By Dale Peterson, MD – Building Health

October is Breast Cancer Awareness month and one of the primary messages given at this time is to be sure to have a mammogram.  A mammogram may be the right thing for you to do, but first take a few moments to consider the controversies surrounding this procedure.

The recommendation that every woman have an annual mammogram beginning at the age of fifty is nearly universal.  Many advocate beginning screening mammograms at age forty and some argue that they should be instituted at age twenty-five for individuals who carry BRCA1, a gene that has been associated with a high risk of developing breast cancer.

Mammograms, however, are not entirely free of risks.  A mammogram is an x-ray of the breast, and x-ray exposure is a known risk factor for cancer development.  This risk is rarely mentioned, but in an article published in January 2009 researchers from Johns Hopkins University, the National Cancer Institute, and Memorial Sloan-Kettering Cancer Center concluded that the number of breast cancers resulting from five annual mammography examinations between the ages of 25 and 29 would be 26 per 10,000 women studied.  Between the ages of 30 and 34 twenty cancers per 10,000 women studied would be expected to be caused by the radiation exposure, and 13 cancers would appear per 10,000 women screened between the ages of 35 and 39.  They concluded that the benefit of early cancer detection did not outweigh the risk of radiation induced breast cancer in high-risk women under the age of forty.

If the radiation risk of annual mammography screening cannot be justified in women at the highest risk for breast cancer, what can one conclude about the risk/benefit ratio in women who are at average risk?  The justification for screening mammography has been based upon the assumption that early detection of breast cancer will significantly improve the survival rate.

This does not appear to be the case.  Studies comparing the breast cancer death rate in unscreened women to that of women who have undergone routine mammography screening have failed to show a significant difference.  The most recent review, published in April 2009 by Biomed Central, reported a survival percentage of 99.12 % in unscreened women and 99.29 % in screened women between the ages of 40 and 65.  The average benefit of a single screening mammogram was determined to be 0.034 %, meaning that one life would be saved for every 2970 women screened.  Even this may be overstating the benefit.

One of the longest running studies looking at the outcome of screening mammography is the Canadian National Breast Cancer Study.  The study has been under attack ever since its findings were first published in 1992.  The study has consistently shown that while the overall death rate from breast cancer in screened and unscreened women is identical, the death rate among women less than fifty is greater in screened women than in those who are unscreened.  Proponents of mammography screening discount this, but there is a logical explanation.  Many of the cancers found in young women by mammography are ductal carcinoma in situ (DCIS).  Breast cancer research is now suggesting that DCIS represents a collection of latent (inactive) cancer cells that may disappear spontaneously if untreated.  Some believe that surgical trauma triggers aggressive tumor growth by activating these latent cancer cells.  Some enter the bloodstream at the time of surgery and become foci of distant metastases.

Tragically, many breast cancer organizations have stopped recommending monthly self-breast examinations.  I believe that this is a great mistake, as over the course of my forty year medical career I have seen more breast cancers detected by self-examination than by mammography.

A woman who makes a habit of examining her breasts monthly soon becomes an expert on the character of her own breasts.  Any variation from the norm should signal the need for further evaluation, even if a screening mammogram was reported as normal a few months earlier.  Self-breast exams are painless, cost nothing, and carry no risks.  If you are unfamiliar with the technique, instructions are available online oryour personal physician should be able to demonstrate the procedure during your next visit.


Dale Petersen MD

By Dale Peterson, MD- Building Health

Dr. Dale Peterson is a graduate of the University of Minnesota College of Medicine. He completed his residency in FamilyMedicine at the University of Oklahoma. He is a past president of the Oklahoma Academy of  Family Physicians. He had a full-time family practice in Edmond, Oklahoma, for over 20 years and was a Chief of Staff of the Edmond Hospital. He was active in teachingfor many years as a Clinical Professor of Family Medicine through the Oklahoma University Health Sciences Center.

Dr. Peterson left his full-time family practice in 1999 to consult with individuals who are seeking ways to restore and maintain their health through improved nutrition and other lifestyle changes. He founded the Wellness Clubs of America to give people access to credible information on supporting and maintaining their health.  His monthly wellness letter, Health by Design, and his Health by Design E-Newsletter provide helpful information to individuals interested in preventing and conquering health challenges.  He is the author of Building Health by Design:  Adding Life to Your Years and Years to Your Life .

Dr. Peterson speaks regularly on subjects related to health and nutrition. He hosted a weekly radio program,Your Health Matters, on KTOK in Oklahoma City for five years. For the past nine years he has addressed questions from across the nation on his Your Health Matters weekly teleconference.He offers a free video LifeXtension course at

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