Preventing and Diagnosing Colorectal Cancer with a Limited Colonoscopy Resource

This paper explores how the capacity of colonoscopy services should be allocated for screening and diagnosis of colorectal cancer to improve health outcomes. Both of these services are important since screening prevents cancer by removing polyps, while diagnosis is required to start treatment for cancer. This paper first presents a basic compartmental model to illustrate the trade‐off between these two analytically. Further, a more realistic population dynamics model with resource constraints is introduced for colorectal cancer screening and analyzed numerically. The best resource allocation decisions are investigated with the objectives of minimizing mortality or incidence rates. We provide a sensitivity analysis with respect to policy and disease‐related parameters. We conclude that to minimize mortality, the capacity should be rationed to ensure that the wait for diagnosis is at reasonable levels. When the relevant performance measure is the incidence rate, screening is allocated more capacity compared to the case with mortality rate measure. We also show that benefits from increasing compliance to screening programs can only be realized if there is sufficient service capacity.     

17例中老年人缺血性结肠炎的临床回顾分析

目的总结缺血性结肠炎的临床及内镜特征。方法回顾性分析2006年至2009年间17例缺血性结肠炎患者的临床诊治经过及内镜特征。结果本病多发生于50岁以上中老年人(16/17,94.1%),女性多见(男:女为1:2.7),且多数患者(83.3%)伴有心脑血管疾病、糖尿病、便秘及腹部手术史等基础疾病或诱因。临床主要表现为突发左下腹疼痛、便血、腹泻三联征。病变部位主要发生在左半结肠,内镜下表现为与正常粘膜界限分明的结肠粘膜水肿、充血、糜烂、溃疡及增生性改变,病变多为一过型,如能早期诊断与治疗,多数预后良好。结论中老年人出现急性腹痛及便血时应警惕缺血性结肠炎的可能,早期诊断和治疗是预后良好的关键。