Women Smokers Have High Nicotine Concentrations in Their Cervical Mucus

SAN FRANCISCO--For 15 years, there has been a clear, epidemiologiclink between cigarette smoking and an increased risk of cervicalcancer, Steven Waggoner, MD, said at a poster presentation atthe Society of Gynecologic Oncol-ogists meeting.

"This holds true even after controlling for other confoundingfactors, such as age, method of birth control, number of children,and whether other cervical infections are present," he said.

About 10 years ago, some investigators identified nicotine inthe cervical mucus of women who smoked cigarettes. The surprisingpart of that finding, he said, was that the nicotine level inthe cervical mucus was substantially higher than the subjects'bloodstream levels.

Designing a study to correlate the amount of nicotine taken inthrough smoking to the amount of nicotine and other potentiallycarcinogenic substances found in cervical mucus posed a challenge,Dr. Waggoner said, because nicotine levels in the cervical mucusvary greatly among smoking women, ranging from barely detectableto extremely high.

"There are big differences among people who smoke cigarettes.Some smoke more than others, some inhale more deeply, and somesmoke cigarette brands that have more nicotine than others,"he said.

Nicotine patches, which have been available for several yearsto help smokers kick the habit, provided Dr. Waggoner with a standardand predictable vehicle of nicotine exposure in women.

The University of Chicago study included 9 women using nicotinepatches as part of a smoking cessation program. They agreed tostop smoking, use the patch, and have blood tests and vaginalexaminations to measure nicotine levels.

Nicotine levels among the women averaged 1,799 ng/g of cervicalmucus, Dr. Waggoner said. These levels were significantly higherthan the levels in their blood serum, which averaged 18 ng/mL.

Dr. Waggoner's research also suggests that there are significantdifferences in the metabolism and absorption of the componentsof tobacco. "Even when these women were exposed to similaramounts of nicotine from the patch, the amount showing up in thecervical mucus varied tremendously," he said, from an averageof 323 to 5,350 ng/g.

To date, carcinogens related to cigarette smoking have not yetbeen reliably identified in cervical mucus, he stressed. He alsopointed out that nicotine itself is not carcinogenic. "Ourcurrent research focuses on looking for carcinogenic metabolitesof nicotine. If carcinogens can be identified in cervical mucus,we'll have much stronger evidence of a link between cigarettesmoking and cervical cancer."

Even though only a small fraction of women smokers will eventuallydevelop cervical cancer, all women should recognize that nicotineand other possible carcinogenic ingredients in tobacco may maketheir way to the cervix. "These study data should reinforceevery woman's resolve to stop smoking," he said.