HER2 Support Group Forums - View Single Post - New Proposed Changes to Mammogram Guidelines

gdpawel · 11-25-2009, 06:37 AM

The other side of the coin is radiation risk imposed by mammography. It is not simply of negligible value in younger women, but may have a net harm effect, if women who have mammograms at age 40 start having higher rates of cancer in irradiated breasts 25 or 35 years later.

The recommendation not to begin mammography until age 50 has to do with medical issues, more than cost effectiveness issues. Mammography is not harmless. You are subjecting women to annual doses of ionizing radiation to the breasts, with some unavoidable scatter to chest wall and lungs. We do not know how many women who are irradiated by mammography in their 40s will develop radiation-induced breast cancer (or even lung cancer) in their 60s, 70s, and 80s.

The other problem is that women in their 40s tend to have very dense breasts, making it more difficult to get an accurate exam. These women often are called back for additional views, giving them even more radiation. There are more false positives, leading to breast biopsies and sometimes unnecessary lumpectomies, in cases where the biopsies are technically suboptimal.

In contrast, in older women, their breasts are less dense, making the examination more accurate, with fewer false positives, and there are fewer years of remaining life to develop a radiation-induced malignancy.

The fact is that we have no truly long term follow up studies to determine very long term risks of carcinogenesis from radiation exposure in mammography.

1. J Radiol Prot. 2009 Jun;29(2A):A123-32. Epub 2009 May 19.

Mammography-oncogenecity at low doses.

Heyes GJ, Mill AJ, Charles MW.

Department of Medical Physics, University Hospital Birmingham NHS Foundation Trust, Birmingham B15 2TH, UK.

Controversy exists regarding the biological effectiveness of low energy x-rays used for mammography breast screening. Recent radiobiology studies have provided compelling evidence that these low energy x-rays may be 4.42 +/- 2.02 times more effective in causing mutational damage than higher energy x-rays.

The risk/benefit analysis, however, implies the need for caution for women screened under the age of 50, and particularly for those with a family history (and therefore a likely genetic susceptibility) of breast cancer. In vitro radiobiological data are generally acquired at high doses, and there are different extrapolation mechanisms to the low doses seen clinically. Recent low dose in vitro data have indicated a potential suppressive effect at very low dose rates and doses. Whilst mammography is a low dose exposure, it is not a low dose rate examination, and protraction of dose should not be confused with fractionation. Although there is potential for a suppressive effect at low doses, recent epidemiological data, and several international radiation riskassessments, continue to promote the linear no-threshold (LNT) model.

11-25-2009, 06:37 AM	#24
gdpawel Senior Member Join Date: Aug 2006 Location: Pennsylvania Posts: 1,080	The other side of the coin - radiation risk The other side of the coin is radiation risk imposed by mammography. It is not simply of negligible value in younger women, but may have a net harm effect, if women who have mammograms at age 40 start having higher rates of cancer in irradiated breasts 25 or 35 years later. The recommendation not to begin mammography until age 50 has to do with medical issues, more than cost effectiveness issues. Mammography is not harmless. You are subjecting women to annual doses of ionizing radiation to the breasts, with some unavoidable scatter to chest wall and lungs. We do not know how many women who are irradiated by mammography in their 40s will develop radiation-induced breast cancer (or even lung cancer) in their 60s, 70s, and 80s. The other problem is that women in their 40s tend to have very dense breasts, making it more difficult to get an accurate exam. These women often are called back for additional views, giving them even more radiation. There are more false positives, leading to breast biopsies and sometimes unnecessary lumpectomies, in cases where the biopsies are technically suboptimal. In contrast, in older women, their breasts are less dense, making the examination more accurate, with fewer false positives, and there are fewer years of remaining life to develop a radiation-induced malignancy. The fact is that we have no truly long term follow up studies to determine very long term risks of carcinogenesis from radiation exposure in mammography. 1. J Radiol Prot. 2009 Jun;29(2A):A123-32. Epub 2009 May 19. Mammography-oncogenecity at low doses. Heyes GJ, Mill AJ, Charles MW. Department of Medical Physics, University Hospital Birmingham NHS Foundation Trust, Birmingham B15 2TH, UK. Controversy exists regarding the biological effectiveness of low energy x-rays used for mammography breast screening. Recent radiobiology studies have provided compelling evidence that these low energy x-rays may be 4.42 +/- 2.02 times more effective in causing mutational damage than higher energy x-rays. The risk/benefit analysis, however, implies the need for caution for women screened under the age of 50, and particularly for those with a family history (and therefore a likely genetic susceptibility) of breast cancer. In vitro radiobiological data are generally acquired at high doses, and there are different extrapolation mechanisms to the low doses seen clinically. Recent low dose in vitro data have indicated a potential suppressive effect at very low dose rates and doses. Whilst mammography is a low dose exposure, it is not a low dose rate examination, and protraction of dose should not be confused with fractionation. Although there is potential for a suppressive effect at low doses, recent epidemiological data, and several international radiation riskassessments, continue to promote the linear no-threshold (LNT) model.