Seong Heum Park

Expression of estrogen receptors in gastric cancer and their clinical significance.

The male predominance of gastric cancer suggests that female sex hormones may have a protective effect against gastric cancer. We evaluated the expression of estrogen receptors in gastric cancer tissue and cells and the clinical significance of ER‐β expression in gastric cancer.

Gastric cancer histology: clinicopathologic characteristics and prognostic value.

Gastric cancer can be divided into two major histologic categories, that is, differentiated and undifferentiated types. In the present study, we sought to clarify the prognoses and clinicopathologic characteristics of signet ring cell carcinoma and mucinous carcinoma, both of which are mucin‐producing tumors of the undifferentiated type.

Benefit of Post-operative Surveillance for Recurrence after Curative Resection for Gastric Cancer

BackgroundAlthough most clinicians perform surveillance after gastrectomy, there is no consensus on the optimal follow-up schedule. This study aimed to evaluate the benefit of postoperative surveillance for recurrence after curative resection for gastric cancer.MethodWe retrospectively studied 110 patients who had recurrences after undergoing curative gastrectomies between 2000 and 2004 at Korea University Hospital. We analyzed the clinico-pathologic factors and oncologic results according to the presence of recurrence symptoms.ResultsFifty-five (50%) patients had symptomatic recurrences. There were significant differences in recurrence patterns; locoregional (29.1%) and peritoneal recurrences (27.3%) were dominant in asymptomatic group; peritoneal (47.3%) and hematogenous recurrences (25.5%) were dominant in symptomatic group. The median recurrence-free survival was not different for both groups (p = 0.054). However, median overall and post-recurrence survival was poor in the symptomatic group (p = 0.004, p < 0.001). The presence of symptoms and short disease-free survival were independent poor prognostic factors for post-recurrence survival.ConclusionPatients with asymptomatic recurrences could have increased survival compared to symptomatic patients. Although our post-operative surveillance could not be any benefit to improve outcomes for recurrent gastric cancer, it is important to discriminate the nature of recurrent gastric cancer by the presence of symptoms for planning further treatment.

Clinical Significance of Immunohistochemically-Identified Lymphatic and/or Blood Vessel Tumor Invasion in Gastric Cancer

BACKGROUND Tumor invasion and lymph node metastasis are significant prognostic factors for gastric cancer, and lymphatic and vascular tumor invasion are also significant risk factors for gastric cancer recurrence. Recently, the immunohistochemical detection of lymphatic and blood vessel tumor invasion (LBVI) has been shown to have a higher sensitivity and specificity than hematoxylin-eosin staining methods. MATERIALS AND METHODS One hundred forty-nine gastric cancer patients who underwent curative resection at Korea University Hospital between November 2003 and December 2006 served as the study subjects. Lymphatic vessel invasion was evaluated by immunostaining with the new selective marker, D2-40, and blood vessel invasion was assessed with anti-CD31 antibody. Patients were divided according to the presence of LBVI, clinicopathologic factors were compared, and postoperative surgical outcomes were analyzed. RESULTS LBVI was present in 66 patients (44.3%). LBVI was significantly correlated with depth of tumor invasion (P < 0.001), lymph node stage (P < 0.001), and lymph node micrometastasis (P = 0.013). Cancer recurrence was more common in the LBVI group (P = 0.007), and peritoneal seeding was the most prevalent type of recurrence (P = 0.028). Univariate analysis showed tumor size, depth of tumor invasion, lymph node stage, and LBVI to have a significant impact on survival. Based on multivariate analysis, however, depth of tumor invasion and lymph node stage were correlated with survival. CONCLUSION Immunohistochemical demonstration of LBVI is an additional prognostic marker, and provides useful information for planning treatment strategies in gastric cancer patients.

Surgical outcomes and prognostic factors for T4 gastric cancers.

