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© 2003 American Society for Clinical Oncology Intervention to Reduce Intentions to Use Tobacco Among Pediatric Cancer Survivors
From the Division of Behavioral Medicine, the Department of Biostatistics, and the Department of Nursing, St. Jude Children’s Research Hospital; and the Department of Pediatrics, University of Tennessee, College of Medicine, Memphis, TN. Address reprint requests to Vida L. Tyc, PhD, Division of Behavioral Medicine, St. Jude Children’s Research Hospital, 332 N. Lauderdale, Memphis, TN 38105-2794; email: vida.tyc{at}stjude.org.
Purpose: In this randomized controlled trial, we sought to determine whether a risk counseling intervention would increase knowledge and perceived vulnerability to tobacco-related health risks and decrease future intentions to use tobacco among preadolescents and adolescents previously treated for cancer. Patients and Methods: Participants included 103 cancer survivors between the ages of 10 and 18 years who were randomly assigned to either a standard care control (SCC) group or a tobacco intervention (TI) group. Patients in the SCC group received standard advice about the risks of tobacco use. Patients in the TI group received more intensive late effects risk counseling in addition to an educational video, goal setting, written physician feedback, smoking literature, and follow-up telephone counseling. The effect of our intervention was assessed by self-reported knowledge, perceived vulnerability, and intentions at baseline, 6, and 12 months. Results: Compared with the SCC group, patients who received our intervention had significantly higher knowledge scores, higher perceived vulnerability scores, and lower intention scores at 12 months. No significant differences between the SCC and TI groups at 6 months, across all measures, were found. Conclusion: Pediatric survivors’ knowledge, perceived vulnerability to health risks, and intentions to use tobacco can be modified by a risk counseling intervention. The delayed effect of our intervention indicates that these changes may evolve over time. Implications for health care providers who engage in tobacco counseling with young cancer survivors are discussed. Additional longitudinal studies are needed to determine definitive long-term intervention effects on actual tobacco use in this high-risk population.
TOBACCO USE is a behavioral health problem that poses serious health risks for patients previously treated for cancer. A number of antineoplastic therapies commonly used in the treatment of pediatric cancer patients are associated with cardiopulmonary toxicities that may be potentiated by tobacco use. Selected subgroups of patients treated with cardiopulmonary toxic agents and/or thoracic radiation therapy may be most susceptible to the detrimental long-term consequences of tobacco use.1–3 Pediatric cancer patients are already at risk for developing second cancers because of treatment-induced and genetic predispositions,4–6 and tobacco use may exacerbate these vulnerabilities. Despite the health risks associated with tobacco use, the experience of having survived childhood cancer seems to have had minimal effect on the smoking habits of survivors. Mulhern et al7 found that among young adult cancer survivors 18 to 29 years of age treated at St. Jude’s Children’s Research Hospital, 47.5% admitted to trying tobacco and 32.5% were currently using tobacco. In another study of young survivors of childhood acute myeloid leukemia, 29% of patients were identified as current smokers.8 A comparison of the smoking habits of young adult survivors of childhood acute lymphoblastic leukemia with that of their siblings found that survivors were significantly less likely to have ever smoked, were significantly less likely to be regular daily smokers, but were less likely to quit smoking than sibling controls.9 Risk counseling interventions delivered by health care professionals have been found to be effective in modifying perceptions of health risk and reducing smoking behavior in adult head and neck cancer patients and other patient groups.10–12 Similar risk counseling approaches with pediatric cancer patients have not been conducted. Several studies have reported an inverse relationship between adolescents’ perceived vulnerability (PV) to health risks, a well-recognized component of current cognitive-motivational models of health behavior,13 and the practice of some risky health behaviors.14,15 A previous study with young cancer survivors indicates that survivors seem to have a generalized notion that their health is vulnerable because of their cancer treatment experience,7 although the specific association between PV and tobacco use has not been adequately studied. Interventions that can capitalize on the survivors’ PV to tobacco-related health risks may, therefore, have an effect on tobacco-related outcomes. The primary purpose of this randomized controlled trial was to evaluate the efficacy of a tobacco risk counseling intervention as compared with a standard care control condition for preadolescent and adolescent cancer survivors, as measured by knowledge, PV, and intentions to smoke. We hypothesized that patients who received our intervention would be more knowledgeable about tobacco-related health risks, perceive themselves to be more vulnerable to tobacco-related health risks, and report fewer future intentions to use tobacco. Self-reported intention to use tobacco has consistently been used as a proximal outcome measure in adolescent smoking research because prospective studies16,17 have demonstrated smoking intentions to be a strong predictor of future smoking behavior. As a secondary objective, demographic, medical, and other psychosocial variables that best predict adolescents’ intention to smoke were identified. To our knowledge, this was the first empirical study to document the efficacy of a clinical intervention promoting tobacco abstinence among young cancer survivors in a clinical setting. This study was unique in that it evaluated an intervention that capitalized on the survivors’ perceptions of health vulnerability, relied on the motivational enhancements provided by the cancer treatment setting, employed a prospective design, and assessed cognitive-motivational variables that have particular relevance for adolescent cancer survivors but that have not been previously explored. Unlike traditional approaches, this intervention was delivered by health care professionals in the context of the patient’s routine medical care.
