"If I saw a couple more drugs with the impact Gleevec has had I'd be much more excited," said Dr. Otis Brawley, an oncologist and professor at Emory University in Atlanta. "I still think the targeted therapies are the right direction to go, but I think it's important we don't promise the American people something we don't have."

Virtually everyone agrees, too, that any progress will come not only from drugs, but from better means of detecting cancer early, when it is most easily treated, and by preventive steps like getting people to quit smoking.

....Targeted therapies attack molecular mechanisms that spur tumor growth, or even cause the cancer. Cancer arises after a series of genetic mutations remove the normal checks on cell growth.

Ideally, targeted therapies would be tailored to the genetic mechanisms responsible for a particular patient's tumor. In the future, scientists say, the genes in tumors will be routinely checked when cancer is diagnosed. And cancers will be classified mainly by their genetic characteristics, not by where in the body they arise or how they look under a microscope.

....But BAY 43-9006 has not worked well against melanoma when used by itself. Dr. Flaherty, however, combined it with chemotherapy and found tumors shrank in 7 of the first 14 patients he treated, including Mr. Smith.

But does the drug work better in the patient with the RAF mutation? That is not yet clear, suggesting full understanding of this target is not yet in hand.

Mr. Smith is not troubled by such questions. "I left the science to them," he said, "and I sit back and enjoy the benefits." And I am very happy for him, but there are still hundreds of thousands in the U.S. each year who are less fortunate, and virtually every one of those has people who miss them dearly. Cancer is still a terrible disease.