Oncology patients were found to understand and accept the Trials within Cohorts design

Background and Objective: The Trials within Cohorts design aims to reduce recruitment difficulties and disappointment bias in pragmatic trials. On cohort enrollment, broad informed consent for randomization is asked, after which cohort participants can be randomized to interventions or serve as controls without further notification. We evaluated patients' recollection, understanding, and acceptance of broad consent in a clinical oncology setting. Methods: We surveyed 610 patients with cancer participating in ongoing TwiCs; 482 patients (79%) responded, of which 312 patients shortly after cohort enrollment, 108 patients after randomization to an intervention (12-18 months after cohort enrollment), and a random sample of 62 cohort participants who had not been selected for interventions (1-6 months after cohort enrollment). Results: Shortly after providing cohort consent, 76% of patients (238/312) adequately remembered whether they had given broad consent for randomization. Of patients randomly offered interventions, 76% (82/108) remembered giving broad consent for randomization; 41% (44/108) understood they were randomly selected, 44% (48/108) were not interested in selection procedures, and 10% (11/108) did not understand selection was random. Among patients not selected for interventions, 42% (26/62) understood selection was random; 89% felt neutral regarding the scenario of "not being selected for an intervention while your data were being used in comparison with patients receiving interventions,"10% felt reassured (6/62) and 2% scared/insecure (2/62). Conclusion: Patients adequately remember giving broad consent for randomization shortly after cohort enrollment and after being offered an intervention, but recollection is lower in those never selected for interventions. Patients are acceptant of serving as control without further notifications. (c) 2020 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

The ethics of ‘Trials within Cohorts’ (TwiCs): 2nd international symposium - London, UK. 7-8 November 2016

On 7-8 th November 2016, 60 people with an interest in the ‘ Trials within Cohorts ’ (TwiCs) approach for randomised controlled trial design met in London. The purpose of this 2 nd TwiCs international symposium was to share perspectives and experiences on ethical aspects of the TwiCs design, discuss how TwiCs relate to the current ethical frame- work, provide a forum in which to discuss and debate ethical issues and identify future directions for conceptual and empirical research. The symposium was supported by the Wellcome Trust and the NIHR CLAHRC Yorkshire and Humber and organised by members of the TwiCs network led by Clare Relton and attended by people from the UK, the Netherlands, Norway, Canada and USA. The two-day sympo- sium enabled an international group to meet and share experiences of the TwiCs design (also known as the ‘ cohort multiple RCT design ’ ), and to discuss plans for future research. Over the two days, invited plenary talks were interspersed by discussions, posters and mini pre- sentations from bioethicists, triallists and health research regulators. Key findings of the symposium were: (1) It is possible to make a compelling case to ethics committees that TwiCs designs are ap- propriate and ethical; (2) The importance of wider considerations around the ethics of inefficient trial designs; and (3) some questions about the ethical requirements for content and timing of informed consent for a study using the TwiCs design need to be decided on a case-by-case basis

Utility Scores and Preferences for Surgical and Organ-Sparing Approaches for Treatment of Intermediate and High-Risk Rectal Cancer

BACKGROUND: Organ-sparing approaches, including wait-and-see and local excision, are increasingly being offered to patients with rectal cancer following a good response to neoadjuvant therapy. Preferences regarding these treatment strategies are yet unknown. OBJECTIVE: This study aimed to determine the preferences and utility scores for rectal cancer treatment approaches. DESIGN: This is a cross-sectional study. SETTING: This study was conducted at the Radiation-Oncology Department of the University Medical Center Utrecht. PATIENTS: Fifty-seven patients with a history of rectal cancer and 38 volunteers were included. MAIN OUTCOME MEASURES: Participants assessed 6 hypothetical treatment-outcome scenarios, including short-course radiotherapy or chemoradiation followed by abdominoperineal resection, low anterior resection, local excision, or a wait-and-see approach. The hierarchy in preferences between scenarios was assessed by using ranking. Utilities were estimated with a visual analog scale and time trade-off. RESULTS: Organ-sparing approaches were ranked as the first preferred treatment option by 51% of the participants. Among all scenarios, wait-and-see was most often ranked highest by patients and volunteers (36% and 50%). Meanwhile, a substantial proportion ranked wait-and-see as their lowest preference (38% in patients and 35% in volunteers). Utility scores differed significantly between scenarios. Wait-and-see received a significantly higher score on the visual analog scale than the scenarios including abdominoperineal resection and the scenario including chemoradiation with low anterior resection, and a score similar to the scenarios including local excision and short-course radiotherapy with low anterior resection. LIMITATIONS: The study population consisted of patients with a history of rectal cancer treatment and volunteers related to patients. This may have influenced preferences. CONCLUSIONS: This study suggests that there is a wide disparity in preferences concerning organ-sparing approaches for rectal cancer in both patients with a history of rectal cancer and volunteers. Wait-and-see is often the highest preferred treatment, but it is also among the least preferred treatment options. These findings give insights into how patients may value the current rectal cancer treatment options. See Video Abstract at http://links.lww.com/DCR/A521

