Over-diagnosis is an acknowledged problem with screening mammography, leading to treatment that for some people may be both unnecessary and intrinsically damaging in its own right. The danger of a false positive reading, with all the attendant anxiety and ensuing interventions, is also always a risk in current screening mammography programs. Similarly, the real possibility of a false negative – a clean bill of health that turns out to be illusory – is inherent in screening mammography. Moreover, there is no guarantee whatever that a breast cancer identified by screening mammography will be curable. Furthermore, as we have seen, for some premenopausal women, particularly those with node-positive disease, there is.
Cornelia J. Baines, MD, of the University of Toronto, deputy director of the prestigious Canadian National Breast Screening Study, has written several papers that are critical of screening mammography. She writes: “An unacknowledged harm [of screening mammography, ed.] is that for up to 11 years after the initiation of breast cancer screening in women aged 40-49 years, screened women face a higher death rate from breast cancer than unscreened control women, although that is contrary to what one would expect” (Baines 2003). How could this happen? How can it be that instead of saving their lives, earlier detection might actually result in a greater likelihood of death in these women?.
False Negatives Mammograms can and do sometimes miss cancers entirely. A woman may have a normal mammogram at one screening but still develop a so-called “interval cancer” before her next examination. As we have seen in our previous newsletters, this kind of cancer tends to be the most deadly. The “false negative” rate – that is, the rate at which mammography gives a clean bill of health to those who in reality do have cancer, has been estimated to be somewhere between 10 and 15 percent (Welch 2004). The Problem of DCIS Meanwhile, the number of cases of premalignant, non-invasive lesions such as ductal carcinoma in situ (DCIS) being diagnosed.
Mammography Does Not Predict Cure Before a breast malignancy becomes detectable by mammography it has typically been present for 8 years. It is also worth remembering that simply because a tumor is detected by mammography does not necessarily mean that it will be cured. For example, half of the breast cancer deaths recorded in two important Swedish studies of screening were among women whose tumors had first been discovered by mammography (Duffy 1991). Consider this: while 6 out of 1,000 50-year old women may die in the next 10 years if they do not have mammography, as many as 4 in 1,000 will still die even though they have had.
Mammography is the term used to describe any imaging technique used for the screening and diagnosis of breast disease – and in particular, breast cancer. There are various ways of creating a mammographic image of the breast – ultrasound, thermography, MRI, etc., but by far the commonest form of mammography used for mass screening utilizes ionizing radiation (X-rays) to detect ‘lesions’ (i.e., areas of abnormal tissue) that are suspicious for breast cancer. The terms ‘mammography’ and ‘mammogram’ as used in this article therefore refer exclusively to the X-ray imaging technique. There is a widespread belief that screening mammography unequivocally saves lives. The National Cancer Institute, the American Cancer Society, and.