The application of stepped-wedge cluster-randomized controlled trial study designs in oncology settings: A systematic review

Stepped-wedge cluster-randomized trials (SW-CRTs) offer advantages for implementation research in healthcare and have been increasingly utilised in the oncology setting. Cancer-related SW-CRTs need to be robust to deliver impactful trial outcomes and support effective translation into practice. This review aimed to examine the application of the SW-CRT design in oncology settings including the trial design features and protocol deviations, the interventions tested, and the implementation aspects of those interventions. Five databases were searched from database inception to July 2023 for SW-CRTs which evaluated interventions in adults with cancer. Intervention characteristics, design features, protocol deviations, statistical approach, implementation strategies, and outcomes were described and evaluated narratively. The search yielded 3395 unique records with representing 15 trials which are reported over 49 publications. The 15 trials (n = 8 efficacy trials and n = 7 implementation trials) described diverse interventions in healthcare settings. Trials supported implementation of the intervention via educating and training healthcare professionals (n = 12; 80 %), met or exceeded recruitment targets (n = 10, 67 %) and evaluated a new model of care (n = 7; 47 %). 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. SW-CRTs were a utilised design for implementing diverse and complex healthcare interventions in the oncology setting. Trialists should consider the need to incorporate implementation frameworks, strategies and outcomes into their trial planning and resource allocation. This strategic approach can enhance the design and impact of SW-CRTs, leading to improved patient outcomes and advancements in cancer care.