Kwan Hee Hong

Adipose-tissue-derived Stem Cells Enhance the Healing of Ischemic Colonic Anastomoses: An Experimental Study in Rats

Purpose This experimental study verified the effect of adipose-tissue-derived stem cells (ASCs) on the healing of ischemic colonic anastomoses in rats. Methods ASCs were isolated from the subcutaneous fat tissue of rats and identified as mesenchymal stem cells by identification of different potentials. An animal model of colonic ischemic anastomosis was induced by modifying Nagahatas method. Sixty male Sprague-Dawley rats (10-week-old, 370 ± 50 g) were divided into two groups (n = 30 each): a control group in which the anastomosis was sutured in a single layer with 6-0 polypropylene without any treatment and an ASCtreated group (ASC group) in which the anastomosis was sutured as in the control group, but then ASCs were locally transplanted into the bowel wall around the anastomosis. The rats were sacrificed on postoperative day 7. Healing of the anastomoses was assessed by measuring loss of body weight, wound infection, anastomotic leakage, mortality, adhesion formation, ileus, anastomotic stricture, anastomotic bursting pressure, histopathological features, and microvascular density. Results No differences in wound infection, anastomotic leakage, or mortality between the two groups were observed. The ASC group had significantly more favorable anastomotic healing, including less body weight lost, less ileus, and fewer ulcers and strictures, than the control group. ASCs augmented bursting pressure and collagen deposition. The histopathological features were significantly more favorable in the ASC group, and microvascular density was significantly higher than it was in the control group. Conclusion Locally-transplanted ASCs enhanced healing of ischemic colonic anastomoses by increasing angiogenesis. ASCs could be a novel strategy for accelerating healing of colonic ischemic risk anastomoses.

T4 stage and preoperative anemia as prognostic factors for the patients with colon cancer treated with adjuvant FOLFOX chemotherapy.

BackgroundFOLFOX-based adjuvant chemotherapy is a benefit for high-risk stage II and stage III colon cancer after curative resection. But, the prognostic factor or predictive marker for the efficacy of FOLFOX remains unclear. This study was aimed to identify the prognostic value and cumulative impact of adjuvant FOLFOX on the stage II and III colon cancer patients.MethodsA total of 196 stage II and III colon cancer patients were retrospectively enrolled in prospectively collected data. They underwent curative resection followed by FOLFOX4 adjuvant chemotherapy. The oncological outcomes included the 5-year disease-free survival (DFS) rate and 5-year overall survival (OS) rate. Cox-regression analysis was performed to identify the prognostic value, and its cumulative impact was analyzed.ResultsThe 5-year DFS rate of the patients was 71.94% and the 5-year OS rate was 81.5%. The prognostic values for the 5-year DFS rate and 5-year OS rate were T4 stage and preoperative anemia in a multivariate analysis. Each patient group who had no prognostic value, single, or both factors revealed 95.35%, 69.06%, and 28.57% in the 5-year DFS rate, respectively (p < 0.0001). The 5-year OS rate also showed the significant differences in each group who had no prognostic value, single, or both factors revealed 100%, 79.3%, and 45.92%, respectively (p < 0.0001).ConclusionOur results showed similar efficacy to MOSAIC study in stage II and stage III colon cancer patients treated with adjuvant FOLFOX chemotherapy after curative resection. Patients who had T4 stage and/or preoperative anemia showed worse prognosis than patients without any prognostic value. These findings suggest that FOLFOX could not be effective in the patients with T4 stage colon cancer accompanied by preoperative anemia.

Massive small bowel bleeding caused by scrub typhus in Korea

A 79-year-old man was diagnosed with scrub typhus based on fever, eschar, skin rash and a markedly elevated serum tsutsugamushi antibody and doxycycline was started. Five days later, hematochezia developed and multiple small bowel ulcerations with hemorrhage were seen on colonoscopy. Despite intensive therapy, the massive hematochezia worsened and the distal small bowel was resected. Multiple ulcerated lesions were identified pathologically as vasculitis caused by scrub typhus. This is the first reported case of pathologically proven small bowel involvement in scrub typhus infection.

