Abstract
Background
Cancer survivors have a high rate of participation in cigarette-smoking cessation programs but their smoking-abstinence rates remain low. In the current study, we evaluated the readiness to quit smoking in a cancer-survivor population.
Methods
Cross-sectional data survey conducted among 112 adult cancer survivors who smoked cigarettes in Tennessee. Analyses were conducted using a two-sample t-test, χ2 test, Fishers Exact test, and multivariable logistic regression with smoker’s readiness to quit as the dependent variable. We operationally defined a smoker not ready to quit as anyone interested in quitting smoking beyond the next 6 months or longer (or not at all), as compared to those that are ready to quit within the next 6 months.
Results
Thirty-three percent of participants displayed a readiness to quit smoking in the next 30 days. Smokers ready to quit were more likely to display high confidence in their ability to quit (OR = 4.6; 95% CI, 2.1–9.7; P < 0.0001) than those not ready to quit. Those ready to quit were nearly five times more likely to believe smoking contributed to their cancer diagnosis (OR = 4.9; 95% CI, 1.1–22.6; P = 0.0432). Those ready to quit were also much more likely to attempt smoking cessation when diagnosed with cancer (OR = 8.9; 95% CI, 1.8–44.3; P = 0.0076) than smokers not ready to quit. Finally, those ready to quit were more likely to endorse smoking more in the morning than other times of the day, compared to those not ready to quit (OR = 7.9; 95% CI, 1.5–42,3; P = 0.0148), which increased odds of readiness to quit within the next 6 months.
Conclusions
Despite high participation in smoking-cessation programs for cancer survivors, only one-third of participants were ready to quit. Future research is needed to develop programs targeting effective strategies promoting smoking cessation among cancer survivors who are both ready and not ready to quit smoking.
Keywords: Smoking, Smoking cessation, Cancer survivors, Health behavior
INTRODUCTION
Cigarette smoking is the single most important preventable cause of morbidity, mortality, and excess health care costs in the United States, causing approximately 480,000 premature deaths and accounting for 30% of all cancer deaths annually.1 Smoking increases the risk of 19 types of cancer,2 and is attributable to over 90% of lung cancer mortality.3 And yet, while approximately one-half of cancer survivors quit smoking at or around the time of their cancer diagnosis,4 many of these survivors relapse following treatment. Smoking cessation among cancer survivors is an escalating concern as their numbers in the US continue to grow.5
In 2016, there were an estimated 15.5 million cancer survivors; 98% of these individuals had a cancer diagnosis as an adult.6,7 The National Coalition for Cancer Survivorship and the National Cancer Institute defines an adult cancer survivor as any individual diagnosed with cancer (from initial diagnosis until death).8 While smoking cessation after a cancer diagnosis is associated with greater response to cancer treatment1,9,10 and reduced mortality risk,1,3,9 as well as a reduction in risk of non-cancer related health conditions, such as heart disease, stroke, and chronic obstructive lung disease,1 there is still a lack of effective smoking cessation treatments for cancer survivors.
Despite a growing body of literature examining the effectiveness of smoking cessation interventions tailored for both adult cancer survivors and survivors of childhood cancer, these interventions have proven ineffective.11 In a systematic review and meta-analysis in oncology populations, Nayan et al.11 concluded that “tobacco cessation interventions in the oncology populations, in both the short-term and long-term follow-up groups, do not significantly affect cessation rates.” However, it is unclear why behavioral and pharmacologic interventions for smoking cessation have not been shown to be efficacious in this population.12
Interestingly, despite the low rates of cessation in cancer survivors, the extant literature suggests that cancer survivors join smoking cessation programs in high numbers. In a study of adult smokers who were survivors of child hood cancer, 67% of eligible participants contacted through a telephone based recruitment strategy agreed to participate.13 In a another study of cancer survivors with adult onset, a staggering 99.5% of survivors approached through a face-to-face recruitment strategy agreed to participate.13 However, consistent with the rest of the extant literature, in both of these studies cotinine verified cessation rates were low (< 4%). Unfortunately, there is a lack of research regarding the ‘disconnect’ between the high participation rates of cancer survivors in smoking cessation programs and the extremely low rates of cessation.
