RESUMO
BACKGROUND: There is no consensus on the use of postoperative antibiotic prophylaxis (PAP) after mastectomy with indwelling drains. We explored the utility of continued PAP in reducing surgical site infection (SSI) rates after mastectomy without immediate reconstruction and with indwelling drains. PATIENTS AND METHODS: A multicenter, two-armed, randomized control superiority trial was conducted in Pakistan. We enrolled all consenting adult patients undergoing mastectomy without immediate reconstruction. All patients received a single preoperative dose of cephalexin within 60 min of incision, and postoperatively were randomized to receive either continued PAP using cephalexin (intervention) or a placebo (control) for the duration of indwelling, closed-suction drains. The primary outcome was the development of SSI within 30 days and 90 days postoperatively. Secondary outcomes included study-drug-associated adverse events. Intention-to-treat analysis was performed using multivariable Cox regression. RESULTS: A total of 369 patients, 180 (48.8%) in the intervention group and 189 (51.2%) in the control group, were included in the final analysis. Overall cumulative SSI rates were 3.5% at 30 days and 4.6% at 90 days postoperatively. PAP was not associated with SSI reduction at 30 (hazard ratio, HR 1.666 [95% confidence interval CI 0.515-5.385]) or 90 (1.575 [0.558-4.448]) days postoperatively, or with study-drug-associated adverse effects (0.529 [0.196-1.428]). CONCLUSIONS: Continuing antibiotic prophylaxis for the duration of indwelling drains after mastectomy without immediate reconstruction offers no additional benefit in terms of SSI reduction. There is a need to update existing guidelines to provide clearer recommendations regarding use of postoperative antibiotic prophylaxis after mastectomy in the setting of indwelling drains.