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Cancer Survivors Awaiting Rehabilitation Rarely Meet Recommended Physical Activity Levels

An Observational Study

Dennett, Amy M., PT, BPhty (Hons)1; Peiris, Casey L., PT, PhD2; Shields, Nora, PT, PhD3; Prendergast, Luke A., PhD4; Taylor, Nicholas F., PT, PhD5

doi: 10.1097/01.REO.0000000000000132
RESEARCH REPORTS

Objective: We aimed to describe physical activity levels and identify factors associated with physical activity of cancer survivors awaiting oncology rehabilitation.

Methods: A pilot observational study evaluating physical activity levels of 49 cancer survivors referred to outpatient rehabilitation was assessed using accelerometers worn continuously for 6 days. Multiple linear regression analyses were completed to identify factors associated with physical activity. Variables included demographic factors (cancer type, treatment, body mass index), physical factors (walking capacity, physical performance), and psychological factors (anxiety).

Results: Four participants achieved recommended physical activity levels. Participants recorded an average of 12 minutes (SD = 12) of daily moderate-intensity activity. Walking capacity had the strongest independent association with physical activity (P < .001). A 10-m increase in distance in the 6-Minute Walk Test was associated with a 7% improvement in physical activity. Breast cancer diagnosis (P = .005), increased anxiety (P = .007), and lower body mass index (P = .014) were also independently associated with high physical activity. The final model explained 70.5% of the variance in physical activity levels (P ≤ .001).

Conclusion: Few cancer survivors awaiting rehabilitation achieve recommended physical activity levels. Factors associated with low levels of physical activity such as reduced walking capacity may be modified by oncology rehabilitation.

1PhD Candidate, Physical Therapy, School of Allied Health, La Trobe University, Bundoora, Victoria, Australia; and Allied Health Clinical Research Office, Eastern Health, Box Hill, Victoria, Australia

2Academic Lecturer, School of Allied Health, La Trobe University, Bundoora, Victoria, Australia

3Professor, School of Allied Health, La Trobe University, Bundoora, Victoria, Australia; and Northern Health, Epping, Victoria, Australia

4Associate Professor, Department of Mathematics and Statistics, La Trobe University, Bundoora, Victoria, Australia

5Professor, School of Allied Health, La Trobe University, Bundoora, Victoria, Australia; and Allied Health Clinical Research Office, Eastern Health, Box Hill, Victoria, Australia

Correspondence: Amy M. Dennett, PT, BPhty (Hons), School of Allied Health, La Trobe University, Bundoora, VIC 3083, Australia (Dennett.a@students.latrobe.edu.au).

Grant Support: This work was supported by Eastern Health, La Trobe University, and an Australian Government Research Training Program Scholarship.

There are no conflicts of interest to declare. The authors have full control of primary data, which is available on request.

Overwhelming evidence supports the integration of physical activity into ongoing management across the cancer trajectory. Physical activity interventions alleviate many side effects of cancer treatment including fatigue, aid improvements in strength and fitness, and enhance quality of life.1 , 2 High volumes of physical activity postdiagnosis are associated with reductions in cancer recurrence and improved survival in a variety of cancers including breast, colorectal, and prostate cancer.3 Physical activity also plays a role in management and prevention of chronic comorbidities such as cardiovascular disease and diabetes.4 It is recommended that cancer survivors complete at least 150 minutes of moderate-intensity physical activity per week to achieve health benefits.5 Moderate-intensity activity refers to activities of between 3 and 6 metabolic equivalents that cause people to sweat lightly (eg, brisk walking, cycling, or swimming).6 Moderate intensity differs from light intensity, which includes domestic and occupational activities such as cooking and office duties, and vigorous activity, which causes people to breathe harder such as jogging or aerobics.6

