Potential problems with routine
If the Cochrane Analysis is true that routine mammogram screening is not beneficial, then why are there so many forces strongly encouraging women to have regular imaging? Why do professional medical societies recommend regular screening mammograms?
There are still many questions that need to be answered regarding the most effective age group to screen, and which screening methods are the best. Professional societies are resistant to changing their long-held positions regarding mammograms. There are some who disagree with the Cochrane analysis. (Fletcher, et al. 2003. NEJM, 348,(17), 1672-80)
For decades, it was assumed the potential benefit of routine mammograms was good. Scrutiny of what happens to those who have routine mammograms compared to those who do not have regular mammograms reveals many complications that may not be reported.
Women should be aware of the potential benefits and harms of routine mammogram screening.
Potential Benefits – for every 2,000 women screened for 10 years, one will benefit from having her cancer diagnosed and treated.
The most reliable results come from trials where the women have been randomly assigned to be screened with mammography or not to be screened. About 600,000 healthy women have participated in such trials. (Gøtzsche PC, Nielsen M. Screening for breast cancer with mammography.Cochrane Database Syst Rev 2009;4:CD001877)
Half of the trials have been carried out in Sweden. A review of the Swedish trials from 1993 showed that screening reduced breast cancer mortality by 29%. (Nyström L, Rutqvist LE, Wall S, et al. Breast cancer screening with mammography: overview of Swedish randomised trials. Lancet 1993; 341: 973–8)
While this appears to be a large effect, here’s what the 29% actually means. The review noted that after 10 years of screening, this reduction in breast cancer mortality corresponded to one woman out of 1000 avoiding dying from breast cancer.
The benefit of screening is thus very small. The reason for this is that in a period of 10 years only 3 women out of 1000 get breast cancer and die from it. The absolute reduction in breast cancer mortality was therefore only 0.1% (1 out of 1000) after 10 years in the Swedish trials. Screening for more than 10 years might increase the benefit, but it will also increase the harms.
Potential Harms – for every 2,000 women screened for 10 years, ten will be treated as having cancer but they do not. Approximately 20% will have a portion or all of their breast removed, and may receive radiation and chemotherapy. Half of the women who have a portion or all of their breast removed will have chronic breast pain.
Ductal carcinoma in situ is the most common finding and more than half of these will not progress to cancer. (Zahl PH, Gøtzsche PC, Mæhlen J. Natural history of breast cancers detected in the Swedish mammography screening program; a cohort study. Lancet Oncol 2011 Oct 11 [Epub ahead of print].)
Mammograms may overlook a cancer. Women may be given a false assurance that they do not have cancer. Screening mammography may miss 25-50% of cancers noted later on reexamination of the films. (Ferris M. Hall, M.D. NEJM 2007; 356:1464-1466April 5, 2007)
David Newman, MD suggests that if women in the United States undergo routine mammograms, we can estimate an additional seven thousand cases of breast cancer as a result of the radiation exposure. (Hippocrates Shadow, p 37. Feig SA1, Hendrick RE J Natl Cancer Inst Monogr. 1997;(22):119-24)
So what should women and physicians do with so much uncertainty regarding screening mammograms as the gold standard?
The time has come to re-assess whether universal mammography screening should be recommended for any age group. Declining rates of breast cancer mortality are mainly due to improved treatments and breast cancer awareness, and therefore we are uncertain as to the benefits of screening today. Over diagnosis has human costs and increases mastectomies and deaths. The chance that a woman will benefit from attending screening is small at best, and – if based on the randomized trials – ten times smaller than the risk that she may experience serious harm in terms of over diagnosis. Women, clinicians and policy makers should consider the trade-offs carefully when they decide whether or not to attend or support routine screening.
Clarity is needed regarding the pain that is associated with breast lumps. This pain may be the result of hormonal imbalances. The fact that many women have chronic pain after undergoing aggressive intervention might be the answer as to the cause for the abnormal finding on the mammogram. Nutritional research should be promoted that reverses the inflammation associated with questionable breast lesions.
Younger women have dense breasts. Ultrasound imaging or MRI may be better options to consider. Women with a strong family history of breast cancer and older women will probably benefit from close surveillance. A thorough breast exam by a well-trained clinician is still the best option for monitoring.
We must continue to try and find the best screening methods. Diligent research that is free of bias is needed. Information on cancer sites may not be complete, and often misleading. It is not ethical to magnifying the potential benefit and minimizes the potential harm for mammograms.