Background: There is a large unused potential for risk reduction in the preoperative period via effective lifestyle intervention targeting co-existing risky lifestyles: Smoking, malNutrition, obesity, risky Alcohol intake and insufficient Physical activity (SNAP). This trial compares the efficacy of the integrated STRONG programme with standard care on preoperative risk reduction and secondly on SNAP factor improvement and frailty, postoperative complications and quality of life. A nested interview study explores the patient preferences and the multi-perspective view of patients, relatives and health professionals. Methods: In total, 42 surgical patients with ≥1 SNAP factor are allocated to individually tailored STRONG programme or usual care during adjuvant chemotherapy prior to radical bladder cancer surgery. The STRONG programme has ≥6 weekly sessions with patient education, motivational and pharmaceutical support. It is based on intensive smoking and alcohol cessation interventions reporting perioperative quit rates > 50%. Surgical risk reduction is measured as ≥1 step for 1 or more risky lifestyles on the ASA-score, secondly as having no risky SNAP factors, and as any SNAP improvement. The outcomes are validated by measurements and biomarkers. Postoperative complications are categorised according to the Clavien-Dindo classification. Health-related quality of life is measured by EQ-5D. The patients are followed up after 6 weeks at surgery and 6 weeks and 6 months postoperatively. A representative sample of the participants, their relatives and the clinical staff are interviewed until data saturation. Transcription, triangulated analyses and data management are conducted using NVivo computer software. Discussion: The surgical agenda is characterised by fixed dates for surgery focusing on clear risk reduction within a short time. This requires a clinical useful lifestyle intervention programme with a high effect and coverage as well as containing all SNAP factors and tailored to individual needs. The STRONG programme seems to meet these requirements. After development in multi-professional collaboration, STRONG is delivered by a specially trained nurse as part of the surgical patient journey. Overall, this study will bring important new knowledge about risk reduction in a frail patient group undergoing major cancer surgery. Trial registration: Registration at www.clintrials.gov (NCT04088968) The manuscript form from https://trialsjournal.biomedcentral.com/bmc/journal and the SPIRIT guidelines are followed.