Utility Scores and Preferences for Surgical and Organ-Sparing Approaches for Treatment of Intermediate and High-Risk Rectal Cancer

BACKGROUND: Organ-sparing approaches, including wait-and-see and local excision, are increasingly being offered to patients with rectal cancer following a good response to neoadjuvant therapy. Preferences regarding these treatment strategies are yet unknown. OBJECTIVE: This study aimed to determine the preferences and utility scores for rectal cancer treatment approaches. DESIGN: This is a cross-sectional study. SETTING: This study was conducted at the Radiation-Oncology Department of the University Medical Center Utrecht. PATIENTS: Fifty-seven patients with a history of rectal cancer and 38 volunteers were included. MAIN OUTCOME MEASURES: Participants assessed 6 hypothetical treatment-outcome scenarios, including short-course radiotherapy or chemoradiation followed by abdominoperineal resection, low anterior resection, local excision, or a wait-and-see approach. The hierarchy in preferences between scenarios was assessed by using ranking. Utilities were estimated with a visual analog scale and time trade-off. RESULTS: Organ-sparing approaches were ranked as the first preferred treatment option by 51% of the participants. Among all scenarios, wait-and-see was most often ranked highest by patients and volunteers (36% and 50%). Meanwhile, a substantial proportion ranked wait-and-see as their lowest preference (38% in patients and 35% in volunteers). Utility scores differed significantly between scenarios. Wait-and-see received a significantly higher score on the visual analog scale than the scenarios including abdominoperineal resection and the scenario including chemoradiation with low anterior resection, and a score similar to the scenarios including local excision and short-course radiotherapy with low anterior resection. LIMITATIONS: The study population consisted of patients with a history of rectal cancer treatment and volunteers related to patients. This may have influenced preferences. CONCLUSIONS: This study suggests that there is a wide disparity in preferences concerning organ-sparing approaches for rectal cancer in both patients with a history of rectal cancer and volunteers. Wait-and-see is often the highest preferred treatment, but it is also among the least preferred treatment options. These findings give insights into how patients may value the current rectal cancer treatment options. See Video Abstract at http://links.lww.com/DCR/A521

Inter-observer agreement of MRI-based tumor delineation for preoperative radiotherapy boost in locally advanced rectal cancer

Background While surgery remains the cornerstone of rectal cancer treatment, organ-preservation is upcoming. Therefore, neo-adjuvant treatment should be optimized. By escalating doses, response can be increased. To limit toxicity of boost, accurate gross tumor volume (GTV) definition is required. MRI, especially undeformed fast spin echo diffusion-weighted MRI (DWI), looks promising for delineation. However, inconsistencies between observers should be quantified before clinical implementation. We aim to find which MRI sequence (T2w, DWI or combination) is optimal and clinically useful for GTV definition by evaluating inter-observer agreement. Methods Locally advanced rectal cancer patients (tumors 2). Three independent observers delineated T2w, DWI and combination (Combi) after training-set. Volumes, conformity index (CI), and maximum Hausdorff distance (HD) were calculated between any observer-pair per patient per modality. Results Twenty-four consecutive patients were included. One patient had cT2 (4.2%), 19 cT3 (79.1%) and 4 cT4 (16.7%), with 2 clinical node negative (8.3%), 4 cN1 (16.7%), and 18 cN2 (75.0%) on MRI. From 24 patients, 70 sequences were available (24x T2, 23x DWI, and 23x Combi). Between observers, no significant volume differences were observed per modality. T2 showed significantly largest volumes compared to DWI (mean difference 19.85 ml, SD 17.42, p 0.61). Average HD was largest on T2 (18.60 mm, max 31.40 mm, min 9.20 mm). Discussion Delineation on DWI resulted in delineation of the smallest volumes with similar consistency and mean distances, but with slightly lower Hausdorff distances compared to T2 and Combi. However, with lack of a gold standard it remains difficult to establish if delineations also represent true tumor. Study strengths were DWI adaptation to exclude geometrical distortions and training-set. DWI shows great potential for delineation purposes as long as sufficient experience exists and geometrical distortions are eliminated

Does setup on rectal wall improve rectal cancer boost radiotherapy?

BACKGROUND: Rectal cancer patients that show a pathological complete response (pCR) after neo-adjuvant chemo-radiotherapy, have better prognosis. To increase pCR rates several studies escalate the tumor irradiation dose. However, due to lacking tumor contrast on online imaging techniques, no direct tumor setup can be performed and large boost margins are needed to ensure tumor coverage. The purpose of this study was to evaluate the feasibility of performing a setup on rectal wall for rectal cancer boost radiotherapy, thereby using rectal wall nearby the tumor as tumor position surrogate. METHODS: For sixteen patients, daily MRI's were performed during 1 week of radiotherapy. On each of these images, tumor and rectum were delineated. Residual displacements were determined per surface voxel after setup on bony anatomy or nearby rectal wall and setup errors for both setups were compared. Furthermore for every rectal wall voxel nearby the tumor, displacement was compared with the closest tumor point and correlation was determined. RESULTS: Mean (SD) setup error was 2.7 mm (3.3 mm) and 2.2 mm (3.2 mm) after setup on bony anatomy and rectal wall respectively. Nevertheless, similar PTV-margin estimates i.e. 95th percentile distances, were found; 8.0 mm. Also, a merely moderate correlation; ρ = 0.66 was found between rectal wall and tumor displacement. Further investigation into tumor and rectal mobility differences showed that the rectal wall lacks appropriate anatomical landmarks to find true displacements, especially to capture motion along the rectal wall. CONCLUSIONS: Setup on rectal wall slightly reduces mean setup errors but requires a similar PTV-margin as compared to setup on bony anatomy. Rectal mobility might be similar to tumor mobility, but due the absence of anatomical landmarks in the rectum, displacements along the rectal wall are not detected on current online imaging. Therefore, to further reduce tumor position uncertainties, direct or indirect online tumor visualization is needed

