On Oct. 10, 2006, our 3-year-old son Esten was diagnosed with leukemia. As has so often happened during this experience, we dodged a bullet: He has acute lymphocytic leukemia, with more than a 90 percent chance of complete remission. Other forms of the disease, such as acute myelogenous leukemia, have a much lower survivability rate.

“I never thought I’d tell somebody’s parents that their kid has the good cancer,” a pediatric oncology ward nurse told me as she stood in our hospital room’s doorway.

On the day of Esten’s diagnosis, we were told about the treatment course, including all the different (though remote) ways his medication could kill him. As bewildered as we were, we understood that there was no alternative. The “induction phase” hosed him down with chemotherapy. Steroids made him blow up like the Michelin Man; unresponsive to tickles and highly emotional. His legs became weak from the weight and under-use. My friend Jill remembers the time as “when Esten could only crawl around and cry.”

In November and December, he was hospitalized five times in six weeks. Once was for chicken pox. We couldn’t understand how he caught it, living such a hermetic life. The doctors speculated the normally inactive virus in his vaccine took advantage of his virtually nonexistent immune system.

By November, there were no detectable traces of the leukocytes in Esten’s marrow. He was in remission.

The treatment gradually backed off in intensity. The chemo kept coming, sometimes as a home infusion. We would push the stuff from a syringe into the obscene umbilical line that fed into a catheter placed under the skin near his heart. It was a hard sell convincing him that this “medicine” would make him feel better, when we both knew it was the opposite.

“I don’t know how you do it,” friends would say. “I don’t think I could handle it as well as you.”

“You don’t know how you’ll act under fire until the bullets start flying,” I replied.

Esten is in “long-term maintenance” now. He’s back in school and thriving. He will be on this treatment course of mild doses of chemo and the occasional spinal tap until 2010. Then it will be a waiting game, to see if the leukemia comes back. The longer it stays away, the better the chance it will never return. We won’t really know if he’s beaten it until sometime in 2015.

By the spring, Esten was well enough to play outside. He and his sister climbed on the lowest branches of the big magnolia in the yard. Esten cautiously walked down a wide branch toward the ground. “Help me, Daddy!” he said, in mock distress. I made a show of holding his hand as he stepped off onto the brittle floor of leaves. He turned and looked up at me.

“Thank you for saving my life,” he said.

“You’re welcome,” I managed, steadying myself on a branch.