Prevention: Is it just the right drug away?

Sporn calls this the "long uphill battle" that advocates of cancer chemoprevention face. And it is a battle made harder by the fact that a person's cancer risk -- in most cases a complex interaction between genetic predisposition, environmental exposures and pure bad luck -- is poorly defined. Without blood tests or other clear indicators that a patient will likely develop cancer, physicians have shown they are reluctant to prescribe drugs for prevention, even where their benefits have been shown.

The FDA, too, remains wary of the use of drugs to treat patients without clearer signs of impending disease.

But though cancer experts have not found easy markers of cancer risk, Sporn says, there are plenty of patients whose polyps, moles, family history or chromosomes offer ample warning of trouble ahead.

For such people, he says, the risk profile of a potential cancer-preventing drug really should be compared to the very real prospect that the patient will develop a life-threatening cancer and that oncology in many cases will have little prospect of a cure to offer him.

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Rethinking cancer

Advocates of cancer-prevention research see a model for the way things should be in the treatment of cardiovascular disease. In that field, primary care doctors and heart specialists, armed with medications to lower cholesterol and blood pressure, have jumped wholeheartedly into the prevention of heart attacks and strokes. And even as they debate how to measure a patient's future risk, the field has agreed on blood pressure levels and cholesterol measures that are "markers" for heart disease and stroke and has used those to guide medication decisions.

The search for equally reliable indicators of cancer risk remains in its infancy. But doctors who treat cancer and the organs it invades should follow the cardiovascular model, says Dr. Leslie Ford, associate director for clinical research at the National Cancer Institute's Division of Cancer Prevention.

"I challenge oncologists to think differently -- to find people with risk factors for cancer and think about prevention," Ford says. "They haven't gotten there. It's not where the money is . . . and primary care physicians are overcome with other problems. It's a real challenge, but we're plugging along. I'm cautiously optimistic."

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melissa.healy@latimes.com

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On the Web

The hurdles are high for cancer-prevention drugs, as shown by the story of celecoxib, also known as Celebrex. Read about it at latimes.com/cancerextra.