复旦大学公共卫生学院：《预防医学英文班（Preventive Medicine I）》参考讲义_8 - Strategies for early detection of disease（Secondary Prevention）

http://www.premed.fudan.edu.cn 国家精品课程 探 创 Preventive Medici Secondary Prevention 倾 Sha tao Department of Preventive Medicine, School of Public Health, Fudan University

Department of Preventive Medicine, School of Public Health, Fudan University http://www.premed.fudan.edu.cn 国 家 精 品 课 程 探 索 倾 听 思 考 创 新 Secondary Prevention Sha Tao

outline What is secondary prevention and screening What are the principles of screening Potential bias for screening analyses e US Preventive Services Task Force o Recommendations for screening 8 March 2018 2/80

8 March 2018 2/80 Outline  What is secondary prevention and screening  What are the principles of screening  Potential bias for screening analyses  US Preventive Services Task Force  Recommendations for screening

oI What is Secondary Prevention o Secondary prevention is concerned with early detection of disease through either screening or case finding followed by treatment Pre-clinical phase Clinical phase Onset of Onset of Early symptoms Exposure disease detection and/or signs D, Cure A B D, disability D Death Primary Secondary Tertiary prevention prevention prevention 8 March 2018 3/80

8 March 2018 3/80 What is Secondary Prevention  Secondary Prevention is concerned with early detection of disease, through either screening or case finding, followed by treatment

3州 What is Screening EA RCH Screening is the testing of apparently healthy populations to identify previously undiagnosed diseases or people at high risk of developing a disease o Screening aims to detect early disease before it becomes symptomatic Screening is an important aspect of prevention, but not all diseases are suitable for screenin 8 March 2018 4/80

8 March 2018 4/80 What is Screening  Screening is the testing of apparently healthy populations to identify previously undiagnosed diseases or people at high risk of developing a disease.  Screening aims to detect early disease before it becomes symptomatic.  Screening is an important aspect of prevention, but not all diseases are suitable for screening

i The Principles of Screening The choice of disease for which to Disease screen Test The nature of the screening test or tests to be used R Treatment o The availability of a treatment for those found to have the disease ?s Cost The relative costs of the screening Programm 8 March 2018 5/80

8 March 2018 5/80 The Principles of Screening  The choice of disease for which to screen;  The nature of the screening test or tests to be used;  The availability of a treatment for those found to have the disease;  The relative costs of the screening

The Principles of Screening The condition should be an important health problem There should be a latent stage of the disease Disease The natural history of the disease should be adequately Test There should be a test or examination for the condition The test should be acceptable to the population There should be a treatment for the condition R Treatment Facilities for diagnosis and treatment should be available There should be an agreed policy on whom to treat ?s Cost The total cost of finding a case should be economicall balanced in relation to medical expenditure as a whole Case-finding should be a continuous process, not just a"once pRogramm and for all "pre 8 March 2018 6/80

8 March 2018 6/80 The Principles of Screening – The condition should be an important health problem. – There should be a latent stage of the disease. – The natural history of the disease should be adequately understood. – There should be a test or examination for the condition. – The test should be acceptable to the population. – There should be a treatment for the condition. – Facilities for diagnosis and treatment should be available. – There should be an agreed policy on whom to treat. – The total cost of finding a case should be economically balanced in relation to medical expenditure as a whole. – Case-finding should be a continuous process, not just a "once and for all" project

十Ds sease The disease must be an important health problem o There should be a recognizable latent or early symptomatic stage The natural history of the disease, including latent to declared disease, should be adequately understood o Facilities for diagnosis and treatment should be available o There should be a test or examination for the condition and the test should be acceptable to the population 8 March 2018 7/80

8 March 2018 7/80  The disease must be an important health problem.  There should be a recognizable latent or early symptomatic stage.  The natural history of the disease, including latent to declared disease, should be adequately understood.  Facilities for diagnosis and treatment should be available.  There should be a test or examination for the condition and the test should be acceptable to the population

A suitable disease for screening ◆Why? 8 March 2018 8/80

8 March 2018 8/80  A suitable disease for screening  Why?

i Colorectal Cancer 9 CRC is the third leading cause of cancer death worldwide o a slow progression from detectable and curable precancerous lesions, advanced adenoma o 5 years survival rate depends on the stage at diagnosis StageI>90% Stage II 70-85% Stage Ill 25-65% Stage Iv<10% 8 March 2018 9/80

8 March 2018 9/80 Colorectal Cancer  CRC is the third leading cause of cancer death worldwide  A slow progression from detectable and curable precancerous lesions, advanced adenoma  5 years survival rate depends on the stage at diagnosis – Stage I > 90 % – Stage II 70-85% – Stage III 25-65% – Stage IV < 10%

Lead time bias Clinical Onset of B detectable diagnosis dIsease p symptoms Lead time Benefit Earl Death diagnosis Screening 8 March 2018 10/80

8 March 2018 10/80 Lead time bias Onset of disease Begin detectable phase Clinical diagnosis symptoms Early diagnosis Death Death Lead time survival Benefit Screening