PURPOSE In locally advanced gastric carcinomas that have invaded adjacent organs, the prognosis is poor. When combined resections are performed in T4 gastric cancers, a high morbidity rate is reported and it is inconclusive as to whether or not there is an improvement in the survival rate. We investigated surgical outcomes and analysed the prognostic factors for T4 gastric cancers. PATIENTS AND METHODS Between January 1992 and December 2000, 132 patients underwent surgery for T4 gastric cancer; they were divided into three groups: combined resections in group I, gastrectomy alone in group II, and resections not performed but palliative gastrojejunostomy or intraperitoneal chemotherapy in group III. Surgical outcomes and clinicopathologic factors were compared and prognostic factors were evaluated. RESULTS Among the three groups, statistically significantly different factors were tumour location, Borrmann type, tumour size, distant metastasis and peritoneal metastasis. The most commonly resected organ was the transverse colon, and 14 post-operative morbidities developed. In the multivariate analysis, the treatment group and curability were proved to be independent prognostic factors. CONCLUSION In patients with T4 gastric carcinoma, an aggressive surgical approach can be beneficial when curative resection is performed. If curative resection is not possible, palliative resection can be performed for a better quality of life.

Laparoscopy Assisted versus Open Distal Gastrectomy with D2 Lymph Node Dissection for Advanced Gastric Cancer: Design and Rationale of a Phase II Randomized Controlled Multicenter Trial (COACT 1001)

Purpose Laparoscopy-assisted distal gastrectomy for early gastric cancer has gained acceptance and popularity worldwide. However, laparoscopy-assisted distal gastrectomy for advanced gastric cancer is still controversial. Therefore, we propose this prospective randomized controlled multi-center trial in order to evaluate the safety and feasibility of laparoscopy assisted D2-gastrectomy for advanced stage gastric cancer. Materials and Methods Patients undergoing distal gastrectomy for advanced gastric cancer staged cT2/3/4 cN0/1/2/3a cM0 by endoscopy and computed tomography are eligible for enrollment after giving their informed consent. Patients will be randomized either to laparoscopy-assisted distal gastrectomy or open distal gastrectomy. Sample size calculation revealed that 102 patients are to be included per treatment arm. The primary endpoint is the non-compliance rate of D2 dissection; relevant secondary endpoints are three-year disease free survival, surgical and postoperative complications, hospital stay and unanimity rate of D2 dissection evaluated by reviewing the intraoperative video documentation. Discussion Oncologic safety is the major concern regarding laparoscopy-assisted distal gastrectomy for advanced gastric cancer. Therefore, the non-compliance rate of clearing the N2 area was chosen as the most important parameter for the technical feasibility of the laparoscopic procedure. Furthermore, surgical quality will be carefully reviewed, that is, three independent experts will review the video records and score with a check list. For a long-term result, disease free survival is considered a secondary endpoint for this trial. This study will offer promising evidence of the feasibility and safety of Laparoscopy-assisted distal gastrectomy for advanced gastric cancer.Trial Registration: NCT01088204 (international), NCCCTS-09-448 (Korea).

Expression of intercellular adhesion molecule-1 and e-selectin in gastric cancer and their clinical significance.

Purpose Among cell adhesion molecules, serum levels of intercellular adhesion molecule-1 and E-selectin are known to be correlated with the metastatic potential of gastric cancer. In the present study, the authors investigated the expression of intercellular adhesion molecule-1 and E-selectin in gastric cancer tissues and cultured gastric cancer cells, and examined their clinical value in gastric cancer. Materials and Methods The protein was extracted from gastric cancer tissues and cultured gastric cancer cells (MKN-28 and Kato-III) and the expression of intercellular adhesion molecule-1 and E-selectin was examined by western blotting. The clinical significance of intercellular adhesion molecule-1 and E-selectin was explored, using immunohistochemical staining of specimens from 157 gastric cancer patients. Results In western blot analysis, the expressions of intercellular adhesion molecule-1 in gastric cancer tissues and cultured gastric cancer cells were increased, however, E-selectin in gastric cancer tissues and cells were not increased. Among 157 gastric cancer patients, 79 patients (50%) were intercellular adhesion molecule-1 positive and had larger tumor size, an increased depth of tumor invasion, lymph node metastasis and perineural invasion. The intercellular adhesion molecule-1 positive group showed a higher incidence of tumor recurrence (40.5%), and a poorer 3-year survival than the negative group (54.9 vs. 85.9%, respectively). Conclusions Intercellular adhesion molecule-1 is overexpressed in gastric cancer tissues and cultured gastric cancer cells, whereas E-selectin is not overexpressed. Increased expression of intercellular adhesion molecule-1 in gastric cancer could be related to the aggressive nature of the tumor, and has a poor prognostic effect on gastric cancer.

