Randomized Trial of a Physical Activity and Meditation Intervention for Young Adult Cancer Survivors

Abstract

Purpose:

Young adult cancer survivors have a number of increased health and psychosocial risks. To minimize these risks, they must address any modifiable risk factors, for example increase their physical activity (PA) and reduce stress. Unfortunately, more than half of young survivors remain sedentary, and few participate in a structured form of relaxation. This study evaluated the feasibility, acceptability, and effects of a theory-based PA and meditation intervention for young survivors.

Methods:

Young adult cancer survivors (age 18–39 years) were randomized to receive the 12-week “RElaxation aNd Exercise for Wellness” (RENEW) intervention right away (intervention group) or after a 12-week wait (control group). Participants were assessed at baseline, 12 weeks, and 24 weeks.

Results:

Thirty-five survivors were enrolled and randomized. Results indicate that 89% of intervention calls were delivered, and most participants felt that intervention goals and the number and duration of intervention calls were appropriate. Satisfaction ratings indicate that the intervention was acceptable, and 100% of participants would recommend it to others. Comparison of the intervention and control groups at the 12-week assessment (i.e., before controls received the intervention) revealed that the intervention group was performing more minutes of at least moderate intensity PA/week (p = 0.002; M = 113.8, SE = 23.5 vs. M = –8.7, SE = 27.1) and outperformed controls on a test of cardiovascular fitness (p = 0.008; M = –1.76, SE = 0.41 vs. M = –0.03, SE = 0.45). When data from the intervention and control groups were pooled, pre- to post-intervention analyses indicated a trend toward improved mood.

Conclusion:

This theory-based intervention for young adult cancer survivors was feasible and acceptable, and may have helped survivors increase PA, improve fitness, and enhance mood.

Addressing health risk behaviors is particularly important for young adult cancer survivors (YACS), as cancer diagnosis and treatment leave many with a legacy of increased medical and psychosocial risks. The risk of cardiovascular disease is often elevated as a result of cardiotoxic chemotherapy, chest-focused radiation treatment,^1–3 or treatment-induced menopause.⁴ The risk of second malignancies may be increased from chemotherapy and/or radiation treatment.^4–6 In addition, YACS may be impacted by treatment-related weight gain and fatigue.^4,7–9 YACS are also at greater risk for emotional distress than older survivors are^10,11; distress may be related to fear of cancer recurrence, treatment-related infertility, disfigurement, or other factors.^12,13

Unfortunately, YACS often compound these physical and mental health risks by engaging in unhealthy behaviors. One notable example is that nearly 60% of survivors between 18 and 39 years of age are not regularly physically active.¹⁴ This is concerning, as a sedentary life-style, and any resulting weight gain, increases risk for cardiovascular disease and certain forms of cancer.^15–17 Insufficient levels of physical activity (PA) may also increase fatigue¹⁸ and diminish quality of life¹⁹ among survivors. Thus, YACS who are not physically active are compounding their already increased health risks.

By contrast, adopting healthy behaviors, such as increased PA, provides an array of relevant benefits. Research with (primarily older) cancer survivors has shown that PA can reduce fatigue and improve cardiovascular fitness, mood, emotional well-being, and quality of life.^20–22 These benefits are achievable even with brief, home-based interventions focused on moderate-intensity PA (e.g., brisk walking).^23–25 Although PA can positively impact on mood, YACS might also benefit from strategies—such as relaxation training—to target emotional well-being more directly. Cancer survivors offered mindfulness meditation interventions report reduced stress/distress and improved quality of life.^26–29 Thus, YACS may be able to address some of their physical and mental health risks by adopting healthy behaviors, including PA and mindfulness meditation.

To date, few behavioral interventions have been developed for those diagnosed with cancer during young adulthood. One of the few PA interventions for YACS was grounded in social cognitive theory and delivered through Facebook.³⁰ The intervention did not significantly increase moderate-to-vigorous PA or improve quality of life, and fewer than half of those receiving it would recommend it to others.³⁰ An individually tailored web-based intervention for YACS (grounded in social cognitive theory and the Transtheoretical Model) demonstrated greater acceptability: 86% would recommend the intervention to others. Participants receiving this intervention did not demonstrate significant increases in at least moderate-intensity activity relative to the control group (likely due to the small sample size), though group differences represented a medium-sized effect.³¹ Although web-based interventions may maximize convenience for YACS, this population may need more intensive contact to overcome barriers to life-style change. Findings from qualitative research support this: YACS want behavioral interventions that fit into their busy lives (given work and family demands) but also provide support from others who understand their experience.³² The YACS interviewed noted that telephone-based interventions would provide greater support than online interventions.³² These findings informed the design of the present intervention.