Physical activity levels in cancer survivors may be influenced by various disease-related factors, including disease severity, treatment status, and symptoms such as fatigue.7 , 8 Physical activity levels among cancer survivors are low.9 A recent study found that only 8% of survivors achieved physical activity recommendations and they performed less light-intensity activity and were more sedentary than noncancer survivors.9 Physical activity levels decline during treatment and frequently do not return to prediagnosis levels after treatment.10 While disease and treatment side effects are identified as barriers to physical activity,11 psychosocial factors such as mental health and self-efficacy may also be important.12 It is well established that depression is associated with low levels of physical activity, but the relationship between physical activity and anxiety is unclear.13 In addition, low self-efficacy and psychosocial support are associated with low levels of physical activity among breast cancer survivors, which may be mediated by levels of depression.14 , 15

To date, physical activity data from cancer survivors have been collected retrospectively using questionnaires that are subject to recall bias16 and may not provide accurate information on physical activity intensity.17 An increasing number of studies use accelerometry to measure physical activity in people with cancer.18 However, these studies are limited to participants many months or years after finishing treatment. Information about physical activity in newly diagnosed patients is important, given the efficacy of exercise-based rehabilitation during this period.1 , 2 Meanwhile, only one large study has quantified physical activity levels objectively of both short- and long-term survivors, reporting inactivity as a major issue during early survivorship and treatment.9 Participants in early survivorship (<5 years postdiagnosis) completed 111 minutes of moderate- to vigorous-intensity physical activity weekly that did not differ from activity levels of long-term survivors (107 minutes).9 However, limitations to this study were that activity was not continuously recorded (24 hours per day) and that a minimum of 1 day of accelerometer wear was included in the analyses.9 Inclusion of only 1 day of physical activity data may not be an accurate reflection of a person's physical activity.18

Cancer diagnosis has been described as a “teachable moment” when people are more likely to make lifestyle changes that improve their health.19 Oncology rehabilitation aims to address impairments and restore function after cancer diagnosis to maximize independence and improve quality of life.20 Rehabilitation is also described as an opportunity to improve physical activity behavior.21 Despite this, few oncology rehabilitation programs exist21 and the characteristics of patients entering such programs are unknown. Given the potential benefits of rehabilitation, there is a need to identify cancer survivors who are most at risk of low levels of physical activity to prescribe and design appropriate programs.

Therefore, the aims of this exploratory study were to:

  1. Describe the physical activity levels of cancer survivors awaiting entry to an oncology rehabilitation program, and whether they meet recommended physical activity levels.
  2. Identify demographic, physical, and psychological factors associated with physical activity in cancer survivors awaiting oncology rehabilitation.
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METHODS

Design

A prospective, cross-sectional pilot study was completed. Ethical approval was obtained from hospital and university ethics committees prior to study commencement. All participants provided written informed consent.

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Participants and Setting

Participants were identified consecutively from the wait-list of a publicly funded established outpatient oncology rehabilitation program run by a large public health organization. Participants were eligible to take part if they were aged 18 years and older, diagnosed with cancer, undergoing treatment or had completed adjuvant therapy in the last 12 months (except for long-term hormonal therapies), not receiving end-of-life care (estimated <3 months to live), and capable of providing consent. Participants were excluded if they had a known skin condition precluding them from wearing an activity monitor. Cancer survivors could self-refer or were referred to the program by health care professionals including oncologists, general practitioners, nurses, and allied health clinicians. The program followed a cardiac rehabilitation model, with participants completing 1 hour of individualized exercise and 1 hour of education provided by a multidisciplinary team comprising physical therapy, nursing, occupational therapy, and dietetics. Assessments were completed prior to commencement of oncology rehabilitation.

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Outcome Measurement: Dependent Variable

The dependent variable, physical activity, was measured using an accelerometer-based activity monitor (activPAL, PAL Technologies Ltd, Glasgow, United Kingdom). The activPAL provides valid estimates of energy expenditure and body transitions in nonhospitalized cancer survivors22 and has demonstrated high compliance (98%) with continuous wear in people with cancer.23 Participants wore the monitor on the thigh, continuously 24 hours per day, for a period of at least 7 consecutive days prior to them commencing rehabilitation. Accelerometers were affixed and activated immediately following the assessment. Data were sampled at 20 Hz and summed in 15-second epochs. The monitor was secured in a ziplock bag with waterproof medical dressing to allow for continuous monitoring and was only removed for complete water immersion (swimming and bathing). Participants were asked to continue with their usual level of activity and keep an activity diary to supplement the activity monitor data. Minutes of moderate to vigorous activity (MVPA) recorded in the diary during periods of nonwear (confirmed by inspection of the activPAL report) were included.