One possible explanation may be that while cancer survivors recognize the need to quit smoking and may even feel compelled or obligated to participate in smoking cessation programs, similar to the general population of adult smokers they demonstrate variable readiness to quit smoking. While 69% of smokers in the general population want to quit in the next year,14 fewer than 10% of smokers are ready to make a serious smoking cessation attempt in the next 30 days.15 Little is known about the readiness to quit smoking among cancer survivors.16–18
The purpose of the current investigation is to evaluate the level of readiness to quit smoking in a sample of cancer survivors who smoke as well as determine predictors of those ready to quit.
MATERIALS AND METHODS
1. Design and setting
This study was a cross-sectional assessment of readiness to quit smoking among cancer survivors. We recruited and surveyed participants at the four West Cancer Center locations around the Memphis, Tennessee area.
2. Participants and eligibility
Subjects were eligible to participate if they were: 1) ≥ 18 years of age; 2) currently receiving treatment at one of the West Cancer Centers; and 3) have received, understood, and signed the informed consent. Patients interested in participating were referred to a University of Tennessee Health Science Center (UTHSC) staff member to assess eligibility and describe their participation in the study. Once consent was obtained, the participant had the option to complete the survey individually or have the UTHSC staff member read the survey to them. The survey was anonymous, and was approved by the UTHSC Intuitional Review Board.
3. Measures
The survey assessed (1) demographics, (2) smoking history, (3) readiness to quit smoking (including stages of change), (4) self-efficacy to quit (measured on a five-point scale with 5 being extremely confident), (5) reasons for smoking (measured on a five-point scale with 5 being extremely true), (6) perceived benefit of quitting smoking (measured on a five point scales with 5 being strongly agree) and (7) cancer diagnosis and status. We had participants complete the Fagerström Test for Nicotine Dependence.19 Based on the Transtheoretical Model of the Stages of Change,20 we operationally defined a smoker not ready to quit as anyone interested in quitting smoking beyond the next 6 months or longer (or not at all), as compared to those that are ready to quit within the next 6 months.
4. Statistical data analysis
Statistical analyses were conducted using SAS/STAT v.14.1 (SAS Institute Inc., Cary, NC, USA). Descriptive statistics including means and their standard deviations, or frequencies and proportions of key demographic and tobacco variables were computed for the overall study population, and by readiness to quit among current smokers (N = 110): ready to quit within the next 6 months (n = 72) and not ready to quit within 6 months (n = 38). Differences in means between the respective groups of current smokers were tested using two-sample t-test while differences in proportions were compared using a χ2 test or Fishers Exact test, respectively. We applied a multivariable logistic regression model to determine the relative odds with which demographic variables and intrapersonal factors were associated with smoker’s readiness to quit. The initial regression model was based on the univariate findings. Covariates significant at P < 0.5 were entered into a multivariate model. The final multivariate model was reduced using a manual backwards selection approach to retain only significant variables and important confounders. All associations were considered significant at the alpha level of 0.05 while confounders were retained at 0.1 alpha level.
RESULTS
We surveyed a total of 631 cancer survivors (Table 1). Participants were predominantly female (63.8%), white (59.8%), non-Hispanic (99.5%), and with an average age of 60.7 years (SD = 14.2). Over one-half were married (54.1%), had greater than a high school education (57.4%) and were currently being treated for cancer (51.3%).
Table 1.
Sample characteristics of all cancer survivors surveyed (N = 631)
| Demographic | Value |
|---|---|
| Age (yr) | 60.7 ± 14.2 |
| Gender (female) | 63.8 |
| Race | |
| White | 59.8 |
| African American | 38.3 |
| Other | 1.9 |
| Non-Hispanic | 99.5 |
| Married | 54.1 |
| Education | |
| <High school | 10.4 |
| High school/general education development | 32.2 |
| >High school | 57.4 |
| Smoking status | |
| Never | 50.2 |
| Former | 32.0 |
| Current | 17.8 |
Values are presented as mean ± SD or percent only.
