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Screen Detection Has Both Winners and Losers

Screen Detection Has Both Winners and Losers Dr Welch is a pioneer in presenting the benefits and harms of screening to both clinicians and the public. However, Keen and Keen1,2 were the first to devise the method to calculate the life-saving proportion (LSP) of screen-detected breast cancers, using matched 15-year periods. The follow-up analysis promoting screening mammography insight used 10-year periods.3 The higher percentage of screen-detected cancers (61%-64% vs 50%-56%) in the article by Welch and Frankel4 makes our estimates higher, while the mixed 20-year/10-year death/diagnosis risk makes our estimates lower. Our screen-free absolute death risk over 15 years at age 50 years is 8.83 (range, 8.1-9.7) per 1000 women.2 Combining analyses3 for a mixed 15-year/10-year scenario gives an LSP of 11% vs Welch and Frankel's 9%, at a 20% relative risk reduction (RRR).4 With the assumption of a screening trials–based 15% RRR (range 10%-20%), the LSP is 8% (5%-10%) for patients aged 40 to 49 years. The LSP would also be 8% (5%-11%) for patients aged 50 to 59 years and 8% (5%-10%) for patients aged 60 to 69 years. Clearly, the LSP is age independent and at maximum is 1 woman in 10. Jorgensen et al5 review the improved treatment and breast cancer awareness since the trials, which support a 10% or lower RRR (9 in 10 women with lethal cancers die despite an invitation to screening). Therefore, radiologists must detect more than 20 cancers to prolong 1 life.2,3 From this perspective, screening mammography is a lottery. Regrettably, there are both winners and losers. Before choosing participation, women should know what proportion of screen-detected cancers represents pseudodisease, which turns healthy women into patients with cancer. When a base case overdiagnosis rate of 30% is used,5 the fraction of pseudodisease is 41% to 46%, depending on patient age.3 With the assumption that 90% of ductal carcinoma in situ is screen detected and only half progresses, the fraction of pseudodisease is 16% to 18% and equivalent to a 10% overdiagnosis rate. Realistically, allowing for some invasive cancer overdiagnosis with a 20% rate, pseudodisease represents at least 1 in 3 screen-detected cancers (30%-33%).3 The pseudodisease ratio (PDR = pseudodisease/lives prolonged) therefore varies from 5:1 to 6:1 (41/8 to 46/8), at a 15% RRR. Half of women with screen-detected breast cancer starting at age 50 years are either harmed (42%) or helped (8%); the other half receiving an early diagnosis with no effect includes the 20% of women who die of breast cancer. Unfortunately, the overdiagnosis rate is more likely on the order of 52% (PDR from 8:1 to 9:1) and is getting worse with new technology.5 With the benefit shrinking and the harm growing over time, women deserve informed consent before screening. This is best coordinated by clinicians1 ordering the mammogram to circumvent the inherent conflict of interest of radiologists and other screening advocates (such as http://www.mammographysaveslives.org). Back to top Article Information Correspondence: Dr J. D. Keen, Department of Radiology, Cook County John H. Stroger Jr Hospital, 1901 W Harrison St, Chicago, IL 60612 (jkeen@cookcountyhhs.org). Financial Disclosure: None reported. References 1. The trouble with screening. Lancet. 2009;373(9671):122319362654PubMedGoogle ScholarCrossref 2. Keen JD, Keen JE. What is the point: will screening mammography save my life? BMC Med Inform Decis Mak. 2009;9:1819341448PubMedGoogle ScholarCrossref 3. Keen JD. Promoting screening mammography: insight or uptake? J Am Board Fam Med. 2010;23(6):775-78221057074PubMedGoogle ScholarCrossref 4. Welch HG, Frankel BA. Likelihood that a woman with screen-detected breast cancer has had her “life saved” by that screening. Arch Intern Med. 2011;171(22):2043-204622025097PubMedGoogle ScholarCrossref 5. Jørgensen KJ, Keen JD, Gøtzsche PC. Is mammographic screening justifiable considering its substantial overdiagnosis rate and minor effect on mortality? Radiology. 2011;260(3):621-62721846758PubMedGoogle ScholarCrossref http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Internal Medicine American Medical Association

Screen Detection Has Both Winners and Losers

Archives of Internal Medicine , Volume 172 (5) – Mar 12, 2012

Screen Detection Has Both Winners and Losers

Abstract

Dr Welch is a pioneer in presenting the benefits and harms of screening to both clinicians and the public. However, Keen and Keen1,2 were the first to devise the method to calculate the life-saving proportion (LSP) of screen-detected breast cancers, using matched 15-year periods. The follow-up analysis promoting screening mammography insight used 10-year periods.3 The higher percentage of screen-detected cancers (61%-64% vs 50%-56%) in the article by Welch and Frankel4 makes our estimates...
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Publisher
American Medical Association
Copyright
Copyright © 2012 American Medical Association. All Rights Reserved.
ISSN
0003-9926
eISSN
1538-3679
DOI
10.1001/archinternmed.2011.1885
Publisher site
See Article on Publisher Site

