Background: Preoperative core needle biopsies may increase the risk of surgical site infection (SSI) in breast cancer surgery. The purpose of this randomized trial was to determine whether a prophylactic antibiotic would prevent SSI under these conditions.
Methods: Imaging-guided multiple core needle biopsies were performed one to two weeks prior to surgery to obtain confirmation of the presence of breast cancer. Then the patients were randomized to receive either a single intravenous dose of 1.0 g of dicloxacillin (n = 144) or placebo infusion of saline (n = 148) 30 min prior to operation. After breast surgery, incisional morbidity was monitored for 30 days. The number of SSIs was compared with that in 672 patients treated before the implementation of core needle biopsies.
Results: The patient characteristics and risk factors for SSI were similar in the antibiotic prophylaxis and placebo groups. The incidence of SSI was 7.2% (21/292) in the prospective trial compared with 6.8% (46/672) in the retrospective cohort (p = 0.890). The incidence of postoperative SSIs was 5.6% (8/144) in the dicloxacillin group and 8.8% (13/148) in the placebo group (p = 0.371). For the first two weeks, there was a non-significant trend to fewer SSIs in the antibiotic group (n = 1) than the placebo group (n = 4). Body mass index, smoking, or previous illness did not affect the likelihood of SSI.
Conclusions: Core needle biopsy did not increase the incidence of SSI. Antibiotic prophylaxis did not prevent SSI, probably because so few infections occurred.