Crown 2019.

Study characteristics
Methods	Retrospective single‐centre cohort January 2009 to December 2010 for control January 2013 to July 2015 for intervention Virgina Mason Medical Center, Seattle, USA 561 participants
Participants	Inclusion: women with breast cancer undergoing breast conserving surgery with adequate follow up and information on complications Exclusion: patients treated with OPS between January 2011 and December 2012 were excluded from the study to allow for the learning period needed during the adoption of new surgical techniques.
Interventions	Intervention: volume displacement ‐ mammoplasty (18%), mastopexy (23%), racquet mammoplasty (26%), (n = 288) Control: standard BCS, (n = 273)
Outcomes	Primaryoutcomes: No outcomes of interest Secondaryoutcomes: Re‐excisions ‐ extracted from Crown 2015 as this had a greater number of patients therefore this is a duplicate patient group Complications
Notes	No disclosures/funding declared Same as Crown 2015 but have had chart review for all patients, therefore, can extract complications from this study