Nearly one-half of the sample reported smoking at least 100 cigarettes in their lifetime, with 17.8% self-identifying as current daily smokers and 32.0% as former smokers. Current smokers (N = 112) reported smoking an average of 34.3 years (SD = 13.5) with an average of 13.3 (SD = 10.3) cigarettes per day for the past seven days and were retained for further analyses.
Only 32.7% of current smokers reported a readiness to quit in the next 30 days, which is a common criteria for inclusion into many smoking cessation studies.12 Another one-third (32.7%) indicated they were ready to quit smoking within the next 1 to 6 months and nearly 35% (34.6%) of smokers were not ready to quit smoking within the next six months.
Analyses indicate that the 65.4% who were either ready to quit in the next 30 days or 6 months were quite similar whereas contrasts were observed between these two groups and the 34.6% of the sample who were not ready to quit in the next six months. As such, multivariate analyses were conducted between (a) those ready to quit in the next 30 days or next six months (‘ready to quit’; n = 72) with (b) those not ready to quit within the next six months (‘not ready to quit’; n = 38).
Univariate comparisons among current smokers presented in Table 2 indicated that those ready to quit were more likely to be younger (56.8 years vs. 62.2 years; P = 0.0263), have smoked less years on the average (32.1 cigarettes vs. 38.2 cigarettes; P = 0.0240), use e-cigarettes at a higher rate (20.8% vs. 5.3%; P = 0.0317), are trying to quit now (84.5% vs. 28.9%; P < 0.0001), have tried quitting in their lifetime (84.7% vs. 56.8%; P = 0.0014), are more confident in their ability to quit (P < 0.0001), believe smoking contributed to their cancer (48.4% vs. 16.1%; P = 0.0023), have tried quitting when they were diagnosed (61.8% vs. 17.7%; P < 0.0001), believe quitting would result in health benefits (P < 0.0001), believe quitting would increase chances of cancer survival (P = 0.0008), think that quitting would decrease the chances of recurrence (P < 0.0001), and continued to smoke because they were also consuming alcohol (P = 0.0229), or out of weight gain concern (P = 0.0377). They were also less likely to use roll your own tobacco (5.6% vs. 21.1%; P = 0.0132) or smoke cigarillos (1.4% vs. 10.5%; P = 0.0287), and try quitting cold turkey (58.3% vs. 84.6%; P = 0.0211).
Table 2.
Univariate comparisons between survivor smokers who were ready to quit and not ready to quit within 6 months (N = 110)
| Variable | Ready to quit within 6 months (n = 72) | Not ready to quit within 6 months (n = 38) | P-valueb |
|---|---|---|---|
| Age (yr) | 56.8 ± 12.5 | 62.2 ± 10.6 | 0.0263* |
| Gender (male) | 45.1 | 54.1 | 0.3752 |
| Race | 0.5729 | ||
| White | 57.8 | 57.9 | |
| Non-white | 39.4 | 42.1 | |
| Multiracial | 2.8 | 0.0 | |
| Marital status (married) | 46.5 | 42.1 | 0.6618 |
| Education | 0.3211 | ||
| Less than high school | 16.9 | 21.1 | |
| Diploma or general education development | 36.6 | 47.4 | |
| Some college | 46.5 | 31.6 | |
| Cancer status | 0.3327 | ||
| Evaluation | 12.9 | 10.5 | |
| Diagnoses | 12.9 | 2.6 | |
| Treatment | 61.4 | 73.7 | |
| Remission | 12.9 | 13.2 | |
| Lung and/or bronchus cancer | 34.7 | 18.4 | 0.0735 |
| Other tobacco product use | |||
| Smokeless tobacco | 9.7 | 7.9 | 0.7512 |
| Snus | 5.6 | 2.6 | 0.4839 |
| Hookah | 4.2 | 2.6 | 0.6826 |
