Dong Sup Yoon

A Prospective Randomized Controlled Study Comparing Outcomes of Standard Resection and Extended Resection, Including Dissection of the Nerve Plexus and Various Lymph Nodes, in Patients With Pancreatic Head Cancer

Objective:To prospectively evaluate the survival benefit of dissection of the nerve plexus and lymphadenectomy in patients with pancreatic head cancer. Background:Despite randomized controlled trials on the extent of surgery in pancreatic cancer, attempts have been made to perform more extended resections. Methods:A total of 244 patients were enrolled; of these, 200 were randomized to undergo standard resection or extended resection, with the latter including the dissection of additional lymph nodes and the right half of the nerve plexus around the superior mesenteric artery and celiac axis. We evaluated 167 patients from 7 centers who fulfilled all of the required criteria. Result:Operation time was longer and estimated blood loss was higher in the extended resection group than in the standard resection group, but the R0 resection rate was comparable. The mean number of lymph nodes retrieved per patient was higher in the extended resection group than in the standard resection group (33.7 vs 17.3; P < 0.001). The morbidity rate was slightly higher in the extended resection group than in the standard resection group. Two patients in the extended resection group died in hospital. Median survival after R0 resection was similar in the extended resection and standard resection groups (18.0 vs 19.0 months; P = 0.239) regardless of lymph node metastasis. Adjuvant chemoradiation had a positive impact on overall survival. Conclusions:This study suggests that extended lymphadenectomy with dissection of the nerve plexus does not provide a significant survival benefit compared with standard resection in pancreatic head cancer. Standard resection can be performed safely and efficiently, without negatively affecting oncologic efficacy or long-term survival, when compared with extended pancreaticoduodenal resection. (NCT00679913)?

Early Experiences of Robotic-assisted Laparoscopic Liver Resection

Purpose The surgical robotic system is superior to traditional laparoscopy in regards to 3-dimensional images and better instrumentations. Robotic surgery for hepatic resection has not yet been extensively reported. Patients and Methods Between March and May 2007, we performed 3 robot-assisted left lateral sectionectomies of the liver. Case 1 had a hepatocellular carcinoma (HCC), case 2 had colon cancer with liver metastasis, and case 3 had intrahepatic duct stones. Results All patients had successful operation and recovered without complications. Shorter length of hospital stays, earlier start of oral feeding and less amount of ascites were found. However, case 1 had recurrent HCC at 3 months after operation. Conclusion Robotic-assisted liver surgery is still a new field in its developing stage. In patients with small malignant tumors and benign liver diseases, robotic-assisted laparoscopic resection is feasible and safe. Through experience, the use of robotics is expected to increase in the treatment of benign diseases and malignant neoplsms. However, careful patient selection is important and long-term outcomes need to be evaluated.

Importance of Sox2 in maintenance of cell proliferation and multipotency of mesenchymal stem cells in low‐density culture

Objectives:  This study has aimed to repopulate ‘primitive’ cells from late‐passage mesenchymal stem cells (MSCs) of poor multipotentiality and low cell proliferation rate, by simply altering plating density.

Understanding the development of human bladder cancer by using a whole-organ genomic mapping strategy.

The search for the genomic sequences involved in human cancers can be greatly facilitated by maps of genomic imbalances identifying the involved chromosomal regions, particularly those that participate in the development of occult preneoplastic conditions that progress to clinically aggressive invasive cancer. The integration of such regions with human genome sequence variation may provide valuable clues about their overall structure and gene content. By extension, such knowledge may help us understand the underlying genetic components involved in the initiation and progression of these cancers. We describe the development of a genome-wide map of human bladder cancer that tracks its progression from in situ precursor conditions to invasive disease. Testing for allelic losses using a genome-wide panel of 787 microsatellite markers was performed on multiple DNA samples, extracted from the entire mucosal surface of the bladder and corresponding to normal urothelium, in situ preneoplastic lesions, and invasive carcinoma. Using this approach, we matched the clonal allelic losses in distinct chromosomal regions to specific phases of bladder neoplasia and produced a detailed genetic map of bladder cancer development. These analyses revealed three major waves of genetic changes associated with growth advantages of successive clones and reflecting a stepwise conversion of normal urothelial cells into cancer cells. The genetic changes map to six regions at 3q22–q24, 5q22–q31, 9q21–q22, 10q26, 13q14, and 17p13, which may represent critical hits driving the development of bladder cancer. Finally, we performed high-resolution mapping using single nucleotide polymorphism markers within one region on chromosome 13q14, containing the model tumor suppressor gene RB1, and defined a minimal deleted region associated with clonal expansion of in situ neoplasia. These analyses provided new insights on the involvement of several non-coding sequences mapping to the region and identified novel target genes, termed forerunner (FR) genes, involved in early phases of cancer development.

