Many find that smoking affects them long after they quit

Kathy Conn comes from a family of smokers. She started at 15, thinking she looked good with a cigarette in her mouth. As an adult, she poured drinks in smoky bars for a few years, fuming at laws that “took smokers’ rights away.” After meals, she lit a cigarette for dessert. “What an addiction! I thought they were delicious,” she said. In 2002, doctors diagnosed Conn with pancreatic cancer, which kills 19 in 20 victims. She was 48. She quit smoking. Radiation and chemotherapy so nauseated Conn that she dropped to 82 pounds. The surgery to remove her pancreas left her a diabetic. But she survived. At her final checkup, Conn told her doctor she was grateful but would be glad never to see him again.

I’m sorry, he said, you will: X-rays show a spot in your right lung. Surgeons cut out that lung’s upper lobe last month. It held sooty lumplets of dust and smoke, akin to a coal miner’s black lung.

“I thought, ‘How could I have lung cancer?’ ” Conn said. “Well, I smoked.”

A fifth of U.S. adults – 45 million people – are, like Conn, former smokers. By quitting cigarettes, they dramatically cut their chances of getting heart disease, stroke and many cancers. But roughly a quarter will die from diseases caused by their old habit. Tens of thousands of former smokers will be diagnosed with lung cancer this year.

“When people stop smoking, their lung cancer risk tends to decrease over time,” said Dr. Stephen Chui, an oncologist at the Cancer Institute of Oregon Health and Science University. “On the other hand, we’ve all had the experience of someone who smoked for a couple of years 25 years ago showing up with a horrible lung cancer.”

New science is helping explain why cigarettes’ threat doesn’t vanish. Maria Teresa Landi and her National Cancer Institute co-workers looked at cells from the lungs and lung tumors of 28 smokers, 26 ex-smokers and 20 people who never smoked but still developed lung cancer. In both current and former smokers, more than 120 genes worked at far different rates than in the tissues of nonsmokers.

And a surprisingly small number of smokes could harm your health for a surprisingly long time. Doctors have long noted lingering risks in people who in their lives smoked at least 100 cigarettes – just five packs. And while smokers who quit lower many cancer risks within five or 10 years, they remain at least twice as likely to die of cancers of the lung, mouth, voice box, esophagus and bladder as people who never lit up.

Cancer is a spawning mass of cells gone wild. And the genetic work altered in smokers helps cells spawn. Some genes that help make the mitotic spindle, a comb of microscopic threads that parcels out DNA in dividing cells, were working double-time in ex-smokers. That’s notable because spindle threads that fail to split chromosomes precisely create genetic mutants, the force that drives cancers. Other genes that help stop spawning mutant cells from growing were working only half as much in ex-smokers as in people who never smoked.

Some of these genes were altered in people who hadn’t smoked in more than 20 years.

Health experts are firm on one point: The fact that risk lingers long after the smoke from your last cigarette clears is no reason to keep smoking. While most smokers won’t develop lung cancer, smoking is the main cause of lung cancer and the main preventable cause of death from all causes.

And quitting quickly makes you much less prone to many fatal problems.

Knowing that smoking may permanently alter genes in your lungs is a great reason not to start. So is knowing that even a few packs can hurt you permanently. Cigarettes aren’t like alcohol, where a daily drink might help your health.

“Any amount of exposure to tobacco smoke is potentially bad,” Chui said. “Every little bit adds to your risk. How many bullets do you want to put in that revolver before you spin it and put it to your head and pull the trigger?”

The message is especially important for kids. Young adults – people ages 18-24 – smoke more than people of other ages. And girls are among the fastest-growing group of smokers in the nation, even though lung cancer already kills far more women than breast cancer.

As yet, routine screening of all former smokers isn’t recommended. If you’re a former smoker, though, make sure your doctor knows.

“It’s a horrendous disease,” Chui said. “Ninety-two percent of people diagnosed with lung cancer will be dead within five years.”

Conn might beat those grim odds. Surgeons told the Medford, Ore., resident last week that they caught her cancer early and think they cut it all out.

But she feels different now when she breathes. And she said she regrets exposing herself and others to smoke.

Conn’s father died of lung cancer in 1999, three years before she quit smoking. Her mother, also a smoker, died of heart disease in 2003. Last year, cancer crept from Conn’s sister’s lung into her brain. “I got to watch her die here in my living room from cigarettes,” Conn said.

“You think, ‘How crazy could I have been?’ You take your life for granted,” Conn said. “My family’s gone, from smoking. I have no family, other than my children.”

They don’t smoke.