CI) 2% to 9%), reducing overall survival from 58% to 53%. Subgroup analyses showed no differences in effects of PORT by any participant subgroup covariate.We did not undertake analysis of the effects of PORT on quality of life and adverse events. Investigators did not routinely collect quality of life information during these trials, and it was unlikely that any benefit of PORT would offset the observed survival disadvantage. We considered risk of bias in the included trials to be low.

AUTHORS' CONCLUSIONS

Results from 11 trials and 2343 participants show that PORT is detrimental to those with completely resected non-small cell lung cancer and should not be used in the routine treatment of such patients. Results of ongoing RCTs will clarify the effects of modern radiotherapy in patients with N2 tumours.

Postoperative radiotherapy for non-small cell lung cancer

BACKGROUND

The role of postoperative radiotherapy (PORT) in the treatment of patients with completely resected non-small cell lung cancer (NSCLC) was not clear. A systematic review and individual participant data meta-analysis was undertaken to evaluate available evidence from randomised controlled trials (RCTs). These results were first published in Lung Cancer in 2013.

OBJECTIVES

To evaluate the effects of PORT on survival and recurrence in patients with completely resected NSCLC. To investigate whether predefined patient subgroups benefit more or less from PORT.

SEARCH METHODS

We supplemented MEDLINE and CANCERLIT searches (1965 to 8 July 2016) with information from trial registers, handsearching of relevant meeting proceedings and discussion with trialists and organisations.

SELECTION CRITERIA

We included trials of surgery versus surgery plus radiotherapy, provided they randomised participants with NSCLC using a method that precluded prior knowledge of treatment assignment.

DATA COLLECTION AND ANALYSIS

We carried out a quantitative meta-analysis using updated information from individual participants from all randomised trials. We sought data on all participants from those responsible for the trial. We obtained updated individual participant data (IPD) on survival and date of last follow-up, as well as details on treatment allocation, date of randomisation, age, sex, histological cell type, stage, nodal status and performance status. To avoid potential bias, we requested information on all randomised participants, including those excluded from investigators' original analyses. We conducted all analyses on intention-to-treat on the endpoint of survival.

MAIN RESULTS

We identified 14 trials evaluating surgery versus surgery plus radiotherapy. Individual participant data were available for 11 of these trials, and our analyses are based on 2343 participants (1511 deaths). Results show a significant adverse effect of PORT on survival, with a hazard ratio of 1.18, or an 18% relative increase in risk of death. This is equivalent to an absolute detriment of 5% at two years (95% confidence interval (CI) 2% to 9%), reducing overall survival from 58% to 53%. Subgroup analyses showed no differences in effects of PORT by any participant subgroup covariate.We did not undertake analysis of the effects of PORT on quality of life and adverse events. Investigators did not routinely collect quality of life information during these trials, and it was unlikely that any benefit of PORT would offset the observed survival disadvantage. We considered risk of bias in the included trials to be low.

AUTHORS' CONCLUSIONS

Results from 11 trials and 2343 participants show that PORT is detrimental to those with completely resected non-small cell lung cancer and should not be used in the routine treatment of such patients. Results of ongoing RCTs will clarify the effects of modern radiotherapy in patients with N2 tumours.

Adjuvant chemotherapy for resected early-stage non-small cell lung cancer

BACKGROUND

To evaluate the effects of administering chemotherapy following surgery, or following surgery plus radiotherapy (known as adjuvant chemotherapy) in patients with early stage non-small cell lung cancer (NSCLC),we performed two systematic reviews and meta-analyses of all randomised controlled trials using individual participant data. Results were first published in The Lancet in 2010.

OBJECTIVES

To compare, in terms of overall survival, time to locoregional recurrence, time to distant recurrence and recurrence-free survival:A. Surgery versus surgery plus adjuvant chemotherapyB. Surgery plus radiotherapy versus surgery plus radiotherapy plus adjuvant chemotherapyin patients with histologically diagnosed early stage NSCLC.(2)To investigate whether or not predefined patient subgroups benefit more or less from cisplatin-based chemotherapy in terms of survival.

SEARCH METHODS

We supplemented MEDLINE and CANCERLIT searches (1995 to December 2013) with information from trial registers, handsearching relevant meeting proceedings and by discussion with trialists and organisations.

SELECTION CRITERIA

We included trials of a) surgery versus surgery plus adjuvant chemotherapy; and b) surgery plus radiotherapy versus surgery plus radiotherapy plus adjuvant chemotherapy, provided that they randomised NSCLC patients using a method which precluded prior knowledge of treatment assignment.

DATA COLLECTION AND ANALYSIS

We carried out a quantitative meta-analysis using updated information from individual participants from all randomised trials. Data from all patients were sought from those responsible for the trial. We obtained updated individual participant data (IPD) on survival, and date of last follow-up, as well as details of treatment allocated, date of randomisation, age, sex, histological cell type, stage, and performance status. To avoid potential bias, we requested information for all randomised patients, including those excluded from the investigators' original analyses. We conducted all analyses on intention-to-treat on the endpoint of survival. For trials using cisplatin-based regimens, we carried out subgroup analyses by age, sex, histological cell type, tumour stage, and performance status.

MAIN RESULTS

We identified 35 trials evaluating surgery plus adjuvant chemotherapy versus surgery alone. IPD were available for 26 of these trials and our analyses are based on 8447 participants (3323 deaths) in 34 trial comparisons. There was clear evidence of a benefit of adding chemotherapy after surgery (hazard ratio (HR)= 0.86, 95% confidence interval (CI)= 0.81 to 0.92, p< 0.0001), with an absolute increase in survival of 4% at five years.We identified 15 trials evaluating surgery plus radiotherapy plus chemotherapy versus surgery plus radiotherapy alone. IPD were available for 12 of these trials and our analyses are based on 2660 participants (1909 deaths) in 13 trial comparisons. There was also evidence of a benefit of adding chemotherapy to surgery plus radiotherapy (HR= 0.88, 95% CI= 0.81 to 0.97, p= 0.009). This represents an absolute improvement in survival of 4% at five years.For both meta-analyses, we found similar benefits for recurrence outcomes and there was little variation in effect according to the type of chemotherapy, other trial characteristics or patient subgroup.We did not undertake analysis of the effects of adjuvant chemotherapy on quality of life and adverse events. Quality of life information was not routinely collected during the trials, but where toxicity was assessed and mentioned in the publications, it was thought to be manageable. We considered the risk of bias in the included trials to be low.