Participants Participants included 103 preadolescents and adolescents who were previously treated for cancer at St. Jude Children’s Research Hospital (SJCRH, Memphis, TN) who were currently disease-free and who were at least 1 year from completion of all antineoplastic therapy. The sample was composed of 57.3% patients who were previously treated for leukemia and 42.7% who were treated for solid tumors. Patients with brain tumors were excluded because of the cognitive and functional impairments that are characteristic of many of these patients after treatment.18 The median time from diagnosis was 6.3 years (range, 1.7 to 15.7 years). Survivors ranged in age from 10 to 18 years (median, 15.0 years) and were equally distributed in terms of sex (males, 51.5%; females, 48.5%). The sample consisted of 78.6% whites and 21.4% African-Americans. Consistent with institutional referral patterns, 20.4% were from high, 67.0% were from middle, and 12.6% were from lower socioeconomic status levels.19
Procedure On enrollment, patients were randomly assigned to either a standard care control (SCC) or a tobacco intervention (TI) group and followed longitudinally. The random assignment for all patients was stratified by age (10 to 13 years v 14 to 18 years), sex, race (white v minority), and self-reported smoking status (smoker v nonsmokers) using the randomization scheme proposed by Zelen.20 Patients in both groups were assessed via self-report measures at baseline, 6, and 12 months following the intervention. The groups were defined as follows. SCC group. Patients in the SCC group were asked about their tobacco use and briefly advised about the health risks associated with tobacco use. All tobacco users were advised to stop and nonsmokers were encouraged to continue to resist tobacco. This ask-and-advise counseling approach represents the minimal intervention that is commonly incorporated into routine medical care and is therefore denoted standard care. TI group. The intervention was designed to be administered in a single session with periodic reinforcement of tobacco goals by telephone. This was done to ensure that it could be practically implemented at most pediatric oncology settings and incorporated into routine medical care that is often time-limited. The content was designed to be relevant to both nonsmokers and smokers because the goal was the promotion of tobacco abstinence. The intervention consisted of an educational video that discussed the short- and long-term physical and social consequences of tobacco use; late effects risk counseling focused on potential chemotherapy and radiation treatment-related toxicities that can be exacerbated by tobacco use and the survivors’ increased vulnerability to tobacco-related health risks relative to their healthy peers; goal setting involving tobacco abstinence or cessation depending on the survivor’s smoking status; a physician feedback letter that reinforced the antitobacco message delivered in the intervention; tobacco literature; and follow-up telephone counseling at 1 and 3 months after the intervention to reinforce previously established goals and address barriers to achieving goals of tobacco abstinence or cessation. The face-to-face counseling component of the intervention was conducted by a master’s level psychologist over a 50- to 60-minute period, and the follow-up telephone counseling was conducted by a research nurse trained by V.L.T. The intervention was delivered using a scripted protocol that was tailored to the patients’ individual responses to questions posed during the intervention and individual goal setting.