| Roll your own tobacco | 5.6 | 21.1 | 0.0132* |
| Cigarillo | 1.4 | 10.5 | 0.0287* |
| Electronic cigarettes | 20.8 | 5.3 | 0.0317* |
| Years smoked currently | 32.1 ± 13.7 | 38.2 ± 12.4 | 0.0240* |
| Daily use | 88.4 | 94.7 | 0.2816 |
| Average cigarettes per day | 12.9 ± 10.6 | 14.4 ± 9.5 | 0.4918 |
| Trying to quit now | 84.5 | 28.9 | <0.0001* |
| Tried to quit in the past | 84.7 | 56.8 | 0.0014* |
| Times tried to quit | 5.3 ± 5.8 | 4.0 ± 2.7 | 0.1669 |
| Self-efficacy to quita | 4.0 ± 1.1 | 2.5 ± 1.0 | <0.0001* |
| Believe smoking contributed to cancer | 48.4 | 16.1 | 0.0023* |
| Tried to quit when diagnosed with cancer | 61.8 | 17.7 | <0.0001* |
| Doctor advised to quit | 75.0 | 72.2 | 0.7585 |
| Doctor provided smoking cessation resources | 38.2 | 51.4 | 0.1945 |
| Methods tried | |||
| Nicotine replacement therapy | 78.6 | 88.9 | 0.2698 |
| Medication prescription | 80.0 | 82.4 | 0.7838 |
| Cold turkey | 58.3 | 84.6 | 0.0211* |
| Group program | 96.9 | 100.0 | 0.5345 |
| Counseling | 96.9 | 100.0 | 0.5366 |
| Telephone quit line | 93.9 | 97.2 | 0.4538 |
| Electronic cigarettes | 90.4 | 91.7 | 0.8370 |
| Perceived benefit of quittinga | 4.2 ± 1.0 | 2.8 ± 1.6 | <0.0001* |
| Quitting would increase chances of cancer survivala | 3.4 ± 1.3 | 2.5 ± 1.3 | 0.0008* |
| Quitting would decrease cancer recurrencea | 3.5 ± 1.1 | 2.2 ± 1.2 | <0.0001* |
| I continued to smoke because···a | |||
| I never intended to stay tobacco free | 1.4 ± 1.0 | 2.6 ± 1.7 | 0.0008* |
| I was too stressed and anxious about my cancer | 3.0 ± 1.7 | 3.4 ± 1.7 | 0.2982 |
| To alleviate boredom | 2.1 ± 1.3 | 1.8 ± 1.4 | 0.2679 |
| Other smokers around me continued to smoke | 2.6 ± 1.6 | 2.7 ± 1.7 | 0.8020 |
| I was feeling depressed | 2.5 ± 1.6 | 2.2 ± 1.7 | 0.3742 |
| I was drinking alcohol | 2.2 ± 1.5 | 1.5 ± 1.2 | 0.0229* |
| I was concerned about gaining weight | 2.0 ± 1.5 | 1.4 ± 1.1 | 0.0377* |
| FND Score Categories | 3.7 ± 1.9 | 3.9 ± 2.1 | 0.4663 |
Values are presented as mean ± SD or percent only.
Measured on a five-point Likert scale with 5 being a higher endorsement for the item.
Chi-square or exact P-value for %; or t-test for means.
P < 0.05.
When univariate comparisons were adjusted for other variables in the model, four significant associations remained with one confounding factor. First, those that used roll your own tobacco had over a 90% lower odds of readiness to quit in the next six months (OR = 0.04; 95% CI, 0.01–0.67; P = 0.0244). Second, smokers ready to quit were more likely to display a higher confidence in their ability to quit smoking (OR = 3.49; 95% CI, 1.72–7.09; P = 0.0005) than those not read to quit. Third, cancer survivors ready to quit were over ten times more likely to believe that smoking contributed to their cancer diagnosis (OR = 10.37; 95% CI, 1.96–54.89; P = 0.0059). Finally, those ready to quit were more likely to attempt smoking cessation when they were diagnosed with cancer (OR = 6.39; 95% CI, 1.12–36.43; P = 0.0366) than those smokers who were not ready to quit. Even though trying to quit now was associated with almost 4 times increased odds of readiness to quit within 6 months, it didn’t reach traditional significance at the 0.05 level. However, we retained it in the model as a confounder for adjustment purposes. The final model had high predictive power with area under the receiver operating characteristic curve of 0.94 (Table 3).
Table 3.