AUTHORS' CONCLUSIONS

Results from 47 trial comparisons and 11,107 patients demonstrate the clear benefit of adjuvant chemotherapy for these patients, irrespective of whether chemotherapy was given in addition to surgery or surgery plus radiotherapy. This is the most up-to-date and complete systematic review and individual participant data (IPD) meta-analysis that has been carried out.

Platinum versus platinum-combination chemotherapy in platinum-sensitive recurrent ovarian cancer: a meta-analysis using individual patient data

BACKGROUND

The majority of women with ovarian cancer develop recurrent disease. For patients with a platinum-free interval of >6 months, platinum-based chemotherapy is a treatment of choice. The benefit of platinum-based combination chemotherapy in randomized trials varies, and a meta-analysis was carried out to gain more secure information on the size of the benefit of this treatment.

MATERIALS AND METHODS

We initiated a systematic review and meta-analysis following a pre-specified protocol to determine whether combination chemotherapy is superior to single-agent platinum chemotherapy in women with relapsed platinum-sensitive ovarian cancer.

RESULTS

A total of five potentially eligible randomized trials were identified that had used combination-platinum chemotherapy versus single-agent platinum chemotherapy in women with relapsed platinum-sensitive ovarian cancer. For one trial (190 patients), adequate contact with the investigators could not be established. Therefore, four trials that randomly assigned 1300 patients were included, with a median follow-up of 36.1 months. Overall survival (OS) analyses were based on 865 deaths and demonstrated evidence for the benefit of combination-platinum chemotherapy (HR = 0.80; 95% CI, 0.64-1.00; P = 0.05). Progression-free survival (PFS) analyses were based on 1167 events and demonstrated strong evidence for the benefit of combination-platinum chemotherapy (HR = 0.68; 95% CI, 0.57-0.81; P < 0.001). There was no evidence of a difference in the relative effect of combination-platinum chemotherapy on either OS or PFS in patient subgroups defined by previous paclitaxel (Taxol) treatment (OS, P = 0.49; PFS, P = 0.66), duration of treatment-free interval (OS, P = 0.86; PFS, P = 0.48) or the number of previous lines of chemotherapy (OS, P = 0.21; PFS, P = 0.27).

CONCLUSIONS

In this individual patient data (IPD) meta-analysis, we have demonstrated that combination-platinum chemotherapy improves OS and PFS across all subgroups. This provides the strongest evidence to date of the benefit of combination-platinum over single-agent platinum.

Flexible trial design in practice - stopping arms for lack-of-benefit and adding research arms mid-trial in STAMPEDE: a multi-arm multi-stage randomized controlled trial

BACKGROUND

Systemic Therapy for Advanced or Metastatic Prostate cancer: Evaluation of Drug Efficacy (STAMPEDE) is a randomized controlled trial that follows a novel multi-arm, multi-stage (MAMS) design. We describe methodological and practical issues arising with (1) stopping recruitment to research arms following a pre-planned intermediate analysis and (2) adding a new research arm during the trial.

METHODS

STAMPEDE recruits men who have locally advanced or metastatic prostate cancer who are starting standard long-term hormone therapy. Originally there were five research and one control arms, each undergoing a pilot stage (focus: safety, feasibility), three intermediate 'activity' stages (focus: failure-free survival), and a final 'efficacy' stage (focus: overall survival). Lack-of-sufficient-activity guidelines support the pairwise interim comparisons of each research arm against the control arm; these pre-defined activity cut-off becomes increasingly stringent over the stages. Accrual of further patients continues to the control arm and to those research arms showing activity and an acceptable safety profile. The design facilitates adding new research arms should sufficiently interesting agents emerge. These new arms are compared only to contemporaneously recruited control arm patients using the same intermediate guidelines in a time-delayed manner. The addition of new research arms is subject to adequate recruitment rates to support the overall trial aims.

RESULTS

(1) Stopping Existing Therapy: After the second intermediate activity analysis, recruitment was discontinued to two research arms for lack-of-sufficient activity. Detailed preparations meant that changes were implemented swiftly at 100 international centers and recruitment continued seamlessly into Activity Stage III with 3 remaining research arms and the control arm. Further regulatory and ethical approvals were not required because this was already included in the initial trial design.(2) Adding New Therapy: An application to add a new research arm was approved by the funder, (who also organized peer review), industrial partner and regulatory and ethical bodies. This was all done in advance of any decision to stop current therapies.

CONCLUSIONS

The STAMPEDE experience shows that recruitment to a MAMS trial and mid-flow changes its design are achievable with good planning. This benefits patients and the scientific community as research treatments are evaluated in a more efficient and cost-effective manner.

TRIAL REGISTRATION

ISRCTN78818544, NCT00268476. First patient into trial: 17 October 2005. First patient into abiraterone comparison: 15 November 2011.

Initial toxicity assessment of ICON6: a randomised trial of cediranib plus chemotherapy in platinum-sensitive relapsed ovarian cancer

BACKGROUND

Cediranib is a potent oral vascular endothelial growth factor (VEGF) signalling inhibitor with activity against all three VEGF receptors. The International Collaboration for Ovarian Neoplasia 6 (ICON6) trial was initiated based on evidence of single-agent activity in ovarian cancer with acceptable toxicity.

METHODS

The ICON6 trial is a 3-arm, 3-stage, double-blind, placebo-controlled randomised trial in first relapse of platinum-sensitive ovarian cancer. Patients are randomised (2 : 3 : 3) to receive six cycles of carboplatin (AUC5/6) plus paclitaxel (175 mg m(-2)) with either placebo (reference), cediranib 20 mg per day, followed by placebo (concurrent), or cediranib 20 mg per day, followed by cediranib (concurrent plus maintenance). Cediranib or placebo was continued for 18 months or until disease progression. The primary outcome measure for stage I was safety, and the blinded results are presented here.