To address some of the unmet needs of YACS, the RENEW (“RElaxation aNd Exercise for Wellness”) intervention was developed: a telephone-delivered PA and meditation intervention for cancer survivors currently 18–39 years of age. RENEW was based on the principles of social cognitive theory and the Transtheoretical Model (see Table 1).^33,34 Eligibility was restricted to those diagnosed with cancer during young adulthood (i.e., aged 18–39). Thus, this intervention targeted a particularly vulnerable group who had not had the benefit of specialized pediatric oncology services during or after treatment.³⁵ The aim of the Survivors RENEW Study was to determine the feasibility and acceptability of the RENEW intervention. A secondary aim was to explore whether those receiving the intervention increased PA, and improved fitness and mood.

Table 1.

Intervention Components Targeting Social Cognitive Theory and Transtheoretical Model Constructs

	Intervention strategy for targeting construct
Social cognitive theory construct
Self-efficacy	Suggested weekly PA goals were minimal during the first few weeks of the program to increase the probability of participants' success and build confidence. Goals were negotiated with the participant to increase the likelihood of success.
Self-monitoring	Participants set weekly PA and meditation goals and tracked performance of PA and meditation on log sheets.
Reinforcement	During weekly calls, participants were encouraged to reward themselves for meeting weekly goals. In addition, efforts at behavior change were reinforced through praise during weekly calls.
Social support	During weekly calls, participants were encouraged to enlist social support for PA and meditation. For example, they were encouraged to ask spouses/partners to help them protect time to meditate and to reach out to others who might want to exercise with them.
Transtheoretical Model construct
Stages of change	Weekly behavioral coaching was matched to participants' readiness to adopt regular PA and meditation. For example, participants in the pre-contemplation stage for PA were encouraged to weigh the pros and cons of becoming more active. Those in the contemplation stage were encouraged to think about forms of moderate-intensity PA that might appeal to them. Those in the preparation stage were encouraged to consider how to accommodate more frequent PA in their schedule. Those in the action stage were encouraged to plan ahead so that potential obstacles to PA (e.g., bad weather) did not prevent them from remaining regularly active.
Processes of change	During weekly calls, participants were encouraged to use processes of change known to facilitate advancement through the stages of change. For example, participants were encouraged to use the behavioral process of stimulus control by leaving their exercise clothing in a visible location to remind them to exercise.

PA, physical activity.

Methods

Recruitment

The study protocol was approved by the Miriam Hospital Institutional Review Board prior to participant recruitment. Several recruitment strategies were used: in-person recruitment at oncology clinics; mailings to YACS in a hospital-based cancer registry; advertisement on radio, Web sites, and listservs; and providing brochures at hospitals, community locations, and cancer/health-related events. Recruitment was rolling and carried out over a period of 48 months.

Participants

YACS interested in the study were screened (in-person or by telephone) to determine whether they met these eligibility criteria: currently between 18 and 39 years of age; diagnosed with cancer between 18 and 39 years of age; diagnosed with cancer in the past 10 years; completed all cancer treatment (with the possible exception of hormone treatment); in cancer remission; able to read, write, and speak fluently in English; not regularly participating in a form of relaxation (e.g., yoga); and sedentary. Individuals were considered sedentary if they participated in less than 20 minutes of vigorous-intensity PA once a week and less than 30 minutes of moderate-intensity PA twice a week. Individuals were excluded from participation if they were pregnant or had any medical or psychiatric condition that would make participation dangerous or very difficult. Those considered eligible after screening provided the name of a physician who could verify that it was safe for them to participate and confirm their remission status. Once written confirmation was received, survivors were eligible to participate.

Procedure

Eligible survivors were scheduled for the baseline assessment, which involved two meetings with the project director (PD) separated by 1 week. After obtaining informed consent, the PD assessed the participant's demographics, PA, fitness, and mood (see Measures). Participants were then randomly assigned to receive the 12-week intervention right away (intervention group) or after a 12-week delay (control group). Randomization was stratified by age (i.e., 18–25, 26–39) and sex. (Randomization assignments were generated by a statistician and sealed in an envelope; the PD was blind to assignments until they were revealed to participants.) Follow-up assessments—using the same measures—were conducted at 12 weeks and 24 weeks post-baseline.

