Lung cancer is the most prevalent type of cancer and the leading cause of cancer death in the world.1 Lung cancer patients have reported a significantly lower quality of life (QOL) compared with patients who have other cancers.2,3 Quality of life is a multidimensional construct incorporating the physical, social, emotional, and functional aspects of well-being.4 It is a vital clinical end point in cancer populations, and particularly in lung cancer patients. Exercise is an element of wellness promotion that can enhance the QOL of cancer patients.5–9
Regular exercise can play a valuable role in improving the QOL among lung cancer patients.10,11 Coups et al12 studied physical activity across the cancer trajectories of 175 early-stage lung cancer patients and determined that the active participants had a superior QOL compared with the sedentary participants. In addition, Solberg et al13 surveyed the association between physical activity level and QOL among long-term lung cancer survivors, discovering that the survivors who engaged in regular exercise attained a significantly higher QOL than did the sedentary survivors; thus, increased exercise was associated with an improved QOL. Similarly, Clark et al14 surveyed the motivational readiness for physical activity of 272 lung cancer survivors, indicating that high levels of motivational readiness for physical activity were associated with high levels of QOL. These results suggest that exercise can enhance QOL, warranting further research; however, no prospective studies have evaluated the longitudinal relationship between walking exercise and QOL among lung cancer patients.
The QOL of cancer patients can be improved by implementing walking programs.15,16 Lin et al17 surveyed the exercise preferences of lung cancer patients, discovering that walking was the most preferred exercise. To date, research remains lacking regarding the relationship between walking exercise and the QOL of lung cancer patients. The effectiveness of exercise primarily depends on the adherence by cancer survivors. However, exercise adherence is a challenge after a cancer diagnosis. Knowledge regarding the factors that influence the changes in walking of cancer patients could enhance patient adherence to walking exercise. A review of relevant research indicated that this study is the first longitudinal study to examine how walking affects the QOL of lung cancer patients. We also explored the factors predicting changes in walking during a 6-month study of lung cancer patients, determining that patient QOL can be improved by incorporating walking programs into cancer care.
Materials and Methods
This study involved a longitudinal, correlational design, and convenience sampling was conducted to collect data from survey questionnaires. The participants were recruited from the chest outpatient clinics of 2 teaching hospitals in Taiwan. The inclusion criteria were as follows: diagnosed with lung cancer by a primary physician, no evidence of recurrent or progressive disease, age 18 years or older, and able to communicate in Mandarin or Taiwanese. The initial sample comprised 109 lung cancer patients. Data for 2 of the original participants were removed because they refused to participate throughout the study period.
DEMOGRAPHIC AND DISEASE CHARACTERISTICS
The demographic characteristics of patients were age, gender, education level, marital status, and comorbidities (ie, other chronic diseases, including hypertension, diabetes, and cardiovascular disease). The disease and treatment conditions captured the disease stage, treatment modalities, and current treatment status.
QUALITY OF LIFE
In this study, the QOL was measured using the Functional Assessment of Cancer Therapy–Lung Cancer (FACT-L), which comprised 34 questions.4 The evaluation involved a 5-point Likert scale that ranged from 0 (“not at all”) to 4 (“very much”), and a high score represented a correspondingly high QOL. The FACT-L is composed of the Functional Assessment of Cancer Therapy–General (27 items) and an additional lung cancer–specific subscale (7 items). The FACT-General comprises 4 subscales: physical well-being (PWB; 7 items), social well-being (7 items), emotional well-being (6 items), and functional well-being (FWB; 7 items). The reliability and validity of the FACT-L have been previously established.18,19
Walking exercise was measured using a modified version of the Godin Leisure-Time Exercise Questionnaire, which was developed by Godin and Shephard.20 The exercise questionnaire indicated the average frequency of mild (leisurely walking), moderate (not exhausting), and strenuous (producing a rapid heartbeat) activity undertaken that lasted more than 15 minutes during the free time of the patients in a typical week. In addition, the scale was adapted to enable the participants to indicate the average number of minutes spent on walking exercise. The Godin Leisure-Time Exercise Questionnaire yielded test-retest reliabilities of 0.69 to 0.80 and 0.24 to 0.56 with VO2max.20,21 Miller et al22 demonstrated a concurrent validity coefficient of 0.45 by using a Caltrac accelerometer.
