Sung Tae Oh

Laparoscopy in the management of gastric submucosal tumors.

Background: Gastric tumors, including early gastric cancers, can be safely removed laparoscopically. They do not require an open laparotomy.Methods: From March 1995 to December 1998, we used laparoscopy to resect gastric submucosal lesions in 32 patients. There were 22 men and 10 women. The patients ranged in age from 23 to 67 years (median, 51.4 yr). The lesions were located in the upper third in one patient, in the middle third in 20 patients, and in the lower third in 11 patients. The tumors ranged in size from 2 to 6 cm in diameter. The operative procedures were wedge resection in 19 patients, wedge resection with gastrotomy in two patients, intragastric surgery in nine patients, intragastric surgery with gastrotomy in one patient, and proximal gastrectomy in one patient, using a four- or five-port technique. The exophytic mass was resected with an Endo-GIA, and the tumors on the mucosal surface were exposed via a gastrotomy and excised. The gastrotomy was closed with an intracorporeal suture. In all cases, the operation was finished after the confirmation of tumor-free margins on frozen-section biopsy specimens.Results: The duration of the operation ranged from 80 to 180 mins. The final pathologic findings were leiomyoma in 24 patients, adenomyoma in three patients, hyperplastic polyp in two patients, lipoma in one patient, hamartoma in one patient, and leiomyosarcoma in one patient. One case (3.1%) was converted to a mini-laparotomy due to technical difficulty; in one other case, more margin was resected laparoscopically due to the tumor-positive margin; and in one further patient, leakage was repaired by laparoscopic suturing on the 1st postoperative day. There were no other major complications and no deaths. The hospital stay ranged from 6 to 7 days. The maximum follow-up to date in these patients, including a case of leiomyosarcoma, was 42 months. There has been no evidence of tumor recurrence.Conclusion: The application of laparoscopy to submucosal tumors of the stomach is technically feasible, safe, and useful. It should be considered a viable alternative to open surgery and gastroscopic management because of its low invasiveness and good postoperative results.

Extended indication of endoscopic resection for mucosal early gastric cancer: Analysis of a single center experience

Background:  Endoscopic resection (ER) has become an important therapeutic option for early gastric cancer (EGC). Some investigators have suggested that this indication should be extended. We aimed to compare the extended indication of ER for intramucosal EGC based on data from a large, single‐center study.

Clinicopathological Analysis of Borrmann Type IV Gastric Cancer

PURPOSE Borrmann type IV gastric cancer is often diagnosed only at an advanced stage, resulting in a prognosis poor. We performed a retrospective study of the clinical characteristics of Borrmann type IV gastric cancer and the prognostic factors affecting the survival rate in such patients. MATERIALS AND METHODS Of 4,063 patients with all gastric cancers, 370 (9%) with Borrmann type IV gastric cancer were analyzed. RESULTS The clinical characteristics of these patients included a higher incidence rate in young females, and higher rates of serosa exposure, metastasis to lymph nodes and early peritoneal dissemination. Of patients presenting with peritoneal seeding, those resected had a higher survival rate than those that were not. A univariate analysis showed that the prognostic factors affecting the survival rate following a curative resection were the location, occupied area and depth of the primary tumor, as well as the presence of lymph node metastasis and the tumor stage. A multivariate analysis indicated that the tumor location and stage were significant independent prognostic factors after a curative resection for Borrmann type IV gastric cancer. CONCLUSION In conclusion, the early diagnosis and treatment of patients with Borrmann type IV gastric cancer are essential for the better survival of these patients. Even in patients with advanced tumors, a noncurative palliative resection may improve the prognosis.

A phase I / II trial of docetaxel, capecitabine, and cisplatin as a first line chemotherapy for advanced gastric cancer

