 |
 |
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Summaries for Patients are a service provided by Annals to help patients better understand the complicated and often mystifying language of modern medicine.
SUMMARIES FOR PATIENTS
Mammograms in Women Age 40 to 49: Results of The Canadian Breast Cancer Screening Study
3 September 2002 | Volume 137 Issue 5 Part 1 | Page I-28
Summaries for Patients are presented for informational purposes only. These summaries are not a substitute for advice from your own medical provider. If you have questions about this material, or need medical advice about your own health or situation, please contact your physician. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the American College of Physicians-American Society of Internal Medicine.
The summary below is from the full report titled "The Canadian National Breast Screening Study-1: Breast Cancer Mortality after 11 to 16 Years of Follow-up. A Randomized Screening Trial of Mammography in Women Age 40 to 49 Years." It is in the 3 September 2002 issue of Annals of Internal Medicine (volume 137, pages 305-312). The authors are AB Miller, T To, CJ Baines, and C Wall.
What is the problem and what is known about it so far?
Breast cancers are often found when a woman or her doctor feels a lump in the breast. Mammograms are special x-rays of the breast that can identify breast cancers before lumps are felt. The goal of screening mammograms is to identify breast cancers before they have spread. Recently, there has been much debate about whether mammograms decrease rates of death from breast cancer. The controversy is greatest for mammograms in women age 40 to 49 years. The Canadian Breast Cancer Screening study is a large study of screening (mammograms and breast examinations by doctors) for women in that age group. Seven to 10 years after the first screening visit, screening had not reduced deaths from breast cancer. However, some experts suggested that it would take longer than 10 years to demonstrate benefit from screening.
Why did the researchers do this particular study?
The researchers report results of the Canadian Breast Cancer Screening Study that were obtained an average of 13 years after the women entered the study.
Who was studied?
50,430 Canadian women age 40 to 49 years who had no previous breast cancer and no mammogram for at least 12 months before they entered the study.
How was the study done?
The researchers enrolled women between 1980 and 1985 and randomly assigned them to have either yearly mammograms and breast examinations by doctors for the next 5 years or to receive usual care. "Usual care" meant that mammograms and breast exams were done only if the patient's doctor suggested them. Women in both groups received instructions on how to examine their own breasts. The researchers then contacted the women yearly by mail for 5 years and examined cancer registries thereafter to see who developed breast cancer. They compared the frequency of death due to breast cancer in the women in the mammogram group to the frequency in the usual care group.
What did the researchers find?
105 of the 25,214 women in the mammogram group and 108 of the 25,216 in the usual care group died of breast cancer. The numbers of invasive (cancer that had spread into surrounding areas) and in situ (cancer that had not spread) cancers were similar in both groups. These results suggest that mammograms and regular breast examinations do not reduce breast cancer deaths.
What were the limitations of the study?
Although this study included more women than other studies on this topic, it had too few patients to detect reductions in breast cancer deaths smaller than 20%.
What are the implications of the study?
This study suggests that mammograms decrease the breast cancer death rate in women 40 to 49 years of age by less than 20%.
Related articles in Annals:
This article has been cited by other articles:
|
|
 |
|
  P.-H. Zahl, J. Maehlen, and H. G. Welch The Natural History of Invasive Breast Cancers Detected by Screening Mammography Arch Intern Med, November 24, 2008; 168(21): 2311 - 2316. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. S. Weiss, T. D. Koepsell, and B. M. Psaty Generalizability of the Results of Randomized Trials Arch Intern Med, January 28, 2008; 168(2): 133 - 135. [Full Text] [PDF]
|
|
|
|
 |
|
 R. L. Ellis, A. A. Meade, M. A. Mathiason, K. M. Willison, and W. Logan-Young Evaluation of Computer-aided Detection Systems in the Detection of Small Invasive Breast Carcinoma Radiology, October 1, 2007; 245(1): 88 - 94. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. W. Rooke Controversies in vascular screening art versus science Vascular Medicine, August 1, 2007; 12(3): 235 - 242. [Abstract] [PDF]
|
|
|
|
 |
|