RESULTS

Sixty patients were included in the stage I analysis. A total of 53 patients had received three cycles of chemotherapy and 42 patients had completed six cycles. In all, 19 out of 60 patients discontinued cediranib or placebo during chemotherapy because of adverse events/intercurrent illness (n=9); disease progression (n=1); death (n=3); patient decision (n=1); administrative reasons (n=1); and multiple reasons (n=4). Grade 3 and 4 toxicity was experienced by 30 (50%) and 3 (5%) patients, respectively. No gastrointestinal perforations were observed.

CONCLUSION

The addition of cediranib to platinum-based chemotherapy is sufficiently well tolerated to expand the ICON6 trial and progress to stage II.

Active symptom control with or without chemotherapy in the treatment of patients with malignant pleural mesothelioma (MS01): a multicentre randomised trial

BACKGROUND

Malignant pleural mesothelioma is almost always fatal, and few treatment options are available. Although active symptom control (ASC) has been recommended for the management of this disease, no consensus exists for the role of chemotherapy. We investigated whether the addition of chemotherapy to ASC improved survival and quality of life.

METHODS

409 patients with malignant pleural mesothelioma, from 76 centres in the UK and two in Australia, were randomly assigned to ASC alone (treatment could include steroids, analgesic drugs, bronchodilators, palliative radiotherapy [n=136]); to ASC plus MVP (four cycles of mitomycin 6 mg/m2, vinblastine 6 mg/m2, and cisplatin 50 mg/m2 every 3 weeks [n=137]); or to ASC plus vinorelbine (one injection of vinorelbine 30 mg/m2 every week for 12 weeks [n=136]). Randomisation was done by minimisation, with stratification for WHO performance status, histology, and centre. Follow-up was every 3 weeks to 21 weeks after randomisation, and every 8 weeks thereafter. Because of slow accrual, the two chemotherapy groups were combined and compared with ASC alone for the primary outcome of overall survival. Analysis was by intention to treat. This study is registered, number ISRCTN54469112.

FINDINGS

At the time of analysis, 393 (96%) patients had died (ASC 132 [97%], ASC plus MVP 132 [96%], ASC plus vinorelbine 129 [95%]). Compared with ASC alone, we noted a small, non-significant survival benefit for ASC plus chemotherapy (hazard ratio [HR] 0.89 [95% CI 0.72-1.10]; p=0.29). Median survival was 7.6 months in the ASC alone group and 8.5 months in the ASC plus chemotherapy group. Exploratory analyses suggested a survival advantage for ASC plus vinorelbine compared with ASC alone (HR 0.80 [0.63-1.02]; p=0.08), with a median survival of 9.5 months. There was no evidence of a survival benefit with ASC plus MVP (HR 0.99 [0.78-1.27]; p=0.95). We observed no between-group differences in four predefined quality-of-life subscales (physical functioning, pain, dyspnoea, and global health status) at any of the assessments in the first 6 months.

INTERPRETATION

The addition of chemotherapy to ASC offers no significant benefits in terms of overall survival or quality of life. However, exploratory analyses suggested that vinorelbine merits further investigation.

Preoperative radiotherapy for esophageal carcinoma

BACKGROUND

The existing randomized evidence has failed to conclusively demonstrate the benefit or otherwise of preoperative radiotherapy in treating patients with potentially resectable esophageal carcinoma.

OBJECTIVES

This meta-analysis aimed to assess whether there is benefit from adding radiotherapy prior to surgery and whether or not any pre-defined patient subgroups benefit more or less from preoperative radiotherapy

SEARCH STRATEGY

MEDLINE and CancerLit searches were supplemented by information from trial registers and by hand searching relevant meeting proceedings and by discussion with relevant trialists, organisations and industry. The search strategy was run again in MEDLINE, EMBASE and the Cochrane Library on 30th April 2001, two years after original publication. No new trials were found. The search strategy was re-run August 2002 and August 2003 on MEDLINE, EMBASE , CancerLit and The Cochrane Library, and July 2004 and 2005 on MEDLINE, EMBASE and the Cochrane Library. No new relevant trials were identified on any of these occasions.

SELECTION CRITERIA

Trials were eligible for inclusion in this meta-analysis provided they randomized patients with potentially resectable carcinoma of the esophagus (of any histological type) to receive radiotherapy or no radiotherapy prior to surgery. Trials must have used a randomization method which precluded prior knowledge of treatment assignment and completed accrual by December 1993, to ensure sufficient follow-up by the time of the first analysis (September 1995).

DATA COLLECTION AND ANALYSIS

A quantitative meta-analysis using updated data from individual patients from all properly randomized trials (published or unpublished) comprising 1147 patients (971 deaths) from five randomized trials. This approach was used to assess whether preoperative radiotherapy improves overall survival and whether it is differentially effective in patients defined by age, sex and tumour location.

MAIN RESULTS

With a median follow-up of 9 years, in a group patients with mostly squamous carcinomas, the hazard ratio (HR) of 0.89 (95% CI 0.78-1.01) suggests an overall reduction in the risk of death of 11% and an absolute survival benefit of 3% at 2 years and 4% at 5 years. This result is not conventionally statistically significant (p=0.062). No clear differences in the size of the effect by sex, age or tumor location were apparent.

AUTHORS' CONCLUSIONS

Based on existing trials, there was no clear evidence that preoperative radiotherapy improves the survival of patients with potentially resectable esophageal cancer. These results indicate that if such preoperative radiotherapy regimens do improve survival, then the effect is likely to be modest with an absolute improvement in survival of around 3 to 4%. Trials or a meta-analysis of around 2000 patients (90% power, 5% significance level) would be needed to reliably detect such an improvement (from 15 to 20%).

Monitoring of large randomised clinical trials: a new approach with Bayesian methods

BACKGROUND

In judging whether or not to continue enrolling patients into a randomised clinical trial, most data-monitoring and ethics committees (DMECs) rely on the p value for the difference in effect between the study groups. In the 1990s, two randomised controlled trials-one in patients with lung cancer and one in those with head and neck cancer-were instead monitored by Bayesian methods. We assessed the value of this approach in the monitoring of these clinical trials.

METHODS

Before the trials opened, participating clinicians were asked their opinions on the expected difference between the study treatment (continuous hyperfractionated accelerated radiotherapy [CHART]) and conventional radiotherapy. These opinions were used to form an "enthusiastic" and a "sceptical" prior distribution. These prior distributions were combined with the trial data at each of the annual DMEC meetings. If, during monitoring, a result in favour of CHART was seen, the DMEC was to decide whether the results were sufficiently convincing to persuade a sceptic that CHART was worthwhile. Conversely, if there was apparently no or little difference, the DMEC was asked whether they thought the results sufficiently convincing to persuade an enthusiast that CHART was not worthwhile.