Intervention

At the baseline assessment (following randomization), intervention participants received an overview of the intervention. Participants were told they would be guided in gradually increasing the frequency and duration of their moderate-intensity aerobic activity toward a final goal of 30 minutes per day on at least 5 days a week.^15,36 Participants were shown how to take their pulse and provided with a safe heart rate range to maintain during PA (i.e., between 55% and 69% of their maximum heart rate estimated using the formula 220 – age). Participants were given a pedometer to track their activity during planned PA. The PD then provided guidance in setting the first weekly PA goal; this was often a modest goal (e.g., walking twice for 10 minutes per session) to increase the likelihood of success and build self-efficacy.

The PD also provided participants with an introduction to the philosophy and practice of mindfulness meditation. Participants were given a mindfulness CD (containing sitting meditation, body scan, and yoga stretches—techniques used to teach mindfulness to those with medical illness³⁷) and asked to practice meditation on at least 4 days a week. They were asked to practice the sitting meditation during intervention weeks 1 and 2, body scan during weeks 3 and 4, and yoga stretches during weeks 5 and 6. For the final 6 weeks of RENEW, participants chose which mindfulness exercise to do.

The PD called intervention participants weekly for 12 weeks to review progress, problem solve barriers to meeting weekly PA and meditation goals, and set a goal for the following week. This behavioral coaching was tailored to participants' readiness to make life-style changes (see Table 1). Weekly calls were brief (i.e., M = 19.0 minutes, SD = 7.0 minutes). Following the 12-week intervention, the PD called intervention participants monthly for 3 months to assist with maintaining PA and meditation. (For more information on the behavioral coaching, see Pinto et al.,³⁸ which describes the intervention on which RENEW was based.) In addition, while receiving the intervention, participants were given access to an online forum (monitored by the principal investigator) enabling them to connect with other participants.

Control condition

Those in the control group received the intervention immediately following the 12-week assessment (i.e., between the 12- and 24-week assessments). Their intervention was identical to that provided to intervention participants except that control participants did not receive three monthly booster calls (as their participation was concluded after the 24-week assessment).

Measures

Participants completed a measure assessing basic demographic information at the baseline assessment. To measure intervention feasibility, the number and duration of intervention phone calls delivered to participants were tracked. The measures described below were used at the baseline and 12- and 24-week assessments, unless otherwise indicated.

Participant evaluation

Participants completed an evaluation of RENEW after finishing the intervention (i.e., at the 12-week assessment for intervention participants and 24-week assessment for control participants). Participants rated their overall satisfaction with the PA and meditation components of the intervention—the primary acceptability measure—on a scale from 1 = “not at all satisfied” to 5 = “very satisfied.” Participants also rated the difficulty of taking part in weekly phone sessions, appropriateness of weekly PA and meditation goals, helpfulness of various aspects of the program, and whether they would recommend the program to others.

Seven-Day Physical Activity Recall (PAR)

The PAR is a widely used, well-validated, interviewer-administered measure of PA.³⁹ It has been validated with young adults⁴⁰ and used to assess PA among cancer survivors in intervention studies.^25,31,38 Participants reported time spent in sleep, moderate activity, hard activity, and very hard activity over the prior week; minutes of at least moderate-intensity PA was the outcome of interest.

Treadmill walk

Participants were asked to walk 1 mile on a treadmill as quickly as possible (One Mile Walk Test),⁴¹ and their time was recorded—a well-validated measure of aerobic fitness.

Profile of Mood States (POMS)

The POMS—a validated, reliable, 65-item questionnaire—was used to assess mood.⁴² Participants identified the degree to which they experienced a number of moods (e.g., “tense”) over the past week using a scale from 0 = “not at all” to 4 = “extremely.” Responses were used to create six mood subscale scores (e.g., tension/anxiety) and an estimate of overall mood disturbance—the outcome of interest. Higher scores indicate less favorable mood.

Accelerometer

Although participants were given pedometers to track steps during weekly exercise, IM Systems-3 dimensional accelerometers (“Biotrainer-Pro”) were used to measure PA objectively at the three assessments. Participants were given an accelerometer to wear for 3 days prior to each assessment. The average of the activity counts recorded over the 3 days was used as a measure of PA and to derive an estimate of energy expenditure.