In this study, social support was measured based on the scale of “perceived social support specific to health-related exercise behaviors,” using 13 questions.23 The evaluation involved a 5-point Likert scale, where 1 = “never,” 2 = “rarely,” 3 = “sometimes,” 4 = “usually,” and 5 = “always.” The scale of social support indicated how much exercise support the patients received from their family, friends, and medical staff members. Sallis et al23 surveyed the level of support that friends and family members provided regarding patient physical activity, yielding a test-retest reliability of 0.55 to 0.79 in a 2-week period. The reliability and validity of this scale were previously established.24
SELF-EFFICACY FOR EXERCISE
We used a self-efficacy questionnaire designed by Marcus et al25 that comprised 5 questions, each scored from 1 point, indicating no self-confidence, to 5 points, indicating strong self-confidence. This questionnaire has been used to evaluate how much self-confidence a patient requires to maintain his/her exercise habits during unfavorable situations. Williams et al24 studied the predictable psychosocial factors concerning physical activity adjustment and maintenance in 205 healthy adults, determining that the scale exhibited favorable reliability and an internal consistency value of 0.86.
This study was reviewed and approved by the Institutional Review Board Committee of the study hospital in Taiwan. The study was initiated by enrolling lung cancer patients from the chest outpatient clinic. The patients agreed to provide data at the beginning of the study and at 2 follow-ups after 3-month intervals. During patient enrollment, we explained the study purpose and data collection methods, ensuring the participants that their right to receive appropriate medical care would not be affected regardless of whether they participated in the study; all participants provide their written consent. We instructed the patients on how to complete the questionnaire, and they required approximately 15 minutes to complete the basic personal information portion and structured questionnaire. Patients who could not complete the survey questionnaire (ie, illiterate participants) were assisted by a researcher who read each question and recorded the answers. During the study, the right of the patients to withdraw for any reason was fully respected.
The SPSS software package version 17.0 (SPSS, Chicago, Illinois) was used to analyze the data. Descriptive statistics were used to present the demographic and disease-related characteristics and mean (SD) of the walking and QOL scores. A generalized estimating equation (GEE) was used to account for the dependence of repeated measurements. The GEE method extends the quasi-likelihood approach, which is increasingly used to analyze longitudinal data because it does not require the participants to undergo the same numbers of assessments.26–28 Therefore, the effects of walking exercise on QOL were analyzed using the GEE method, which was also used to control the baseline heterogeneity. Treatment status was added to the analytic models as a confounding variable. The GEE was also used to identify the predictors for changes in walking exercise during the 6-month study period.
Demographic and Disease Characteristics
Table 1 lists the participant and disease-related characteristics. Of the 107 participants, 57 were men and 50 were women; the average age was 63.75 (SD, 10.38) years. Most patients (87.9%) were married. The disease and treatment information indicated that 47.7% of participants were at stage I, and 73.8% had undergone surgery. On average, the participants were diagnosed 43.91 (SD, 28.15) months previously.
Changes in QOL and Walking Over the 6-Month Study Period
Table 2 lists the changes in the QOL and cancer symptoms from the baseline to the 2 follow-up points. The QOL was measured using the FACT-L, which yielded a score range of 0 to 136, and mean scores of 114.19 (SD, 12.34), 113.30 (SD, 15.37), and 112.74 (SD, 17.76) at the baseline, 3-month, and 6-month follow-ups, respectively.
The results indicated that the patients exhibited average walking times of 282.29 (SD, 152.47), 248.23 (SD, 170.13), and 217.90 (SD, 180.16) minutes per week, at the baseline, 3-month, and 6-month follow-ups, respectively. Regarding the frequency of walking, the patients walked a mean number of 6.19 (SD, 1.57), 5.21 (SD, 2.67), and 4.55 (SD, 2.96) days per week at the 3 time points. Over 6 months, the data indicated that the frequency of walking decreased or stopped in 36% of patients, was maintained in 32% of patients, and increased in 10% of patients.
Effect of Walking on QOL
Table 3 shows how walking affected the QOL of lung cancer patients. The GEE results demonstrated a significant relationship (95% confidence interval [CI], 0.01–0.04; P = .010) between walking and QOL at the 6-month follow-up. The patients who engaged in walking exercise demonstrated a significantly higher overall QOL than did those who did not, and the overall QOL increased by 0.03 points per additional minute of walking time per week.
We also analyzed the relationships among QOL and walking, discovering a significant difference in PWB (95% CI, −3.19E-005 to 0.02; P = .051) and FWB (95% CI, 0.003–0.02; P = .004) at the 6-month follow-up.
