论文部分内容阅读
在致癌物暴露和癌症发展的进程中,人体的生物学证据可以用中间终点来反映。这种终点有的象大肠息肉的形式,是一个独立终点;有的象上皮细胞增殖率一样是量变终点。因为癌症发展慢、发生相对稀少,研究可疑致癌因素与癌的关系,要求有大量的观察对象并长期随访。然而,应用中间终点比用肿瘤本身能更早地评估。另外,某些独立终点往往比癌更多见,能使研究工作快速、小样本和省钱。如饮食与血清雌二醇或大肠上皮细胞增殖关系的研究,只需用几十个观察对象、为期数月即可,但以大肠癌或乳腺癌为终点指标的营养干预研究,要求数千研究对象并随访5年以上。
In the process of carcinogen exposure and cancer progression, biological evidence of the human body can be reflected by the intermediate endpoint. Some of these endpoints, like those in the form of large intestine polyps, are an independent end point; some, like the proliferation rate of epithelial cells, are the end points of quantitative changes. Because of the slow development of cancer and the relatively rare occurrence of cancer, the study of the relationship between suspected carcinogenic factors and cancer requires a large number of observations and long-term follow-up. However, the use of intermediate endpoints can be assessed earlier than using the tumor itself. In addition, some independent endpoints tend to be more common than cancer, enabling rapid, small sample, and cost-saving research. Studies on the relationship between diets and the proliferation of serum estradiol or colonic epithelial cells require only dozens of observations for several months, but nutritional intervention studies using colorectal cancer or breast cancer as end points require thousands of studies. Subjects were followed up for more than 5 years.