Christy Smith, 13, is alive today because of the intensive treatment -- some of it experimental -- she endured to fight her cancer. "I'm really grateful for being here today," she said in a recent interview. "If it weren't for those doctors, I wouldn't be alive."

She and her family, who live in Dundalk, Md., are aware that many other cancer patients have endured experimental treatments that did not work. They say they sympathize with those patients and their families, and offer support to them.

"You can't say that they the patients who died in experiments were wasted or even were guinea pigs," said Linda Bost, Christy's mother. "What was learned in those experiments might be used to help others. You've got to always hold on to that hope."

Christy was 9 when she first learned she had cancer. "I woke up one morning with a pain in my left side, near my ribs, and it wouldn't go away," she recalled. Within days, doctors found a large tumor that was diagnosed as neuroblastoma, a nerve cell cancer.

"In the beginning they gave us about a 5 percent chance she would live," said her father, Robert. "They couldn't offer any promises at all."

On and off for more than a year, Christy was treated at the Johns Hopkins Oncology Center in Baltimore. Her treatment included chemotherapy, radiation and surgery -- seven operations in all. Each time, doctors removed more tumor cells and then administered drugs to try to kill other cells. But each time, the cancer cells returned.

The constant barrage of surgery and drugs left Christy sick much of the time. She went from 92 pounds to 50 pounds. She lost her hair three times. Her blood counts dropped to the point where she had to stay inside all day to avoid possible infections. She was nauseous and vomiting for days on end.

"It was terrible," Christy recalled. "When I could go to school, I had to wear either a hat or a bandanna. I was embarrassed . . . . Sometimes the other kids would make fun of me."

Finally, about two years ago, doctors suggested an unusual procedure in an attempt to kill her cancer. They proposed using two potent anticancer drugs -- Adriamycin and Cytoxin -- at extremely high doses. The suggested doses would be so high that the drugs would destroy all of her bone marrow. So the doctors suggested removing all of her bone marrow before the drug infusion and freezing it so that it could be put back in her after the therapy.

After the drug treatment, Christy would receive full body radiation therapy.

The family realized the procedure was experimental, but they agreed to take the chance. "It was like a last straw," said her mother. "There was nothing else we could do." (Mrs. Bost knew the difficulties of fighting cancer all too well. Her first husband died of leukemia when Christy was 3.)

In September 1979, Christy went in to the hospital for treatment. Two months later, she checked out of Johns Hopkins. All signs of her cancer were gone. Her doctors -- Brigid Leventhal, Herbert Kaiser and David Hall -- have remained in contact with Christy, and today she is still free of the disease.

She is back to normal health. Her hair has grown back, she goes bowling and roller skating every weekend, she rides her bicycle along with her 14-year-old sister, Robyne, and she plans to get married some day.

"It's been a long, rough road," said her mother. "But it's been . . ."

Christy finished the sentence.