This article assesses the long-term impact of PFH, the first large-scale intervention targeting smoking cessation among childhood cancer survivors. Although the length of follow-up varies, this study provides an important opportunity to examine the experiences of smokers several years out from a smoking cessation program. Cessation rates continue to be significantly higher among participants in the PC condition versus SH, although the differences are not large. There was a trend toward higher continuous smoking rates among those in SH, with these participants being almost twice as likely to be smoking at every follow-up, compared with those in PC; PC participants had more active engagement with smoking cessation throughout the follow-up period.
Long-term cessation rates were lower among men, those who were nicotine dependent, and those of lower educational levels, and were higher among those who used NRT and who had higher self-efficacy. These mediators are similar to those typically found in the literature. In particular, it is important to note that use of NRT, which was provided at no cost, increased LT outcomes. Increasing NRT use among survivors would be consistent with Agency for Health Care Policy and Research guidelines.31
Further, recent work has also found that offering free NRT in the general population of smokers through a tobacco quit line increases both quit line utilization and quit rates as previously reported.32,33
Recent studies using ecological momentary assessment have elucidated the role of fluctuating self-efficacy in the onset of lapses.34
There is also some very recent work that is beginning to look at the role of self-efficacy versus satisfaction with outcomes in longer-term maintenance.35
Future work with survivors should explore the differential role of self-efficacy and satisfaction with outcomes as key predictors of cessation.
Relapse rates, although higher in the PC group, were not significantly different. It is unclear if additional support or continued counseling would have been helpful to these smokers, or if relapse was an effect of the withdrawal of support. The fact that both continued cessation rates and relapse rates were higher among those receiving a higher intervention dose suggests that greater understanding of the characteristics of individuals who might benefit from a higher dose is needed. Some individuals may benefit from self-directed ongoing support, such as through a web site.
There are few studies that address long-term quit rates in randomized control trials. Kadowaki et al36
reported 5-year cessation rates of 10.9% among 251 Japanese men in a physician-delivered smoking intervention. Cessation rates at 2.5 years among Veterans’ Affairs patients were 17.6% to 20.3%, with no between-group differences.37
Manfredi et al38
reported quit rates of 11% (no group differences) at 18 months in public health smoking clinics for women. Overall, there are few examples in the literature of interventions that have yielded long-term intervention effects.
In 2000, Ockene and colleagues39
reviewed the evidence on LT maintenance for smoking cessation and recommended that the field systematically move to longer follow-up assessments, with a minimum of 2-year follow-ups. There has only been limited movement in this direction. The recent Cochrane review of telephone counseling interventions for smoking cessation reported that the longest follow-up for any studies reviewed was 12 months;40
rarely do follow-up periods extend beyond 1 year.41
This study took advantage of an opportunity to collect LT outcomes, but the follow-up period varied (see limitations below). Exploratory subgroup analyses by similar follow-up periods confirmed the overall findings of higher rates of continuous smoking in SH, and higher rates of both quitting and relapse in the PC condition. Of note, in the analysis of those with 4+ years of follow-up data, there were no continuous quitters in the SH group, versus almost 7% in the PC group. Overall, there was a higher level of engagement with cessation among the PC group over the follow-up periods examined. This is important, as younger smokers are typically less likely to quit, and activating the cessation process as early as possible is critical given survivors’ health vulnerabilities.
This study highlights the need to develop an effective infrastructure for delivery of smoking cessation services to childhood cancer survivors. A recent study of clinics treating childhood cancer survivors found that only 3% of programs follow national guidelines on treating smoking in the health-care setting.42
Further, this study demonstrated that the infrastructure for identifying survivors within treatment/LT care programs is largely missing, and a more systematic approach to patient tracking and follow-up is needed.
LT smoking outcomes and quit attempts were not associated with subsequent cancer diagnosis, although recurrence was common (32% reported a cancer or benign tumor at follow-up). Recurrence or new diagnoses may offer a teachable moment for those who continue to smoke, although it would be important not to place blame for recurrence on continued smoking.43,44
Study limitations should be noted. First, the response rate to PFH was impacted by difficulties in reaching potential participants in this young and highly mobile population, although retention among those enrolled was high (> 70%), particularly given the length of the follow-up period. Intention-to-treat analyses assessed long-term outcomes, conservatively assuming that those who did not respond were smokers. Another limitation was the variable length of the long-term follow-up interval. Although it would be have been ideal to have had a standardized length of follow-up, accrual to CCSS was done on a rolling basis, which meant differing lengths of time between the PFH and CCSS follow-ups. Although not ideal, the follow-up approach utilized represented efforts to be cost-efficient, and to take advantage of long-term CCSS follow-up to assess smoking outcomes in PFH participants. It is extremely difficult to maintain an intervention cohort over several years after intervention completion, and thus there are few studies in the literature that evaluate LT outcomes. Thus, the added benefit of this unique data may off-set this methodologic limitation to some extent. Use of self-report cessation outcomes is also a limitation in population-level studies such as PFH.45
However, the PFH outcomes evaluation did use the bogus pipeline procedure, a well-accepted strategy for increasing the accuracy of self-report.46
There are several important strengths to note. The study sample was drawn from the largest and most comprehensively characterized research cohort of childhood cancer survivors.17
The large sample of smokers provided sufficient power to detect study outcomes. Data were conservatively analyzed using intention to treat. This study also highlights the importance of cohort studies in general, and the CCSS Long-Term Follow-Up Study of cancer survivors in particular. There are significant barriers to conducting long-term follow-up of behavior change interventions. This study of LT outcomes in PFH was possible only because we were able to embed it in the context of the CCSS data collection effort, which was separately funded.
It is particularly important to activate smoking cessation efforts among childhood cancer survivors as early as possible in order to decrease the chances of the deleterious health effects of smoking. These findings suggest that efforts should be made to increase smoking cessation among survivors, and that providing brief interventions lead to improved LT outcomes, which may improve health outcomes of childhood cancer survivors overall. The impact of the PFH intervention was significant but relatively small, although not atypical of smoking cessation programs that target all smokers, including those who are not interested in quitting. Further, it is important to consider the population-level impact of such findings, which can be considerable in shifting distribution of disease.