Purpose: We sought to determine site-specific patterns of risk factors for incisional and organ/space surgical site infections in patients with colorectal cancer to develop predictive models using inflammatory mediators.
Methods: We analyzed data for 285 consecutive elective patients at our institution. The surgical site infections were grouped as incisional or organ/space according to the criteria of the Centers for Disease Control and Prevention. Peripheral venous blood samples were obtained perioperatively and the serum interleukin-6, interleukin-1 receptor antagonist, and interleukin-6 soluble receptor levels were measured.
Results: Surgical site infections were identified in 60 of 285 patients (21 percent) and included 27 incisional surgical site infections and 33 organ/space surgical site infections. The perioperative risk factors for incisional surgical site infections included male gender, operating time, operative blood loss, blood transfusion, tumor location, and concomitant medical problems, whereas those for organ/space surgical site infections were operating time, operative blood loss, blood transfusion, tumor location, obesity, and concomitant medical problems. A multivariate logistic regression analysis revealed that operating time and concomitant medical problems were independent common factors that predicted both incisional and organ/space surgical site infections. Postoperatively, an intense postoperative increase in the serum interleukin-6 level predicted both incisional and organ/space surgical site infections. In contrast, the maximum postoperative systemic consumption of interleukin-6 soluble receptor could differentiate the odds of developing organ/space surgical site infections from those of developing incisional surgical site infections.
Conclusions: The risk factors and indicators for incisional and organ/space surgical site infections after surgery for colorectal carcinoma differ, suggesting different mechanisms for their pathogenesis. A postoperative decrease in the serum interleukin-6 soluble receptor level may be an early predictor for organ/space surgical site infections.