Evidence-based risk factors for seroma formation in breast surgery

Background: Seroma is a common problem in breast surgery. The aim of this systematic review was to identify risk factors for seroma formation. Methods: Articles published in English were obtained from searches of Medline and additional references were found in the bibliographies of these articles. Risk factors were graded according to the quality and strength of evidence and to the direction of association. Results: One meta-analysis, 51 randomized controlled trials, 7 prospective studies and 7 retrospective studies were identified. There was no risk factor supported by strong evidence, but there was moderate evidence to support a risk for seroma formation in individuals with heavier body weight, extended radical mastectomy as compared with simple mastectomy, and greater drainage volume in the initial 3 days. On the other hand, the following factors did not have a significant influence on seroma formation: duration of drainage; hormone receptor status; immobilization of the shoulder; intensity of negative suction pressure; lymph node status or lymph node positivity; number of drains; number of removed lymph nodes; previous biopsy; removal of drains on the fifth postoperative day versus when daily drainage volume fell to minimal; stage; type of drainage (closed suction versus static drainage); and use of fibrinolysis inhibitor. In contrast, sentinel lymph node biopsy reduced seroma formation. Evidence was weak, or unproven, for other factors that were commonly cited in the literature. Conclusions: Although a number of factors have been correlated with seroma formation, strong evidence is still scarce. However, there is evidence showing that sentinel lymph node biopsy reduces seroma formation.