The dependent variable was physical activity expressed as minutes of MVPA completed in at least 10-minute bouts. This was derived from the accelerometer data using customized software based on a cut point of 100 steps per minute.24 Activity bouts allowed up to 2 minutes break within each bout, as normal walking may be disrupted by short breaks.25 Physical activity data were compared with physical activity guidelines.5 , 26 Total MVPA achieved over the recording period (ie, not in a 10-minute bout), daily steps, daily time walking, and daily sedentary time (minutes) were also reported.

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Independent Variables

Independent variables included demographic, physical, and psychological factors and were chosen as evidence suggests that they might have an influence on physical activity levels.7–12 Specific measures were chosen on the basis of their measurement properties. Quality of life was assessed using the global health status/quality-of-life subscale of the European Organization for Research and Treatment of Cancer QOL Questionnaire-C30 (EORTC-QLQ C30). This measure has demonstrated validity and reliability across a range of cancer settings.27 Fatigue was assessed using the Brief Fatigue Inventory, a reliable measure for cancer survivors.28 The Hospital Anxiety and Depression Scale was used to measure psychological status.29 Self-efficacy for physical activity was assessed using the Physical Activity Appraisal Inventory, which has demonstrated validity and reliability in women with breast cancer.30 The Karnofsky Performance Scale (KPS) was used as an assessment of physical performance.31 This scale can be administered quickly and has demonstrated strong construct validity and interrater reliability among cancer patients.32 The 6-Minute Walk Test was used to assess walking capacity, as it is a valid and reliable measure of physical function in cancer survivors.33 It was completed according to published recommendations34 without a practice test. The 5-repetition Sit-to-Stand Test was used to assess functional lower-limb strength.35 A hand grip dynamometer (Jamar, Patterson Medical, Warrenville, Illinois) was used to assess grip strength. The mean of 3 trials was recorded.36 The hand grip dynamometer is a reliable outcome of strength that can predict all-cause mortality and functional decline.37

Demographic data including age, sex, body mass index, living situation, location and type of cancer, treatment status, and comorbidities were recorded from the medical record. Comorbidities were assessed using an updated age-adjusted Charlson Comorbidity Index (ACCI).38 , 39

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Sample Size

On the basis of the recommendation that the sample size should equal 5 to 10 times the number of independent variables,40 with a minimum of 2 subjects per variable required to estimate regression coefficients,41 a sample of 50 participants was required for this study.

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Data Analysis

Data were included if there were at least 6 full days of physical activity data (24 hours). The number of participants meeting physical activity guidelines was described on the basis of the proportion of physical activity completed in comparison with the guidelines over 6 days. Participants were deemed to have met guidelines if they achieved 129 minutes of at least moderate-intensity physical activity over 6 days in at least 10-minute bouts (based on the recommended average of 21.4 minutes of activity per day over a 7-day week).

Descriptive analysis was completed for all variables. Missing data from items on questionnaires were imputed using the mean score if most items were completed. Normality was tested using the Kolmogorov-Smirnov statistic. Associations between independent variables—demographic factors (age, body mass index, cancer type), physical factors (physical performance, walking capacity, strength), psychological factors (self-efficacy, depression, anxiety), fatigue, and quality of life in relation to MVPA (minutes)—were carried out using nonparametric Spearman rank correlations. Point-biserial correlations were used for binary outcomes. Multiple linear regression analyses were completed to determine the ability of the independent variables to explain the amount of physical activity completed (dependent variable) using least-squares estimation. An analysis of residuals from the initial model provided evidence of heteroscedasticity and thus violated the multiple linear regression assumptions required for testing. Consequently, the dependent variable was transformed using the natural log transformation (1 minute was added to activity levels to ensure the few individuals with zero activity were retained). The first regression model was fitted to the transformed dependent variable and all independent variables. To avoid overfitting, aid in interpretation, and help protect against issues arising with multicollinearity, stepwise variable selection was used with the Bayesian Information Criterion (BIC), which favors the simplest model.42 The stepwise variable selection procedure is a combination of both forward selection and backward elimination, where, at each step, it is considered whether a variable should be included in, or removed from, the regression model. The BIC is used to determine which variables should be included or removed from the model and stops when all variables not included offer no more than trivial improvements.42 To ensure that multicollinearity was not evident in the final model, variance inflation factors (VIFs) were assessed. An analysis of residuals was carried out for the final fitted model, with no evident model violations and no outliers (based on standardized residuals with a cutoff of ±3.3 denoting significant outliers).43 Cook's distance did not reveal a problem with influence observations. Standardized regression coefficients are reported to enable simpler comparisons between the contributions of variables to the model. Data were analyzed using SPSS 24.0 and R version 3.3.3.

