Kang Hong Lee

Background The guidelines for reducing surgical site infection in colorectal surgery recommend mechanical bowel preparation with oral antibiotics; however, this recommendation remains controversial. This study aimed to reveal the effect of oral antibiotics combined with mechanical bowel preparation in colorectal surgery. Methods This study was a nationwide population-based retrospective study. Data between January 1, 2016, and December 31, 2018, from the Korean National Health Insurance Service database were analyzed. Patients who underwent elective colorectal cancer surgery were included. Results A total of 20,740 patients were finally included, comprising 14,554 (70.2%) who underwent mechanical bowel preparation alone and 6186 (29.8%) who underwent mechanical bowel preparation with oral antibiotics. The mechanical bowel preparation alone group was older than the mechanical bowel preparation with oral antibiotics group (65.7 ± 11.9 vs. 64.7 ± 11.8 years, p < 0.001). Rectal cancer patients and patients who underwent open surgery were more likely to receive mechanical bowel preparation with oral antibiotics. Patients who underwent mechanical bowel preparation with oral antibiotics demonstrated lower surgical-site infection rate (2.9% vs. 9.4%, p < 0.001), shorter hospital stay (11.7 ± 5.5 vs. 13.5 ± 7.3 days, p < 0.001), and lower medical cost (US$7414 ± 2762 vs. US$7791 ± 3235, p < 0.001) than those who underwent mechanical bowel preparation alone. The 30-day readmission rates and mortality were not significantly different. Conclusions The use of mechanical bowel preparation with oral antibiotics reduces surgical site infection, hospital stay, and medical cost in colorectal cancer surgery.

Purpose Right-sided diverticulitis has different epidemiologic features compared to left-sided diverticulitis. However, data on the appropriate treatment of right-sided diverticulitis are lacking. This systematic review aimed to examine the outcomes of conservative treatment for uncomplicated right-sided diverticulitis. Methods MEDLINE, Embase, and the Cochrane Library were searched for articles published from January 1, 1990, to May 31, 2020. A total of 21 studies were included in the systematic review. We calculated proportions and 95% confidence intervals (CIs) to assess the outcomes of individual studies and pooled the results using a random effects model. Results A total of 2811 patients (59.1% men; mean and median age, 37–54 years) with right-sided diverticulitis were included. The pooled rate of treatment failure was 2.5% (95% CI 1.2–4.3%; p 2 = 64.0%). The recurrence rate ranged from 0 to 26.9%, and the pooled recurrence rate was 10.9% (95% CI 8.1–14.1%; p 2 = 78.2%). The pooled rate of complicated diverticulitis at recurrence was 4.4% (95% CI 1.4–9.0%; p = 0.84; I² = 0%). The pooled rate of emergency surgery at recurrence was 9.0% (95% CI 4.6–14.7%; p = 0.12; I² = 30.3%). Conclusions Conservative treatment of uncomplicated right-sided diverticulitis results in a low rate of recurrence and complicated diverticulitis at recurrence. Based on these results, unnecessary surgery may be avoided and a new treatment paradigm for uncomplicated right-sided diverticulitis may be introduced.