Statistical analyses

All descriptive and outcome analyses were conducted using SPSS Statistics for Windows v20.0.0 (IBM Corp., Armonk, NY). First descriptive analyses were conducted to examine overall participant demographic characteristics, and to check for potential baseline treatment group differences. Next repeated measures analyses were conducted to examine any differential changes across time by treatment group on key outcome variables, with specific focus on the interaction of group by time. Paired t-tests were also conducted using the pooled sample (i.e., intervention and control groups) to examine for treatment effects over time on the outcome variables. Completer analyses were conducted (rather than intent to treat) for this pilot study to assess effects among those who had been offered the full intervention. Cohen's d effect size measure was computed for significant between-group differences.⁴³

Results

A total of 119 cancer survivors were screened for the study (see Fig. 1): 60 were ineligible, 21 were eligible but not interested, and 38 were eligible and interested. The most common reasons for ineligibility were medical or psychiatry contraindication (22%) and not sedentary (25%). Of the 38 eligible survivors, three signed the consent form but withdrew prior to randomization. Thus, 35 YACS were enrolled and randomized to the intervention (n = 19) or control (n = 16) groups. Of these, 27 participants completed the intervention and all three assessments—a 77% retention rate (similar to other PA intervention research with YACS³⁰). Baseline demographic data (and baseline values on outcomes) are presented in Table 2.

FIG. 1.

Flow diagram of progress through the RENEW (“RElaxation aNd Exercise for Wellness”) study.

Table 2.

Participant Demographics, Physical Activity, and Psychosocial Variables at Baseline

Variable	Total	I	C	Test value (df)	p-Value
Sample size	35	19	16
Sex, n (%)				χ²(1) = 0.45	0.45
Females	29 (82.9%)	15 (78.9%)	14 (87.5%)
Males	6 (17.1%)	4 (21.1%)	2 (12.5%)
Hispanic/Latino, n (%)				χ²(1) = 0.48	0.49
Yes	5 (14.3%)	2 (10.5%)	3 (18.8%)
No	30 (85.7%)	17 (89.5%)	13 (81.2%)
Race, n (%)				χ²(1) = 0.47	0.49
White	26 (74.3%)	15 (78.9%)	11 (68.8%)
Non-white	9 (25.7%)	4 (21.1%)	5 (31.2%)
Marital status, n (%)				χ²(1) = 0.02	0.88
Married or living with partner	18 (51.4%)	10 (52.6%)	8 (50.0%)
Single, separated, divorced	17 (48.6%)	9 (47.4%)	8 (50.0%)
Employment, n (%)				χ²(1) = 0.10	0.75
Full-time and part-time	25 (71.4%)	14 (73.7%)	11 (68.8%)
Unemployed	10 (28.6%)	5 (26.3%)	5 (31.2%)
Age, M (SD)	33.6 (4.0)	33.3 (4.6)	33.9 (3.5)	F(1, 33) = 0.24	0.63
Years since diagnosis, M (SD)	2.5 (2.1)	2.6 (2.2)	2.3 (2.0)	F(1, 33) = 0.13	0.72
PAR total activity, M (SD)	34.6 (53.2)	44.5 (62.0)	22.8 (39.3)	F(1, 33) = 1.46	0.24
Treadmill in minutes, M (SD)	20.4 (4.3)	20.8 (5.5)	20.0 (2.4)	F(1, 33) = 0.32	0.57
Biotrainer: weight Adjusted, M (SD)	479.0 (259.2)	527.6 (291.3)	421.3 (209.7)	F(1, 33) = 1.48	0.23
POMS total score, M (SD)	45.5 (32.4)	44.4 (28.5)	46.8 (37.4)	F(1, 33) = 0.05	0.83

I, intervention group; C, control group.

Descriptive analyses were performed to determine whether the intervention was feasible and acceptable. Eighty-nine percent of intervention calls were delivered to participants in the intervention and control groups, supporting the feasibility of intervention delivery. Furthermore, 96% of participants said the length of weekly calls was “just right,” 100% said the number of calls was “about right,” and most felt that weekly PA (71%) and meditation (64%) goals were just the right amount of time. Regarding intervention acceptability, 97% of participants gave one of the two highest satisfaction ratings for the PA component of the intervention (i.e., 4 or 5 out of 5), and 61% gave one of the two highest satisfaction ratings for the meditation component. All of those completing the participant evaluation indicated that they would recommend the intervention to others.