Postoperative Nutritional Effects of Early Enteral Feeding Compared with Total Parental Nutrition in Pancreaticoduodectomy Patients: A Prosepective, Randomized Study

The benefits of early enteral feeding (EEN) have been demonstrated in gastrointestinal surgery. But, the impact of EEN has not been elucidated yet. We assessed the postoperative nutritional status of patients who had undergone pancreaticoduodenectomy (PD) according to the postoperative nutritional method and compared the clinical outcomes of two methods. A prospective randomized trial was undertaken following PD. Patients were randomly divided into two groups; the EEN group received the postoperative enteral feed and the control group received the postoperative total parenteral nutrition (TPN) management. Thirty-eight patients were included in our analyses. The first day of bowel movement and time to take a normal soft diet was significantly shorter in EEN group than in TPN group. Prealbumin and transferrin were significantly reduced on post-operative day (POD) 7 and were slowly recovered until POD 90 in the TPN group than in the EEN group. EEN group rapidly recovered weight after POD 21 whereas it was gradually decreased in TPN group until POD 90. EEN after PD is associated with preservation of weight compared with TPN and impact on recovery of digestive function after PD.

Preoperative staging accuracy of multidetector row computed tomography for extrahepatic bile duct carcinoma

Purpose: This study sought to evaluate the accuracy of multidetector computed tomography (MDCT) for preoperative staging of extrahepatic bile duct (EHD) carcinoma and to assess the value of coronal reformations from isotropic voxels. Materials and Methods: Thirty patients with surgically proven EHD cancer underwent dynamic MDCT with coronal reformation. Two experienced radiologists independently evaluated contrast-enhanced dynamic transverse CT images (axial approach) and combined transverse and coronal images (combined approach). The radial extent (TNM staging) and the vertical extent of tumors were assessed and correlated with pathological findings of surgical specimen. Results: All of primary tumors were detected by axial and combined CT imaging (100%). Overall accuracy of the T staging was 73% (22/30) with axial and 77% (23/30) with combined CT imaging (P > 0.05). The accuracy of N staging was 57% (17/30) with axial and 63% (19/30) with combined CT imaging (P > 0.05). The accuracy of M staging was 97% (29/30) with both axial and combined CT imaging. Upper margin accuracy was 97% (29/30) for axial and 100% for combined CT imaging (P > 0.05), whereas that of the lower margin was 90% (27/30) for axial and 93% (28/30) for combined CT imaging (P > 0.05). Conclusions: Multidetector computed tomography was sufficiently accurate for evaluating the vertical extents, but radial extents of EHD cancer. The addition of coronal reformatted images did not improve the accuracy for staging of EHD cancer.

The Effect of Visceral Fat Mass on Pancreatic Fistula after Pancreaticoduodenectomy

ABSTRACT Background: Obesity is associated with perioperative complications and has been considered a risk factor for surgical outcomes of patients undergoing abdominal surgery. The aim of this study is to evaluate the impact of the amount of visceral fat on postoperative morbidity of patients who underwent pancreaticoduodenectomy (PD). Methods: We reviewed 181 patients who underwent surgery for periampullary lesions at the Department of Surgery, Gangnam Severance Hospital, Yonsei University Health System between January 2003 and June 2010. The visceral fat area (VFA) and subcutaneous fat area were calculated by computed tomography software. Results: The mean body mass index (BMI) was 23.4 kg/m2 (±3.1 kg/m2), and the mean VFA was 94.4 cm2 (±49.5 cm2). The mean intraoperative blood loss, and the incidence of clinically relevant pancreatic fistula (grade B/C) and clinically relevant delayed gastric emptying (grade B/C) were significantly higher in the high-VFA group (≥100 cm2). In univariate analysis, the incidence of clinically relevant pancreatic fistula (grade B/C) was significantly higher in the high-BMI group (≥25 kg/m2), the high-VFA group(≥100 cm2), the large intraoperative blood loss and transfusion group, and in patients with pathology of nonpancreatic origin (ampulla, bile duct, or duodenum). In multivariate analysis, the high-VFA group (≥100 cm2) and patients with pathology of nonpancreatic origin were identified as independent factors for clinically relevant pancreatic fistula. Conclusion: VFA is a better indicator for the development of pancreatic fistula after PD than BMI. High VFA (≥100 cm2) is a risk factor for developing a pancreatic fistula after PD.