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RESULTS

Eighty-five patients were wait-listed for oncology rehabilitation between January and November 2016. Fifty participants (34 were female) were eligible and consented to participate (Figure 1, Table 1). Complete physical activity data (6 days) were obtained for 49 participants. Data for 1 participant were excluded, as the monitor was removed after 1 day because of a local skin irritation from the dressing, which resolved quickly without further intervention. No other adverse events were reported.

Fig. 1

Fig. 1

TABLE 1

TABLE 1

The mean age of participants was 61 years (SD = 12). Twenty-four participants (49%) were diagnosed with breast cancer and 14 (28%) had metastatic disease. Twenty-four patients were undergoing current treatment (48%). The average ACCI score was 2.8 (SD = 1.9) (Table 1).

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Achievement of Physical Activity Guidelines

Four participants met physical activity guidelines. Twenty-eight participants (56%) did not complete any MVPA in a 10-minute bout during the 6 testing days. The average daily MVPA completed in at least a 10-minute bout was 6 minutes (SD = 8). The amount of total MVPA completed varied from 0 to 53 minutes daily (mean = 12 minutes, SD = 12). Participants took a mean of 6131 daily steps (SD = 2808; range, 358-20 490). Participants spent on average 18.5 hours lying or sitting down each day. Visual inspection of the results suggested there was no difference in demographic, physical, or psychological variables between the groups of people achieving and not achieving the guidelines, nor in the amount of time spent sedentary over the week (Table 2). Differences between the groups were not analyzed statistically because of uneven group numbers.

TABLE 2

TABLE 2

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Factors Related to Physical Activity

As more than half of the participants did not record any MVPA in a bout of 10 minutes, total MVPA over 6 days was used as the dependent variable. Bivariate correlations between the amount of MVPA and demographic, physical, and psychological variables are presented in Table 3.

TABLE 3

TABLE 3

Following stepwise variable selection, 6 independent variables were included in the final multiple regression model (body mass index, cancer type, physical performance, treatment status, walking capacity, and anxiety score) (Table 4). Multicollinearity was not evident in the model (all VIFs <2.0). For comparative purposes, the estimated β values later refer to standardized coefficients. The unstandardized regression coefficients and associated confidence intervals can be found in Table 4 (for the log-transformed dependent variable), as too can the corresponding estimates of the percent change on MVPA per unit change of the independent variable. The multiple linear regression model found that increased walking capacity had the strongest independent association with MVPA (β = 0.560, P < .001), followed by better physical performance (β = 0.251, P = .017), having a breast cancer diagnosis (β = 0.245, P = .005), lower body mass index (β = −0.244, P = .014), and increased anxiety (β = 0.244, P = .007). The model accounted for more than 70% of the variance in MVPA (R 2 = 74.2%, R 2-adj = 70.5%). Other psychosocial and demographic variables were not significantly associated with MVPA.