A comparison of change in outcomes between the intervention and control groups at the 12-week assessment found a significant interaction effect in favor of the intervention group on the change in the number of minutes of at least moderate-intensity PA performed per week (p = 0.002; M = 113.8, SE = 23.5 vs. M = –8.7, SE = 27.1; d = 1.30) and a reduction in treadmill walk test time (p = 0.008; M = –1.76, SE = 0.41 vs. M = –0.03, SE = 0.45; d = 1.06). Significant differences were not seen when comparing activity assessed by the Biotrainer or mood disturbance assessed by the POMS. When paired comparisons were performed, pooling data from the intervention and control groups (and looking at differences from before to after the intervention), significant improvement was still seen in the mean change across time in the number of minutes of at least moderate-intensity PA per week (p < 0.001, M = 140.9, SE = 23.2) and fitness (p < 0.001; M = –2.33, SE = 0.37), and a trend (p = 0.06) was seen for improved (reduced) mean change in overall mood disturbance on the POMS (M = –16.0, SE = 8.2). No significant differences were seen in Biotrainer recordings of PA. Finally, data from the intervention group were analyzed to assess whether there were any changes in outcomes between the 12- and 24-week assessments, which might indicate decline, maintenance, or additional improvement; no statistical differences were seen, indicating that intervention effects were maintained post-treatment.

Discussion

The RENEW study evaluated the feasibility, acceptability, and effects of a theory-based PA and meditation intervention for YACS. Findings indicate that the intervention was feasible to deliver and receive, and generally acceptable to YACS. It is noteworthy that participants felt that receiving intervention calls and pursuing intervention goals were feasible, as competing demands can make it very difficult for YACS to participate in behavioral interventions.³²

Despite the small sample, this study was able to take a preliminary look at intervention effects. The results indicate that the intervention helped YACS increase their PA and improve fitness. These findings are consistent with prior research in which cancer survivors receiving brief home-based interventions delivered by telephone successfully increased levels of PA.^25,38 Although data from the objective measure of PA (the Biotrainer) did not show significant group differences, data from the Seven Day PAR better captured participants' PA. To reduce burden, participants were asked to wear the Biotrainer only on 3 days during the week prior to assessments, whereas the Seven Day PAR captured data for all 7 days prior to assessments. Although this was intended to increased Biotrainer compliance, it also meant that even participants who exercised on 5 days a week (RENEW's final goal) might seem under-active if 2 of the 3 days they wore the Biotrainer happened to be days they did not exercise. By contrast, all exercise over the week was captured by the PAR. Thus, PAR data more comprehensively captured PA over the course of the week (although we cannot definitively rule out possible demand bias). In addition, analyses pooling data from the intervention and control groups revealed a trend toward improvement in overall mood from pre- to post-intervention. Additional research is needed to confirm this.

Creating a program that meets the needs of YACS was a key focus when designing the RENEW intervention. This was the rationale for: keeping calls brief, providing calls whenever most convenient for participants (including early morning, evening, and weekends), and providing a means for survivors to receive social support.³² Regarding the latter, participants had the opportunity to receive support for behavior change during weekly calls and from other YACS via the online forum. Unfortunately, because the study was small and enrollment was rolling, there were rarely enough survivors simultaneously receiving the intervention to achieve a critical mass of participants in the forum. Nonetheless, this low-cost strategy for offering support is worth pursuing in larger studies in the future, as it provides YACS with contact from peers who are attempting to make the same healthy life-style changes.

It is worth noting that satisfaction ratings were generally higher for the PA component of the intervention than for the meditation component. Anecdotally, some participants expressed greater interest in PA than in meditation when they enrolled in the study, though only 11% indicated (on the participant evaluation) that they would have preferred the intervention focus only on PA. It is possible, therefore, that some participants would have been more enthusiastic about the meditation component if delivered differently, perhaps in-person.

Study limitations include the small, relatively homogenous sample. Twenty-one of the 59 survivors eligible when screened chose not to enroll; although these survivors did not differ from those who enrolled on basic demographic variables (e.g., age, race/ethnicity), this may indicate that the sample was not representative. Another study limitation was the lack of group effect on the objective measure of PA, though, as noted, the PAR better reflects participants' PA. Finally, the PD was not blinded to participants' randomization assignment, as she was responsible for both data collection and intervention delivery. This could potentially have impacted results. It will be important to conduct a larger, randomized controlled efficacy trial of RENEW that includes a greater diversity of participants and is adequately powered to detect more subtle group differences (such as changes in mood). Nonetheless, findings are encouraging and support the utility of this brief, multi-behavior intervention designed to reduce health risks among YACS.