The Actual Five-year Survival Rate of Hepatocellular Carcinoma Patients after Curative Resection

The five-year survival rate of patients after curative resection of hepatocellular carcinoma (HCC) has been reported to be 30 to 50%, however the actual survival rate may be different. We analyzed the actual 5-year survival rate and prognostic factors after curative resection of HCC. Retrospective analysis was performed on 63 HCC patients who underwent curative resection from 1998 to 1999. A total of 63 cases were reviewed, consisting of 53 men and 10 women, with a median age of 49 years. These cases included all four pathologic T stages (pT stage) and had the following representation: stage 1 (1 case), stage 2 (17 cases), stage 3 (38 cases), and stage 4 (7 cases). In our study, the actual 5-year survival rate was 57.0% and the median survival time was 60 months. In addition, the patients in our study had an actual 5-year disease-free survival rate of 50.2% and a median disease-free survival time of 46 months. Thirty-one patients had recurrences, with a majority occurring within one year (65%). These patients with early recurrences had a poor actual 5-year survival rate of 5%. A univariate analysis showed that the prognostic factors influencing survival rate were the presence of satellite nodules, increased pT stage, HCC recurrence, and the time to recurrence (within one year). Interestingly, microvascular invasion made a difference in survival rate but was not statistically significant (p = 0.08). Furthermore, factors influencing the disease free survival rate include the presence of satellite nodules, microvascular invasion, and pT stage. Multivariate analysis identified pT stage as the only statistically related factor in determining the disease-free survival rate. The most important prognostic factor of HCC is recurrence. Moreover, the major risk factor for recurrence is an advanced pT stage. Therefore, performing prospective studies of postoperative adjuvant therapy is necessary to prevent recurrences after hepatic resection. Furthermore, active preventative treatment and early diagnosis of recurrences should be of the highest priority in the care of high-risk patient groups that have an advanced pT stage.

High-resolution whole-organ mapping with SNPs and its significance to early events of carcinogenesis

We attempted to identify deleted segments in two model tumor suppressor gene loci on chromosomes 13q14 and 17p13 that were associated with clonal expansion of in situ bladder preneoplasia using single nucleotide polymorphisms (SNPs)-based whole-organ histologic and genetic mapping. For mapping with SNPs, the sequence-based maps spanning approximately 27 and 5 Mb centered around RB1 and p53, respectively, were assembled. The integrated gene and SNP maps of the regions were used to select 661 and 960 SNPs, which were genotyped by pyrosequencing. Genotyping of SNPs was performed on DNA samples corresponding to histologic maps of the entire bladder mucosa in human cystectomy specimens with invasive urothelial carcinoma. By using this approach, we have identified deleted regions associated with clonal expansion of intraurothelial neoplasia; which ranged from 0.001 to 4.3 Mb (average 0.67 Mb) and formed clusters of discontinuous deleted segments. The high resolution of such maps is a prerequisite for future positional targeting of genes involved in early phases of bladder neoplasia. This approach also permits analysis of the overall genomic landscape of the involved region and discloses that a unique composition of noncoding DNA characterized by a high concentration of repetitive sequences may predispose to deletions.

Current Status of Laparoscopic Liver Resection in Korea

Since laparoscopic liver resection was first introduced in 2001, Korean surgeons have chosen a laparoscopic procedure as one of the treatment options for benign or malignant liver disease. We distributed and analyzed a nationwide questionnaire to members of the Korean Laparoscopic Liver Surgery Study Group (KLLSG) in order to evaluate the current status of laparoscopic liver resection in Korea. Questionnaires were sent to 24 centers of KLLSG. The questionnaire consisted of operative procedure, histological diagnosis of liver lesions, indications for resection, causes of conversion to open surgery, and postoperative outcomes. A laparoscopic liver resection was performed in 416 patients from 2001 to 2008. Of 416 patients, 59.6% had malignant tumors, and 40.4% had benign diseases. A total laparoscopic approach was performed in 88.7%. Anatomical laparoscopic liver resection was more commonly performed than non-anatomical resection (59.9% vs 40.1%). The anatomical laparoscopic liver resection procedures consisted of a left lateral sectionectomy (29.3%), left hemihepatectomy (19.2%), right hemihepatectomy (6%), right posterior sectionectomy (4.3%), central bisectionectomy (0.5%), and caudate lobectomy (0.5%). Laparoscopy-related serious complications occurred in 12 (2.8%) patients. The present study findings provide data in terms of indication, type and method of liver resection, and current status of laparoscopic liver resection in Korea.