TABLE 4

TABLE 4

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DISCUSSION

Physical activity levels among cancer survivors referred to oncology rehabilitation are low, with more than 90% of participants not achieving recommended physical activity levels. Regression models demonstrated that increased walking capacity and physical performance, lower body mass index, having a breast cancer diagnosis, and higher levels of anxiety were independently associated with high physical activity levels. Other demographic and psychosocial factors were not related to physical activity levels. Results reinforce previous studies that physical activity levels among cancer survivors are low.9 Physical activity levels may be lower in those entering rehabilitation, as many are still receiving treatment or experiencing acute side effects such as fatigue. Furthermore, given exercise-based rehabilitation has a physical focus, physical impairments may be a reason why participants are referred to oncology rehabilitation programs and thus their physical activity levels may be lower than other cancer survivors.

Walking capacity had the strongest association with physical activity. This finding is consistent with those of the previous studies showing positive correlations between the 6-Minute Walk Test and physical activity in patients post–stem cell transplantation and colorectal resection.44 , 45 It is plausible that physical capacity dictates physical activity levels during rehabilitation, as muscular strength and cardiovascular fitness are required to be active.46 Given physical activity independently reduces the risk of cancer mortality,3 this supports the role of physical rehabilitation for cancer survivors.

Physical activity levels were largely influenced by modifiable factors including walking capacity, physical performance, and body mass index. Demographic factors, including treatment status, time since diagnosis, and the presence of metastatic disease, were not associated with physical activity levels of those awaiting cancer rehabilitation, consistent with findings of the previous research.14 , 47–49 This is important, given the role rehabilitation plays in addressing modifiable factors. For example, clinicians can devise physical rehabilitation programs to improve fitness and functional capacity and draw on other team members such as dietitians to promote weight loss.20

Psychosocial factors played a lesser role in determining physical activity levels. It is well established that physical activity can improve psychological well-being in people with cancer1 and that mental health is associated with positive physical activity behavior.50 Self-efficacy, an individual's belief he or she is capable of successfully executing a course of action in response to situational demands,51 has also been described as a strong predictor of physical activity in cancer survivors.14 It is possible that in this cohort, patients with higher psychosocial needs were not referred or declined rehabilitation. As rehabilitation is often focused on physical functioning and impairment, those who lack confidence to exercise may be less inclined to seek out this type of intervention. However, it should be acknowledged that anxiety was independently associated with physical activity, whereby those who were more anxious were more active. This could be explained by people who are anxious using physical activity as a coping mechanism.52

People with breast cancer were independently more active than those with other cancers. Breast cancer is the world's second leading cancer53 but boasts high survival rates, with up to 90% of women surviving 5 years.54 Given the large number of breast cancer survivors, most research in this area is dominated by exercise studies in the breast cancer setting. It is possible this has generated more health promotion and survivorship initiatives targeting those with breast cancer compared with other cancers, given the known time lag of translation of research findings into practice.55 It is also possible that those with cancers with poorer prognosis may experience greater symptom burden, impacting on physical function affecting physical activity.

Access to cancer rehabilitation is poor, with only 0.5% of patients who could potentially benefit being referred to programs.21 Patients are often fearful of exercise, and clinicians reluctant to refer to programs due to lack of knowledge about the benefits.21 With limited guidelines on who should be referred to programs, results from this study could inform screening practices when promoting physical activity. As demonstrated in the current study, the KPS may give a better indication of cancer-related disease burden affecting physical activity, rather than relying on individual demographic characteristics. This scale is quick, reliable, and correlated highly with other functional and psychosocial variables. Such a measure could play a valuable role in screening to identify those at risk of low levels of physical activity who may benefit from a formal rehabilitation program as opposed to other health promotion initiatives. However, further studies on larger cohorts would be required to determine appropriate cutoff thresholds.

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Study Limitations

This study was the first to consider factors relating to physical activity in people referred for cancer rehabilitation. A strength of this study is that it used objective, continuous physical activity data obtained over 6 days. The main limitation was the relatively small sample size, which may overestimate or lead to unstable estimates of associations reported. Although more than 10 candidate factors were considered initially, our final regression model contained fewer than 10 factors that fit within our sample estimates. Results were consistent with previous research. Another limitation is that physical activity recorded by accelerometers may be inaccurate, as they are unable to account for contextual information about type and setting of physical activity. They are unable to detect intensity of upper-limb activities, static exercise, activity on inclines, and cycling and cannot be worn for aquatic physical activity such as swimming.18 This study was completed in a heterogeneous population of cancer survivors, with breast cancer representing half the sample and small numbers of a large variety of other cancers represented. Therefore, differences in physical activity levels of specific tumor streams were not investigated. However, the variety of cancers represented is representative of a “real-world” rehabilitation setting. We were also unable to record disease severity, as accurate information about tumor staging was not available. However, nonmodifiable clinical factors were not as important as modifiable factors in predicting physical activity levels. In addition, the associations reported are not an indication of causation and should be interpreted with caution.

