Cancer screening: indications, benefits and myths

Transcription

1 Cancer screening: indications, benefits and myths Silvia Deandrea Institute for Health and Consumer Protection Public Health Policy Support Unit Healthcare Quality Team Joint Research Centre The European Commission s in-house science service Disclaimer: The contents of this presentation are the views of the author and do not necessarily represent an official position of the European Commission. European Union, 2013

2 What we talk about when we talk about cancer screening? cit. Raymond Carver

3 Cancer screening myth #1 "Breast cancer screening is when you make an appointment with your doctor once a year for mammography and clinical breast examination"

4 Screening definition Systematic application of a screening test in a presumably asymptomatic population It aims to identify individuals with an abnormality suggestive of a specific cancer These individuals require further investigation WHO,

5 Screening & friends Early diagnosis is the awareness (by the public or health professionals) of early signs and symptoms of cancer in order to facilitate diagnosis before the disease becomes advanced. This enables more effective and simpler therapy. Opportunistic screening is the unsystematic application of screening tests in routine health services. WHO,

6 The screening process Source: Australia Health Minister's Advisory Council, Population-based screening framework,

7 Cancer screening in Europe - Council recommendation of 2 December 2003 on cancer screening The screening tests listed in the Annex (=pap smear yrs; mammography yrs; fecal occult blood test yrs) can only be offered on a population basis in organised screening programmes with quality assurance at all levels [ ] Source: Report of a European survey on the organisation of breast cancer care services, in press 7

8 Cancer screening myth #2 "Giving to all people the opportunity to get free medical check-ups in order to find cancers at an early stage would be great!"

9 General principles for the introduction of screening for a given malignancy 1. The disease should be an important health problem. 2. The disease should have a detectable preclinical phase. 3. The natural history of the disease should be known. 4. The disease and the lesions recognised by the screening test should be treatable. 5. The screening test should be effective, acceptable, and safe. 6. There should be healthcare facilities able to treat every cancer diagnosed Segnan et al., modified 9

10 Cancers & tests for screening Cancer sites recommended for population-based programmes: 1. Cervical cancer (pap smear, in combination with HPV testing) 2. Colorectal cancer (fecal occult blood test, flexible sigmoidoscopy, colonoscopy) 3. Breast cancer (mammography) Cancers for which screening is of uncertain or debated benefit: 1. Lung cancer (CT scan) 2. Skin cancer (skin examination) Cancers for which routine early diagnosis activities are not recommended: 1. Prostate cancer (PSA) 2. Pancreatic cancer 3. Ovarian cancer 4. Testicular cancer Source: EU Council Recommendations, USPTF Recommendations 10

11 Cancers & tests for screening Cancer sites recommended for population-based programmes: 1. Cervical cancer (pap smear, in combination with HPV testing) 2. Colorectal cancer (fecal occult blood test, flexible sigmoidoscopy, colonoscopy) 3. Breast cancer (mammography) IMPORTANT: any kind of screening can be unbeneficial or even harmful if done outside the suggested are range and/or with the wrong periodicity Cancers for which screening is of uncertain or debated benefit: 1. Lung cancer (CT scan) 2. Skin cancer (skin examination) Cancers for which routine early diagnosis activities are not recommended: 1. Prostate cancer (PSA) 2. Pancreatic cancer 3. Ovarian cancer 4. Testicular cancer Source: EU Council Recommendations, USPTF Recommendations 11

12 Cancer screening myth #3 "Screening prevents cancer"

13 Is screening really preventing cancer? YES for cervical and colorectal cancer screening: pre-cancer lesions are detected and less cancer cases will occur in the screened population NO for breast cancer (and other cancer sites) For the cancer sites for which screening is effective (i.e. it reduces mortality) and recommended, to be screened can help in "preventing" the cause-specific death and the consequences of a diagnosis in a late disease stage 13

14 Cancer screening myth #4 and myth #5 #4: "Mammography saves lives. We should provide an annual mammography (plus ultrasound plus clinical breast examination plus ) to all women from age 35" #5: "Mammography does not save lives. It is harmful because it increases breast cancer incidence. Breast cancer screening programmes should be stopped"

15 What is the truth? 15

16 What is the truth? Courtesy of Livia Giordano 16

17 Breast cancer screening: a delicate balance of benefits and risks BENEFITS Mortality reduction (uncertainty in estimates) Breast cancer can be diagnosed in a less advanced stage, that usually requires a less invasive treatment RISKS Breast cancer screening can detect breast cancer cases that would have never become life-threatening ("overdiagnosis" - uncertainty in estimates) False positive and false negative test results can happen 17 Exposure to X-rays during the test (not as relevant as for other diagnostic tests)

18 Transparent and balanced information is crucial 18

19 Conclusions Screening should be offered only for cancers for which a sustainable benefit-risk balance is demonstrated Screening should be provided in organised and quality-assured programmes A transparent and balanced communication strategy to the population is a must Enhancing benefits and reducing harms is the main goal of cancer screening research 19

20 Thank You for Your Attention Disclaimer: The contents of this presentation are the views of the author and do not necessarily represent an official position of the European Commission. European Union, 2013