Aims: Cancer-related stepped-wedge cluster-randomised trials (SW-CRTs) need to be rigorous to deliver impactful trial outcomes and support effective translation into practice. This review examined design features and protocol deviations, methodological rigor, and implementation aspects of SW-CRT designs in oncology settings and developed recommendations for future trials.
Methods: A systematic review was conducted, searching five databases (MEDLINE Complete, CINAHL Complete, PsycINFO, Embase and CENTRAL) in July 2023. Studies using a SW-CRT design in an oncology setting were eligible. Records were screened using Covidence. Intervention characteristics, design features, protocol deviations, statistical approach, implementation strategies, and outcomes were extracted, coded, and evaluated narratively.
Results: The search yielded 3,395 unique records with 25 publications reporting on 15 trials (n=8 efficacy trials; n=7 implementation trials) testing diverse interventions in healthcare settings. Common protocol deviations included changes to trial duration (n=7; 47%), number of planned clusters (n=4; 27%) and secondary outcomes (n=4; 27%). Despite implementation outcomes being reported in 14 (93%) trials, 12 (86%) did not use an established evaluation framework to guide the selection and reporting of implementation outcomes. Results indicate a need for investment into accurate recruitment projections given the challenges of expanding sites or extending timelines, accurate and clear reporting, and acknowledging and reporting on any deviations to a published protocol or study registration. When resourcing allows, trials should measure both implementation and clinical outcomes and adopt best-quality implementation science methodology to guide any future implementation.
Conclusions: SW-CRTs provide a valuable design for testing efficacy and implementation of complex healthcare interventions in the oncology setting. Trials should aim to be proactive in managing the risks associated with executing the SW-CRT design and for methodology to be reported rigorously according to guidelines. Taking a strategic approach can enhance the design and impact of SW-CRTs, leading to improved patient outcomes and advancements in cancer care.