Lush D T
Division of General Medicine, Medical College of Pennsylvania, Philadelphia 19129.
Postgrad Med. 1994 Jul;96(1):99-106.
The goal of screening for colorectal cancer is to find early, asymptomatic cancers and adenomatous polyps that are 1 cm or more in diameter or that are villous or tubulovillous histologically. A study using fecal occult blood testing with rehydration and no sigmoidoscopy found that deaths from colorectal cancer can be reduced by screening. Although this protocol is effective in screening, whether it is the optimal approach remains to be determined. Flexible sigmoidoscopy as a screening method has not been studied, except in nonrandomized tests. However, since endoscopic diagnosis and treatment is ultimately the means by which benefits from fecal occult blood testing are realized and since flexible sigmoidoscopy visualizes more than half of colon cancers and colon polyps, it seems logical that this method would be an effective screening test. Whether doing both rehydrated fecal occult blood testing and flexible sigmoidoscopy enhances results is unknown. It seems appropriate to use the rehydration method when fecal occult blood testing is done and flexible sigmoidoscopy when endoscopy is done. Fecal occult blood testing should precede sigmoidoscopy so that patients with a positive result can go directly to colonoscopy and avoid two procedures.
结直肠癌筛查的目标是发现早期无症状癌症以及直径1厘米或更大、组织学上为绒毛状或管状绒毛状的腺瘤性息肉。一项使用粪便潜血试验并进行补液且未进行乙状结肠镜检查的研究发现，通过筛查可降低结直肠癌的死亡率。尽管该方案在筛查中有效，但它是否为最佳方法仍有待确定。除了非随机试验外，尚未对乙状结肠镜检查作为一种筛查方法进行研究。然而，由于内镜诊断和治疗最终是实现粪便潜血试验益处的手段，且由于乙状结肠镜检查能观察到一半以上的结肠癌和结肠息肉，所以这种方法似乎是一种有效的筛查测试，这是合乎逻辑的。同时进行补液粪便潜血试验和乙状结肠镜检查是否能提高筛查效果尚不清楚。进行粪便潜血试验时采用补液方法、进行内镜检查时采用乙状结肠镜检查似乎是合适的。粪便潜血试验应先于乙状结肠镜检查，以便检测结果呈阳性的患者可直接进行结肠镜检查，避免进行两项检查。