Evolution of motion uncertainty in rectal cancer : implications for adaptive radiotherapy

Reduction of motion uncertainty by applying adaptive radiotherapy strategies depends largely on the temporal behavior of this motion. To fully optimize adaptive strategies, insight into target motion is needed. The purpose of this study was to analyze stability and evolution in time of motion uncertainty of both the gross tumor volume (GTV) and clinical target volume (CTV) for patients with rectal cancer. We scanned 16 patients daily during one week, on a 1.5 T MRI scanner in treatment position, prior to each radiotherapy fraction. Single slice sagittal cine MRIs were made at the beginning, middle, and end of each scan session, for one minute at 2 Hz temporal resolution. GTV and CTV motion were determined by registering a delineated reference frame to time-points later in time. The 95th percentile of observed motion (dist95%) was taken as a measure of motion. The stability of motion in time was evaluated within each cine-MRI separately. The evolution of motion was investigated between the reference frame and the cine-MRIs of a single scan session and between the reference frame and the cine-MRIs of several days later in the course of treatment. This observed motion was then converted into a PTV-margin estimate. Within a one minute cine-MRI scan, motion was found to be stable and small. Independent of the time-point within the scan session, the average dist95% remains below 3.6 mm and 2.3 mm for CTV and GTV, respectively 90% of the time. We found similar motion over time intervals from 18 min to 4 days. When reducing the time interval from 18 min to 1 min, a large reduction in motion uncertainty is observed. A reduction in motion uncertainty, and thus the PTV-margin estimate, of 71% and 75% for CTV and tumor was observed, respectively. Time intervals of 15 and 30 s yield no further reduction in motion uncertainty compared to a 1 min time interval

Inter-observer agreement of MRI-based tumor delineation for preoperative radiotherapy boost in locally advanced rectal cancer

Background While surgery remains the cornerstone of rectal cancer treatment, organ-preservation is upcoming. Therefore, neo-adjuvant treatment should be optimized. By escalating doses, response can be increased. To limit toxicity of boost, accurate gross tumor volume (GTV) definition is required. MRI, especially undeformed fast spin echo diffusion-weighted MRI (DWI), looks promising for delineation. However, inconsistencies between observers should be quantified before clinical implementation. We aim to find which MRI sequence (T2w, DWI or combination) is optimal and clinically useful for GTV definition by evaluating inter-observer agreement. Methods Locally advanced rectal cancer patients (tumors 2). Three independent observers delineated T2w, DWI and combination (Combi) after training-set. Volumes, conformity index (CI), and maximum Hausdorff distance (HD) were calculated between any observer-pair per patient per modality. Results Twenty-four consecutive patients were included. One patient had cT2 (4.2%), 19 cT3 (79.1%) and 4 cT4 (16.7%), with 2 clinical node negative (8.3%), 4 cN1 (16.7%), and 18 cN2 (75.0%) on MRI. From 24 patients, 70 sequences were available (24x T2, 23x DWI, and 23x Combi). Between observers, no significant volume differences were observed per modality. T2 showed significantly largest volumes compared to DWI (mean difference 19.85 ml, SD 17.42, p 0.61). Average HD was largest on T2 (18.60 mm, max 31.40 mm, min 9.20 mm). Discussion Delineation on DWI resulted in delineation of the smallest volumes with similar consistency and mean distances, but with slightly lower Hausdorff distances compared to T2 and Combi. However, with lack of a gold standard it remains difficult to establish if delineations also represent true tumor. Study strengths were DWI adaptation to exclude geometrical distortions and training-set. DWI shows great potential for delineation purposes as long as sufficient experience exists and geometrical distortions are eliminated

The cohort multiple randomized controlled trial design : A valid and efficient alternative to pragmatic trials?

Randomized controlled trials (RCTs)-the gold standard for evaluating the effects of medical interventions-are notoriously challenging in terms of logistics, planning and costs. The cohort multiple randomized controlled trial approach is designed to facilitate randomized trials for pragmatic evaluation of (new) interventions and is a promising variation from conventional pragmatic RCTs. In this paper, we evaluate methodological challenges of conducting an RCT within a cohort. We argue that equally valid results can be obtained from trials conducted within cohorts as from pragmatic RCTs. However, whether this design is more efficient compared with conducting a pragmatic RCT depends on the amount and nature of non-compliance in the intervention arm