Results from the final multivariate modela
| Variable | Crude OR | Crude 95% CI | Crude P-value | Adjusted OR | Adjusted 95% CI | Adjusted P-value |
|---|---|---|---|---|---|---|
| Roll your own cigarettes | 0.22 | 0.06–0.80 | 0.0214 | 0.04 | 0.01–0.67 | 0.0244 |
| Trying to quit now | 13.20 | 5.08–34.09 | <0.0001 | 3.89 | 0.85–17.81 | 0.0794 |
| Self-efficacy to quit | 3.46 | 2.14–5.59 | <0.0001 | 3.49 | 1.72–7.09 | 0.0005 |
| Contributed to cancer | 4.73 | 1.61–13.88 | 0.0047 | 10.37 | 1.96–54.89 | 0.0059 |
| Tried quitting when diagnosed | 7.39 | 2.67–20.47 | 0.0001 | 6.39 | 1.12–36.43 | 0.0366 |
Predictors entered into the final multivariate model that were not retained included age, other tobacco use, years smoked, tried to quit in the past, believed smoking contributed to their cancer, tried to quit cold turkey, perceived benefits of quitting, continued to smoke because they never intended to stay quit, continued to smoke because they were drinking alcohol, and continued to smoke because they were concerned about gaining weight.
DISCUSSION
We observed that only about one third of cancer survivors who smoke are ready to make a cessation attempt in the next 30 days and one third of smoking cancer survivors indicate an unwillingness to engage in a smoking cessation attempt within the next six months. Those ready to engage in a cessation attempt within the next six months, relative to those not ready, were more likely to report a higher confidence in their ability to quit smoking, more likely to acknowledge that smoking contributed to their cancer diagnosis, and were more likely to attempt cessation when they were diagnosed with cancer.
The finding that the majority of cancer survivors that smoke are not ready to quit in the next 30 days may help explain why participation in stop smoking programs is very high in cancer survivors yet cessation rates are low.13,21 Traditional smoking cessation programs often include having the smoker set a quit date within 6 months, and most often it is within 30 days of entering the program.12 Our research indicates that two-thirds of cancer survivors are not ready to quit in such a short time frame. A possible explanation for this observation is that cancer survivors are joining stop-smoking cessation programs because they feel obligation or pressured by health care providers, not because they feel ready to quit.
Given the apparent disconnect between cancer survivor participation in smoking cessation programs and their readiness to quit smoking, interventions need to account for differing levels of readiness. A growing literature exists utilizing combined behavioral and pharmacologic rate reduction with the outcome of cessation at follow-up among smokers not ready to quit.22–24 The rationale is that self-efficacy may be enhanced through a gradual reduction in smoking over time. In a systematic review of rate reduction studies among smokers not ready to quit, Asfar et al. concluded that combined behavioral and pharmacologic (typically nicotine replacement therapy in the form of the patch or gum) rate reduction more than doubled the odds of total cessation at follow-up in smokers not ready to quit relative to control or comparison groups.22
To our knowledge, no study has compared, in any population, the efficacy of a smoking cessation program that tailors the intervention goals to the readiness level of participants. While the readiness rate of smoking among cancer survivors is slightly higher (33%) than that of the general smoking population (20%–30%),25,26 the majority of cancer survivors are not ready to make a cessation attempt in the next 30 days. Future research is needed to compare the effectiveness of traditional smoking cessation programs with rate reduction programs among cancer survivors.
Our study has several strengths. To our knowledge few studies have evaluated readiness to quit smoking in cancer survivors.16–18 Our study participants represented a diverse sample of cancer survivors. However, our study has several limitations. First, we relied on self-reports of smoking status, and there is some indication that cancer survivors are more likely to underreport their tobacco status than the general population of smokers.13,21 As such, our estimates to tobacco use in our sample may be underestimates. While we conducted surveys anonymously in the hope that this would increase honest reporting of tobacco status, future studies should consider using biochemical verification. Additionally, we recruited survivors from a single cancer center. However, because we recruited from four locations representing a diverse range of socio-economic status, racial, and ethnic characteristics, we do not feel that this biased our results. Finally, our assessment was cross-sectional which prevented us from examining changes in readiness to quit over time.
