Amid the sounds of crashing helmets and colliding shoulder pads, Gerry Ahearn finds peace.

"It's like an escape from the world," the 5-10, 210-pound lineman said. ". . . You can forget everything and relax. You don't have to deal with school and the stresses of life.

"Football . . . it's freedom."

The Sachem East senior has been to hell and back.

But you wouldn't know it by the smile he flashes or the way his face lights up as he dons his red-and-gold football uniform each week.

He's as engaging as any teenager, yet far wiser than his 17 years would ever let on.

One day in October 2005, Ahearn was diagnosed with Ewing's sarcoma, the second most common malignant bone tumor in children and adolescents between the ages of 10 and 20.

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It started with a swollen leg.

Ahearn and his mother assumed it was the result of a rigorous summer lacrosse schedule that led straight into football. He went to football practice that day, but on the advice of the team's trainer, saw the school doctor.

By midnight, the 13-year-old was admitted to Schneider Children's Hospital.

A biopsy revealed a tumor on his fibula. Scans of Ahearn's body showed tumors in his lungs and a large tumor on his brain, which doctors believed had been growing for at least four months.

The next day, he had brain surgery and doctors later removed three-quarters of his fibula. He spent the next 11½ months receiving chemotherapy and radiation.

"His only thought was: 'What do I have to do to move on?' " his mother, Teri, said. "We tried to stay positive. It got hard, very hard. When you're looking at your son with this turban on his head and a big drain coming out, it's solemn. It's terrible."

Ahearn's orthopedic oncologist said he might never walk properly after the surgery, let alone play sports. But Ahearn wouldn't waver from his goal.

He missed most of eighth grade, but returned to Sachem East halfway through his freshman year and played junior varsity football the following season.

Then the cancer returned.

While working out during a team lifting session the summer before his junior year, Ahearn's head began to throb. His heart rate increased and his face went numb. A tumor had been growing on a blood vessel in his brain for nearly two weeks. He had another brain surgery and had a stem cell transplant.

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"People were coming into my room with biohazard suits on," said Ahearn, who was kept in isolation during his three-week hospital stay. "One germ could have gotten me really sick."

He refused to think about his own mortality. Instead, a return to sports motivated him to recover even faster.

"I was sick and tired of hearing 'You're not going to do this, or that,' " said Ahearn, who also plays goalie in lacrosse. "It's a great feeling to play football. That's why I kept fighting for it."

The day before his birthday - Feb. 25 - he returned to school. He wasn't medically cleared to play lacrosse, so he focused on varsity football.

His doctors were skeptical. So were his coaches.

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But Ahearn played in all but one game for Sachem East (1-7) and started upon his return. But because his ankles are weak, he can't play as much as he'd like. He appeared briefly in the Flaming Arrows' 44-23 loss to Longwood on Friday night.

"It's a miracle he just has his equipment on," said his coach, Brian Harvey. "He's an inspiration. He's the heartbeat of the team."

Ahearn is now cancer-free, but the remnants of his ordeal remain. His hair has yet to grow back because of the chemotherapy and he still has regular checkups to monitor his blood and immunity levels.

But despite facing two bouts of Ewing's sarcoma, he is taking honors and AP classes and will graduate on time.

"It was scary," said Ahearn, who plans to play lacrosse this spring. "The reality is you're making life or death decisions in the eighth grade. But I had to jump headfirst. I was even luckier to have my family, friends and my team behind me."