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CONCLUSION

Few cancer survivors awaiting rehabilitation achieve recommended physical activity levels. Walking capacity had the strongest association with physical activity in this cohort. Results suggest that risk factors for low levels of physical activity are modifiable. These include physical performance, walking capacity, and body mass index, which can be addressed during rehabilitation. The low levels of observed physical activity and the associated modifiable factors highlight the important role rehabilitation can play for cancer survivors.

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ACKNOWLEDGMENTS

We thank Melissa Reed for her contribution to data collection and the staff and participants at Eastern Health Oncology Rehabilitation Program for their support.

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REFERENCES

1. Cormie P, Zopf EM, Zhang X, Schmitz KH. The impact of exercise on cancer mortality, recurrence, and treatment-related adverse effects. Epidemiol Rev. 2017;39(1):71–92.
2. Stout NL, Baima J, Swisher AK, Winters-Stone KM, Welsh JA. Systematic review of exercise: systematic reviews in the cancer literature (2005-2017). P M R. 2017;9:S347–S384.
3. Friedenreich CM, Neilson HK, Farris MS, Courneya KS. Physical activity and cancer outcomes: a precision medicine approach. Clin Cancer Res. 2016;22:4766–4775.
4. Wahid A, Manek N, Nichols M, et al Quantifying the association between physical activity and cardiovascular disease and diabetes: a systematic review and meta-analysis. J Am Heart Assoc. 2016;5(9). doi:10.1161/JAHA.115.002495.
5. Rock CL, Doyle C, Demark-Wahnefried W, et al Nutrition and physical activity guidelines for cancer survivors. CA Cancer J Clin. 2012;62:243–274.
6. Norton K, Norton L, Sadgrove D. Position statement on physical activity and exercise intensity terminology. J Sci Med Sport. 2010;13:496–502.
7. Ferriolli E, Skipworth RJ, Hendry P, et al Physical activity monitoring: a responsive and meaningful patient-centered outcome for surgery, chemotherapy, or radiotherapy? J Pain Symptom Manage. 2012;43:1025–1035.
8. Henriksson A, Arving C, Johansson B, Igelstrom H, Nordin K. Perceived barriers to and facilitators of being physically active during adjuvant cancer treatment. Patient Educ Couns. 2016;99:1220–1226.
9. Thraen-Borowski KM, Gennuso KP, Cadmus-Bertram L. Accelerometer-derived physical activity and sedentary time by cancer type in the United States. PLoS One. 2017;12:e0182554.
10. Irwin ML. Physical activity interventions for cancer survivors. Br J Sports Med. 2009;43:32–38.
11. Clifford BK, Mizrahi D, Sandler CX, et al Barriers and facilitators of exercise experienced by cancer survivors: a mixed methods systematic review. Support Care Cancer. 2017;26:685–700.
12. Perkins HY, Baum GP, Taylor CL, Basen-Engquist KM. Effects of treatment factors, comorbidities and health-related quality of life on self-efficacy for physical activity in cancer survivors. Psychooncology. 2009;18:405–411.
13. Biddle S. Psychology of Physical Activity: Determinants, Well-being and Interventions. New York, NY: Routledge; 2008:212.
14. Kampshoff CS, Stacey F, Short CE, et al Demographic, clinical, psychosocial, and environmental correlates of objectively assessed physical activity among breast cancer survivors. Support Care Cancer. 2016;24:3333–3342.
15. Phillips SM, McAuley E. Physical activity and fatigue in breast cancer survivors: a panel model examining the role of self-efficacy and depression. Cancer Epidemiol Biomarkers Prev. 2013;22:773–781.
