BMJ  2006;332:727 (25 March), doi:10.1136/bmj.332.7543.727

Letter

Ramifications of screening for breast cancer

1 in 4 cancers detected by mammography are pseudocancers

The first 150 words of the full text of this article appear below.

EDITOR—In this issue Zackrisson et al report on follow-up data from the Malmö mammographic screening trial and conclude that the rate of overdiagnosis of breast cancer was 10%.¹ They do not, however, calculate the risk we believe is most relevant to women considering mammography: What is the chance that a screen detected cancer represents overdiagnosis?

After 15 years of follow-up, there were 1320 diagnosed in the screened group and 1205 in the control group (table 1). The excess detection of 115 cancers associated with screening led to their conclusion of an overdiagnosis rate of 10% (115/1205).

However, because the intervention had stopped 15 years earlier and yet breast cancer cases continue to accumulate in both groups, the approach understates the risk of overdiagnosis.

A more relevant denominator is the number of cancers found in the screened group at the end of the trial—741 (table 2). This addresses the . . . [Full text of this article]

VA Outcomes Group, White River Junction, VT 05009, USA
h.gilbert.welch@dartmouth.edu

VA Outcomes Group, White River Junction, VT 05009, USA

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

Relevant Articles

Overdiagnosis and mammography screening

H Gilbert Welch
BMJ 2009 339: b1425. [Extract] [Full Text]

Count the harms

Fiona Godlee
BMJ 2006 332: 0. [Extract] [Full Text] [PDF]

Evaluating new screening tests for breast cancer

Les Irwig, Nehmat Houssami, Bruce Armstrong, and Paul Glasziou
BMJ 2006 332: 678-679. [Extract] [Full Text] [PDF]

Rate of over-diagnosis of breast cancer 15 years after end of Malmö mammographic screening trial: follow-up study

Sophia Zackrisson, Ingvar Andersson, Lars Janzon, Jonas Manjer, and Jens Peter Garne
BMJ 2006 332: 689-692. [Abstract] [Full Text] [PDF]

This article has been cited by other articles:

• Welch, H G. (2009). Overdiagnosis and mammography screening. BMJ 339: b1425-b1425 [Full text]  
• Mulshine, J. L. (2008). Commentary: Lung Cancer Screening--Progress or Peril. The Oncologist 13: 435-438 [Full text]  
• Welch, H. G., Woloshin, S., Schwartz, L. M. (2008). The Sea of Uncertainty Surrounding Ductal Carcinoma In Situ--The Price of Screening Mammography. JNCI J Natl Cancer Inst 100: 228-229 [Full text]  
• Welch, H. G., Woloshin, S., Schwartz, L. M., Gordis, L., Gotzsche, P. C., Harris, R., Kramer, B. S., Ransohoff, D. F. (2007). Overstating the Evidence for Lung Cancer Screening: The International Early Lung Cancer Action Program (I-ELCAP) Study. Arch Intern Med 167: 2289-2295 [Abstract] [Full text]  

Rapid Responses:

Read all Rapid Responses

What is a pseudocancer?

David L Bisset
bmj.com, 24 Mar 2006 [Full text]

Online poll

Find out more >>