FINDINGS

At each of the annual meetings, the DMEC concluded that there was insufficient evidence to convert either sceptics or enthusiasts, and that the trials should therefore remain open to recruitment. Neither trial was closed to recruitment earlier than planned. However if a conventional (p-value-based) stopping rule had been used, the lung-cancer trial would probably have been stopped.

INTERPRETATION

This Bayesian approach to monitoring is simple to implement and straightforward for members of the DMEC to understand. In our opinion, it is more intuitively appealing than conventional approaches.

Analysis of messy longitudinal data from a randomized clinical trial. MRC Lung Cancer Working Party

The randomized clinical trial, LU19, conducted by the Medical Research Council Lung Cancer Working Party, was designed to compare ACE (doxorubicin, cyclophosphamide and etoposide) chemotherapy plus G-CSF (granulocyte colony-stimulating factor) at 2-week intervals versus ACE chemotherapy alone at standard 3-week intervals in patients with small-cell lung cancer. This trial investigated whether more intensive administration of ACE would improve overall survival and affect the quality of life of patients. The report on overall survival and other outcome measures will be published in the Journal of Clinical Oncology. In this paper we focus on methods of analysing aspects of data reflecting quality of life. Twelve symptoms of lung cancer and its treatment - cough, haemoptysis, pain, nausea, vomiting, hoarse voice, sore mouth, rash, lethargy, lack of appetite, alopecia, and dysphagia - were scheduled to be assessed on seven occasions for the ACE arm and on eight occasions for the ACE+G-CSF arm by clinicians during the first 18 weeks of the treatment period. However, in practice the number of assessment forms completed per patient ranged from 1 to 9, and assessment time-points were very different from those planned. These 'messy' longitudinal data are explored by both a summary measure approach, in which experience of a symptom is summarized by a single value, and an extensive model-based statistical approach, which explicitly takes into account correlation within repeated measures. These analyses provide a clear picture of symptom comparisons between the two treatments. The application of various methods offers not only an approach to assessing the robustness of the results but also a basis for investigating reasons for inconsistency of results across methods. We conclude that except lethargy, which is worse in the ACE+G-CSF arm, all symptoms are similar across the two arms during the treatment period.

A randomized trial of hypofractionated schedules of palliative radiotherapy in the management of bladder carcinoma: results of medical research council trial BA09

PURPOSE

To compare the efficacy and toxicity of two hypofractionated radiotherapy schedules for the improvement of local symptoms from muscle-invasive bladder cancer.

METHODS AND MATERIALS

A multicenter randomized trial was conducted comparing the efficacy and toxicity of two radiotherapy schedules (35 Gy in 10 fractions and 21 Gy in 3 fractions) for symptomatic improvement in patients considered unsuitable for curative treatment through disease stage or comorbidity. The primary outcome measures were overall symptomatic improvement of bladder-related symptoms at 3 months and changes in bladder- and bowel-related symptoms from pretreatment to end-of-treatment and 3-month assessments. Overall symptomatic improvement was defined prospectively as the improvement in one bladder-related symptom of at least one grade at 3 months, with no deterioration in any other bladder-related symptom.

RESULTS

Five hundred patients were recruited, but data on symptomatic improvement at 3 months was only available on 272 patients. Of these, 68% achieved symptomatic improvement (71% for 35 Gy, 64% for 21 Gy), with no evidence of a difference in efficacy or toxicity between the two arms. There was no evidence of a difference in survival between the two schedules (hazard ratio [HR] = 0.99, 95% CI 0.82-1.21, p = 0. 933).

CONCLUSION

This is the largest prospective trial to date in the palliative treatment of bladder cancer, and provides baseline data against which other results may be compared. The use of 21 Gy in 3 fractions appears as effective as 35 Gy in 10 fractions, although modest differences in survival, symptomatic improvement rates, and toxicity can not be reliably excluded.

Preoperative radiotherapy for esophageal carcinoma. Oeosphageal Cancer Collaborative Group

BACKGROUND

The existing randomized evidence has failed to conclusively demonstrate the benefit or otherwise of preoperative radiotherapy in treating patients with potentially resectable esophageal carcinoma.

OBJECTIVES

This meta-analysis aimed to assess whether there is benefit from adding radiotherapy prior to surgery and whether or not any pre-defined patient subgroups benefit more or less from preoperative radiotherapy

SEARCH STRATEGY

Medline and CancerLit searches were supplemented by information from trial registers and by hand searching relevant meeting proceedings and by discussion with relevant trialists, organisations and industry.

SELECTION CRITERIA

Trials were eligible for inclusion in this meta-analysis provided they randomized patients with potentially resectable carcinoma of the esophagus (of any histological type) to receive radiotherapy or no radiotherapy prior to surgery. Trials must have used a randomization method which precluded prior knowledge of treatment assignment and completed accrual by December 1993, to ensure sufficient follow-up by the time of the first analysis (September 1995).

DATA COLLECTION AND ANALYSIS

A quantitative meta-analysis using updated data from individual patients from all properly randomized trials (published or unpublished) comprising 1147 patients (971 deaths) from five randomized trials. This approach was used to assess whether preoperative radiotherapy improves overall survival and whether it is differentially effective in patients defined by age, sex and tumour location.

MAIN RESULTS

With a median follow-up of 9 years, in a group patients with mostly squamous carcinomas, the hazard ratio (HR) of 0.89 (95% CI 0.78-1.01) suggests an overall reduction in the risk of death of 11% and an absolute survival benefit of 3% at 2 years and 4% at 5 years. This result is not conventionally statistically significant (p=0.062). No clear differences in the size of the effect by sex, age or tumor location were apparent.

REVIEWER'S CONCLUSIONS

Based on existing trials, there was no clear evidence that preoperative radiotherapy improves the survival of patients with potentially resectable esophageal cancer. These results indicate that if such preoperative radiotherapy regimens do improve survival, then the effect is likely to be modest with an absolute improvement in survival of around 3 to 4%. Trials or a meta-analysis of around 2000 patients (90% power, 5% significance level) would be needed to reliably detect such an improvement (from 15 to 20%).