Measures PV. This eight-item scale measures patients’ perceptions of their vulnerability to tobacco-related health risks secondary to cancer treatment. Individual responses were rated on a five-point scale. Total scores range from eight to 40, with higher scores representing greater PV to cancer-related risks. Cronbach’s alpha of 0.74 was computed for this scale and indicates adequate internal reliability. Intentions (I). The I scale consists of six items that measure future intentions to use tobacco as rated on a five-point scale ranging from very unlikely to very likely. Total scores range from six to 30, with higher scores representing greater intentions to use tobacco. Cronbach’s alpha of 0.88 was computed for this scale and indicates good internal reliability. Perceived positive effects of tobacco use. This 13-item scale assesses perceptions of the positive effects that accompany tobacco use such as gaining peer acceptance, improving your image, and so on. A high score indicates a greater association of positive effects with tobacco use. This scale has been used in previous studies of adolescent cigarette smoking.21
Statistical Methods
Descriptive Analyses Table 1  summarizes the demographic variables and smoking status of patients in the SCC and TI groups and indicates a similar distribution according to these variables at baseline between the two groups. The smoking status of parents of patients in the two groups is also shown. The majority of the sample was composed of current non-tobacco users, and only five patients were current tobacco users on the basis of self-report to the question, "Have you used tobacco in any form in the past month?" This question is consistent with criteria used in national surveys of adolescent tobacco use.22,23 All five patients were cigarette smokers. Of the 98 current nonsmoking patients, 13 (13.3%) had tried tobacco in the past. There were 39.8% of patients who had a best friend who used tobacco, and 40.7% of patients had at least one parent who used tobacco. Inspection of the distribution of patients who received pulmonary toxic therapy between the two groups indicated that three patients in the SCC group received mantle radiotherapy (RT), whereas five patients in the TI group received mantle RT or bleomycin.
All patients were scheduled for a 6- and 12-month evaluation. Almost 70% and 78.6% of patients provided data at the 6- and 12-month assessment intervals, respectively. These retention rates, where retention is defined as the percentage of patients who provided follow-up data, are comparable with those reported in other adolescent smoking prevention studies.24 The primary reason that patients did not complete an evaluation was that their clinic visits did not coincide with their scheduled study evaluation. Patients in the SCC and TI groups who completed the 6- and 12-month evaluations were compared with those who did not on the basis of age at enrollment, sex, race, and smoking status, and no significant differences were found (all, P > .10).
Observed mean scores and SDs for K, PV, I, and positive effect measures obtained at baseline, 6, and 12 months for the SCC and TI groups are presented in Table 2
Efficacy of Intervention Inspection of observed baseline means for K, PV, and I measures (Table 2  ) indicated that our sample of young cancer survivors reported generally high knowledge, moderately high PV, and low future intentions to use tobacco. Although there were no significant group differences on the baseline K, PV, and I scores (all, P > .10), adjustments for baseline were made on the transformed data by subtracting baseline observations from subsequent observations. A multivariate comparison of the difference scores (12 month score – baseline score) for the K, PV, and I variables simultaneously for the SCC and TI groups indicated significant group differences (P = .002). This same multivariate analysis was conducted with the smokers excluded, and significant group differences were also found (P = .019). The multivariate result for simultaneous comparison of the 6-month difference from baseline for the K, PV, and I outcomes for the two groups was not significant (P > .10). Similarly, nonsignificant group differences were obtained when smokers were excluded from the analysis (P > .10). There were also no detectable differences in patient smoking status across time for the SCC and TI groups (all, P > .10). To further explore the efficacy results for individual outcome variables, repeated measures analyses were used with effects for study group, time of assessment, and interaction between these two variables. Comparisons between study groups were made at 12 months with adjustments made for baseline values. On the K measure, there was a significant effect for study group (P = .016) and for time of assessment (P < .0001), and only a marginally significant effect for the study group x time of assessment interaction (P = .054). Results indicated significant differences in 12-month scores between the SCC and TI groups for K (P = .018). Higher K scores at 12 months compared with baseline were observed for both the SCC (P = .002) and TI groups (P < .0001). Similar patterns were observed for the PV measure, with significant effects noted for study group (P = .010) and time of assessment (P < .0001) and their interaction (P = .036). Significant differences between the SCC and TI groups were found in the average scores at 12 months for PV (P = .011). Patients in the intervention group had significantly higher 12-month PV scores relative to their baseline scores (P < .0001). Patients in the SCC group had higher PV scores at 12 months relative to their baseline scores, but this increase was not significant (P = .085). For the I measure, the study group main effect (P = .022) and the interaction of study group x time of assessment effect (P = .050) were significant. The time of assessment effect was not significant. There was a statistically significant difference in 12-month scores between the two groups for I (P = .033). This reflects significantly lower I scores obtained by the TI group at 12 months (P = .040), with slightly higher I scores reported by the SCC group at 12 months relative to baseline, although this difference was not statistically significant (P > .10). Because the distribution of the positive effects variable was highly skewed (70% of respondents scored a total score of 0 on this measure), the scale was dichotomized according to scores equal to 0 versus scores more than 0, and a repeated measures analysis for binary data was performed. No significant effects for study group, time of assessment, interaction of study group x time of assessment, or the differences between the 12- or 6-month and baseline scores on this variable were found between the SCC and TI groups (all, P > .10).