Surgeon subspecialty as a factor in improving long-term outcomes for gastric cancer: Twenty years of experience in Korea

BACKGROUND The results of gastric cancer treatment have improved during the past 2 decades. In addition to early diagnosis, surgeon experience and subspecialty may influence long-term outcomes. This study analyzed data accumulated during the past 20 years regarding the impact of surgical subspecialty on gastric cancer prognosis. DESIGN A 20-year, retrospective study. SETTING Korea University Guro Hospital, Seoul. PATIENTS A total of 2797 patients admitted between 1984 and 2003 with surgically treated, pathologically confirmed, primary gastric adenocarcinoma. MAIN OUTCOME MEASURE Long-term survival. RESULTS The incidence of total gastrectomy and the number of retrieved lymph nodes increased during the study period. In curative cases, 5-year survival improved from 66.1% to 76.6%, and this survival gain was restricted to stages I, III, and IV. A Cox proportional hazards regression model showed that age, sex, tumor location, type of resection, stage, and the interaction between period of study and surgical subspecialty were independent prognostic factors. CONCLUSIONS This large, long-term cohort study demonstrates that the management of gastric cancer has been largely successful, with favorable trends in prognostic factors. Successful outcomes are realized more often by gastric surgical specialists. Efforts must be made to improve the treatment of patients with stage II gastric cancer because the improvements in long-term results have plateaued.

Single-port laparoscopic distal pancreatectomy: initial experience.

INTRODUCTION Laparoscopic distal pancreatectomy has become the standard treatment of choice for pancreatic tail cystic and solid tumors when technically feasible. Technological advances have led to the development of single-port laparoscopic surgery, a safe alternative procedure. We present our experiences with single-port laparoscopic distal pancreatectomy. MATERIALS AND METHODS We retrospectively reviewed clinical records and compared clinical outcomes in 40 patients diagnosed with a pancreatic tail mass between 2007 and 2013 who received either conventional laparoscopic (n=28) or single-port laparoscopic distal pancreatectomy (n=12). RESULTS The mean surgery time in the single-port group (279.8±53.0 minutes) was significantly longer than in the conventional group (186.9±86.6 minutes) (P=.001). The mean duration of postoperative hospital stay in the single-port group (12.2±5.4 days) was also significantly longer than in the conventional group (8.3±4.7 days) (P=.028). The spleen was preserved more in the conventional group (60.7%) than in the single-port group (33.3%), but the difference was not significant (P=.112). There were no significant differences in intraoperative blood loss, tumor size, conversion rate, or postoperative complications between the two groups. CONCLUSIONS Blood loss and postoperative complications of single-port laparoscopic distal pancreatectomy are similar to those of conventional laparoscopic distal pancreatectomy. Single-port laparoscopic distal pancreatectomy can be performed safely and effectively in select patients with pancreas tail neoplasms, but is associated with a longer surgery time and postoperative hospital stay.

The significance of mismatch repair genes in gastric cancer

BACKGROUND Microsatellite instability (MSI) is a form of genetic instability characterized by new alleles not present in the normal genotype. This mutation occurs by altered DNA mismatch repair (MMR) genes. Studies of limited numbers of patients have reported conflicting results regarding the association of the MSI phenotype with gastric cancer. This study aims to evaluate the clinical significance of mismatch repair genes in gastric cancer. MATERIALS AND METHODS We studied 156 gastric cancer patients who underwent gastrectomy from March 2010 to February 2011 in our hospital. Mismatch repair status was determined by the immunohistochemical analysis of human MutL Homolog 1 (hMLH1) and human MutS Homolog 2 (hMSH2) expression. RESULTS Seventeen (10.9%) cases did not express hMLH1 but all cases expressed hMSH2. In univariate analyses, the expression of hMLH1 was associated with age, nodal status, and Laurens classification. In multivariate analyses, there was no statistically significant association between the loss of hMLH1 expression and selected clinical parameters. CONCLUSION The expression of hMLH1 was associated with age, nodal status, and Laurens classification. Our results suggest that MMR gene abnormalities play an important role in the tumorigenesis of patients demonstrating gastric cancer.