BACKGROUND:
Skin Cancer is the most common cancer worldwide, with surgery representing the mainstay of treatment. SSIs are a common complication of surgery, and attempts at mitigation include prophylactic antibiotics, either preoperative or postoperatively, administered either intravenously or orally. Scant data exists on the effect of INCISIONAL injection of prophylactic antibiotics at the operative site and its ettect on SSI.
METHOD:
A randomized, double-blind, controlled, prospective clinical trial was run from the Manchester See & Treat unit over 6 months. Patients were randomized to 3 treatment arms: operatve site injection of buffered local anaesthetic alone (control), buffered local anaesthetic + micro-dosed flucloxacillin (500 mcg/cc), or buffered local anaesthetic + micro-dosed clindamycin (500 mcg/cc). Flucloxacilin and clindamyin were selected due to their lack of tissue toxicity and are commonly used prophylactic antibiotics. The concentrations are designed to meet MIC (minimum inhibitory concentration) for skin flora and not dependent on volume injected. The primary endpoint was rate of postoperative SSI, defined as a standardarized Post-Operative Wound Infection (POWI) score > 5 [range, 0-7].
RESULTS:
A total of 681 patients (over 721 presentations and comprising 1,131 lesions) were analyzed. The rate of SSI was 5.7% in the control arm, 5.3% in the flucloxacillin arm, and 2.1%* in the clindamycin arm (*p<0.05, clindamycin vs. control). Significantly fewer lesions in the clindamycin (2.1%, p<0.01) and flucloxacillin (4.0%, p<0.05) arms required postoperative systemic antibiotics compared with the control arm (8.0%). There were no adverse reactions.
CONCLUSION:
Our PICASSO trial represents the first study evaluating incisionally injected antibiotics for SSI prophylaxis in general skin cancer surgery, and the first to compare the efficacy of flucloxacillin versus clindamycin. The significant reduction in SSI with micro-dosed incisional clindamycin provides robust evidence to inform treatment guidelines for this extremely common procedure.