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Large polyps: strangle or blanch them, but do something ▸
Bleeding is not uncommon after polypectomy, yet strategies for minimising bleeding risk are unclear and comparative studies of different methods are few and far between. The authors randomised 488 patients undergoing removal of pedunculated polyps to either placement of a detachable nylon snare (Endoloop), injection of 0.01% epinephrine into the stalk before polypectomy, or snare polypectomy alone (control group). All patients were hospitalised for 24 hours to monitor for early bleeding and followed for 30 days to detect delayed bleeding. Twenty one patients (4.3%) had bleeding and the mean size of bleeding polyps was 29.7 (4) mm, with early bleeding accounting for 15 of these cases. Bleeding episodes were more common in the control group (13) compared with three in the Endoloop group and five in the epinephrine group but this was not statistically significant. When subanalysed however, both Endoloop (2 (2.7%)) and epinephrine injection (2 (2.9%)) significantly reduced bleeding from polyps >2 cm compared with the control group (66 (15.1%)), and both treatment modalities were equally effective. While no substitute for careful patient selection, recognition of lesions at high risk and good diathermy technique, technically simple preventive measures, can significantly reduce bleeding following removal of large polyps. Whether endoscopic clips will be equally or more effective remains to be seen.
Living with lamivudine ▸
Approximately 40% of Asian men with chronic hepatitis B die of either hepatocellular carcinoma or other complications of cirrhosis. Lamivudine is a well tolerated antiviral drug which could suppress viral replication. However, long term therapy with lamivudine leads to emergence of resistant YMDD mutations which in turn could lead to liver failure, especially in those with already advanced fibrosis.
Liaw et al randomly assigned 651 patients (85% male) with chronic hepatitis B and advanced fibrosis (Ishak score 4 or more) to receive lamivudine (100 mg per day) or placebo in a 2:1 ratio. Of 651 patients, 217 had cirrhosis. After a median duration of treatment of 32.4 months, 17.7% in the placebo group and 7.8% of those receiving lamivudine showed evidence of disease progression or developed complications of cirrhosis (hazard ratio for disease progression 0.45; p = 0.001). Hepatocellular carcinoma developed in 3.9% in the lamivudine group and in 7.4% in the placebo group (p = 0.047). YMDD mutation developed in 49% of those treated with lamivudine. Child-Pugh score increased in 7% of those with YMDD mutation compared with less than 1% of those without the mutation. Lamivudine therapy was well tolerated.
This study establishes the safety and effectiveness of lamivudine therapy in patients with chronic hepatitis B and advanced fibrosis as well as its role in preventing the development of hepatocellular carcinoma. The emergence of YMDD mutation reduces the benefit of lamivudine, as expected from the revival of viral replication, but does not negate it (within the period of the study). Evolving strategies of treating drug resistant strains would be the challenge for the future.
Do colonoscopists have tunnel vision? ▸
The introduction of colorectal cancer screening with either faecal occult blood testing or flexible sigmoidoscopy will increase the demand for colonoscopy. This is regarded as the gold standard test for detecting colorectal cancer and adenomatous polyps. The accuracy of colonoscopy however is uncertain as until recently there was no adequate test to act as a reference standard. Pickhardt et al describe an elegant study comparing the results of conventional colonoscopy with virtual colonoscopy (VC) on the same day in 1233 asymptomatic adults. The colonoscopist was unaware of the VC diagnosis but if a polyp was missed, the segment was re-examined with VC images for guidance. The study found that 55/511 (10.8%) of all polyps and 6/51 (11.8%) adenomatous polyps greater than 10 mm were missed by conventional colonoscopy. Most of the polyps missed were located on a fold or were within 10 cm of the anal verge. The results are likely to be worse in clinical practice as the caecal intubation rate in the study was 99.4% compared with an average of 57% in the UK. There are two major implications of this study. Firstly, we need to improve colonoscopy training to minimise missed lesions. Secondly, patients must not be given unrealistic expectations of the performance of the test during consent for the procedure.
Stent it to prevent it! ▸
Post-procedure pancreatitis can be a devastating complication of endoscopic retrograde cholangiopancreatography (ERCP). Endoscopic placement of pancreatic stents is a relatively new approach to reduce the risk of pancreatitis following the procedure. Although the mechanism of action is not clearly understood, in theory, stents preserve the flow of pancreatic juice after instrumentation of the pancreatic duct, so reducing the accumulation of radiographic contrast medium and pancreatic juices within the pancreatic duct. This paper usefully reviews the literature on this subject. A meta-analysis of five prospective studies involving 483 patients has shown the chances of post-ERCP pancreatitis without stents to be threefold higher than with the use of stents (15.5% v 5.8%).
Interestingly, the risk of severe or necrotising pancreatitis was virtually eliminated by properly positioned pancreatic stents. Only a short stent appears to be necessary. In all of the reported studies, including approximately 1500 high risk ERCPs, only one case of severe pancreatitis was reported in a patient receiving a pancreatic stent. By meta-analysis the odds of developing severe pancreatitis were found to be 11.5 times lower in patients receiving pancreatic stents. While pancreatic stent placement appears to have revolutionised the reduction of post-ERCP pancreatitis in some American centres, it is still difficult to decide which individual patients and procedures are at sufficiently high risk to warrant stent usage. Further studies are clearly necessary.
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