Statistical analysis
death
EVENTS, SECONDARY, RECURRENCE
Patients were selected from the same database managed by the Clinical Trials Centre of the IRCCS Ospedale Policlinico San Martino (Genoa, Italy), with the same observation interval. Initially, 2000 patients were planned for enrolment with a minimum 5-year follow-up. The first patient was enrolled in April 2015. Patients were enrolled from 52 Italian institutions. Trial enrolment was ceased prematurely in April 2020 due to low accrual rates and fewer events than expected. The primary endpoint was OS, defined as the interval between the randomization date and the date of last contact or death from any cause. The secondary endpoint was RFS, defined as regional RFS (no axillary recurrence) or distant RFS. The alternative hypothesis was that patients with T1–2 BC presenting one to two macrometastatic SLNs treated with SLNB only did not present higher mortality and recurrence rates compared with those treated with ALND. For this reason, the standard and experimental arms were compared in terms of OS and RFS using the Kaplan–Meier analysis method and the log rank test. Both intention-to-treat (ITT) and per-protocol (PP) populations were analysed. The 5-year cumulative incidence of mortality and recurrence and 95 per cent confidence intervals of the incidence rate per 100 patients were calculated. The cut-off for statistical significance was set at 