4066 Background: Combination of capecitabine and cisplatin (XP) was active and tolerable in advanced gastric cancer (AGC). We added docetaxel (D) to XP regimen and performed a phase I / II study of DXP combination. METHODS Patients (pts) with chemotherapy-naïve inoperable AGC were eligible for this study. For the phase I study, with the fixed dose of P (60 mg/m2 D1), the doses of X (D1-14) and D (D1) were escalated as following schedule: level 1: X 1,875 mg/m2/d, D 60 mg/m2; level 2: X 2,250 mg/m2/d, D 60 mg/m2; level 3: X 2,250 mg/m2/d, D 75 mg/m2; level 4: X 2,500 mg/m2/d, D 75 mg/m2. The cycle was repeated every 3 weeks. The phase II study was planned at the dose level just below the MTD in pts with measurable disease. RESULTS During 1st cycle, 1 DLT (neutropenic fever) among 6 pts at dose level 2 and 2 DLTs (asthenia) among 3 pts at dose level 4 were observed. During 2nd cycle, 2 DLTs were experienced among the 6 pts at dose level 3, which made the dose level 3 as MTD and the subsequent phase II study was begun at dose level 2. After total 17 pts were treated at dose level 2, frequent need for dose reduction made further phase II study performed at dose level 1. Total 40 pts with measurable disease, treated at dose level 1 (23) and 2 (17) were evaluated for phase II portion of the study. Four pts were not evaluable for response because of follow-up loss after 1 cycle of chemotherapy. After median 6 cycles of chemotherapy, there were 4 confirmed CRs and 23 confirmed PRs, with the overall response rate of 67.5% (95% C.I.: 52.7 - 82.3) in intention-to-treat analysis. There was no difference in response rate between the two dose levels. Ten pts underwent surgical resection after clinical response with 4 - 9 cycles of chemotherapy. Four pathologic CRs were identified. With a median follow-up of 14 mo. (range 1 to 28), median time to progression was 7.7 mo. (95% C.I.: 6.9 - 8.5), and median overall survival has not been reached. CONCLUSIONS Asthenia and neutropenia were DLTs in this DXP combination. The dose of D (60 mg/m2, D1), X (1,875 mg/m2/D, D1-14), and P (60 mg/m2, D1) was recommended for the 3 weekly DXP combination. The DXP chemotherapy was highly active and tolerable for the 1st line chemotherapy of AGC. [Table: see text].

Prognostic factors and recurrence pattern in node-negative advanced gastric cancer

AIMS Despite better overall survival in node-negative advanced gastric cancer (AGC), a significant proportion of patients develop recurrence and they may benefit from adjuvant therapy. The aim of this study was to evaluate the prognostic factors and recurrence pattern of node-negative AGC. METHODS A total of 424 patients who underwent curative gastrectomy with extended lymphadenectomy for node-negative AGC between 2003 and 2005 were retrospectively reviewed. Patients with tumor involvement of adjacent organs (T4b), gastric cancer recurrence, tumor in the remnant stomach, less than 15 harvested lymph nodes, and those who received neoadjuvant chemotherapy were excluded. RESULTS Invasion to deeper layers, undifferentiated histology, signet ring cell type compared with tubular adenocarcinoma, and tumor size larger than 6.3 cm correlated with poorer prognosis in univariate analysis. In multivariate one, however, only differentiation and depth of invasion, especially the presence of serosa involvement were significant. The 5-year survival rates of the four groups classified by differentiation and depth of invasion [T2/3 (differentiated type), T2/3 (undifferentiated type), T4a (differentiated type), and T4a (undifferentiated type)] were 98%, 92%, 80%, and 72%, respectively (P < 0.01). In terms of recurrence pattern, Laurens type and depth of invasion were significant. Recurrence with peritoneal seeding was associated with the diffuse type and invasion into the subserosa or serosa, while hematogenous metastasis was related to the intestinal type and invasion to the proper muscle or subserosa layer. CONCLUSIONS Differentiation and serosa involvement should be considered to stratify patients with node-negative AGC for adjuvant treatment.

Differing Clinical Courses and Prognoses in Patients With Gastric Neuroendocrine Tumors Based on the 2010-WHO Classification Scheme

