Statistical methods
SECONDARY
Data were analyzed according to the intention-to-treat (ITT) principle. Given the noninferiority design of the study, we also performed a per-protocol (PP) for the primary outcome. Imputation of missing data was not used.The primary outcome was evaluated by estimating the risk difference between both treatment arms, with adjustment for stratification factor (resection technique). A Farrington–Manning test was used to determine the A significance level of 0.05 was used for two-sided testing. Relative risks were estimated for categorical secondary outcomes, with 95% confidence intervals (CIs), and χData were analyzed using SPSS Statistics for Windows (version 22.0; IBM, Armonk, NY). For the longitudinal analysis and the noninferiority analysis SAS (version 9.4; SAS Institute, Cary, NC) was used. Details on the statistical analyses can be found in the statistical analysis plan (Statistical Analysis Plan in 