Footnotes

Acknowledgments

This research was supported by an award from the American Cancer Society (MRSG# 09-091). We express our gratitude to Lynn Bucknam, Med, and Fred Schiffman, MD, for their valuable contributions to this study.

Author Disclosure Statement

No competing financial interests exist.

References

Huddart

, Norman

, Shahidi

, et al. Cardiovascular disease as a long-term complication of treatment for testicular cancer. J Clin Oncol. 2003; 21(8):1513–23.

van den Belt-Dusebout

, Nuver

, de Wit

, et al. Long-term risk of cardiovascular disease in 5-year survivors of testicular cancer. J Clin Oncol. 2006; 24(3):467–75.

Swerdlow

, Higgins

, Smith

, et al. Myocardial infarction mortality risk after treatment for Hodgkin disease: a collaborative British cohort study. J Natl Cancer Inst. 2007; 99(3):206–14.

Shapiro

, Recht

. Side effects of adjuvant treatment of breast cancer. New Engl J Med. 2001; 344(26):1997–2008.

Travis

, Hill

, Dores

, et al. Cumulative absolute breast cancer risk for young women treated for Hodgkin lymphoma. J Natl Cancer Inst. 2005; 97(19):1428–37.

Travis

, Fossa

, Schonfeld

, et al. Second cancers among 40,576 testicular cancer patients: focus on long-term survivors. J Natl Cancer Inst. 2005; 97(18):1354–65.

Greenfield

, Walters

, Coleman

, et al. Prevalence and consequences of androgen deficiency in young male cancer survivors in a controlled cross-sectional study. J Clin Endocrinol Metab. 2007; 92(9):3476–82.

Langeveld

, Ubbink

, Smets

. “I don't have any energy”: the experience of fatigue in young adult survivors of childhood cancer. Eur J Oncol Nurs. 2000; 4(1):20–28.

Thewes

, Butow

, Girgis

, Pendlebury

. The psychosocial needs of breast cancer survivors; a qualitative study of the shared and unique needs of younger versus older survivors. Psychooncology. 2004; 13(3):177–89.

10.

Burgess

, Cornelius

, Love

, Graham

, Richards

, Ramirez

. Depression and anxiety in women with early breast cancer: five-year observational cohort study. BMJ, 2005; 330(7493):702.

11.

Parker

, Baile

, de Moor

, Cohen

. Psychosocial and demographic predictors of quality of life in a large sample of cancer patients. Psychooncology. 2003; 12(2):183–93.

12.

Avis

, Crawford

, Manuel

. Psychosocial problems among younger women with breast cancer. Psychooncology. 2004; 13(5):295–308.

13.

Bleyer

. Young adult oncology: the patients and their survival challenges. CA Cancer J Clin. 2007; 57(4):242–55.

14.

Coups

, Ostroff

. A population-based estimate of the prevalence of behavioral risk factors among adult cancer survivors and noncancer controls. Prev Med. 2005; 40(6):702–11.

15.

United States Department of Health and Human Services. Physical activity and health: a report of the Surgeon General. Atlanta, GA: United States Department of Health and Human Services, Center for Disease Control and Prevention; 1996.

16.

Thune

, Brenn

, Lund

, Gaard

. Physical activity and the risk of breast cancer. N Engl J Med. 1997; 336(18):1269–75.

17.

Wilson

, D'Agostino

, Sullivan

, Parise

, Kannel

. Overweight and obesity as determinants of cardiovascular risk: the Framingham experience. Arch Intern Med. 2002; 162(16):1867–72.

18.

, Li

, Recklitis

, et al. A comparison between long-term survivors of Hodgkin's disease and their siblings on fatigue level and factors predicting for increased fatigue. Ann Oncol. 2005; 16(12):1949–55.

19.

Courneya

, Karvinen

, Campbell

, et al. Associations among exercise, body weight, and quality of life in a population-based sample of endometrial cancer survivors. Gynecol Oncol. 2005; 97(2):422–30.

20.

Courneya

. Exercise in cancer survivors: an overview of research. Med Sci Sports Exerc. 2003; 35(11):1846–52.

21.

Galvao

, Newton

. Review of exercise intervention studies in cancer patients. J Clin Oncol. 2005; 23(4):899–909.