Effect of Covariates for I
Inspection of the mean scores indicated that patients who used tobacco in the past had significantly higher I scores than those who never used tobacco (P = .019). Patients of tobacco-using parents had comparable mean I scores in both the SCC and TI groups (P = .920). However, for patients whose parents did not use tobacco, those who participated in the intervention had lower I scores than those in the SCC group (P = .003). The parent tobacco use x time of assessment interaction indicated that patients whose parents used tobacco had significantly higher I scores at 12 months compared with scores obtained at 6 months and baseline (P = .044). However, patients of non-tobacco-using parents did not have significantly different I scores across time. A significant difference was observed for perceived positive effect scores according to study group (P = .041). For the SCC group, increased perceived positive effects of tobacco use was associated with increased I (ß = 0.22, P = .014). Likewise, there was a marginally significant difference for PV scores according to study group (P = .058). For the intervention group, an inverse relationship between PV and I (ß = -0.04, P = .030) was obtained (Table 3 ).
Our study was the first of its kind to report the efficacy of a randomized controlled trial aimed at prevention of tobacco use for preadolescents and adolescents who survived cancer. Overall, the results of this study indicated that tobacco-related knowledge, PV to tobacco-related health risks, and intentions to use tobacco in the future among pediatric cancer survivors can be modified with a risk counseling intervention. Specifically, K and PV were increased and I was decreased as a result of the intervention, and these effects were most apparent at 12 months following the intervention. Furthermore, our findings support the feasibility of conducting brief, individualized, single-session tobacco interventions, with telephone follow-up in a medical setting. Because of the time constraints of this study, the effect of our intervention on the long-term tobacco abstinence of patients could not be confirmed. However, self-reported intention to smoke has been found to be a predictor of subsequent self-reported smoking behavior among adolescents followed longitudinally over a 4-year interval.25 Similarly, susceptibility to smoking, defined as the absence of a firm decision not to smoke, has been reported to significantly predict experimentation with smoking 4 years later in a nationally representative sample of 4,500 healthy adolescents.26 Johnson et al27 most recently reported that children who indicated their intentions not to smoke in the fifth grade generally were not smoking in the eighth grade, supporting the notion that smoking intentions predict future smoking behavior. Although this relationship has yet to be studied in young cancer survivors, greater efficacy in preventing smoking onset may be achieved by targeting at-risk survivors who clearly intend to smoke or those whose current intentions to smoke are less clearly established. The results of our study were somewhat consistent with current models of health protective behavior that indicate an inverse relationship between PV to health risks and the practice of health risk behaviors such as tobacco use.13 Examination of predictors of I among patients in our sample indicated that, particularly for the intervention group, higher PV was associated with decreased I. Therefore, informing adolescent cancer survivors about their personal susceptibility to negative health outcomes can play a role in promoting tobacco abstinence in this vulnerable patient population. Although similar changes in K, PV, and I were observed between the SCC and TI groups at 6 months, significant changes between the groups were not evident until 12 months after the intervention. These results reflect the failure of the patients in the SCC group to maintain short-term effects, whereas patients in the TI group demonstrated continued improvement, although minimal, on K and PV measures and further reduction on the I measure at 12 months. The stronger intervention effects observed at 12 months are inconsistent with traditional educational and learning theories that would predict decay of the intervention effects over time. The delayed effect of our intervention indicates that modifying young survivors’ perceptions of risk and intentions to use tobacco may reflect a process that evolves over time. Current theory describes smoking onset as a stage-based process that begins with a preparatory phase during which knowledge and attitudes about smoking and intentions to smoke are established.28 Therefore, it may be that patients who received our intervention became more sensitized to social, environmental, and informational cues over time that better enabled them to recognize the risks associated with tobacco use and to decide not to use tobacco. The limited effectiveness of our intervention at 6 months suggests that a more intensive intervention may be necessary to enhance the short-term effect of our tobacco counseling program with young cancer survivors. Our research findings further indicated that nonsmoking patients who had used tobacco in the past, who had parents who used tobacco, and who perceived greater benefit from tobacco use had higher I scores. Interestingly, patients whose parents were non–tobacco users and who received our intervention reported significantly lower I scores than the control group patients, indicating that these patients may have been highly receptive to tobacco risk