Patients more likely to undergo ALND included those with extracapsular extension ( odds ratio [ OR ] 12.8 , 95 % confidence interval [ CI ] 2.5 to 67.1 ) and those who underwent reoperative surgery ( OR 10.8 , 95 % CI 2.6 to 44.4 ) or intraoperative SLN analysis ( OR 5.1 , 95 % CI 1.2 to 21.9 ) .