Physical and psychological symptoms of quality of life in the CHART randomized trial in head and neck cancer: short-term and long-term patient reported symptoms. CHART Steering Committee. Continuous hyperfractionated accelerated radiotherapy

The randomized multicentre trial of continuous hyperfractionated accelerated radiotherapy (CHART) versus conventional radiotherapy in patients with advanced head and neck cancer showed no good evidence of a difference in any of the major clinical outcomes of survival, freedom from metastases, loco-regional control and disease-free survival. Therefore an assessment of the effect of treatment on physical and psychological symptoms is vital to balance the costs and benefits of the two treatments. A total of 615 patients were asked to complete a Rotterdam Symptom Checklist and the Hospital Anxiety and Depression Scale, which cover a variety of physical and psychological symptoms, at a total of ten time points. The data consisted of short-term data (the initial 3 months) and long-term data (1 and 2 years). The short-term data was split into an exploratory data set and a confirmatory data set, and analysed using subject-specific and group-based methods. Differences were only claimed if hypotheses generated in the exploratory data set were confirmed in the confirmatory data set. The long-term data was not split into two data sets and was analysed using a group-based approach. There was evidence of significantly worse symptoms of pain at day 21 in those treated with CHART and significantly worse symptoms of cough and hoarseness at 6 weeks in those treated conventionally. There was also evidence to suggest a higher degree of decreased sexual interest at 1 year and sore muscles at 2 years in those treated with conventional radiotherapy. There is no clear indication that one regimen is superior to the other in terms of 'quality of life', generally the initially more severe reaction in the CHART group being offset by the longer duration of symptoms in the conventionally treated group.

Intravesical chemotherapy with epirubicin: a dose response study

PURPOSE

We determined the difference in response to high and standard doses of intravesical epirubicin for treatment of superficial bladder cancer.

MATERIALS AND METHODS

A total of 122 patients were entered into a randomized trial to compare the response of a marker tumor at 3 months, time to first recurrence and recurrence rates for 2 years after intravesical chemotherapy for superficial (pTa/pT1) bladder cancer. Patients were randomized to receive treatment for 1 hour with 1 (standard dose) or 2 mg./ml. (high dose) epirubicin (50 or 100 mg./50 ml. solution).

RESULTS

There was no difference in the marker tumor response rate in 24 of 52 patients treated with the standard dose compared with 21 of 50 treated with the higher dose of epirubicin (p = 0.67). Similarly, the higher dose was not superior in regard to time to first recurrence, with a hazard ratio of 1.46 (p = 0.14, 95% confidence intervals 0.88 to 2.42). Considering the upper end of the confidence interval, we can reliably exclude an absolute difference of greater than 4% at 1 year for time to first recurrence in favor of higher dose chemotherapy.

CONCLUSIONS

Epirubicin at double the standard dose for intravesical chemotherapy of superficial bladder cancer is not superior in regard to marker tumor response, time to first recurrence or recurrence rate.

Advanced epithelial ovarian cancer: 1998 consensus statements

BACKGROUND

During an international workshop held in September 1998, a group of specialists in the field of ovarian cancer reached consensus on a number of issues with implications for standard practice and for research of advanced epithelial ovarian cancer.

METHODS

Five groups of experts considered several issues which included: biologic factors, prognostic factors, surgery, initial chemotherapy, second-line treatment, the use of CA 125, investigational drugs, intra-peritoneal treatment and high-dose chemotherapy. The group attempted to arrive at answers to questions such as: Are there prognostic factors, which help to identify patients who will not do well with current therapy? What is the current best therapy for advanced ovarian carcinoma? What directions should research take in advanced ovarian cancer? These issues were discussed in a plenary meeting.

RESULTS

One of the major conclusions drawn by the consensus committee was that in previously untreated advanced ovarian cancer, cisplatin plus paclitaxel has been shown to be superior to previous standard therapy with cisplatin plus cyclophosphamide (level I evidence). However, for many patients, carboplatin plus paclitaxel is a reasonable alternative because of toxicity and convenience considerations. Most participants felt that the benefits in terms of toxicity for the paclitaxel-carboplatin are such that its widespread adoption at this stage is justified. Until mature survival data are available a minority of investigators would recommend continued use of cisplatin plus paclitaxel, specifically for those patients with advanced disease with the best prognostic characteristics. For future clinical research in this area, new end points for randomised clinical trials, together with a new Trials Network, are proposed.

Randomised trials in ovarian cancer: trial design considerations

Randomised clinical trials are considered the definitive source of evidence for guiding decisions in clinical practice. The concept of a clinical trial is based on sound scientific, ethical, and practical principles. The strength of evidence that an individual trial provides is assessed on the manner in which these principles are incorporated into the design and execution of the trial. Since the way these principles are incorporated into a trial is judgmental, the strength of evidence from an individual trial is a matter of degree. The purpose of this paper is to present some of the scientific, ethical and practical considerations surrounding the selection of endpoints and determination of sample size for trials in ovarian cancer.

Intergroup collaboration in ovarian cancer: a giant step forward

The rather slow evolution of so-called "optimal chemotherapy" for ovarian cancer is the result of suboptimal randomised clinical trials, not having the statistical power to identify truly superior regimens, and of the lack of systematic comparisons of new agents with relevant control arms. There is little doubt that we need international collaboration to move the field forward in a timely and coherent manner. European and transatlantic collaboration represents the beginning of the process and point to the success that can await us if the drive to work together remains strong. A similar organisation as for breast cancer (Breast International Group, BIG) needs to be established for ovarian cancer.

Extracting summary statistics to perform meta-analyses of the published literature for survival endpoints

Meta-analyses aim to provide a full and comprehensive summary of related studies which have addressed a similar question. When the studies involve time to event (survival-type) data the most appropriate statistics to use are the log hazard ratio and its variance. However, these are not always explicitly presented for each study. In this paper a number of methods of extracting estimates of these statistics in a variety of situations are presented. Use of these methods should improve the efficiency and reliability of meta-analyses of the published literature with survival-type endpoints.