counseling. Our intervention had less of an effect among patients of parents who used tobacco. Collectively, these findings indicate that health care providers should attempt to not only correct survivors’ misperceptions of the attractive features of tobacco use but also inquire about parental tobacco habits that could affect the survivor’s decision to use tobacco. Unlike previously reported findings with healthy adolescents,29,30 exposure to peers who used tobacco did not significantly predict survivors’ intentions to use tobacco after controlling for other factors. It is not clear whether peer social influences play an equally important role in the cancer survivors’ decision to use tobacco as they do for healthy adolescents, although we are currently investigating this topic. The generally high baseline K scores obtained by the survivors in our sample demonstrated their satisfactory knowledge about general tobacco-related information. The significant improvement in scores on the K measure for intervention participants at 12 months is notable in light of the high baseline scores that likely resulted in a ceiling effect on score changes. Similar measurement problems were noted for our I and positive effects measures, which were endorsed in the direction of low I and positive effects because the majority of survivors were nonsmokers. The ceiling and floor effects on our K and I measures, respectively, made it difficult to assess clinically meaningful change in acquired health information and behavioral intentions as a result of our intervention. Development of more sensitive measures of K and I for use among cancer survivors is certainly warranted to better assess the efficacy of our smoking prevention efforts with this population. Although brief clinician-delivered interventions have been successful in reducing tobacco use among adult head and neck cancer patients,10 efficacy data from smoking prevention studies with chronically ill pediatric populations has not been published. The results reported in this study, however, are comparable with those obtained from brief school-based peer- and nurse-delivered smoking prevention trials with healthy preadolescents and adolescents, using similar outcome measures. For example, decreased intentions, more negative attitudes toward smoking, and higher knowledge about smoking-related outcomes have been reported in preadolescents participating in an intervention that consisted of watching two 30-minute smoking-related theater productions.31 Similarly, preadolescents exposed to two 1-hour tobacco education curricula delivered by health care staff in the classroom demonstrated significant increases in tobacco knowledge but no change in attitudes about tobacco use from pretest to posttest.32 School-based smoking prevention curricula focused on teaching refusal skills combined with mail and telephone booster sessions delivered over 3 years have been effective in reducing tobacco use among preadolescent and adolescent students.33 Building on these studies, a greater intensity of intervention-based contact (ie, a higher intervention dosage) and booster sessions may be necessary to promote more lasting effects on knowledge, perceptions, and intentions to smoke in young cancer patients. Despite the strength of our novel tobacco counseling approach, the results of our study should be interpreted within the context of additional study limitations. First, the outcome measures used relied on patient self-report. Although efforts were made to ensure confidentiality, we cannot exclude the possibility that some youngsters may have underreported their intentions to use tobacco because our assessment was conducted by health care professionals in a medical setting. Furthermore, we did not include a biologic marker of smoking behavior. Although biochemical verification of self-reported smoking quit rates has been more commonly employed in adult cessation studies,34,35 to our knowledge, biologic markers have not been typically used in adolescent smoking prevention trials. However, urine cotinine levels have been used to confirm the smoking status of adolescents presenting to a pediatric practice, suggesting that adolescent regular smokers were generally truthful in completing a questionnaire about smoking habits when they were assured of anonymity.36 Validation of self-report (informant or biochemical) or use of a bogus pipeline procedure to reduce misreporting have been recommended for outcome assessments in high-risk adult medical groups37 and may be equally useful in pediatric populations. Second, many of the outcome measures used were nonstandardized, user-developed, multi-item instruments with limited psychometric data that may have accounted for the measurement problems reported. Third, the sample recruited for the study was primarily white and had a limited number of minority participants such that the results should not be generalized beyond the parameters of the study. Future research with underserved ethnic groups is warranted, given previous findings that ethnicity can moderate the effects of risk factors for smoking onset.38 Additional longitudinal studies are also needed to determine definitive long-term intervention effects on tobacco use in this high-risk population.
Supported in part by grants CA 21765 and CA 70267 from the National Cancer Institute and the American Lebanese Syrian Associated Charities (ALSAC).
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Copyright © 2003 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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ABSTRACT
INTRODUCTION