Prophylactic placement of mesh in the abdominal wall during ileostomy closure can decrease the rate of hernia formation. However, few studies have evaluated the safety of biologic mesh in ileostomy closure. PURPOSE: This study aimed to investigate the safety of biologic mesh in ileostomy closure, specifically the need to remove the mesh due to infection. The rate of surgical site infection (SSI), incisional hernia, surgical site occurrence ([SSO] including seroma and hematoma), and wound pain between primary closure and mesh closure groups also were investigated. METHODS: Using a retrospective study design, data from all consecutive patients who underwent ileostomy closure from January 2015 to June 2016 at the Hanyang University Hospital, Seoul, Republic of Korea, were analyzed. Patients with stage IV colorectal cancer, who were older than 85 years, or who experienced intestinal perforation during the procedure were excluded. Demographic (age, sex, body mass index [BMI], underlying disease) and clinical characteristics as well as SSI, SSO, length of hospital stay, use of additional analgesics, white blood cell count, C-reactive protein, and visual analog scale (VAS) pain scores (noted on days 1, 3, 5, and 14) were abstracted and compared. Clinical and surgical variables were compared using the Mann-Whitney U test, the chi(2)-test, or Fisher's exact test, depending on the nature of the data. RESULTS: Of the 38 patients who underwent ileostomy closure, 33 (18 [54.5%] who received primary closure and 15 [45.5%] who received mesh closure) were included for analysis. Patient, surgical, and clinical characteristics were not significantly different, but the mean age of the primary closure group was significantly higher than that of the mesh closure group (71 +/- 9 vs. 62 +/- 10 years old; P =.014). The median follow-up duration was 25 months (interquartile range 18.0-31.5 months). Six (6) complications were observed in 5 patients in the primary closure group, and 8 complications in 5 patients were noted in the mesh closure group (27.8% vs. 33.3%; P = 1.000). None of the cases required removal of the biologic mesh due to mesh-related infectious complication. Two (2) SSIs occurred in the primary closure group (11.1% vs. 0%; P =.489). Three (3) patients experienced a postoperative incisional hernia (9.1%) - 1 in the primary closure group and 2 in the mesh closure group (5.6% vs. 13.3%; P =.579). No statistically significant differences in pain or length of hospitalization were noted. CONCLUSION: No mesh-related infectious complications required biologic mesh removal, and no significant differences were noted in SSI, incisional hernia, and wound pain between the primary closure and mesh closure groups. Although not significantly different, the higher rates of hernia and SSOs in the mesh group require further study.

Background The function of ASXL1 protein in colorectal cancer has not been investigated yet. The purpose of this study was to investigate the clinicopathological and prognostic impact of ASXL1 protein expression on colorectal cancer.Methods We performed immunohistochemical staining of ASXL1 protein using tissue microarrays of 408 colorectal cancers, 46 normal colonic mucosae, 48 adenomas, and 92 metastatic lymph nodes. The intensity of expression was scored as 0–3, and the extent of staining was scored as 0–4, based on the percentage of positive cells. The immunoreactivity score (IRS) was calculated by multiplying the two scores.Results ASXL1 protein expression rates were 89.1% in normal mucosae, 72.9% in tubular adenomas, 44.4% in adenocarcinomas, and 28.3% in metastatic lymph nodes ( p < 0.001). With respect to the IRS cut-off score, the mean tumor size was smaller in the IRS 0–6 group than in the IRS 8–12 group (4.9 ± 2.1 vs. 6.3 ± 2.7 cm, p = 0.002). Lymph node metastasis was more frequent in the IRS 0–6 group than in the IRS 8–12 group (56.3% vs. 33.3%, p = 0.034). Lymphatic invasion was more frequent in the 0–6 group than in the IRS 8–12 group (56.0% vs. 33.3%, p = 0.035). The 5-year disease-free survival rate did not differ between two groups at stage II and stage III.Conclusions ASXL1 protein might act as a tumor suppressor in colorectal cancer. The loss of ASXL1 expression might be associated with metastasis via the lymphatic system to the lymph nodes.

Background: To analyze for genetic mutations which may presage peritoneal metastasis by using targeted next-generation sequencing (NGS). Materials and Methods: Formalin-fixed, paraffin-embedded primary tumor specimens were obtained from 10 patients with small obstructing colorectal cancer and peritoneal metastasis (group A) and five with large non-obstructing colorectal cancer and no recurrence (group B). DNA was extracted for the sequencing of 409 cancer genes. The distribution of genetic mutations was compared between the two groups to find genetic mutations related to peritoneal metastasis. Results: When the samples were sorted based on similarity of gene expression by hierarchical clustering analysis, the samples were well divided between the two study groups. Mutations in AT-rich interactive domain-containing protein 1A (ARID1A), polycystic kidney and hepatic disease 1 (PKHD1), ubiquitin-protein ligase E3 component n-recognin 5 (UBR5), paired box 5 (PAX5), tumor protein p53 (TP53), additional sex combs like 1 (ASXL1) and androgen receptor (AR) genes were detected more frequently in group A. Conclusion: A number of somatic mutations presumed to be relevant to colorectal cancer with peritoneal metastasis were identified in our study by NGS.

