**Background:** Cancer is the second leading cause of death globally, with 70% of the 9.6 million annual cancer deaths occurring in low- and middle-income countries (LMICs). One-third of global cancer deaths are attributable to modifiable behavioral risk factors including tobacco use, alcohol consumption, unhealthy diet, obesity, and physical inactivity. Workplace health promotion has proven cost-effective in developed countries—with reported savings of US$2.5 to US$10.1 per dollar invested and 25%–30% lower medical and absenteeism costs among participants—but such interventions are rarely implemented in LMICs. In China, cancer deaths accounted for 36.2% of premature deaths in 2018, with 45.2% of all cancer deaths attributable to 23 potentially modifiable risk factors. The WECAN trial aims to develop and test a smartphone application-supported comprehensive workplace cancer prevention model that is feasible for China and adaptable for other LMICs.
**Methods:** This is a stepped-wedge, cluster-randomised controlled trial with 15 workplaces recruited from three cities: Xiangtan (Hunan Province), Nanchong (Sichuan Province), and Wuhai (Inner Mongolia). These sites were selected based on high cancer incidence, low-to-middle local economy, geographic distribution (north, central, and south China), and prior collaboration with local Centers for Disease Control and Prevention (CDCs). Workplaces must have >100 full-time employees, <20% average turnover over 3 years, employer agreement to participate, and regular employee health examinations. A total of 750 employees (50 per workplace) will be randomly selected for evaluation, stratified by gender, age (<40 vs ≥40 years), and work type (production vs office). The project spans 48 months: Phase 1 (12 months) for preparation and enrolment, Phase 2 (24 months) for staggered intervention, and Phase 3 (12 months) for analysis and scale-up strategy development. After baseline data collection, workplaces are randomized by an independent statistician to start intervention sequentially every 6 months in three steps (5 workplaces per step), ensuring at least 1–2 workplaces from each city per step. The intervention is guided by the US CDC Workplace Health Model and the Health Action Process Approach (HAPA), with tailored strategies based on participants' intention to change. Core components include workplace health improvement plans, tobacco and alcohol prohibition policies, health bulletin boards, mandatory 'No smoking' signage, the 'Healthy Workplace' mobile app for health education and risk assessment, and incentives for participation. Optional components include healthy food policies, on-site fitness facilities, standing desks, healthy food in cafeterias, and subsidies for cancer screening. The primary outcome is change in the adapted Healthy Lifestyle Index Score (HLIS), a weighted composite of smoking (weight 1.75), alcohol drinking (weight 1.15), physical activity (weight 0.65), BMI (weight 0.75), and dietary factors (weight 0.70), ranging from 0–20. Each 1-point increase in HLIS is associated with 3%–5% decrease in cancer risk. Secondary outcomes include changes in individual risk behaviors, blood pressure, glucose, lipids, healthcare costs, cancer and NCD incidence, and implementation outcomes assessed via the RE-AIM framework. Sample size calculations assume an HLIS increase from 12 to 13 (SD=5), ICC=0.05, cluster autocorrelation=0.75, individual autocorrelation=0.8, alpha=0.05, yielding power of 0.889 with 5 clusters per step and 40 participants per cluster per step, accounting for 20% dropout. Data collection includes questionnaires, physical measurements (weight, height, waist circumference, blood pressure), workplace self-evaluation using the adapted 2019 Worksite Health ScoreCard, and cancer incidence data. Analysis will use generalized linear mixed models with intention-to-treat principles, adjusting for age, sex, work type, and potential confounders. Health economic evaluation will estimate return on investment (ROI) and value of investment (VOI).
**Key Results:** This is a protocol paper; no results are reported. As of December 2022, workplace recruitment and EDC development were completed. Due to COVID-19, the baseline survey was postponed from December 2022 to March 2023. The 'Healthy Workplace' app is expected to be ready in April 2023, with pilot intervention in May 2023, second evaluation in September 2023, and first intervention sequence starting October 2023.
**Clinical Implications:** If proven effective, the WECAN model could provide a scalable, evidence-based approach for workplace cancer prevention in China, where approximately 180,000 lives could be saved annually if essential cancer prevention services are widely implemented, with projected economic cost savings exceeding RMB 220 billion (approximately US$31 billion). The model is designed to be adaptable for other LMICs facing similar cancer burdens in resource-constrained settings. The stepped-wedge design ensures all workplaces receive the intervention, enhancing participation and enabling rigorous evaluation of both effectiveness and implementation outcomes.