A prospective, randomized double-blind study of the use of antibiotics at the time of mastectomy.

The ability of perioperative cefazolin to reduce the incidence of postoperative wound infection in patients undergoing ablative surgical treatment for carcinoma of the breast was tested in this prospective, randomized, double-blinded study. From May 1983 until December 1985, 118 women were divided into two groups at random. Group 1 consisted of 59 patients and received cefazolin and group 2 was made up of 59 patients who received a placebo. The groups were similar with respect to age, operative procedure, operative time and time to discharge after operation. Three infections occurred among those in group 1 and five among those in group 2 (p = 0.72). The time to onset of infection was delayed in the patients in group 1 versus those in group 2 (17.7 days versus 9.6 days, p = 0.04). Six of eight infections occurred in patients in whom an interval between biopsy and definitive surgical treatment was present. Prophylactic antibiotics in mammary operations did not reduce postoperative wound infections in this study.