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Lung cancer screening 3
The study evaluated annual low-dose helical CT screening versus standard chest x-ray for lung cancer screening in high-risk individuals aged 55-74 years who were heavy smokers. Over 53,000 participants were randomized across 33 sites in the U.S. The trial was stopped early based on a recommendation when interim results found a 20% reduction in lung cancer mortality with CT screening. CT screening found more positive cases but also had higher false positive rates compared to chest x-ray.
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Lung cancer screening 3
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- 2. ¨ High risk population ¡ Heavy smoker or former smoker (quit within last 15 years) ú Smoked 30 pack years equivalent to 1 pack /day x 30 years ¡ Age: 55 to 74 years ¨ Randomized to: ¡ low-dose helical CT OR ¡ standard chest X-ray ¨ Duration: yearly x 3 years and follow up for 5 years ¨ Positive cases are further verified ¨ Endpoint: death from lung cancer
- 3. Process and outcomesin the NLST. Radiology doi:10.1148/radiol.10091808 ©2010 by Radiological Society of North America
- 4. ¨ Started 2002 ¨ Accrued 53 000 in 33 sites in USA over 20 months ¨ DSMB stopped the trial in October 2010
- 5. Spiral CT Chest xray P Numbers 26500 26500 No of cases ? ? Lung cancer mortality 354 442 <0.05 RR of lung cancer death 0.8 (20% lower) 1 All-cause mortality 7% lower Positive findings on imaging during study 24% 7% False positives 95-98% 93-96% Compliance 91%
- 8. ¨ Primary Prevention: ¡ Prevent initial disease occurrence ¨ Secondary Prevention: ¡ Detect the disease early in the asymptomatic stage ¨ Tertiary Prevention: ¡ Prevent re-occurrence and complications and disability and improve QOL
- 10. ¨ High risk groups: ¡ Heavy cigarette smokers ¨ Asymptomatic
- 11. ¨ Primary Prevention: ú Anti-smoking measures bilat mastectomy ú HBV vaccination ú HPV vaccination ¨ Secondary Prevention: ú Breast cancer screening ú HCC screening ¨ Tertiary Prevention: ú Proper treatments ú Adj Tam in breast cancer
- 12. Lung cancer ¨ Clinical exam: X ¡ BSE, CBE ¡ DRE ¨ Lab tests: X ¡ Serum biomarkers: ú PSA ú AFP ¡ Cytology ¨ Radiology: YES ¡ Mammography - Chest X-ray XXXX ¡ TRUS - CT chest ¡ ABD US - MRI? ¨ Other: XXX ¡ Colonoscpoy - Bronchoscopy
- 14. A. Conventional B. Spiral (low dose helical): ¡ scans the entire chest in about 7-15 seconds during a single, breath-hold. The CT scanner rotates around the person, who is lying still on a table as the table passes through the center of the scanner.
- 20. ¨ Lead time bias ¨ Length bias ¨ Overdiagnosis bias
- 21. ¨ Survival is the time from Diagnosis to death ¨ It is longer if cancer is detected early by screening ¨ Lead time= screening survival – symptom survival ¨ To avoid it measure mortality
- 22. ¨ Indolent cancers have long preclinical phase and more amenable to early detection
- 23. ¨ Diagnosis and treatment of non-fatal disease
- 24. ¨ High risk population ¡ Heavy smoker or former smoker (quit within last 15 years) ¡ Age: 55 to 74 years ¨ Randomized to: ¡ low-dose helical CT OR ¡ standard chest X-ray ¨ Duration: yearly x 3 years and follow up for 5 years ¨ Positive cases are further verified ¨ Endpoint: death from lung cancer
- 25. Process and outcomesin the NLST. Radiology doi:10.1148/radiol.10091808 ©2010 by Radiological Society of North America
- 26. ¨ Started 2002 ¨ Accrued 53 000 in 33 sites in USA over 20 months ¨ DSMB stopped the trial in October 2010
- 27. Spiral CT Chest xray P Numbers 26500 26500 Lung cancer mortality 354 442 <0.05 Mortality /100 000 245 308 RR 0.8 (20% lower) 1 All-cause mortality 7% lower Positive findings on imaging during study 24% 7% False positives 95-98% 93-96% Compliance 91%
- 28. ¨ Who is at high risk? ¨ Age? ¨ Schedule? ¨ Compliance? ¨ False positive rates? ¨ Stop or not to stop smoking?
- 29. Lung cancer No lung cancer (cases) (non-cases) Spiral CT mass True positive (TP) False positive (FP) PPV: 5% 95% TP/test positive Spiral CT no mass False negative (FN) True negative (TN) NPV: TN/test negative Test Sensitivity: Test Specificity: TP/cases TN/non-cases
- 30. ¨ Positivity rate or prevalence of positivity = Total positives / Total tested x 100 49.70% ¨ ¨ Negativity rate or prevalenve of negativity = Total negatives / Total tested x 100 50.30% ¨ ¨ Rate of Disagreement = (False positives + False negatives) / Total tested x 100 8.73% ¨ ¨ Rate of Agreement = (True positives + True negatives) / Total tested x 100 91.27% ¨ ¨ Sensitivity = True positives / Total positives x 100 84.85% ¨ ¨ Specificity = True negatives / Total negatives x 100 97.60% ¨ ¨ Predictive value positivity = True positives / Tested positive x 100 97.22% ¨ ¨ Predictive value negativity = True negatives / Tested negative x 100 86.70%
- 31. ¨ Females: ¡ Breast ¡ Cervix ¨ Males: ¡ Prostate ¨ Both sexes: ¡ Colorectal ¡ Lung ¡ ? HCC in Egypt in high risk groups