In summary, only about one third of smoking cancer survivors are ready to quit smoking at any given point in time. These results have implications for treating survivors in the future, as interventions are needed to address both cancer survivors ready to quit as well as those not ready to quit.
ACKNOWLEDGMENTS
The authors gratefully acknowledge Methodist Health Systems and the West Cancer Center for their assistance in providing access to their facilities and patients. This study was supported by a grant from the National Cancer Institute (R01CA127964) awarded to Dr. Klesges, as well as funding from the University of Virginia Center for Addiction Prevention Research.
Footnotes
CONFLICTS OF INTEREST
No potential conflicts of interest were disclosed.
REFERENCES
- 1.National Center for Chronic Disease Prevention and Health Promotion (US) Office on Smoking and Health. The health consequences of smoking-50 years of progress: a report of the surgeon general. Atlanta, Centers for Disease Control and Prevention, 2014. [PubMed] [Google Scholar]
- 2.Secretan B, Straif K, Baan R, Grosse Y, El Ghissassi F, Bouvard V, et al. A review of human carcinogens--Part E: tobacco, areca nut, alcohol, coal smoke, and salted fish. Lancet Oncol 2009;10:1033–4. 10.1016/S1470-2045(09)70326-2 [DOI] [PubMed] [Google Scholar]
- 3.Parsons A, Daley A, Begh R, Aveyard P. Influence of smoking cessation after diagnosis of early stage lung cancer on prognosis: systematic review of observational studies with meta-analysis. BMJ 2010;340:b5569. 10.1136/bmj.b5569 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Cox LS, Africano NL, Tercyak KP, Taylor KL. Nicotine dependence treatment for patients with cancer. Cancer 2003;98:632–44. 10.1002/cncr.11538 [DOI] [PubMed] [Google Scholar]
- 5.de Moor JS, Mariotto AB, Parry C, Alfano CM, Padgett L, Kent EE, et al. Cancer survivors in the United States: prevalence across the survivorship trajectory and implications for care. Cancer Epidemiol Biomarkers Prev 2013;22:561–70. 10.1158/1055-9965.EPI-12-1356 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Siegel R, DeSantis C, Virgo K, Stein K, Mariotto A, Smith T, et al. Cancer treatment and survivorship statistics, 2012. CA Cancer J Clin 2012;62:220–41. 10.3322/caac.21149 [DOI] [PubMed] [Google Scholar]
- 7.National Cancer Institute. Statistics. https://cancercontrol.cancer.gov/ocs/statistics/statistics.html Accessed November 27, 2017.
- 8.National Cancer Institute. NCI dictionary of cancer terms. https://www.cancer.gov/publications/dictionaries/cancer-terms?cdrid=450125 Accessed August 14, 2017.
- 9.Browman GP, Wong G, Hodson I, Sathya J, Russell R, McAlpine L, et al. Influence of cigarette smoking on the efficacy of radiation therapy in head and neck cancer. N Engl J Med 1993;328:159–63. 10.1056/NEJM199301213280302 [DOI] [PubMed] [Google Scholar]
- 10.Kumar B, Cordell KG, Lee JS, Worden FP, Prince ME, Tran HH, et al. EGFR, p16, HPV Titer, Bcl-xL and p53, sex, and smoking as indicators of response to therapy and survival in oropharyngeal cancer. J Clin Oncol 2008;26:3128–37. 10.1200/JCO.2007.12.7662 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Nayan S, Gupta MK, Strychowsky JE, Sommer DD. Smoking cessation interventions and cessation rates in the oncology population: an updated systematic review and meta-analysis. Otolaryngol Head Neck Surg 2013;149:200–11. 10.1177/0194599813490886 [DOI] [PubMed] [Google Scholar]
- 12.Fiore MC, Jaén CR, Baker TB, Bailey WC, Curry SJ, Froelicher ES, et al. Treating tobacco use and dependence: 2008 update. Rockville, MD, U.S. Department of Health and Human Services, Public Health Service, 2008. [Google Scholar]
