Geir Hoff, Department of Research and Development, Telemark Hospital, 3710 Skien, Norway.
World J Gastroenterol. 2013 Dec 14;19(46):8527-30. doi: 10.3748/wjg.v19.i46.8527.
Less than 5% of colorectal adenomas will become malignant, but we do not have sufficient knowledge about their natural course to target removal of these 5% only. Thus, 95% of polypectomies are a waste of time exposing patients to a small risk of complications. Recently, a new type of polyps, sessile serrated polyps, has attracted attention. Previously considered innocuous, they are now found to have molecular similarities to cancer and some guidelines recommend to have them removed. These lesions are often flat, covered by mucous, not easily seen and situated in the proximal colon where the bowel wall is thinner. Thus, polypectomy carries a higher risk of perforation than predominantly left-sided, stalked adenomas - and we do not know what is gained in terms of cancer prevention. Screening is a neat balance between harms and benefit for presumptively healthy participants not interested in risk exposure to obtain confirmation of being healthy. The situation is quite different for patient worried about symptom. Thus, the standards set for evidence-based practice may be higher for screening than for routine clinics - a mechanism which may benefit patients in the long run.
不到 5%的结直肠腺瘤会恶变，但我们对其自然病程的了解还不够充分，无法仅针对这 5%进行有针对性的切除。因此，95%的息肉切除术都是在浪费时间，使患者面临微小的并发症风险。最近，一种新型息肉——无蒂锯齿状息肉引起了人们的关注。这些息肉以前被认为是无害的，但现在发现它们与癌症具有分子相似性，一些指南建议将其切除。这些病变通常是平坦的，被黏膜覆盖，不易被发现，位于近端结肠，肠壁较薄。因此，与主要位于左侧、有蒂的腺瘤相比，息肉切除术穿孔的风险更高——而且我们不知道在预防癌症方面有什么收获。筛查是一种在对风险暴露不感兴趣的假定健康参与者之间进行的、权衡利弊的行为，目的是为了确认他们的健康状况。对于担心症状的患者来说，情况就大不相同了。因此，基于证据的实践标准可能比常规临床实践更高——从长远来看，这一机制可能使患者受益。