16. Shiffman S, Stone AA, Hufford MR. Ecological momentary assessment. Annu Rev Clin Psychol. 2008;4:1–32.
17. van Poppel MN, Chinapaw MJ, Mokkink LB, van Mechelen W, Terwee CB. Physical activity questionnaires for adults: a systematic review of measurement properties. Sports Med. 2010;40:565–600.
18. Broderick JM, Ryan J, O'Donnell DM, Hussey J. A guide to assessing physical activity using accelerometry in cancer patients. Support Care Cancer. 2014;22:1121–1130.
19. Demark-Wahnefried W, Aziz NM, Rowland JH, Pinto BM. Riding the crest of the teachable moment: promoting long-term health after the diagnosis of cancer. J Clin Oncol. 2005;23:5814–5830.
20. Silver JK, Raj VS, Fu JB, Wisotzky EM, Smith SR, Kirch RA. Cancer rehabilitation and palliative care: critical components in the delivery of high-quality oncology services. Support Care Cancer. 2015;23:3633–3643.
21. Dennett AM, Peiris CL, Shields N, Morgan D, Taylor NF. Exercise therapy in oncology rehabilitation in Australia: a methods study. Asia-Pac J Clin Oncol. 2017;13:e515–e527.
22. Skipworth RJ, Stene GB, Dahele M, et al; European Palliative Care Research Collaborative (EPCRC). Patient-focused endpoints in advanced cancer: criterion-based validation of accelerometer-based activity monitoring. Clin Nutr. 2011;30:812–821.
23. Maddocks M, Byrne A, Johnson CD, Wilson RH, Fearon KC, Wilcock A. Physical activity level as an outcome measure for use in cancer cachexia trials: a feasibility study. Support Care Cancer. 2010;18:1539–1544.
24. Tudor-Locke C, Craig CL, Aoyagi Y, et al How many steps/day are enough? For older adults and special populations. Int J Behav Nutr Phys Act. 2011;8:1–19.
25. Peiris CL, Taylor NF, Shields N. Patients receiving inpatient rehabilitation for lower limb orthopaedic conditions do much less physical activity than recommended in guidelines for healthy older adults: an observational study. J Physiother. 2013;59:39–44.
26. World Health Organization. Global Recommendations on Physical Activity for Health. Geneva, Switzerland: World Health Organization; 2010.
27. Lucket T, King MT, Butow PN, et al Choosing between the EORTC QLQ-C30 and FACT-G for measuring health-related quality of life in cancer clinical research: issues, evidences and recommendations. Ann Oncol. 2011;22:2179–2190.
28. Agasi-Idenburga C, Velthuis M, Wittink H. Quality criteria and user-friendliness in self-reported questionnaires on cancer-related fatigue: a review. J Clin Epidemiol. 2010;63:705–711.
29. Zigmond AS, Snaith RP. The Hospital Anxiety and Depression Scale. Acta Psychiatr Scand. 1983;67:361–370.
30. Haas BK, Northam S. Measuring self-efficacy: development of the Physical Activity Assessment Inventory. SOJNR. 2010;10:1–18.
31. Yates JW, Chalmer B, McKegney FP. Evaluation of patients with advanced cancer using the Karnofsky Performance Status. Cancer. 1980;45:2220–2224.
32. Mor VM, Laliberte L, Morris JN, Wiemann M. The Karnofsky Performance Status Scale: an examination of its reliability and validity in a research setting. Cancer. 1984;53:2002–2007.
33. Schmidt K, Vogt L, Thiel C, Jäger E, Banzer W. Validity of the Six-Minute Walk Test in cancer patients. Int J Sports Med. 2013;34:631–636.
34. American Thoracic Society. ATS statement: guidelines for the Six-Minute Walk Test. Am J Respir Crit Care Med. 2002;166:111–117.
35. Bohannon RW. Sit-to-Stand Test for measuring performance of lower extremity muscles. Percept Mot Skills. 1995;80:163–166.
36. Mathiowetz V. Grip and pinch strength measurements. In: Admunsen LR, ed. Muscle Strength Testing: Instrumented and Non-Instrumented Systems. New York, NY: Churchill Livingston; 1990:172.
