队列研究在肿瘤预防和预后评估中不可替代的作用

Indispensability of cohort study in tumor prevention and prognosis assessment

恶性肿瘤是人类死亡的主要原因之一，早期诊断和及时治疗普遍被认为是降低病死率的关键。然而，由于肿瘤异质性等生物学原因和利益驱动等社会因素，肿瘤诊治实践中存在过度诊断和过度治疗问题。避免过度诊断和过度治疗的关键在于鉴别何种癌前病变能够进展成为恶性肿瘤，何种早期肿瘤能够进展为侵袭性癌症，哪些预防、治疗措施能够使患者生存获益，这些均需通过流行病学队列研究进行准确评估。队列研究是明确暴露因素（干预因素）与癌症发生发展之间存在因果关系最可靠的方法，并且能够为癌症的筛查和治疗指明方向。通过队列研究，研究者不但可以明确具有恶性转化潜能的癌症类型，开展更有针对性的人群筛检，而且还可以准确判断临床治疗对改善患者预后的客观作用，纠正传统的临床经验导向。因此，在肿瘤的研究中，流行病学队列研究是不可或缺的重要环节。

Cancer is one of the major causes of human death. Early diagnosis and treatment are widely believed to be important in decreasing cancer mortality rate. However, biological factors （such as tumor heterogeneity） and social factors （such as profits driving）, over-diagnosis and over-treatment exist in the practice of cancer diagnosis and treatment. The keys to avoid such issues are to identify what kinds of precancerous lesions are more likely to progress into malignant tumors, what kind of early cancer are prone to invading surrounding tissues, and what kinds of prophylactic and therapeutic options are of benefit to effective survival of patients. All above need to be accurately evaluated by cohort studies. Cohort study is the most reliable method to crystallize causal relationship of the exposures （interventions） with the development and recurrence of cancers and define the directions of cancer screening and therapy. Cohort studies shed light on the prediction, screening, and active prophylaxis for the occurrence and recurrence of cancers with specific types. Moreover, the prognostic effects of a given clinical treatment can be precisely evaluated in cohort study, rather than experience-directed clinical activity. Therefore, cohort study is indispensable for cancer research.