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. 113: p. 3450-3458.
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 Institute, 2002. 94(5): p. 391-8.
10.    Chan, J.M., et al., Diet after diagnosis and the risk of prostate cancer progression, recurrence, and death (United States). Cancer Causes & Control, 2006. 17(2): p. 199-208.
11.    Hedelin, M., Association of frequent consumption of fatty fish with prostate cancer risk is modified by COX-2 polymorphism. International Journal of Cancer, 2006. 120(2): p. 398-405.
12.    Giovannucci, E., et al., A Prospective Study of Physical Activity and Incident and Fatal Prostate Cancer. Archives of Internal Medicine, 2005. 165: p. 1005-1010.