Oncologic Outcomes and Risk Factors for Recurrence after Tumor-specific Mesorectal Excision of Rectal Cancer: 782 Cases

Purpose The aim of this study was to analyze the oncologic outcomes and the risk factors for recurrence after a tumor-specific mesorectal excision (TSME) of resectable rectal cancer in a single institution. Methods A total of 782 patients who underwent a TSME for resectable rectal cancer between February 1995 and December 2005 were enrolled retrospectively. Oncologic outcomes included 5-year cancer-specific survival and its affecting factors, as well as risk factors for local and systemic recurrence. Results The 5-year cancer-specific survival rate was 77.53% with a mean follow-up period of 61 ± 31 months. The overall local and systemic recurrence rates were 9.2% and 21.1%, respectively. The risk factors for local recurrence were pN stage (P = 0.015), positive distal resection margin, and positive circumferential resection margin (P < 0.001). The risk factors for systemic recurrence were pN stage (P < 0.001) and preoperative carcinoembryonic antigen level (P = 0.005). The prognostic factors for cancer-specific survival were pT stage (P < 0.001), pN stage (P < 0.001), positive distal resection margin (P = 0.005), and positive circumferential resection margin (P = 0.016). Conclusion The oncologic outcomes in our institution after a TSME for patients with resectable rectal cancer were similar to those reported in other recent studies, and we established the risk factors that could be crucial for the planning of treatment and follow-up.

Prognostic Significance of Lymph Node Ratio in Stage III Rectal Cancer

Purpose Although nodal metastasis is the most powerful prognostic factor in rectal cancer, marked heterogeneity exists within stage III rectal cancer. Recent studies of rectal cancer have shown a prognostic superiority of the lymph node ratio (LNR) compared with N stage. The purpose of this study was to investigate the prognostic value of the LNR in the era of the 7th edition of the TNM classification. Methods We included 190 patients who underwent a curative resection for rectal cancer with nodal metastasis. The patients were divided into four groups on the basis of statistically calculated cut-off values as 0.21, 0.32, and 0.61. Results The LNR was an independent risk factor for overall survival (OS; P = 0.008) and for systemic recurrence-free survival (SRFS; P = 0.002). However, the LNR was not a predictive factor for local recurrence. When the N stage of the sixth TNM staging system was separately analyzed as a covariate, the LNR was also found to be a predictive factor for both OS and SRFS (P = 0.012 and P = 0.004, respectively). A LNR value of 0.21 offered the best cut off to separate patients into two prognostic groups. Conclusion The defined cut-off values of the LNR were an independent risk factor for OS and distant metastasis-free survival in patients with rectal cancer, irrespective of the sixth or the seventh version of the TNM classification, and the LNR should be considered as a prognostic variable in any future staging system.

Association Between a Close Distal Resection Margin and Recurrence After a Sphincter-Saving Resection for T3 Mid- or Low-Rectal Cancer Without Radiotherapy

Purpose To maintain the patients quality of life, surgeons strive to preserve the sphincter during rectal cancer surgery. This study evaluated the oncologic safety of a sphincter-saving resection with a distal resection margin (DRM) <1 cm without radiotherapy in T3, mid- or low-rectal cancer. Methods This retrospective study enrolled 327 patients who underwent a sphincter-saving resection for proven T3 rectal cancer located <10 cm from the anal verge and without radiotherapy between January 1995 and December 2011. The oncologic outcomes included the 5-year cancer-specific survival, the local recurrence, and the systemic recurrence rates. Results In groups A (DRM ≤1 cm) and B (DRM >1 cm), the 5-year cancer-specific survival rates were 81.57% and 80.03% (P = 0.8543), the 5-year local recurrence rates were 6.69% and 9.52% (P = 0.3981), and the 5-year systemic recurrence rates were 19.46% and 23.11% (P = 0.5750), respectively. Conclusion This study showed that the close DRM itself should not be a contraindication for a sphincter-saving resection for T3 mid- or low-rectal cancer without radiotherapy. However, a prospective randomized controlled trial including the effect of adjuvant therapy will be needed.

