The primary endpoint is a time-to-event endpoint. However, considering that (a) the duration of recovery will most probably be censored in only 4% of patients at a maximum and that (b) taking the full length of the postoperative observation period as a proxy estimate for the time to recovery in these outlying patients will hardly affect the comparison of the study groups because of the non-parametric testing strategy with the Mann–Whitney U test and, finally, that (c) a power of 80% for a Kaplan–Meier analysis as its best alternative can only be achieved at the cost of a much higher and infeasible patient inclusion rate, we will analyze the data as if no censoring takes place. Additionally, the percentage of patients per study arm who do not recover during the observation period will be reported as a secondary outcome measure.
A difference with a two-tailed P-value < 0.05 will be considered statistically significant. A multivariable linear regression model will be used to assess potential differences in primary outcome between groups in the presence of potentially confounding factors. Linear mixed modeling will be applied to estimate differences between groups in successive EQ-5D-5 L and QLQ-C30 assessments over time. For exploratory purposes, a secondary analysis will be performed, comparing outcomes for patients with pancreatic ductal adenocarcinoma versus other disease, comparing completed minimally invasive (i.e. no conversion) versus open pancreatoduodenectomy and comparing time to functional recovery between minimally invasive and open pancreatoduodenectomy in complicated (Clavien–Dindo grade III or higher complication) and uncomplicated cases and for the impact of robot-assisted versus laparoscopic pancreatoduodenectomy. A non-inferiority analysis will be performed for Clavien–Dindo grade III or higher complications. The study has an 80% power (α = 0.05) to confirm non-inferiority of minimally invasive versus open pancreatoduodenectomy, when 15% fewer patients experience a clinically relevant complication in the intervention group than the control group (non-inferiority margin set at 8%). In the intervention group, robot-assisted procedures may be performed. The amount of robot-assisted procedures is expected to be less than 20%; these will be analyzed separately during cost-analysis.