Extracting summary statistics to perform meta-analyses of the published literature for survival endpoints

Meta-analyses aim to provide a full and comprehensive summary of related studies which have addressed a similar question. When the studies involve time to event (survival-type) data the most appropriate statistics to use are the log hazard ratio and its variance. However, these are not always explicitly presented for each study. In this paper a number of methods of extracting estimates of these statistics in a variety of situations are presented. Use of these methods should improve the efficiency and reliability of meta-analyses of the published literature with survival-type endpoints.

Extracting summary statistics to perform meta-analyses of the published literature for survival endpoints

Meta-analyses aim to provide a full and comprehensive summary of related studies which have addressed a similar question. When the studies involve time to event (survival-type) data the most appropriate statistics to use are the log hazard ratio and its variance. However, these are not always explicitly presented for each study. In this paper a number of methods of extracting estimates of these statistics in a variety of situations are presented. Use of these methods should improve the efficiency and reliability of meta-analyses of the published literature with survival-type endpoints.

Can the published data tell us about the effectiveness of neoadjuvant chemotherapy for locally advanced cancer of the uterine cervix?

The effect of neoadjuvant chemotherapy on survival of patients with locally advanced cervical cancer was investigated by conducting a systematic review and meta-analysis of the published data. Of the 21 randomised trials that we identified, only 15 were published. Furthermore, 2-year survival data could be extracted from only seven trial reports and 3-year survival from only nine trial reports. Meta-analyses of the published data at 2 and 3 years are neither clearly in favour of neoadjuvant chemotherapy nor control (2 years: odds ratio (OR) = 1.09, 95% confidence interval (CI) = 0.83-1.45, P = 0.37; 3 years: OR = 0.96, 95% confidence interval (CI) = 0.73-1.25, P = 0.45). Being restricted to only some of the data from a relatively small fraction of the randomised trials, these analyses potentially suffer from a number of biases and are therefore inconclusive. The only reliable way to judge the value of neoadjuvant chemotherapy in this disease is to perform a meta-analysis of centrally collected, updated, individual data on all patients from all known randomised trials. Such an analysis is currently being carried out by an international collaborative group.

Extracting summary statistics to perform meta-analyses of the published literature for survival endpoints

Meta-analyses aim to provide a full and comprehensive summary of related studies which have addressed a similar question. When the studies involve time to event (survival-type) data the most appropriate statistics to use are the log hazard ratio and its variance. However, these are not always explicitly presented for each study. In this paper a number of methods of extracting estimates of these statistics in a variety of situations are presented. Use of these methods should improve the efficiency and reliability of meta-analyses of the published literature with survival-type endpoints.

First-line chemotherapy for advanced ovarian cancer: paclitaxel, cisplatin and the evidence

As of June 1998, four randomized trials have been completed comparing the combination of paclitaxel and cisplatin with a cisplatin-based control arm. The results of three of these trials are available; one has been published as a full paper, the other two in abstract form only. Two of the reported trials (GOG-111 and the Intergroup trial) provide clear evidence that cisplatin combined with paclitaxel is a more effective regimen than one using the same dose of cisplatin combined with cyclophosphamide. The results of the third reported trial (GOG-132) are rather different, suggesting that a higher dose of single-agent cisplatin may be as effective as the paclitaxel/cisplatin combination tested in the other two trials. A number of explanations for these unexpected results have been proposed: false-positive results in GOG-111 and the Intergroup trial; false-negative results in GOG-132; high crossover in GOG-132 (including crossover before progression); the cyclophosphamide in the control arm of GOG-111 and the Intergroup trial had a negative impact on outcome in the control group in these trials; the higher dose of cisplatin when used as a single agent in GOG-132 had a positive impact on outcome for the control group in this trial. These explanations are discussed in detail, and their implications explored.

A randomized trial comparing methotrexate and vinblastine (MV) with cisplatin, methotrexate and vinblastine (CMV) in advanced transitional cell carcinoma: results and a report on prognostic factors in a Medical Research Council study. MRC Advanced Bladder Cancer Working Party

Transitional cell carcinomas may arise at any site within the urinary tract and are a source of considerable morbidity and mortality. In particular, patients with metastatic disease have a poor prognosis, with less than 5% alive at 5 years. A multicentre randomized trial comparing methotrexate and vinblastine (MV) with cisplatin, methotrexate and vinblastine (CMV) in advanced or metastatic transitional cell carcinoma was conducted in the UK. From April 1991 to June 1995, 214 patients were entered by 16 centres, 108 randomized to CMV and 106 to MV. A total of 204 patients have died. The hazard ratio (relative risk of dying) was 0.68 (95% CI 0.51-0.90, P-value = 0.0065) in favour of CMV. This translates to an absolute improvement in 1-year survival of 13%, 16% in MV and 29% in CMV. The median survival for CMV and MV was 7 months and 4.5 months respectively. Two hundred and eight patients objectively progressed or died. The hazard ratio was 0.55 (95% CI 0.41-0.73, P-value = 0.0001) in favour of CMV. Two hundred and nine patients symptomatically progressed or died. The hazard ratio was 0.48 (95% CI 0.36-0.64, P-value = 0.0001) in favour of CMV. The most important pretreatment factors influencing overall survival were WHO performance status and extent of disease. These two factors were used to derive a prognostic index which could be used to categorize patients into three prognostic groups. We conclude that the addition of cisplatin to methotrexate and vinblastine should be considered in patients with transitional cell carcinoma, taking into account the increased toxicity.

Patient-reported short-term and long-term physical and psychologic symptoms: results of the continuous hyperfractionated accelerated [correction of acclerated] radiotherapy (CHART) randomized trial in non-small-cell lung cancer. CHART Steering Committee

PURPOSE

The randomized multicenter trial of continuous hyperfractionated accelerated radiotherapy (CHART) versus conventional radiotherapy for patients with non-small-cell lung cancer (NSCLC) showed a significant survival benefit to CHART (29% v 20% at 2 years, P=.004). However, an assessment of the effect on physical and psychologic symptoms is vital to balance the costs and benefits of the two treatments.