ERCC1 as a Predictive Marker for FOLFOX Chemotherapy in an Adjuvant Setting.

Purpose The purpose of this study was to identify the excision repair cross-complementation group 1 (ERCC1) as a predictive marker for FOLFOX adjuvant chemotherapy in stages II and III colon cancer patients. Methods A total of 166 high risk stages II and III colon cancer patients were retrospectively enrolled in this study, and data were collected prospectively. They underwent a curative resection followed by FOLFOX4 adjuvant chemotherapy. We analyzed ERCC1 expression in the primary colon tumor by using immunohistochemical staining. The oncological outcomes included the 5-year disease-free survival (DFS) rate. The DFS was analyzed by using the Kaplan-Meier method with the log-rank test. A Cox proportional hazard model was used for the prognostic analysis. Results ERCC1-positive expression was statistically significant in the older patients (P = 0.032). In the multivariate analysis, the prognostic factors for DFS were female sex (P = 0.016), N stage (P = 0.009), and postoperative carcinoembryonic antigen level (P = 0.001), but ERCC1 expression was not a statistically significant prognostic factor for DFS in the univariate analysis (P = 0.397). The 5-year DFS rate was not significantly associated with the ERCC1 expression in all patients (P = 0.396) or with stage III disease (P = 0.582). Conclusion We found that ERCC1 expression was not significantly correlated with the 5-year DFS as reflected by the oncologic outcomes in patients with high-risk stages II and III colon cancer treated with FOLFOX adjuvant chemotherapy.

Difference in Tumor Area as a Predictor of a Pathological Complete Response for Patients With Locally Advanced Rectal Cancer

Purpose This study was conducted to discover the clinical factors that can predict pathologically complete remission (pCR) after neoadjuvant chemoradiotherapy (CRT), so that those factors may help in deciding on a treatment program for patients with locally advanced rectal cancer. Methods A total of 137 patients with locally advanced rectal cancer were retrospectively enrolled in this study, and data were collected retrospectively. The patients had undergone a total mesorectal excision after neoadjuvant CRT. Histologic response was categorized as pCR vs. non-pCR. The tumor area was defined as (tumor length) × (maximum tumor depth). The difference in tumor area was defined as pre-CRT tumor area – post-CRT tumor area. Univariate and multivariate logistic regression analyses were conducted to find the factors affecting pCR. A P-value < 0.05 was considered significant. Results Twenty-three patients (16.8%) achieved pCR. On the univariate analysis, endoscopic tumor circumferential rate <50%, low pre-CRT T & N stage, low post-CRT T & N stage, small pretreatment tumor area, and large difference in tumor area before and after neoadjuvant CRT were predictive factors of pCR. A multivariate analysis found that only the difference in tumor area before and after neoadjuvant CRT was an independent predictor of pCR (P < 0.001). Conclusion The difference in tumor area, as determined using radiologic tools, before and after neoadjuvant CRT may be important predictor of pCR. This clinical factor may help surgeons to determine which patients who received neoadjuvant CRT for locally advanced rectal cancer should undergo surgery.

Prognostic value of positron emission tomography/computed tomography for adjuvant chemotherapy of colon cancer

To assess the prognostic value of preoperative 18F‐fluorodeoxyglucose positron emission tomography/computed tomography in patients with high‐risk stage II or stage III colon cancer who underwent FOLFOX chemotherapy.

Oncological outcomes of complete versus conventional mesocolic excision in laparoscopic right hemicolectomy

Complete mesocolic excision (CME) has been proposed for colon cancer to improve oncological outcomes. The risks and benefits of laparoscopic CME have not been examined fully. We compared short‐ and long‐term outcomes of CME with a conventional mesocolic excision (non‐CME) in laparoscopic right hemicolectomy (RHC) for right‐sided colon cancer.