Abstract

Dr Welch is a pioneer in presenting the benefits and harms of screening to both clinicians and the public. However, Keen and Keen1,2 were the first to devise the method to calculate the life-saving proportion (LSP) of screen-detected breast cancers, using matched 15-year periods. The follow-up analysis promoting screening mammography insight used 10-year periods.3 The higher percentage of screen-detected cancers (61%-64% vs 50%-56%) in the article by Welch and Frankel4 makes our estimates higher, while the mixed 20-year/10-year death/diagnosis risk makes our estimates lower. Our screen-free absolute death risk over 15 years at age 50 years is 8.83 (range, 8.1-9.7) per 1000 women.2 Combining analyses3 for a mixed 15-year/10-year scenario gives an LSP of 11% vs Welch and Frankel's 9%, at a 20% relative risk reduction (RRR).4 With the assumption of a screening trials–based 15% RRR (range 10%-20%), the LSP is 8% (5%-10%) for patients aged 40 to 49 years. The LSP would also be 8% (5%-11%) for patients aged 50 to 59 years and 8% (5%-10%) for patients aged 60 to 69 years. Clearly, the LSP is age independent and at maximum is 1 woman in 10. Jorgensen et al5 review the improved treatment and breast cancer awareness since the trials, which support a 10% or lower RRR (9 in 10 women with lethal cancers die despite an invitation to screening). Therefore, radiologists must detect more than 20 cancers to prolong 1 life.2,3 From this perspective, screening mammography is a lottery. Regrettably, there are both winners and losers. Before choosing participation, women should know what proportion of screen-detected cancers represents pseudodisease, which turns healthy women into patients with cancer. When a base case overdiagnosis rate of 30% is used,5 the fraction of pseudodisease is 41% to 46%, depending on patient age.3 With the assumption that 90% of ductal carcinoma in situ is screen detected and only half progresses, the fraction of pseudodisease is 16% to 18% and equivalent to a 10% overdiagnosis rate. Realistically, allowing for some invasive cancer overdiagnosis with a 20% rate, pseudodisease represents at least 1 in 3 screen-detected cancers (30%-33%).3 The pseudodisease ratio (PDR = pseudodisease/lives prolonged) therefore varies from 5:1 to 6:1 (41/8 to 46/8), at a 15% RRR. Half of women with screen-detected breast cancer starting at age 50 years are either harmed (42%) or helped (8%); the other half receiving an early diagnosis with no effect includes the 20% of women who die of breast cancer. Unfortunately, the overdiagnosis rate is more likely on the order of 52% (PDR from 8:1 to 9:1) and is getting worse with new technology.5 With the benefit shrinking and the harm growing over time, women deserve informed consent before screening. This is best coordinated by clinicians1 ordering the mammogram to circumvent the inherent conflict of interest of radiologists and other screening advocates (such as http://www.mammographysaveslives.org). Back to top Article Information Correspondence: Dr J. D. Keen, Department of Radiology, Cook County John H. Stroger Jr Hospital, 1901 W Harrison St, Chicago, IL 60612 (jkeen@cookcountyhhs.org). Financial Disclosure: None reported. References 1. The trouble with screening. Lancet. 2009;373(9671):122319362654PubMedGoogle ScholarCrossref 2. Keen JD, Keen JE. What is the point: will screening mammography save my life? BMC Med Inform Decis Mak. 2009;9:1819341448PubMedGoogle ScholarCrossref 3. Keen JD. Promoting screening mammography: insight or uptake? J Am Board Fam Med. 2010;23(6):775-78221057074PubMedGoogle ScholarCrossref 4. Welch HG, Frankel BA. Likelihood that a woman with screen-detected breast cancer has had her “life saved” by that screening. Arch Intern Med. 2011;171(22):2043-204622025097PubMedGoogle ScholarCrossref 5. Jørgensen KJ, Keen JD, Gøtzsche PC. Is mammographic screening justifiable considering its substantial overdiagnosis rate and minor effect on mortality? Radiology. 2011;260(3):621-62721846758PubMedGoogle ScholarCrossref

Journal

Archives of Internal MedicineAmerican Medical Association

Published: Mar 12, 2012

Keywords: cancer,death,breast cancer,screening,breast neoplasm screening,overdiagnosis,relative risk reduction,invasive cancer,follow-up,mammography,ductal carcinoma in situ

References