10.29.09 6:31 PM ET
Fighting Cancer With Fruit
Last week, a large study published in the Journal of the American Medical Association and picked up by The New York Times courageously raised the question of whether prostate-cancer screening and mammograms are really useful screening exams for cancer.
It’s a fascinating question to ponder in and of itself. But challenging the need for these common tests illuminates an even more tantalizing fact: Cancer is not the ominous downhill process it has been feared to be for several decades. Yes, cancer starts with genetically abnormal cells that begin to grow wildly. The evidence now shows, however, 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, we now know, is not a one-way street. Small tumors may appear, grow a bit, and then go away.
In one study, women who were treated for their cancer had a 50 percent reduction in relapse risk if they ate five vegetables and fruits per day and practiced 30 minutes of physical activity six days a week.
What this means is that lifestyle choices that weaken or strengthen the natural defenses that protect us against cancer may play a major role in whether early tumors develop—or not—into a dangerous disease.
Yet, over the past 30 years, “early detection” has been the primary and almost exclusive mantra of our medical institutions when it comes to breast- and prostate-cancer prevention. These rather expensive—and lucrative—mammograms and biopsies were based on the assumption that cancer inevitably progresses, and had become a largely unchallenged practice. Even though most experts have known for some time that the benefits of these screenings are limited, and that the downsides of overtreatment are significant, 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 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 percent lower chance of ever getting cancer. This was confirmed by another, larger study a few years later, with a similar reduction in cancer rates.
The benefits of such lifestyle 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 percent reduction in relapse risk if they ate five vegetables and fruits per day and practiced 30 minutes of physical activity six days a week. Even more impressively, after conventional treatment for stage II or III breast cancer, women who participated in a lifestyle and stress-reduction program had a 68 percent reduction in mortality compared to those who followed conventional treatment alone. In the same manner, a variety of simple lifestyle 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.
If early detection of breast or prostate cancer were used to encourage people to adopt these healthier habits instead of sending them to surgery or chemotherapy, there would be no downside. 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 lifestyle interventions worked. Early detection will always have a place in cancer medicine.
The old model of cancer as a purely genetic disorder that thrives outside of our control is slowly disappearing. Even our most conventional medical institutions are beginning to acknowledge the role of the body’s natural defenses—and our lifestyle choices that support them—in controlling whether cancer cells become a threatening disease or not. Now is the time for the funds and efforts directed toward recruitment for screening programs with questionable benefits to be spent differently. We need to teach children in our schools, employees in our corporations, and physicians in our hospitals how to really prevent cancer.
David Servan-Schreiber, MD, Ph.D., 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).