The role of cigarette smoking in causing cancer is not surprising since among the more than 4,000 constituents of tobacco are over 40 known carcinogens. In fact, smoking is responsible for 30.5% of all cancer deaths. In males alone, it accounts for 89% of lung cancer deaths, 90% of oral cancer deaths, 76.7% of esophageal cancer deaths, 79.3% of laryngeal cancer deaths, and 44.6% of kidney cancer deaths.
Smoking-related cancer mortality statistics are similar among women, and in fact, lung cancer has recently surpassed breast cancer as the leading cause of death among women. In addition, 30.8% of cervical cancer deaths are attributable to female cigarette smoking. In all, 23% of cancer deaths among women and 42% among men are due to smoking tobacco products.
Smoking may increase ones risk of cancer, but quitting smoking results in a decline in ones risk of developing malignancy and may even increase survival time in those already affected. Depending on the number of years of abstinence, the risk of developing lung cancer decreases by 20% to 90% when one quits smoking. The risk of developing oral cancer is cut in half after only 3 to 5 years and, after 10 years of abstinence, returns to that of a person who has never smoked.
Given statistics such as these, it is easy to understand the need for smoking cessation treatment and the importance of integrating this service into primary medical care, cancer prevention, and oncologic treatment. The goal of this paper is to review current trends in behavioral and pharmacologic approaches to smoking cessation. These include standard treatment methods, such as behavioral counseling and nicotine(Drug information on nicotine) replacement, as well as adjunctive therapies that are under preliminary investigation.
Although smoking prevalence has decreased dramatically over the past 25 years, the number of people who currently smoke is still substantial. At present, one-fourth (25.5%) of adult Americans, or about 48 million people, smoke. Most of these individuals reportedly want to quit but have great difficulty in doing so. Data from the 1994 National Health Interview Supplement (NHIS-2000) indicated that nearly 70% of smokers want to stop smoking completely and 46.4% had made a serious quit attempt (quitting for at least 1 day) in the year prior to the survey. Testifying to the difficulty of this action, however, only 5.7% of smokers successfully abstained from smoking for at least 1 month and an estimated 2.5% of all smokers quit permanently each year.
Unassisted Quitting and Self-Help Interventions
The small percentage of successful quitters each year probably reflects the fact that most smokers prefer to quit on their own using such methods of quitting as cold turkey, gradual reduction, or some other self-help approach. Only 15% of smokers report using assisted or more intensive treatments (eg, physicians advice, counseling, and nicotine replacement).
Self-help modalities have not generally been proven effective, however. In fact, in a prospective, multicenter study of 5,000 smokers, only 4.3% of self-quitters remained abstinent 1 year after their cessation attempt. A panel of experts convened by the Agency for Health Care Policy and Research (AHCPR) to review the smoking cessation literature and establish clinical practice guidelines concluded that written materials do not increase abstinence rates relative to no intervention at all.
Although other self-help modalities may be more promising, they still require further investigation. For example, slight increases in cessation rates have been noted when telephone counseling hot lines are used for smoker-initiated calls. In addition, the effectiveness of self-help materials appears to be increased by tailoring information to an individuals readiness to quit or specific barriers to cessation.[11-13] At present, it appears that the tailored self-help approaches may be of most benefit to smokers who are in the precontemplation stage of quitting, have low perceived ability to quit, or are less nicotine dependent.
Self-help interventions are attractive in that they are easy to disseminate, are low in cost, and are preferred by the general public. Therefore, further efforts to improve their efficacy are warranted. In their present form, however, self-help materials and unassisted cessation efforts do not significantly enhance quit attempts. More intensive treatment, including behavioral counseling, nicotine replacement, or the combination of the two, is required.
Assisted Smoking Cessation Treatments
The AHCPR recently published a comprehensive review of the empirical smoking cessation literature. A panel of experts in the field of smoking cessation was convened to evaluate the existing literature and make recommendations regarding efficacious cessation treatments. More than 300 controlled studies were reviewed. The results of this meta-analysis delineated three effective components of smoking cessation treatment: nicotine replacement therapy (patch or gum), social support (clinician-provided encouragement and assistance), and problem-solving/skills training (focusing on achieving and maintaining abstinence). Furthermore, the panels findings supported the combined use of behavioral intervention and nicotine replacement as the most effective intervention. Each of these treatments will be reviewed below.
Although there were insufficient data for the review panel to make any recommendations regarding the use of nonnicotine medications (eg, nicotine antagonists, antidepressants, and anxiolytics) in smoking cessation, a number of these medications have been investigated and will be reviewed here as well. Table 1 summarizes the major findings of the AHCPR panel and their recommendations for all health care providers.
Interventions that offer person-to-person contact (ie, group or individual counseling) provide a substantial treatment advantage over unassisted interventions. As shown in Table 2, in comparison to self-help interventions, the more time providers spend (intensity level) with smokers in a treatment session, the higher the likelihood of cessation. In the AHCPRs review, the highest cessation rates were observed for provider counseling sessions lasting longer than 10 minutes, but brief contact lasting 3 to 10 minutes and even minimal contact lasting less than 3 minutes improved a smokers chance of success over that of controls.
In addition, both the duration of treatment in weeks and the total number of treatment sessions improved the odds of cessation, even after controlling for treatment intensity (length of session). Significant improvements in cessation were observed for interventions involving four to seven sessions implemented over a period of 8 or more weeks.
In addition to looking at treatment intensity and duration, the AHCPR panel evaluated the efficacy of various treatment components. Among the components examined were: aversive (rapid) smoking, setting a quit day, counseling for diet or motivation for exercise, contingency contracting, relaxation, cigarette (brand) fading, intra- or extratreatment social support, and problem- solving/skills training. The results indicated that cessation counseling involving either general problem-solving/skills training (eg, relapse prevention, stress management) and/or supportive care provided by the clinician in the treatment session significantly improved cessation rates over no-contact controls.
Scheduled smoking is a unique behavioral approach that gradually weans smokers from their physiologic dependence on nicotine without concomitant nicotine replacement. Smokers are instructed to smoke on a fixed time schedule (eg, one cigarette at the beginning of every hour) with gradually increasing intercigarette intervals. In this way, individuals receive a steady, although declining, dosage of nicotine independent of environmental cues to smoke. This approach may be especially appropriate with special populations, such as individuals with medical conditions that preclude use of nicotine replacement therapy (eg, cardiac patients, presurgical patients, pregnant smokers) or individuals who are unwilling to use nicotine replacement therapy.
Scheduled smoking has been shown to be more effective than either uncontrolled gradual reduction or abrupt (cold turkey) cessation when each was combined with a relapse prevention program. One-year abstinence rates using scheduled smoking ranged from 32% to 44%, which compare favorably to those reported for psychological treatment combined with transdermal nicotine replacement (28% to 38%).[14,15]