METHODS

A total of 356 patients in the United Kingdom completed the Rotterdam Symptom Checklist (RSCL) and the Hospital Anxiety and Depression Scale (HADS) at 10 time points. The principal aim of the analyses was to keep the methods simple, so as to allow the presentation and interpretation of the results to be as clear as possible. This was achieved by (1) considering individual symptoms rather than symptom subscales or domains, (2) assessing short-term effects (up to 3 months) and long-term effects (at 1 and 2 years) separately, and (3) for the short-term analyses, (a) splitting the data randomly into an exploratory data set and a confirmatory data set, and (b) using two different methods of analysis: a subject-specific approach, which used the area under the curve (AUC) as a summary measure, and a group-based method, which plotted the percent of patients with moderate or severe symptoms over time.

RESULTS

The results indicate that apart from CHART causing transient pain on swallowing and heartburn, there was little difference between the regimens in the short or long-term.

CONCLUSION

Combining the results of the patient-assessed symptom comparisons with the clinical results indicates that CHART confers a major benefit without serious morbidity.

Preoperative radiotherapy in esophageal carcinoma: a meta-analysis using individual patient data (Oesophageal Cancer Collaborative Group)

PURPOSE

The existing randomized evidence has failed to conclusively demonstrate the benefit or otherwise of preoperative radiotherapy in treating patients with potentially resectable esophageal carcinoma. This meta-analysis aimed to assess whether there is benefit from adding radiotherapy prior to surgery.

METHODS AND MATERIALS

This quantitative meta-analysis included updated individual patient data from all properly randomized trials (published or unpublished) comprising 1147 patients (971 deaths) from five randomized trials.

RESULTS

With a median follow-up of 9 years, the hazard ratio (HR) of 0.89 (95% CI 0.78-1.01) suggests an overall reduction in the risk of death of 11% and an absolute survival benefit of 3% at 2 years and 4% at 5 years. This result is not conventionally statistically significant (p = 0.062). No clear differences in the size of the effect by sex, age, or tumor location were apparent.

CONCLUSION

Based on existing trials, there was no clear evidence that preoperative radiotherapy improves the survival of patients with potentially resectable esophageal cancer. These results indicate that if such preoperative radiotherapy regimens do improve survival, then the effect is likely to be modest with an absolute improvement in survival of around 3 to 4%. Trials or a meta-analysis of around 2000 patients would be needed to reliably detect such an improvement (15-->20%).

Survey of the Administration of quality of life (QL) questionnaires in three multicentre randomised trials in cancer. The Medical Research Council Lung Cancer Working Party the CHART Steering Committee

We surveyed centres collaborating in two trials in lung cancer (LU12, LU13) and one in lung and head and neck cancer (CHART) to find out how QL questionnaires were being administered, with the aim of standardising procedures and improving compliance. Dedicated local trials staff were funded for CHART but not for the other trials. In all three trials, patients completed a Rotterdam Symptom Checklist (RSCL) and a Hospital Anxiety and Depression Scale (HADS) at specified times. 17 of 22 LU12 centres, 9 of 11 LU13 and all 10 CHART centres returned survey forms. In LU12 and LU13, the category of staff responsible for questionnaires varied widely; in CHART, only research staff were involved. This led to more consistency in CHART centres in the administration and collection of questionnaires, and more frequent checking of forms. However, even the CHART administration, although better than in the other two trials, could not be regarded as standardised. All centres were equally affected by logistical problems. These embraced organisational deficits (e.g. unavailability of staff, lack of questionnaires) and patient-related factors (e.g. patient deemed to be too ill, had difficulty reading or left before completing the form). Patient refusals were an uncommon reason for non-compliance and patients were considered to be generally in favour of QL assessment. As a result of these findings, a number of measures have been put in place to increase standardisation of procedures and improve compliance. These include publishing guidelines for protocol writing, providing centres with guidelines for QL administration and information leaflets for patients, together with introducing staff training.

Survey on the treatment of non-small cell lung cancer (NSCLC) in England and Wales

As an adjunct to a meta-analysis of chemotherapy for non-small cell lung cancer (NSCLC), a survey was conducted in England and Wales of clinicians' views on the role of chemotherapy in NSCLC and the benefits it would have to offer to lead them to change their practice. Radiotherapists, medical oncologists, surgeons and physicians specializing in thoracic medicine, and physicians of palliative medicine were asked their views on the treatment of three case histories of 65 yr old men: Case 1, resected tumour involving a hilar lymph node (tumour (T)2, node (N)1, metastasis (M)0); Case 2, tumour that had spread to mediastinal lymph nodes bilaterally (T2, N3, M0); and Case 3, metastatic cancer (M1) accompanied by minor haemoptysis. Six hundred and ninety eight (85%) of the 821 clinicians responded. For Case 1, 74% would not recommend any adjuvant treatment, 24% would recommend radiotherapy, and <1% chemotherapy, and there was little expectation that adjuvant treatment would improve survival. For Case 2, 68% would recommend radiotherapy, 11% chemotherapy, and 1% surgery, 7% recommending a combination. Adjuvant treatment, regardless of modality, was expected to improve survival. For Case 3, only 11% would recommend chemotherapy, but 26% if the patient was aged < or = 50 yrs. There was little expectation of survival beyond 1 yr, or of improving survival with chemotherapy. For all three cases, most of those not recommending chemotherapy would require it to achieve substantially improved survival for them to use it routinely. Surgery alone is currently considered sufficient for resectable non-small cell lung cancer. Chemotherapy is rarely recommended for disease of any stage.

Tutorial in biostatistics Bayesian data monitoring in clinical trials

Many clinical trials organizations use regular interim analyses to monitor the accruing results in large clinical trials. In disease areas such as cancer, where survival is usually a major outcome variable, ethical considerations may lead to a stipulated requirement for data monitoring of mortality. This monitoring has frequently taken the form of limiting interim analyses to be few in number, and specifying an extreme p-value of, for example, p < 0.001 or p < 0.01 as grounds for early termination of the trial. Group-sequential methods are also used. However, none of these approaches formally assesses the impact that the results of a clinical trial may have upon clinical practice. Thus a trial might be terminated early because of apparent treatment benefits, but might fail to influence sceptical clinicians to modify their future treatment policy. We discuss the application of Bayesian methods, including the use of uninformative, sceptical and enthusiastic priors, and demonstrate that the necessary calculations are both straightforward to perform and easy to interpret statistically and clinically. Methods are illustrated with interim analyses of a clinical trial in oesophageal cancer.