 K. Armstrong, E. Moye, S. Williams, J. A. Berlin, and E. E. Reynolds Screening Mammography in Women 40 to 49 Years of Age: A Systematic Review for the American College of Physicians Ann Intern Med, April 3, 2007; 146(7): 516 - 526. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. G. Hanin, A. Miller, A. V. Zorin, and A. Y. Yakovlev Chapter 10: The University of Rochester Model of Breast Cancer Detection and Survival J Natl Cancer Inst Monographs, October 1, 2006; 2006(36): 66 - 78. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Zabicki, J. A. Colbert, F. J. Dominguez, M. A. Gadd, K. S. Hughes, J. L. Jones, M. C. Specht, J. S. Michaelson, and B. L. Smith Breast Cancer Diagnosis in Women <= 40 versus 50 to 60 Years: Increasing Size and Stage Disparity Compared With Older Women Over Time Ann. Surg. Oncol., August 1, 2006; 13(8): 1072 - 1077. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. A. Berry, K. A. Cronin, S. K. Plevritis, D. G. Fryback, L. Clarke, M. Zelen, J. S. Mandelblatt, A. Y. Yakovlev, J. D. F. Habbema, E. J. Feuer, et al. Effect of screening and adjuvant therapy on mortality from breast cancer. N. Engl. J. Med., October 27, 2005; 353(17): 1784 - 1792. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Shen, Y. Yang, L. Y. T. Inoue, M. F. Munsell, A. B. Miller, and D. A. Berry Role of Detection Method in Predicting Breast Cancer Survival: Analysis of Randomized Screening Trials J Natl Cancer Inst, August 17, 2005; 97(16): 1195 - 1203. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. G. Elmore, K. Armstrong, C. D. Lehman, and S. W. Fletcher Screening for Breast Cancer JAMA, March 9, 2005; 293(10): 1245 - 1256. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. S. Whittemore Re: Reason for Late-Stage Breast Cancer: Absence of Screening or Detection, or Breakdown in Follow-Up? J Natl Cancer Inst, March 2, 2005; 97(5): 400 - 400. [Full Text] [PDF]
|
|
|
|
 |
|
 R. J. Barth Jr., G. R. Gibson, P. A. Carney, L. A. Mott, R. D. Becher, and S. P. Poplack Detection of Breast Cancer on Screening Mammography Allows Patients to Be Treated with Less-Toxic Therapy Am. J. Roentgenol., January 1, 2005; 184(1): 324 - 329. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Hu and M. Zelen Planning of randomized early detection trials Statistical Methods in Medical Research, December 1, 2004; 13(6): 491 - 506. [Abstract] [PDF]
|
|
|
|
|
|
G. D. Leonard and S. M. Swain Ductal Carcinoma In Situ, Complexities and Challenges J Natl Cancer Inst, June 16, 2004; 96(12): 906 - 920. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Carnes and J. E. Mahoney Update in Women's Health Ann Intern Med, April 6, 2004; 140(7): 538 - 544. [Full Text] [PDF]
|
|
|
|
 |
|
 N. S. Consedine, C. Magai, Y. S. Krivoshekova, L. Ryzewicz, and A. I. Neugut Fear, Anxiety, Worry, and Breast Cancer Screening Behavior: A Critical Review Cancer Epidemiol. Biomarkers Prev., April 1, 2004; 13(4): 501 - 510. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Armstrong, J. S. Schwartz, T. Randall, S. C. Rubin, and B. Weber Hormone Replacement Therapy and Life Expectancy After Prophylactic Oophorectomy in Women With BRCA1/2 Mutations: A Decision Analysis J. Clin. Oncol., March 15, 2004; 22(6): 1045 - 1054. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. A Freedman, D. B Petitti, and J. M Robins On the efficacy of screening for breast cancer Int. J. Epidemiol., February 1, 2004; 33(1): 43 - 55. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. C Gotzsche On the benefits and harms of screening for breast cancer Int. J. Epidemiol., February 1, 2004; 33(1): 56 - 64. [Full Text] [PDF]
|
|
|
|
|
|
A. B Miller Commentary: A defence of the Health Insurance Plan (HIP) study and the Canadian National Breast Screening Study (CNBSS) Int. J. Epidemiol., February 1, 2004; 33(1): 64 - 65. [Full Text] [PDF]
|
|
|
|
|
|
D. A Freedman, D. B Petitti, and J. M Robins Rejoinder Int. J. Epidemiol., February 1, 2004; 33(1): 69 - 73. [Full Text] [PDF]
|
|
|
|
|
|
C. J. Baines Mammography Screening: Are Women Really Giving Informed Consent? J Natl Cancer Inst, October 15, 2003; 95(20): 1508 - 1511. [Full Text] [PDF]
|
|
|
|
|
|
S. Narod and J. Lubinski Re: Roles of Radiation Dose, Chemotherapy, and Hormonal Factors in Breast Cancer Following Hodgkin's Disease J Natl Cancer Inst, October 15, 2003; 95(20): 1552 - 1552. [Full Text] [PDF]
|
|
|
|
|
|
H. C. Sox Breast Cancer Screening Ann Intern Med, April 15, 2003; 138(8): 690 - 690. [Full Text] [PDF]
|
|
|
|
|
|
L. L. Humphrey, M. Helfand, B. K.S. Chan, and S. H. Woolf Breast Cancer Screening: A Summary of the Evidence for the U.S. Preventive Services Task Force Ann Intern Med, September 3, 2002; 137(5_Part_1): 347 - 360. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Sox Screening Mammography for Younger Women: Back to Basics Ann Intern Med, September 3, 2002; 137(5_Part_1): 361 - 362. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Article
