Usefulness of Self-expandable Metallic Stents for Malignant Colon Obstruction

PURPOSE: Treatment for malignant colonic obstruction consists of a multiple-staged emergency operation. In recent years, some authors have reported low morbidity and mortality rates using self-expandable metallic stents. This study is designed to evaluate the usefulness of self-expandable metallic stents in patients with malignant colonic obstruction. METHODS: The records of 38 patients who had undergone surgery for malignant colonic obstruction at our institution between January 2004 and August 2006 were reviewed retrospectively. Seventeen patients were treated with elective surgery after stent insertion, bowel decompression, and bowel preparation (stent group), and 21 patients were treated with emergency surgery without stent insertion (control group). RESULTS: There were no significant differences in age, sex, tumor node metastasis (TNM) stage, or cancer position between the two groups (elective operation after stent insertion vs. emergency operation). Of the 17 patients who underwent elective operation after stent insertion, primary anastomosis was possible in 15 (88.2 vs. 57.1% in the control group), with a lower need for a colostomy (11.8 vs. 42.9% in the control group, P=0.036). Also, the number of patients with severe complications (17.6 vs. 47.6% in the control group, P=0.048) and the hospital stay (10.82 vs. 13.43 days in the control group, P=0.032) were significantly lower in the study group. CONCLUSION: Placement of a self-expandable metallic stent for malignant colonic obstruction is a safe and effective procedure. It can reduce the colostomy, mortality, and morbidity rates and the hospital fee for treatment.

Aberrant Promoter Methylation Profile in Low and High Grade Gastric Lymphomas

PURPOSE: Malignant lymphoma arising from mucosa-associated lymphoid tissue (MALT) accounts for a large proportion of a extranodal lymphomas. The stomach is the preferential site of MALT lymphoma, and the pathogenesis of a gastric MALT lymphoma is known to be closely related to Helicobacter pylori infection. Epigenetic silencing of tumor- related genes due to CpG island methylation, has recently been reported in B cell lymphomas, but its role in gastric lymphomas is unclear. METHODS: We analyzed the methylation status of cell cycle control (p16), apoptosis regulation (Death-associated protein kinase, DAPK) and DNA mismatch repair (MGMT, hMLH1, and hMSH3) genes using a methylation-specific polymerase chain reaction in 46 low- and high-grade gastric lymphomas, pathologically documented at Chonnam National University Hospital, between January 1999 and August 2004. RESULTS: Methylation of p16, DAPK, and MGMT was more frequent in the high- than in the low-grade lymphomas (80, 80 and 93 vs. 71, 74 and 84%, respectively). Methylation of hMLH1 and hMSH3 was rare or absent. There was no difference in frequencies of CIMP between the low- and high-grade gastric lymphomas. Of the 46 gastric lymphoma cases, compared with matched normal gastric mucosa, five had an MSI-low phenotype, with two and three in the low- and high-grade lymphomas, respectively. CONCLUSION: Methylation of p16, DAPK, and MGMT may represent a major pathogenetic event in gastric lymphomas, which may contribute to the early tumorigenesis and have clinical applications in the management and follow-up of low and high grade gastric lymphomas.