Risk factors analysis for surgical site infection following elective colorectal resection:a retrospective regression analysis

Background:A surgical site infection(SSI)is a major post-operative complication from elective colorectal surgery;however,few studies have focused on evaluating the risk factors for SSI.This study aimed to analyze the relative correlation of medical and environmental factors as well as patient-related factors that contribute to the incidence of all types of SSI.Methods:A retrospective search for eligible patients was conducted using the patient database of the Gastrointestinal Surgery Center of the Third Affiliated Hospital of Sun Yat-sen University from January 2011 to August 2017.Pre-operative demographic and surgical data were extracted and recoded according to the study protocol.Univariate and multivariate analyses were performed to clarify factors affecting the incidence of SSI.Propensity analysis was conducted to minimize bias in the demographic characteristics to explore the prophylactic effect of pre-operative administration of oral antibiotics.Results:Univariate analysis of the baseline characteristics revealed that younger age(odds ratio[OR]:0.378;95%confidence interval[CI]:0.218–0.657)and pre-operative oral antibiotic use(OR:0.465;95%CI:0.255–0.850)were protective factors,while pre-operative anemia(OR:4.591;95%CI:2.567–8.211),neoadjuvant chemotherapy history(OR:2.398;95%CI:1.094–5.256),and longer surgical duration(OR:2.393;95%CI:1.349–4.246;P=0.002)were identified as risk factors for SSI.Multivariate analysis indicated that age(P=0.003),surgical duration(P=0.001),and pre-operative oral antibiotic use(P<0.001)were independent factors that affect the incidence of SSI.Furthermore,a propensity-matched analysis confirmed the protective effect of oral antibiotic use,with a 1-day course of oral antibiotic producing a similar effect to a 3-day course.Conclusions:Age,surgical duration,and pre-operative oral antibiotic use were associated with the incidence of SSI.However,preoperative oral antibiotic use was the only controllable factor.From the results of our study,pre-operative oral antibiotic use is recommended before elective colorectal surgery and a 1-day course is enough to provide the protective effect.

Predictive Models of Adjuvant Chemotherapy for Patients with Stage II Colorectal Cancer： A Retrospective Study

Background：It remains controversial whether patients with Stage II colorectal cancer would benefit from adjuvant chemotherapy after radical resection.The aim of this study was to establish two mathematical models to identify the suitable patients for adjuvant chemotherapy.Methods：The current study comprised of two steps.In the first step,353 patients with Stage Ⅱ colorectal cancer who underwent surgical procedures at the Third Affiliated Hospital of Sun Yat-sen University between June 2006 and December 2015 were entered and followed up for 6-120 months.Their clinical data were collected and enrolled into the database.We established two mathematical models by univariate and multivariate Cox regression analysis to identify the target patients;in the second step,230 patients under the same standard between January 2012 and December 2016 were entered and followed up for 3-62 months to verify the two models＆#39; validation.Results：In the first step,totally 340 surgical patients with Stage Ⅱ colorectal cancer were finally enrolled in this study.Statistical analysis showed that tumor differentiation （TD） （P 〈 0.001）,lymphovascular invasion （LVI） （P 〈 0.001）,uncertain or positive margins （UPM） （P 〈 0.001）,and fewer lymph nodes （LNs） （〈12） retrieved （P 〈 0.001） were correlated with the overall survival （OS） and disease free survival （DFS）.We obtained two models：（1） OS risk score =1.116 ＆#215; TD ＆#177; 2.202 ＆#215; LVI ＋ 3.676 ＆#215; UPM ＋ 1.438 ＆#215; LN-0.493;（2） DFS risk score =0.789 ＆#215; TD ＋ 2.074 ＆#215; LVI ＋ 3.183 ＆#215; UPM ＋ 1.329 ＆#215; LN-0.432.According to the models and cutoff points [（0.07,1.33） and （-0.04,1.30）,respectively],patients can be divided into three groups：low-risk,moderate-risk,and high-risk.Moreover,the high-risk group patients could benefit from adjuvant chemotherapy.In the second step,totally 221 patients were finally used to verify the models＆#39; validation.The results proved that the models were accurate and feasible （P 〈 0.05）.Conclusions：According to the predictive models,patients with Stage Ⅱ colorectal cancer in the high-risk group are strongly recommended for adjuvant chemotherapy,thus facilitating the individualized and precise treatment.