Action on Smoking and Health A National Legal-Action Antismoking Organization Entirely Supported by Tax-Deductible Contributions    Search  | Info About  | ash.org| To Join |  Email Page

Study Shows Nicotine May Escalate Cancer [02 /28-3]

Excerpts from: Nicotine May Escalate Cancer

By Debbe Geiger, freelance writer, Newsday.com [02 /25/03]

But anti-smoing aids called safe

Nicotine, the highly addictive ingredient in cigarettes, may also promote cancer, according to laboratory research conducted at the National Cancer Institute.

While tar and other components of cigarettes are known carcinogens, the NCI research, published recently in the Journal of Clinical Investigation, is the latest to suggest a link between nicotine and cancer development. According to Dr. Phillip Dennis, an oncologist at NCI and the lead author of the study, carcinogens fall into two basic categories: initiators of tumors and promoters of tumor growth. Nicotine doesn't initiate tumors, he says; rather his work suggests that it may promote the growth of tumors that already exist.

"We identified a communication pathway in human lung cells that is activated by nicotine," he explained. "When this communication pathway is activated, it causes cells to begin to behave abnormally."

When news of these findings broke, many scientists in the smoking-cessation industry were concerned that it served to confuse consumers about nicotine and the dangers of cigarette smoking.

Jack Henningfield, an adjunct professor at Johns Hopkins Medical School's Department of Psychiatry in Baltimore, said that the NCI study may mean even fewer smokers will use smoking-cessation treatments, such as nicotine patches, because of fears that nicotine will promote cancer.

"It's a fascinating basic science story and has important implications for our understanding of lung cancer," said Henningfield. "But it is a mechanism for a phenomenon that isn't known to occur. We know that nicotine is the main biological reason for smoking, but it is not the main harm caused by smoking."

Virginia Reichert, director of the Tobacco Control Center for the North Shore-Long Island Jewish Health System, says nicotine in medicinal form is "a fairly safe drug. Nicotine is a stimulant. It is the drug smokers crave when they smoke. When you inhale it by smoking a cigarette, it is brought right up to the brain from the lungs. The fix is instantaneous."

Nicotine is also the key ingredient in many smoking-cessation therapies, including gums, patches, sprays, lozenges and inhalators, which work by allowing the nicotine to be absorbed through the mouth. The moderate amount of nicotine in the products takes the edge off the cravings and withdrawal symptoms.

"Right now we've got a range of treatments that are safe and effective," Henningfield said. "The U.S. Public Health Service clinical practice guidelines urge health professionals to recommend that people consider using the medications, because they are the most powerful tool there is."

Dennis says his work does not suggest that nicotine replacement therapies be avoided. "Anything is better than smoking." However, he adds, "one should use the nicotine replacement therapy as directed. To use them past the point that they are indicated may have some risk. We don't know. To assume they are completely safe may be wrong."

A 1987 federally funded study of more than 3,000 people found nicotine gum can be used safely for up to five years with no adverse effects. Henningfield says that's one reason why nicotine gum was approved by the FDA for use without a prescription in 1996.

Nearly 47 million adults smoke cigarettes, and 70 percent of them have expressed interest in quitting, according to the Centers for Disease Control and Prevention in Atlanta.

Nicotine has acquired a bad reputation over the years, says Gary Giovino, a senior research scientist and director of the tobacco control research program at the Roswell Park Cancer Institute in Buffalo.

Nicotine and tar levels have always been linked in labels warning consumers about the dangers of cigarette smoking, yet Giovino says it's the tar that is far worse. "The bad stuff is the tar and the gases like carbon monoxide." Cigarettes contain "4,000 plus chemicals, at least 60 of which cause cancer. Tobacco itself has about 2,500 chemicals. When you burn it, you add more cancer-causing chemicals."

Yet in a survey of more than 1,000 adult cigarette smokers, Giovino and colleagues found that more than half believe that nicotine is a cause of cancer, and only one third recognize that nicotine replacement therapy is safer than smoking. "It's possible these are just rationalizations for going back to smoking, but I don't know if that's true," he says. "The reality is people think nicotine is going to give them a disease and that is total misinformation."

What is true, say the experts, is that nicotine replacement therapies double a smoker's chance of success in quitting, says Saul Shiffman, a clinical psychologist with the University of Pittsburgh, who has studied smoking and smoking cessation for 30 years. When the treatments are combined with a behavioral modification program, Shiffman says a smoker's chances of succeeding are even higher. Behavioral programs, he says, help people understand the situations in which they will be vulnerable to cravings and relapse, help them anticipate when they will encounter those situations, and encourage people to develop an effective plan for dealing with them.

Cheryl Green, 40, of Kew Gardens Hills, started smoking when she was 17. She kicked the habit six months ago and credits the six-week multidimensional program at North Shore, which combines behavioral modification techniques and drug therapies, for her success. "I'm amazed. I didn't think I'd be able to do it," said Green, an art director. "Now I can go into a club or a restaurant and people around me are smoking and I don't even want one. It was one of the hardest things I had to do because the addiction was so strong. I never want to go through that again."