22.

Knols

, Aaronson

, Uebelhart

, Fransen

, Aufdemkampe

. Physical exercise in cancer patients during and after medical treatment: a systematic review of randomized and controlled clinical trials. J Clin Oncol. 2005; 23(16):3830–42.

23.

Courneya

, Friedenreich

, Quinney

, Fields

, Jones

, Fairey

. A randomized trial of exercise and quality of life in colorectal cancer survivors. Eur J Cancer Care (Engl). 2003; 12(4):347–57.

24.

Pinto

, Rabin

, Dunsiger

. Home-based exercise among cancer survivors: adherence and its predictors. Psychooncology. 2009; 18(4):369–76.

25.

Rabin

, Pinto

, Dunsiger

, Nash

, Trask

. Exercise and relaxation intervention for breast cancer survivors: feasibility, acceptability and effects. Psychooncology. 2009; 18(3):258–66.

26.

Speca

, Carlson

, Goodey

, Angen

. A randomized, wait-list controlled clinical trial: the effect of a mindfulness meditation-based stress reduction program on mood and symptoms of stress in cancer outpatients. Psychosom Med. 2000; 62(5):613–22.

27.

Carlson

, Speca

, Patel

, Goodey

. Mindfulness-based stress reduction in relation to quality of life, mood, symptoms of stress, and immune parameters in breast and prostate cancer outpatients. Psychosom Med. 2003; 65(4):571–81.

28.

Ott

, Norris

, Bauer-Wu

. Mindfulness meditation for oncology patients: a discussion and critical review. Integr Cancer Ther. 2006; 5(2):98–108.

29.

Smith

, Richardson

, Hoffman

, Pilkington

. Mindfulness-based stress reduction as supportive therapy in cancer care: systematic review. J Adv Nurs. 2005; 52(3):315–27.

30.

Valle

, Tate

, Mayer

, Allicock

, Cai

. A randomized trial of a Facebook-based physical activity intervention for young adult cancer survivors. J Cancer Surviv. 2013; 7(3):355–68.

31.

Rabin

, Dunsiger

, Ness

, Marcus

. Internet-based physical activity intervention targeting young adult cancer survivors. J Adolesc Young Adult Oncol. 2011; 1(4):188–94.

32.

Rabin

, Simpson

, Morrow

, Pinto

. Intervention format and delivery preferences among young adult cancer survivors. Int J Behav Med. 2013; 20(2):304–10.

33.

Bandura

. Social foundations of thought and action: a social cognitive theory. Englewood Cliffs, NJ: Prentice-Hall; 1986.

34.

Prochaska

, DiClemente

. Stages and processes of self-change of smoking: toward an integrative model of change. J Consult Clin Psychol. 1983; 51(3):390–5.

35.

Adolescent and Young Adult Oncology Progress Review Group. Closing the gap: research and care imperatives for adolescents and young adults with cancer. Bethesda, MD: US Department of Health and Human Services, Livestrong Young Adult Alliance; 2006. 06-6067.

36.

Pate

, Pratt

, Blair

, et al. Physical activity and public health. A recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. JAMA., 1995; 273(5):402–7.

37.

Kabat-Zinn

. Full catastrophe living: using the wisdom of your body and mind to face stress, pain and illness. New York: Delacorte Press; 2013.

38.

Pinto

, Frierson

, Rabin

, Trunzo

, Marcus

. Home-based physical activity intervention for breast cancer patients. J Clin Oncol. 2005; 23(15):3577–87.

39.

Blair

, Haskell

, Ho

, et al. Assessment of habitual physical activity by a seven-day recall in a community survey and controlled experiments. Am J Epidemiol. 1985; 122(5):794–804.

40.

Dishman

, Steinhardt

. Reliability and concurrent validity for a 7-d re-call of physical activity in college students. Med Sci Sports Exerc. 1988; 20(1):14–25.

41.

Pober

, Freedson

, Kline

, McInnis

, Rippe

. Development and validation of a one-mile treadmill walk test to predict peak oxygen uptake in healthy adults ages 40 to 79 years. Can J Appl Physiol. 2002; 27(6):575–89.

42.

McNair

, Lorr

, Droppelman

. Profile of mood states: manual. San Diego, CA: Educational and Testing Service; 1971.

43.

Cohen

. Statistical power analysis for the behavioral sciences. 2nd ed. Hillside, NJ: Lawrence Erlbaum; 1988.