37. Bohannon RW. Dynamometer measurements of hand-grip strength predict multiple outcomes. Percept Mot Skills. 2001;93:323–328.
38. Charlson M, Szatrowski TP, Peterson J, Gold J. Validation of a combined comorbidity index. J Clin Epidemiol. 1994;47:1245–1251.
39. Quan H, Li B, Couris CM, et al Updating and validating the Charlson Comorbidity Index and score for risk adjustment in hospital discharge abstracts using data from 6 countries. Am J Epidemiol. 2011;173:676–682.
40. Kleinbaum DG, Kupper LL, Muller KE. Applied Regression Analysis and Other Multivariable Methods. 2nd ed. Boston, MA: PWS-Kent; 1988.
41. Austin PC, Steyerberg EW. The number of subjects per variable required in linear regression analyses. J Clin Epidemiol. 2015;68:627–636.
42. Sheather S. A Modern Approach to Regression With R. Vol 2. New York, NY: Springer; 2009.
43. Pallant JF. SPSS Survival Manual: A Step by Step Guide to Data Analysis Using SPSS. 4th ed. Crows Nest, NSW, Australia: Allen & Unwin; 2011.
44. Pecorelli N, Fiore JF Jr, Gillis C, et al The Six-Minute Walk Test as a measure of postoperative recovery after colorectal resection: further examination of its measurement properties. Surg Endosc. 2016;30:2199–2206.
45. Morishita S, Kaida K, Yamauchi S, et al Relationship of physical activity with physical function and health-related quality of life in patients having undergone allogeneic haematopoietic stem-cell transplantation. Eur J Cancer Care. 2017;(4). doi:10.1111/ecc.12669.
46. Caspersen CJ, Powell KE, Christenson GM. Physical activity, exercise, and physical fitness: definitions and distinctions for health-related research. Public Health Rep. 1985;100:126–131.
47. Zopf EM, Newton RU, Taaffe DR, et al Associations between aerobic exercise levels and physical and mental health outcomes in men with bone metastatic prostate cancer: a cross-sectional investigation. Eur J Cancer Care. 2017;26. doi:10.1111/ecc.12575.
48. Hawkes AL, Patrao TA, Baade P, Lynch BM, Courneya KS. Predictors of physical activity in colorectal cancer survivors after participation in a telephone-delivered multiple health behavior change intervention. J Cancer Surviv. 2015;9:40–49.
49. Crawford JJ, Holt NL, Vallance JK, Courneya KS. A new paradigm for examining the correlates of aerobic, strength, and combined exercise: an application to gynecologic cancer survivors. Support Care Cancer. 2016;24:3533–3541.
50. Kang KD, Bae S, Kim H-J, Hwang IG, Kim SM, Han DH. The relationship between physical activity intensity and mental health status in patients with breast cancer. J Korean Med Sci. 2017;32:1345–1350.
51. McAuley E, Blissmer B. Self-efficacy determinants and consequences of physical activity. Exerc Sport Sci Rev. 2000;28:85–88.
52. Herring MP, O'Connor PJ, Dishman RK. The effect of exercise training on anxiety symptoms among patients: a systematic review. Arch Intern Med. 2010;170:321–331.
53. World Health Organization. GLOBOCAN 2012: estimated cancer incidence, mortality and prevalence worldwide in 2012. http://globocan.iarc.fr/Pages/fact_sheets_cancer.aspx. Published 2017. Accessed March 2, 2017.
54. National Cancer Institute. Cancer stat facts: female breast cancer. https://seer.cancer.gov/statfacts/html/breast.html. Published 2017. Accessed March 2, 2017.
55. Morris ZS, Wooding S, Grant J. The answer is 17 years, what is the question: understanding time lags in translational research. J R Soc Med. 2011;104:510–520.
Keywords:

accelerometers; cancer; physical activity; rehabilitation

Copyright 2018 © Oncology Section, APTA