Another large study looking at screening mammograms for breast cancer has raised the issue of overdiagnosis and overtreatment once again. The purpose of mammography screening is to find cancer when it is small and so prevent cancer from growing and becoming advanced cancer. However, the researchers did not find this - there was a major increase in finding small cancers (the kind that may grow so slowly as to never cause any problems or that may even regress), but the rate of advanced cancers stayed the same.
The problem of overdiagnosis (finding small tumors that may never cause problems) and overtreatment (treating unnecessarily), which is leading to medical experts "rethinking cancer screening" is a major shift in how cancer screening is being viewed for a number of cancers. This is because studies show that overall death rates are basically the same in screened vs non-screened persons for mammography, colon, prostate, and lung cancer screening (see post). The view of how cancer grows and spreads may have to be reexamined and changed. One possibility suggested by Dr. H. Gilbert Welch is that aggressive cancer is already "a systemic disease by the time it's detectable" (Oct. 28, 2015 post).
The following excerpts are from the thoughtful review of the study in Health News Review: Overdiagnosis of ductal carcinoma in situ: ‘the pathology equivalent of racial profiling’
Danish researchers are providing new evidence that many breast cancers found via screening mammograms don’t need to be treated. Women with these non-threatening tumors are said to be “overdiagnosed” with breast cancer. Overdiagnosis occurs when breast screening such as mammography detects small, slow-growing cancers that may never cause the patient any trouble. Yet, women diagnosed with such tumors are exposed to very real harms–possible surgery, chemotherapy, radiation, and living life as a “cancer patient.”
How much overdiagnosis are we talking about? If you don’t include cases of ductal carcinoma in situ (DCIS) in the tallies, anywhere from 14.7% to 38.6% of breast cancers found via screening represent overdiagnosis, the study authors found. The rate ranges from 24.4% to as high as 48.3% when DCIS is included.
DCIS is a collection of abnormal cells inside a milk duct that may–but usually doesn’t–break out to become invasive and potentially lethal cancer. About 60,000 women are told they have DCIS each year in the United States. Some experts estimate that up to 80% of women with DCIS found via screening may not need any treatment at all–and instead should just keep an eye on things. Obviously, women need to be fully and accurately informed about the benefits and risks — including the risk of overdiagnosis — before embarking on any decision to get screened for breast cancer or choosing a course of action following a diagnosis.
Otis Brawley, MD, Chief Medical Officer for the American Cancer Society, says it’s been difficult for modern medicine to wrap its brain around the concept of overdiagnosis. The natural inclination is to assume that cancerous-looking cells “will grow, spread, and eventually kill,” he writes in an editorial accompanying the Danish study. “However, some of these lesions may be genomically predetermined to grow no further and may even regress. In many respects, considering all small breast lesions to be deadly and aggressive types of cancer is the pathologic equivalent of racial profiling.
Excerpts from the original study from the Annals of Internal Medicine: Breast Cancer Screening in Denmark: A Cohort Study of Tumor Size and Overdiagnosis
Background: Effective breast cancer screening should detect early-stage cancer and prevent advanced disease. Objective: To assess the association between screening and the size of detected tumors and to estimate overdiagnosis (detection of tumors that would not become clinically relevant).... Setting: Denmark from 1980 to 2010. Participants: Women aged 35 to 84 years. Intervention: Screening programs offering biennial mammography for women aged 50 to 69 years beginning in different regions at different times.
Conclusion: Breast cancer screening was not associated with a reduction in the incidence of advanced cancer. It is likely that 1 in every 3 invasive tumors and cases of DCIS (ductal carcinoma in situ) diagnosed in women offered screening represent overdiagnosis (incidence increase of 48.3%).
Breast screening is associated with a substantial increase in the incidence of nonadvanced tumors and DCIS (ductal carcinoma in situ) in Denmark but not with a reduction in the incidence of advanced tumors, and the overdiagnosis rate is substantial. These findings support that screening has not accomplished the promise of a reduction in invasive therapy or disease-specific mortality.
I saw mention of this study in a number of places - that low vitamin D levels are linked to chronic headaches. A little too soon to know if that is really true - the researchers in this study looked at the blood vitamin D levels of 2601 men just
Another large study has found negative health effects from living close to high-traffic roadways - this time a higher risk of dementia. The closer to the heavy traffic road, the higher the risk - with the highest risk in people living
A new law in France just banned spanking of children, making it 52 countries in the world that ban spanking of children. Yet in the United States we go so far in the other direction that nineteen states still allow spanking and other forms of physical punishment in school. Of these 19 states, 15 expressly permit it while another four do not prohibit it. According to
The beginning of a new year is a time to think about the future, and perhaps think about healthy lifestyles and how to age well. One important issue to think about is: why do some older people have "young" minds while others do not? Can anything be done to improve our odds later in life of being a "superager" and having a youthful, sharp, clear mind?
The wonderful blog posts of Dr. John Mandrola (physician, blogger, and columnist at Medscape) are always thoughtful, and this latest points out things a number of studies have pointed out for a while. Which is to stop obsessing or focusing on "preventive tests" and screenings and numbers, and instead focus on a healthy lifestyle - which means getting regular exercise or physical activity, don't smoke cigarettes, maintaining a healthy weight, and eating a healthy diet with lots of fruits, vegetables, nuts, seeds, whole grains, and legumes (think Mediterranean-style diet).
Recently some studies have found that a diminished sense of smell occurs in persons with mild cognitive impairment and Alzheimer's disease. Doctors have long observed that patients with Alzheimer's frequently complain that food doesn't taste good anymore (because they can't smell what they are eating). This is because odor signals from the nose are processed in areas of the brain that are among the first to be affected by Alzheimer's disease. It is thought that as dementia starts and progresses, the parts of the brain that distinguish odors start to deteriorate.
The research finding of