CHICAGO (Chicago Sun-Times) -- When ex-Beatle George Harrison died of lung cancer after years of chain-smoking, it was a sobering reminder for baby boomers of the deadly risks of tobacco.

Another longtime smoker, rocker Warren Zevon, recently disclosed that, at 55, he is dying of lung cancer.

And 57-year-old screenwriter Joe Eszterhas, a former smoker who now has throat cancer, recently offered a public apology for having glorified smoking in such movies as "Basic Instinct."

Smoking causes 87 percent of lung cancers, which kill more people than breast, prostate and colon cancers combined. And the oldest baby boomers are approaching 60--the average age lung cancer is diagnosed.

Still, to a remarkable degree, research shows, longtime smokers can reverse the damage by quitting. Within 24 hours of smoking your last cigarette, you already have begun cutting your heart attack risk. After 10 years, you have cut your lung cancer risk in half, and after 15 years your risk of heart disease is the same as if you never smoked.

"Many smokers get discouraged after smoking 20, 30 or 40 years," said Dr. Michael Fiore of the University of Wisconsin Center for Tobacco Research and Intervention. "They think, 'I've already done the damage, I may as well keep smoking.' Nothing could be further from the truth."

Even at 65, a female smoker can expect to live 2.7 to 3.7 years longer by quitting, while a male smoker could live an extra 1.4 to two years, according to a recent Duke University and American Cancer Society study.

Quitting at 35 adds 6.1 to 8.5 years. The researchers did not determine, though, how healthy ex-smokers would be during those added years of life. And, as lead researcher Donald Taylor notes, "People are more afraid of being very disabled and alive than dead."

Not all of the cancer risk can be eliminated because it's difficult for the body to repair smoke-damaged DNA. Consequently, nearly half of all lung-cancer patients are ex-smokers.

On average, a male smoker is 22 times more likely to get lung cancer than a nonsmoker. Quitting cuts that risk sharply. Still, an ex-smoker remains on average nine times more likely to get lung cancer than someone who never smoked. Among women, smokers are 12 times more likely and ex-smokers five times more likely to get lung cancer than women who haven't smoked.

Smoking causes at least 80 percent of chronic lung disorders such as emphysema and bronchitis. Patients who quit can at least stop the disease from getting worse. But quitting does little to reverse the damage.

Some smokers quit too late. Eszterhas, who defiantly smoked for most of his life, gave up cigarettes only after being diagnosed with throat cancer 19 months ago.

"I am alive but maimed," he recently wrote in the New York Times. "Much of my larynx is gone. I have some difficulty speaking; others have some difficulty understanding me. I no longer have the excruciating difficulty swallowing or breathing that I experienced in the first months after surgery."

Characters smoked in many of the 14 movies Eszterhas wrote. In "Basic Instinct," Eszterhas explained, Sharon Stone seduces Michael Douglas "with literal and figurative smoke that she blows into his face."

Eszterhas has difficulty forgiving himself for glorifying smoking. "I don't think smoking is every person's right anymore," he wrote. "I think smoking should be as illegal as heroin."

Copyright 2002 The Chicago Sun-Times. All rights reserved.