Table 4 shows the results of the GEE analysis, indicating that social support (95% CI, 0.16–4.96; P = .037), self-efficacy (95% CI, 4.19–13.12; P < .001), and treatment status (95% CI, −147.67 to −15.97; P = .015) can be used to predict the changes in walking among lung cancer patients. The participants who were off treatment were more likely to participate in and maintain walking exercise than were those who were being actively treated. In addition, participants who exhibited high levels of social support and self-efficacy were more likely to participate in and maintain walking exercise than were those who exhibited low levels of social support and self-efficacy.
Walking is a physical activity that lung cancer patients prefer. Physical activities enhance the health of cancer patients and improve their QOL; however, few studies have examined how walking affects the QOL of lung cancer patients. In this study, the walking habits of lung cancer patients were observed for 6 months. The results indicated that lung cancer patients who engaged in regular walking spent 30 to 40 min/d walking for at least 4 to 6 d/wk. Notably, walking is a physical activity in which patients can engage in at any time. In a review of the physical activities undertaken by cancer survivors, Irwin29 indicated that regular physical exercise was difficult for cancer patients. During the current 6-month observation period, approximately 40% of the lung cancer patients gradually reduced their walking frequency. Although walking is simple, additional studies must be conducted to determine how to reinforce and maintain the walking habits of patients.
During the 6-month observation period, the patient QOL was relatively stable; these results were similar to those of Sarna et al30 regarding female cancer patients and Kenny et al31 regarding non–small cell lung cancer patients. Concerning the influence of walking on QOL, we determined that lung cancer patients who engaged in regular walking activities for 6 months exhibited an improved overall QOL. In addition, the PWB and FWB aspects of QOL improved. These results were similar to those of Newton et al16 regarding ovarian cancer patients who engaged in individualized walking exercise programs and Wang et al15 regarding patients with newly diagnosed breast cancer who engaged in walking exercise. However, Tang et al32 evaluated cancer patients engaging in home exercise, indicating that walking improved only the psychological dimension of QOL and did not enhance the physical dimension, possibly because of the varying intensity levels or durations of walking. Evidence has indicated that walking effectively enhances the QOL of lung cancer patients; therefore, health providers should recommend walking as a treatment that benefits lung cancer patients. However, the mechanisms underlying the effects of walking on improvements in the physical and function domains of QOL require further investigation.
The results also indicated that self-efficacy, social support, and treatment status can predict the trends in walking activity among patients diagnosed with lung cancer. Pinto et al33 examined the relationship between the QOL and exercise participation of patients diagnosed with breast cancer, reporting that a high level of social support was a predictive indicator of exercise involvement. Coups et al12 identified significant correlations between participation in leisurely walking exercise with self-efficacy and social support among patients with non–small cell lung cancer. Based on the empirical results of these studies, efforts to improve support systems and patient self-efficacy should be considered in addition to treatment status when planning walking exercise programs for patients with lung cancer. The importance of social support for walking tends to be underestimated because it is considered an exercise that can be performed individually; however, social support and self-efficacy are key factors that motivate patients with lung cancer to maintain regular walking exercise, and improving these factors ultimately enhances the QOL of lung cancer patients.
Several limitations should be considered for this study. First, the reasons that the frequency of walking decreased among the patients may not be reflected by the closed questionnaire method used in this study. Qualitative interviews or a survey involving open-ended questions will be used in the future studies. Second, the generalizability of the study is limited to outpatient samples and cannot be extended to all patients with lung cancer. A larger and more homogeneous sample of lung cancer patients will be used in the future studies. Third, we did not assess the functional capacities of the patients (ie, pulmonary function) that could affect their walking. Finally, walking is a simple type of exercise, but the illness conditions of lung cancer patients may limit their willingness to exercise. Thus, the appropriate timing for implementing walking programs among lung cancer patients should be considered in the future.
This is the first longitudinal study to specifically investigate how walking affects the QOL of lung cancer patients in Taiwan. The results indicated that QOL can be improved by engaging in walking exercise for 6 months; furthermore, social support, self-efficacy, and treatment status can enhance the practice of walking exercise among lung cancer patients. These results should provide a valuable reference for healthcare providers, who should consider incorporating walking programs in their cancer treatment recommendations. Furthermore, integrating psychological strategies (ie, social support, self-efficacy) may be necessary to strengthen the effects of walking exercise to ensure QOL improvement among lung cancer patients.
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