- 13.Klesges RC, Krukowski RA, Klosky JL, Liu W, Srivastava DK, Boyett JM, et al. Efficacy of a tobacco quitline among adult cancer survivors. Prev Med 2015;73:22–7. 10.1016/j.ypmed.2014.12.019 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Centers for Disease Control and Prevention (CDC). Quitting smoking among adults: United States, 2001–2010. MMWR Morb Mortal Wkly Rep 2011;60:1513–9. [PubMed] [Google Scholar]
- 15.Wewers ME, Stillman FA, Hartman AM, Shopland DR. Distribution of daily smokers by stage of change: current population survey results. Prev Med 2003;36:710–20. 10.1016/S0091-7435(03)00044-6 [DOI] [PubMed] [Google Scholar]
- 16.Gritz ER, Carr CR, Rapkin D, Abemayor E, Chang LJ, Wong WK, et al. Predictors of long-term smoking cessation in head and neck cancer patients. Cancer Epidemiol Biomarkers Prev 1993;2:261–70. [PubMed] [Google Scholar]
- 17.Emmons KM, Puleo E, Park E, Gritz ER, Butterfield RM, Weeks JC, et al. Peer-delivered smoking counseling for childhood cancer survivors increases rate of cessation: the partnership for health study. J Clin Oncol 2005;23:6516–23. 10.1200/JCO.2005.07.048 [DOI] [PubMed] [Google Scholar]
- 18.Schnoll RA, Malstrom M, James C, Rothman RL, Miller SM, Ridge JA, et al. Correlates of tobacco use among smokers and recent quitters diagnosed with cancer. Patient Educ Couns 2002;46:137–45. 10.1016/S0738-3991(01)00157-4 [DOI] [PubMed] [Google Scholar]
- 19.Heatherton TF, Kozlowski LT, Frecker RC, Fagerström KO. The Fagerström Test for Nicotine Dependence: a revision of the Fagerström Tolerance Questionnaire. Br J Addict 1991;86:1119–27. 10.1111/j.1360-0443.1991.tb01879.x [DOI] [PubMed] [Google Scholar]
- 20.Prochaska JO, Velicer WF, Rossi JS, Goldstein MG, Marcus BH, Rakowski W, et al. Stages of change and decisional balance for 12 problem behaviors. Health Psychol 1994;13:39–46. 10.1037/0278-6133.13.1.39 [DOI] [PubMed] [Google Scholar]
- 21.Klesges RC, Krukowski RA, Klosky JL, Liu W, Srivastava DK, Boyett JM, et al. Efficacy of a tobacco quitline among adult survivors of childhood cancer. Nicotine Tob Res 2015;17:710–8. 10.1093/ntr/ntu216 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Asfar T, Ebbert JO, Klesges RC, Relyea GE. Do smoking reduction interventions promote cessation in smokers not ready to quit? Addict Behav 2011;36:764–8. 10.1016/j.addbeh.2011.02.003 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Carpenter MJ, Hughes JR, Solomon LJ, Callas PW. Both smoking reduction with nicotine replacement therapy and motivational advice increase future cessation among smokers unmotivated to quit. J Consult Clin Psychol 2004;72:371–81. 10.1037/0022-006X.72.3.371 [DOI] [PubMed] [Google Scholar]
- 24.Chan SS, Leung DY, Abdullah AS, Wong VT, Hedley AJ, Lam TH. A randomized controlled trial of a smoking reduction plus nicotine replacement therapy intervention for smokers not willing to quit smoking. Addiction 2011;106:1155–63. 10.1111/j.1360-0443.2011.03363.x [DOI] [PubMed] [Google Scholar]
- 25.Papadakis S, Tulloch HE, Gharib M, Pipe AL. Profile of tobacco users identified in primary care practice and predictors of readiness to quit: a cross-sectional survey. CMAJ Open 2016;4:E41–7. 10.9778/cmajo.20150055 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Velicer WF, Fava JL, Prochaska JO, Abrams DB, Emmons KM, Pierce JP. Distribution of smokers by stage in three representative samples. Prev Med 1995;24:401–11. 10.1006/pmed.1995.1065 [DOI] [PubMed] [Google Scholar]