Statistical analysis
lymphoedema, infection, 24‐months, TOI
LYMPHOEDEMA, INFECTION, REGRESSION
The sample size calculation was based on a two‐tailed two‐sample chi‐square test comparing the proportion of patients developing lymphoedema within 24‐months post‐randomisation, with a 1:1 treatment allocation ratio. Estimating that 45% of patients develop lymphoedema, to detect a 20% difference (i.e. 45% vs. 25%) in lymphoedema rate by 24‐months between the two treatment groups with 90% power and 5% significance level, requires 120 patients in each group but was increased to 135 per group to allow for dropouts.Descriptive statistics are presented as Mean (SD) or Median (IQR), and as number (%) for continuous and categorical variables, respectively, unless otherwise stated. The analyses involved two‐tailed two‐sample tests with 5% significance level, performed on an intention‐to‐treat basis using statistical software R version 4.0.2. The primary analysis, incidence of lymphoedema within 24‐months post‐surgery, was assessed by chi‐square test. Quality of Life, measured by FACT‐B + 4 and TOI, was assessed by t‐test. Incidence of infection during follow‐up, and incidence of moderate/severe lymphoedema within 24‐months were assessed by Fisher's Exact test. Survival analysis was performed for time‐to‐lymphoedema, involving Kaplan–Meier curves and Cox regression. Additional exploratory analyses were performed for the primary outcome, to investigate the effect of BMI, and a per‐protocol analysis to take into account of protocol deviations.