AbstractThe aim of this study is to test the prognostic accuracy of the 2010-WHO classification for postsurgery survival in nonmetastatic gastric neuroendocrine tumor (NET) cases. Whether the 2010-WHO classification of NETs can predict relapse after surgical resection has not yet been established.We selected 175 nonmetastatic gastric NET patients at Asan Medical Center, Seoul, Korea between 1996 and 2013. All tumors were classified using the WHO-2010 scheme.Among 175 patients with gastric NETs, we diagnosed 39 cases as WHO grade 1, 13 cases as grade 2, 66 cases as grade 3 (neuroendocrine carcinomas; NECs), and 57 cases as mixed with adenocarcinoma. Patients with grade 3 had a lower relapse-free survival (RFS) and overall survival (OS) than those with WHO grade 1/2 and had a lower OS than patients with mixed type tumors. Patients with grade 1/2 had a better OS than patients with mixed type. There was no significant difference in RFS and OS between small and large cell type lesions. Among WHO grade 1/2 patients with ⩽1 cm sized lesions, none exhibited lympho-vascular, perineural, mucosal, or submucosal invasion, and we detected no lymph node metastases or recurrences.Our findings strongly suggest that WHO grade 3 behaves more aggressively than adenocarcinoma. Additionally, the survival of cases with large and small cell NEC was similar. Among WHO grade 1/2 patients who had ⩽1 cm lesions, none exhibited lympho-vascular, perineural, mucosal, or submucosal invasion and all could be treated by endoscopic resection or minimally invasive surgery without node dissection.

Serum CA 19-9 as a prognostic factor in patients with metastatic gastric cancer.

To evaluate tumor markers as prognostic factors in patients with metastatic or recurrent gastric cancer receiving first‐line chemotherapy.

Modified radical lymphadenectomy without splenectomy in patients with proximal gastric cancer: Comparison with standard D2 lymphadenectomy for distal gastric cancer

We assessed the optimal extent of lymph node dissection and the effect of splenectomy in patients with proximal gastric cancer.

Predictors of recurrence after resection of small gastric gastrointestinal stromal tumors of 5 cm or less.

Goals To evaluate the recurrence predicting factors of small gastric gastrointestinal stromal tumors (GISTs) through the long-term follow-up after surgical/endoscopic resection. Background Although small gastric GISTs are known to have a low risk of recurrence after complete resection, the prognostic factors are not well known. Study The study retrospectively analyzed the records of 136 patients with primary gastric GISTs of 5 cm or less without metastasis who underwent surgical/endoscopic resection between March 1997 and December 2008 at the Asan Medical Center, and who were followed-up for at least 3 months after resection. Specimens were assessed for tumor size, mitotic index, and microscopic resection margin. Specimen sections were immunohistochemically stained to determine the levels of expression of the cell cycle proteins p53, p16INK4, pRb, cyclin D1, and Ki-67. DNA was extracted from high-risk tumors to analyze for KIT mutations. Results Among 136 patients, 5 (3.7%) patients with tumors with a high mitotic index showed recurrence at a median 23 months post resection. None of 14 patients with microscopic positive resection margins showed recurrence during a median follow-up time of 32 months. A high mitotic index was a predictor of recurrence (P<0.001), but that tumor size, method of resection, or margin status were not. In addition, abnormal p53 expression was found to be associated with recurrence (P=0.004). All assessable high-risk tumors had a KIT exon 11 mutation. Conclusions Predictors of recurrence of gastric GISTs of 5 cm or less were a high mitotic index and abnormal p53 expression. A positive microscopic resection margin was not associated with recurrence.

PDGFRα Gene Mutation and Protein Expression in Gastrointestinal Stromal Tumors

Objective: Mutation of the PDGFRα is a potential candidate in the pathogenesis of KIT wild-type gastrointestinal tumors (GISTs). In this study, we evaluated the prevalence of PDGFRα mutations and corresponding protein expression in GISTs, to determine their usefulness in obtaining a prognosis. Methods: Genomic DNA was extracted from paraffin-embedded tumor tissues from 194 GISTs. Exons 12, 14 and 18 of the PDGFRα were amplified and sequenced. Immunohistochemical staining was performed in 179 patients. Results: Mutations in the PDGFRα were detected in 6 (3.1%) patients, and were observed solely in KIT wild-type GISTs. Among the 6 patients with PDGFRα gene mutations, 5 patients with localized GISTs showed no relapse after resection during the 19- to 80-month follow-up period. Intensity of PDGFRα expression was classified as 0 in 26 (14.5%), 1+ in 69 (38.5%), 2+ in 71 (39.7%) and 3+ in 13 (7.3%) patients. Levels of PDGFRα expression showed no correlation with relapse-free survival. Conclusion:PDGFRα mutations in GISTs were found to be rare in this Korean population. Although localized GISTs with PDGFRα mutations showed relatively good prognosis after resection, the difference was not statistically significant.