April 4, 2006
American Cancer Society

Nicotine Makes Lung Cancer Chemo Less Effective.
May Explain Worse Outcome for Patients Who Keep Smoking

Smokers have yet another reason to kick the habit if they're diagnosed with lung cancer. Early research on lung cancer cells suggests nicotine may make chemotherapy treatments less effective.

In a paper published online in the Proceedings of the National Academy of Sciences, researchers from Florida's H. Lee Moffitt Cancer Center and Research Institute show that nicotine interferes with the tumor-killing ability of 3 drugs used against non-small cell lung cancer: gemcitabine, cisplatin, and taxol. The results were also presented to researchers attending the annual meeting of the American Association for Cancer Research.

The scientists exposed different cancer cell lines to the amount of nicotine that would be found in the blood of a person who smokes about a pack a day. The nicotine seemed to protect the cancer cells by cranking up the action of 2 genes that keep cells from dying naturally.

"These studies are showing that nicotine by itself, in any form, has the potential to make tumors worse and make them less responsive to cancer drugs," said study co-author Srikumar Chellappan, PhD, an associate professor in the oncology department at Moffitt Center.

The findings may help explain why lung cancer patients who continue to smoke tend to do worse than those who quit, Chellappan and his colleagues write.

Quitting by Any Means the Best Strategy

But they also raise a troubling question: Could nicotine replacement products interfere with cancer treatment the way nicotine from cigarettes does?

Chellappan says it's possible. He says cancer patients who are trying to quit by using nicotine replacement therapies should try to wean themselves off these products as quickly as they can.

"Nicotine in any form should be avoided," he said.

Oncologist Herman Kattlove, MD, a medical editor with the American Cancer Society, agrees that smokers undergoing chemotherapy should avoid nicotine replacement. If they can't quit without nicotine replacement, he says, perhaps they can use it for just 2-3 weeks before starting chemotherapy and then give it up altogether.

There are other tools to help smokers kick the habit, he notes. The antidepressant drug buproprion (Zyban) has helped some smokers quit. Counseling and support are also effective options. Most states offer some kind of telephone helpline for smokers trying to kick the habit, and many communities have support groups.

Of course, "the best time to quit smoking is as soon as possible, before one develops lung cancer," said Michael Thun, MD, vice president of epidemiology and surveillance for the American Cancer Society. But quitting at any time and by any means is important, he added -- even if the results of this study are confirmed by other research.

"The benefits of short-term nicotine replacement therapy in helping smokers quit smoking far exceed any risks from nicotine replacement therapy," Thun said.

That's true even for smokers who need to use nicotine replacement more regularly to avoid relapsing back into smoking, he added.

The drugs used in this study are also used to treat other cancers besides non-small cell lung cancer. But Chellappan said researchers don't yet know if nicotine will interfere with the drugs when used against other cancers.

"Those studies are in progress," he said.

Citation: "Nicotine inhibits apoptosis induced by chemotherapeutic drugs by up-regulating XIAP and survivin." Published online the week of April 3, 2006, in the Proceedings of the National Academy of Sciences. First author: Piyali Dasgupta, H. Lee Moffitt Cancer Center and Research Institute.