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A Closer Look at Screening Mammography
Dr Laura Esserman of the University of California startled the medical community with an article questioning screening mammography published in the Journal of the American Medical Association (JAMA ). Dr Laura Esserman reviewed 20 years of breast cancer data. Her conclusion is not favorable:
"Mammography screening for breast cancer has significant drawbacks, and expected survival benefits have not materialized. "
"While the incidence of early stage breast cancer has decreased due to mammography, the incidence rates for the killer cancers, (the advanced cancers) have remained stable. While it is true that overall mortality rates have declined slightly, this is attributed to better treatment rather than increased detection." Dr Laura Esserman.
Let's take a look at the Data Charts Dr Esserman used for her JAMA Article. ( Below Image Courtesy of Rethinking Screening for Breast Cancer and Prostate Cancer Laura Esserman, MD, JAMA. 2009;302(15):1685-1692.)
The above chart shows the critical information in Dr Esserman's JAMA article. The Pink line is TOTAL breast cancer incidence annually. Note increase beginning in 1983 with introduction of mammography screening. Below the pink line, we see three more lines: this is the breakdown of the total incidence into localized, regional and metastatic cases. The turquoise line is localized cancer. The light purple line is regional cancer and the black line (lowest) is metastatic cancer. The killer cancers are the regional and metastatic cases. Note that these numbers have remained stable with little change in spite of detection of massive numbers of localized cases
Here is another chart looking at incidence and mortality from breast cancer annually (below) (all cases):
Source for above two charts: http://caonline.amcancersoc.org/cgi/content/full/59/4/225
Figure 3 and Figure 4 combined, FIGURE 3 (upper pink line) Annual Age-adjusted Cancer Incidence Rates among Females for Breast Cancer, United States, 1975– 2005. FIGURE 4 (lower pink line) Annual Age-adjusted Cancer Death Rates among Females for Breast Cancers, United States, 1930–2005.
The upper pink line (red arrow) is the incidence of breast cancer since 1976. Notice the dramatic increased detection of cases in the early 1980s with introduction of screening mammography. The lower pink line (green arrow) is the annual mortality rate for breast cancer from 1930 to 2006. Note this is stable at about 30 cases per 100,000 women, and declines over the last section (green arrow) to about 25 cases per 100,000. Dr. Esserman suggests this rather modest decline in mortality (green arrow) is not due to increased detection with mammography, rather it is due to improvement in treatment.
Annual Breast Cancer Mortality – Where's the Benefit?
While the incidence of early stage breast cancer has decreased by 2.8% per year since 2001, incidence rates of advanced (distant-stage) disease have remained stable.(link). In 2009, 192,370 women will be diagnosed with breast cancer and 40,170 women will die of breast cancer.(link) Mammography has increased the detection of very early stage cancer, called DCIS, with 60,000 cases of DCIS detected annually.
Esserman's 2009 Observations were made in 2002 by Barnett Kramer
Seven years ago, Dr. Barnett Kramer, director of the Office of Disease Prevention at the National Institutes of Health, was interviewed in a 2002 article in the New York Times, in which said:
"The number of women with breast cancers with the worst prognosis, those that spread to other organs, had been fairly constant in the years before mammography was introduced, and that trend did not change after the introduction of mammography...If screening worked perfectly, every cancer found early would correspond to one fewer cancer found later. That did not happen. Mammography, instead has resulted in a huge new population of women with early stage cancer but without a corresponding decline in the numbers of women with advanced cancer."
Weighing the Pluses and Minuses of Screening Mammography
Dr Gilbert Welch in his BMJ editorial, says the following about mammography screening for breast cancer:
•1 in 1,000 women annually screened for 10 years will avoid dying from breast cancer.
•2 to 10 women will be over-diagnosed and treated needlessly
•10 to 15 women will be told they have breast cancer earlier than they would otherwise have been told, but this will not affect their prognosis.
