Preoperative oral antibiotics reduce infections after colorectal cancer surgery

AIM: The objectives were to recognize the risk factors for surgical site infections (SSIs) after surgery due to colorectal cancer and to assess the impact of mechanical bowel preparation (MBP) and oral antibiotic prophylaxis (ABX) on SSIs. METHODS: Records from two colorectal centers were used. Risk factors of SSIs were categorized into patient-, disease-, and treatment-dependent. RESULTS: A group of 2240 patients was included. SSIs were noted in 364 patients (16.3 %). MBP+/ABX+ was connected with a lower incidence of anastomotic leak (AL) and organ-space SSIs: 2.4 vs. 6.3 %; p = 0.008 and 3.6 vs. 7.2 %; p = 0.017, respectively. Patient-dependent factors: obesity increased the risk of skin superficial SSIs, adjusted OR 1.53 (1.47–1.59 95 % confidence interval (95 % CI)), and deep incisional SSIs 1.42 (1.39–1.45 95 % CI). Disease-dependent factors: rectal cancer was associated with a higher risk of skin superficial and deep incisional SSIs, adjusted OR 1.28 (1.22–1.34 95 % CI) and 1.13 (1.09–1.15 95 % CI). Treatment-dependent factors: MBP+/ABX+ was associated with a lower risk of organ-space SSIs, adjusted OR 0.53 (0.44–0.59 95 % CI). Radiotherapy increased the risk of organ-space SSIs, adjusted OR 1.78 (1.75–1.80 95 % CI). The risk of organ-space SSIs was the highest after low anterior resection, adjusted OR 1.62 (1.60–1.64 95 % CI). CONCLUSIONS: If possible, MBP and ABX should always be administered to decrease the risk of AL and organ-space SSIs. Factors strictly related to the treatment mostly increased the risk of organ-space SSIs.