Cancer Prevention

Our most feared disease, cancer, is the result of uncontrolled cell growth. This can result from increased cell division or, surprisingly, reduced cell death. DNA or genes within the cell regulate these processes, so in one sense all cancer is genetic in origin. Having a family history of cancer increases your risk, but most cancers are not strictly inherited- we inherit a predisposition or vulnerability to develop cancer. This vulnerability can be greatly influenced by our environment- the carcinogens we are exposed to and the lifestyle we lead. We can't change our genes, but we can change our environment, particularly what we eat. As a specialist in Urologic Oncology, that is cancer of the genitourinary system (kidney, bladder, prostate, testes), I will review preventive measures for bladder and prostate cancer. Though you don't hear much about bladder cancer, it is actually the fourth most prevalent cancer in the US, not counting skin cancer. Prostate cancer is the most common cancer and the second most common cause of cancer death in men. Much of what applies to these cancers is also true for other malignancies such as breast and colon cancer.

Cigarette Smoking and Other Carcinogens

"Doctors blame everything on cigarettes," a patient once told me. There is some truth in this: studies show that smoking increases just about everything associated with aging, including wrinkles, clogged arteries, cataracts, impotence, and, yes, cancer. Everyone associates smoking with lung cancer, but did you know that smoking is responsible for 60% of bladder cancer? Smoking increases the risk of bladder, kidney, and, would you believe, even cancer of the colon? Prostate cancer is one of the few malignancies that is not increased by cigarette smoking. If you smoke or live with a smoker, eliminating cigarettes is the best and most cost-effective way to reduce your risk of cancer.

Other carcinogens to avoid include arsenic (which when found in drinking water increases bladder and other cancers) pesticides, dyes, and chemicals such as benzidine, beta-naphylamine (previously used in making rubber), and gas and diesel fumes. Occupations at increased risk for bladder cancer include painters, laundry workers, chemical and petroleum workers, machinists, textile workers, truck drivers, clerical workers and those of us in the medical profession. Certain medicines, ironically even those used to treat cancer, as well as radiation also increase cancer risk.

Diet

The current epidemic of obesity poses a risk for increased cancer. Studies show that dietary fat increases the risk of cancer of the breast, ovary, prostate, bladder and kidney. Remarkably, animal studies and early clinical research suggest that marked reduction in fat can prolong survival in prostate cancer. Animal fat (red meat particularly) appears to be especially bad, but it is suggested that fatty acids present in fish oil may even reduce the risk of prostate cancer. Dr. Dean Ornish's book "A Program for Reversing Heart Disease," contains recipes for the highly committed that will reduce weight as well as risk of heart disease and prostate cancer.

Good Foods

The National Cancer Institute (NCI) has recommended that everyone eat 5 servings of fruit or vegetables a day- 8 may be better. Fresh fruit and vegetables contain vitamins and other nutrients that can actually block chemicals that cause cancer. For example, cigarette smoke contains carcinogens such as aminobiphenyl that attaches to DNA. This abnormal DNA, measured in bladder cells, is increased with smoking, but decreases when smokers eat fruit and vegetables.

Prostate cancer is rare in Japan, but Japanese who emigrate to the US markedly increase their risk. The low risk in Japan is thought to be largely due to the increased intake of soy, which contains plant estrogens, and fish. Prostate cancer risk appears to be lower in those who take selenium, vitamin E, and tomato products (lycopene). Vegetables have been associated with a reduced risk of prostate cancer. There is evidence that vitamin D lowers the risk but milk and dairy products have been associated with an increased risk.

Our Research

In bladder cancer we did the first double blind study showing that natural vitamins can prevent cancer. In bladder cancer patients high doses of vitamins A, B6, C, E and zinc ("Oncovite," Mission Pharmacal) when compared with RDA vitamins reduced tumor recurrence by 40%. In a mouse model we found that aged garlic extract added to drinking water significantly reduced growth of transplanted bladder cancer and prolonged survival. For patients with bladder cancer who wish to advance this science I will soon have a study sponsored by the NCI that will evaluate Green Tea and a chemical that blocks growth factors. In prostate cancer, this time in a rat model, we found that moderate exercise, but not excessive exercise, reduced tumor growth.

Bladder Cancer Prevention
Oncovite:Vitamins A, B6,
C, D, E, Folic acid
Garlic, Selenium, Green Tea

Prostate Cancer Prevention
Vitamins D, E
Selenium, Soy, Lycopene
Low-fat Diet, Exercise

Yin and Yang

Medical advice, like any other, needs to be taken at times with a grain of salt. For example, water contaminated with arsenic or pesticides should be avoided, but studies have shown that risk of bladder cancer is reduced with increased fluid intake. Sun exposure increases the risk of skin cancer, but is associated with a reduced risk of prostate cancer. Soy is associated with a reduced risk of prostate cancer, but may increase bladder cancer risk and the isothyanates in cruciferous vegetables that are effective in reducing cancer risk can, in excess, have the opposite effect. Similar findings are reported with vitamin C. Moderation, it seems, is good advice in all things.

Cancer Prevention

Cigarette Smoking and Other Carcinogens

Diet

Good Foods

Our Research

Yin and Yang

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