•100 to 500 women will have at least one "false alarm" (about half of these women will undergo a biopsy)
Source above left image: SEER Cancer Statistics Review 1975-2006
Mammography Finds the DCIS Lesions
The left chart above shows annual incidence of DCIS (ductal carcinoma in situ). Note huge increase in 1983 (green arrow) with introduction of screening mammography.
Finding the Reservoir of DCIS
Mammography screening finds the small indolent cancers called DCIS that represent a reservoir of silent disease in up to 18% of the population (at autopsy). This leads to overdiagnosis and overtreatment. For the invasive cancers found in 1-2% of the population (at autopsy series), screening detection is of little help, with little change in the number of advanced cancer cases, and about 40,000 deaths every year.
Dr. Gilbert Welch sums it up with the following sage advice: "doctors who recommend less-aggressive mammography (less frequently, waiting until you are age 50, or stopping it when you are older) or are less quick to biopsy may not be bad doctors but good ones."
Just Stop Calling It Cancer – DCIS
One glaring problem with screening mammography is the detection of DCIS at a rate of 60,000 case per year. DCIS is ductal carcinoma in situ, a pathology diagnosis which carries a very good prognosis, a 98% – 5 year survival with no treatment. In spite of the rather benign natural history of DCIS, mainstream medicine treats these lesions aggressively with surgery and radiation. Recently, the NIH has called for a change in terminology, asking pathologists to stop calling it "cancer".
Left Image : typical appearance of DCIS with punctate calcifications on mammogram (arrow). Courtesy Wikimedia Commons.
Here is the NIH consensus statement: "Because of the noninvasive nature of DCIS, coupled with its favorable prognosis, strong consideration should be given to elimination of the use of the anxiety-producing term "carcinoma" from the description of DCIS. "
A Large Reservoir of Silent Disease – For All Three
All three types of cancer, breast, thyroid and prostate have a large reservoir of indolent or biologically insignificant disease that remains silent during the patient's lifetime. We know this from autopsy studies. One autopsy study of 110 women from Finland using specimen radiographs of thin sections found breast cancer in 20% of the cases. (2 % had invasive cancer, and 18% of the 110 cases had In-Situ Cancer).
Left Image: Breast Cancer Awareness Month with Pink Ribbons. Courtesy of WIkimedia Commons.
Spontaneous Remission of Breast Cancer ?
One screening study reported by Welch in the Annals of Internal Medicine actually concluded that many small breast cancers spontaneously regress. Gina Kolata wrote a New York Times piece about it. Actually, spontaneous regression of breast cancer has been reported many times in the medical literature. Sir William Osler, a legendary and revered doctor reported 14 cases himself.
See this 1901 report: The Medical Aspects of Carcinoma of the Breast, with a Note on the Spontaneous Disappearance of Secondary Growths, OSLER W., American Medicine: April 6 1901; 17-19; 63-66.
Perhaps breast cancer remission was more common during his lifetime. I personally have seen a case of spontaneous regression of breast cancer documented by follow up MRI scan.
The real challenge is for medical science to investigate spontanous regression, and once understood, use it induce a cure in the cancer patient, thereby winning the war against cancer. Perhaps a mouse model discovered in 2003 showing spontaneous regression of advanced cancer in genetically determined mice could help make some progess with this research. This would be a good subject for an NIH grant.
Diagnosis is Not Screening
We must be careful about the difference between screening, and diagnosis. Screening pertains to mass screening of a healthy population. We had found this leads to overdiagnosis and overtreatment. Diagnosis pertains to evaluation and workup of a symptomatic patient, which is what the doctor does every day. PSA testing, mammography and ultrasound remain excellent diagnostic tools for workup and evaluation of the symptomatic patient.
How to Prevent Breast Cancer
1) Vitamin D Supplementation.
2) Iodine Supplementation
3) Natural Progesterone
4) Avoid carcinogenic chemicals, xenoestrogens, pesticides, etc.
Links and References
see the full list of links on Dr. Jeffrey Dach's website: http://jeffreydachmd.com/rethink-pink-and-screening-mammography/