Tutorial in biostatistics Bayesian data monitoring in clinical trials

Many clinical trials organizations use regular interim analyses to monitor the accruing results in large clinical trials. In disease areas such as cancer, where survival is usually a major outcome variable, ethical considerations may lead to a stipulated requirement for data monitoring of mortality. This monitoring has frequently taken the form of limiting interim analyses to be few in number, and specifying an extreme p-value of, for example, p < 0.001 or p < 0.01 as grounds for early termination of the trial. Group-sequential methods are also used. However, none of these approaches formally assesses the impact that the results of a clinical trial may have upon clinical practice. Thus a trial might be terminated early because of apparent treatment benefits, but might fail to influence sceptical clinicians to modify their future treatment policy. We discuss the application of Bayesian methods, including the use of uninformative, sceptical and enthusiastic priors, and demonstrate that the necessary calculations are both straightforward to perform and easy to interpret statistically and clinically. Methods are illustrated with interim analyses of a clinical trial in oesophageal cancer.

Evaluation and follow-up of patients with N1-3 M0 or NXM1 prostate cancer in phase III trials

OBJECTIVES

The aim of this discussion is to review the design and conduct of phase III trials in metastatic prostate cancer, to seek ways of improving their study design, accuracy, relevance to clinical practice, acceptability to patients, and ease of participation by clinicians. We also aim to try to set uniform definitions for the evaluation of the different endpoints used in clinical trials on metastasized prostate cancer.

METHODS

The work was started by correspondence between the participants in the group for the year before the consensus meeting. Two comprehensive questionnaires were circulated and the answers were distributed to all the members of the group. The statements were finalized during the consensus meeting.

RESULTS

There were some differing opinions concerning the methods of evaluation of endpoints for follow-up, such as time to tumor progression and time to treatment failure. After the consensus conference, there were no major disagreements within the group.

CONCLUSIONS

The aim of phase III trials is to influence clinical management. To obtain a credible result they require a sound statistical basis with appropriate power and encompassing patients from small urologic practices as well as large or academic institutions. However, deviation from routine practice may affect the accrual rate, and the trial procedure should therefore be as similar as possible to routine management. Trials inevitably involve extra work and cost. Both should be kept to a minimum to encourage participation and hasten a timely conclusion. It is mandatory to create uniform ways of designing and evaluating clinical trials in prostate cancer.

Thirty years of Medical Research Council randomized trials in solid tumours

This paper reviews the survival outcome from the randomized Phase III trials in solid tumours published on behalf of, or in collaboration with, the Cancer Therapy Committee (CTC) of the British Medical Research Council over a 30-year period to 31 December 1995. We review briefly the innovations in statistical methodology that have occurred over the period. We also note the ways in which standards of reporting the trials have improved, with more recent publications including, for example, estimates of the size of effect and confidence intervals. In all, 32 trials, involving over 5000 deaths in more than 8000 patients, have been published. Tumour types have included bladder, bone, brain, cervix, colon and rectum, head and neck, kidney, lung, ovary, prostate and skin. This paper presents a bibliography of these trials and gives details of the treatment comparisons made, the numbers of patients randomized and included in the analysis for each treatment arm, the observed numbers of deaths, and an estimate of the hazard ratio with associated 95% confidence intervals. The bibliography also indicates the main endpoint of each trial, whether recurrence-free survival or survival, and whether the trial was aimed at finding a difference or showing equivalence. The MRC trials have made an impact on both clinical practice and research activities. For example, the lung cancer programme has helped to establish the role of chemotherapy in small cell lung cancer and has developed better palliative treatment for non-small cell lung cancer. Trials of the radiosensitizer misonidazole have demonstrated that it has no role in the treatment of a number of cancers, trials of hyperbaric oxygen have defined the biological activity of this approach, and the appropriate dose of radiotherapy in patients with brain tumours has been found. The individual trials recruited between 44 and 824 patients (median 213). A better measure of the information in a trial is the number of deaths reported, which varied from 28 to 661 (median 145). A large proportion of the comparisons (8/29 or 28%) anticipating a survival difference, demonstrated such a difference at the 5% level of significance. Despite this, it is concluded that some of the trials should have been larger. In such cases, hindsight suggests either that an overoptimistic view of the anticipated survival benefit was taken at the design stage, or, for equivalence trials, the planned confidence interval was too wide for definitive statements to be made. As a consequence, the current CTC profolio of ongoing randomized trials open to patient accrual at 1 January 1996 have a projected median size of 600 and range from 120 to 2000 patients.

A combined analysis of European Organization for Research and Treatment of Cancer, and Medical Research Council randomized clinical trials for the prophylactic treatment of stage TaT1 bladder cancer. European Organization for Research and Treatment of Cancer Genitourinary Tract Cancer Cooperative Group and the Medical Research Council Working Party on Superficial Bladder Cancer

PURPOSE

The use of prophylactic agents after primary resection can decrease the incidence of tumor recurrence in patients with stage TaT1 bladder cancer. However, the long-term impact on progression to muscle invasive disease as well as on duration of survival is unknown. A combined analysis of individual patient data from previously performed European Organization for Research and Treatment of Cancer (EORTC) and Medical Research Council (MRC) randomized clinical trials was done in an attempt to answer these crucial questions. We compared immediate versus no adjuvant prophylactic treatment after transurethral resection with respect to disease-free interval, time to progression to muscle invasive disease, time to appearance of distant metastases, duration of survival and progression-free survival.

MATERIALS AND METHODS

All EORTC and MRC prophylactic, randomized phase III trials with primary or recurrent, stage TaT1 transitional cell bladder cancer that compared transurethral resection alone or with adjuvant prophylactic treatment were included in the study. Four EORTC and 2 MRC trials using intravesical chemotherapy or oral agents and including a total of 2,535 patients were studied.

RESULTS

A statistically significant effect of adjuvant treatment over no adjuvant treatment was found in terms of the duration of the disease-free interval (p < 0.01). No clear advantage of adjuvant treatment was shown with respect to progression to invasive disease, time to appearance of distant metastases or duration of survival and progression-free survival. Median survival followup was 7.8 years.

CONCLUSIONS

Despite prologation of the disease-free-interval adjuvant treatment has no apparent long-term impact on the evolution of stage TaTi bladder cancer.