Purpose Apoptotic protease activating factor-1 (APAF-1) is a key regulator in the mitochondrial apoptotic pathway and an important diagnostic and therapeutic biomarker. Loss of APAF-1 expression has been observed in various tumors including colorectal cancer. The aim of our study was to evaluate the relationship between loss of APAF-1 expression and early recurrence of stage I–III colorectal cancer. Methods We investigated 165 out of 492 patients who had undergone curative resection for colorectal cancer between 1991 and 2001. Sixty-one patients (37.0 %) had early recurrence within 1 year after surgery. Tissue microarrays were used for immunohistochemical detection of APAF-1. Results The mean age of patients with recurrence was 58 years (range, 24–85); 88 (53.3 %, 88/165) were male. APAF-1 was expressed in 32 (19.4 %, 32/165) cases and was not expressed in 133 (80.6 %, 133/165). In univariate analysis, early recurrence significantly correlated with loss of APAF-1 expression (p = 0.017), tumor stage (p = 0.005), N category (p = 0.001), and lymphatic invasion (p = 0.008). In a logistic regression model, loss of APAF-1 expression (p = 0.015, 95 % CI = 1.280–10.063) and N category (p = 0.001, 95 % CI = 0.004–0.739) proved to be independent risk factors associated with early recurrence. In patients with lymph node metastasis, early recurrence was more frequent in the APAF-1-negative group than in the APAF-1-positive group (46.2 % (54/117) vs. 22.2 % (6/27), p = 0.023). Conclusions Loss of APAF-1 expression is associated with early recurrence in stage I–III colorectal cancer, suggesting that APAF-1 may have clinical value as a predictive marker of early recurrence.

We assessed the short- and long-term outcomes of intracorporeal ileocolic anastomosis (IA) in laparoscopic right hemicolectomy for colon cancer compared with extracorporeal anastomosis (EA). A retrospective chart review of 86 consecutive patients who underwent laparoscopic right hemicolectomy for colon cancer from March 2005 to June 2010 was performed. There were 51 and 35 patients who underwent intracorporeal and extracorporeal anastomosis, respectively. The two groups were demographically comparable. The conversion rate to open surgery was 8.6 % in the EA group, but none in the IA group (p = 0.064). There was no significant difference in operative time, estimated blood loss, complications (intra-abdominal abscess, anastomotic leak, ileus, and wound infection), and length of hospital stay between the groups. There was no perioperative mortality in both groups. There was no significant difference in median number of retrieved lymph node. The overall survival and the disease-free survival at 3 years were not different between the groups. Compared with the extracorporeal anastomosis technique, intracorporeal ileocolic anastomosis produces comparable short- and long-term outcomes in laparoscopic right hemicolectomy for colon cancer.

The aim of this study was to investigate the hypothesis that prevention of surgical site infection (SSI) is equally effective when patients receive single-dose (SD) or three-dose antibiotic prophylaxis with second-generation cephalosporin and metronidazole in elective colorectal surgery. Ninety-three patients were enrolled from May 2009 to November 2010. The SD group received only one preoperative prophylactic intravenous dose and the three-dose or multiple-dose (MD) group received one preoperative prophylactic and two additional post-operative doses of second-generation cephalosporin and metronidazole. The incidence of infectious complications (SSI of the incision site and organ/space) was compared in the two groups. The overall post-operative infection rate did not differ between the two groups (16.7% in the SD versus 13.3% in the MD, P = 0.653). The incidence of SSI of the incision site and organ/space also did not differ between the groups (6.3% (3/48) versus 4.4% (2/45), P = 0.700; 4.2% versus 6.7%, P = 0.593, respectively). The number of antibiotics administered was not an independent risk factor for SSIs in multivariable analysis. SD antibiotic prophylaxis with second-generation cephalosporin and metronidazole is equivalent to a three-dose prophylaxis for preventing SSI in elective colorectal surgery. But further study would be needed to clarify this because of the small number of participants.