Beyond Mammograms and PSAs: Real cancer prevention
This week, a large study published in JAMA [1] and picked up by the New
York Times courageously raised the question of whether prostate cancer
screening and mammograms are or are not useful screening exams for
cancer.
Beyond this question, the challenge to these common tests goes further: it
points out that cancer is not the ominous down-hill process that it has been
feared to be for several decades. Yes, cancer starts with genetically abnormal
cells that start to grow wildly. But the evidence now shows that many small
tumors of cancer cells are perfectly well contained by our body’s natural
defenses and often even disappear on their own. Cancer is not a one-way street.
Small tumors may appear, grow a bit, and go away.
What this means is that life-style factors that weaken or strengthen such
natural defenses may play a major role in whether early tumors develop – or not
– into a dangerous disease.
Yet, over the past thirty years, “early detection” has been the primary and
almost exclusive answer of our medical institutions to the call for breast and
prostate cancer prevention. This was based on our assumption of the inevitable
progression of cancer.
These rather expensive – and lucrative – mammograms and biopsies had become a
largely unchallenged practice. Most experts have known for some time that the
benefits are limited, and that the downsides of overtreatment are significant.
But they have been hesitant to say so publicly for lack of an
alternative.
Missing from this debate is the fact that well proven prevention methods do
exist for breast, prostate, and other cancers. For example, an 11 country
European study published in JAMA in 2004 [2] observed that people who did not
smoke for at least 15 years, used moderate amounts of alcohol, had 30 minutes
of physical activity (e.g., walking) six days a week, and ate a diet rich in
anticancer ingredients (such as the Mediterranean diet, with fish, olive oil,
plenty of vegetables and fruits, whole grains, and low in refined sugar and red
meat), had a 60% lower chance of ever getting cancer. This was confirmed by
another and larger study a few years later, with a similar reduction in cancer
rates. [3]
The benefits of such life-style intervention even extend to women who already
have cancer. In a large California-based study, women who were treated for
their cancer had a 50% reduction of relapse risk if they ate 5 vegetables and
fruits per day and practiced 30 minutes of physical activity six days a week.
[4] Even more impressively, after conventional treatment for stage II or III
breast cancer, women who participated in a life style and stress reduction
program had a 68% reduction in mortality compared to those who followed
conventional treatment alone. [5] In the same manner, a variety of simple life
style interventions have been found to dramatically slow down the growth of
prostate cancer, even when it is already in place. These include ground flax
seeds for breakfast, pomegranate juice, green tea, tomato sauce, fatty fish,
and physical exercise. [6 , 7 , 8 , 9 , 10 , 11 ,
12]
If early detection of breast or prostate cancer were used to encourage people
to adapt such healthier habits instead of sending them to surgery or
chemotherapy, there would be no down-side. Of course, the most advanced cases
would still need immediate treatment, and the others would need to be followed
closely to make sure that the life-style interventions worked. Early detection
will always have a place in cancer medicine.
But isn’t it time for some of the funds expended on large recruitment for
screening programs with questionable benefits be spent on teaching children in
our schools, employees in our corporations and physicians in our hospital how
to really prevent cancer ?
David Servan-Schreiber, MD, PHD, is clinical professor of psychiatry at the
University of Pittsburgh and a founding board member of Doctors Without
Borders, USA. He is the author of "Anticancer - A new way of life."
(Viking)
Literature Cited
1. Esserman, L., Y. Shiey, and I. Thomson, Rethinking
Screening for Breast Cancer and Prostate Cancer. JAMA, 2009. 302(15): p.
1685-1692.
2. Knoops, K.T.B., et al., Mediterranean Diet, Lifestyle
Factors, and 10-Year Mortality in Elderly European Men and Women - The HALE
Project. JAMA, 2004. 292: p. 1433-1439.
3. Khaw, K.-T., et al., Combined Impact of Health Behaviours
and Mortality in Men and Women: The EPIC-Norfolk Prospective Population Study.
PLoS Medicine, 2008. 5(1): p. e12.
4. Pierce, J.P., et al., Greater Survival After Breast Cancer
in Physically Active Women With High Vegetable-Fruit Intake Regardless of
Obesity. Journal of Clinical Oncology, 2007. 25(17): p. 2345-2351.
5. Andersen, B.L., et al., Psychologic Intervention Improves
Survival for Breast Cancer Patients: A Randomized Clinical Trial. Cancer, 2008.
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6. Demark-Wahnefried, W., et al., Flaxseed supplementation
(not dietary fat restriction) reduces prostate cancer proliferation rates in
men presurgery. Cancer Epidemiology, Biomarkers & Prevention, 2008. 17(12):
p. 3577-87.
7. Pantuck, A.J., Phase-II Study of Pomegranate Juice for Men
with Prostate Cancer and Increasing PSA, in American Urological Association
Annual Meeting. 2005: San Antonio, TX
8. Kurahashi, N., et al., Green Tea Consumption and Prostate
Cancer Risk in Japanese Men: A Prospective Study. Am. J. Epidemiol., 2007.
167(1): p. 71-77.
9. Giovannucci, E., et al., A prospective study of tomato
products, lycopene, and prostate cancer risk. Journal of the National Cancer
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10. Chan, J.M., et al., Diet after diagnosis and the risk of
prostate cancer progression, recurrence, and death (United States). Cancer
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11. Hedelin, M., Association of frequent consumption of fatty
fish with prostate cancer risk is modified by COX-2 polymorphism. International
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12. Giovannucci, E., et al., A Prospective Study of Physical
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2005. 165: p. 1005-1010.
