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Complementary therapies are often used as adjuncts to conventional treatment by individuals with cancer. Patterns of use of these practices and products represent important data for health care providers in delivering adequate patient care.
This study compared use of complementary therapies between the cancer and noncancer populations in the United States through secondary analyses of the 2007 National Health Interview Survey data. The analysis compared use by cancer survivors (those individuals self-reporting a diagnosis of cancer; n=1785) and individuals without cancer (n=21,585), as well as self-report of symptoms affecting health-related quality of life (HQoL).
Data suggest similar patterns of use between cancer survivors and the general population; however, a greater percentage of cancer survivors use complementary modalities. Individuals with cancer reported a greater percentage of use of complementary therapies overall, with cancer status significantly associated with ever having used complementary and alternative medicine (p<0.001). The five most common complementary practices and products used by individuals with cancer and controls were vitamin/mineral supplements, prayer for self, intercessory prayer, chiropractic/osteopathic manipulation, and herbal therapies. Additionally, as might be expected, individuals with cancer experience greater frequency of deleterious symptoms associated with decreased HQoL. Individuals with cancer were more likely to sleep fewer than 7 hours (p=0.0108) or greater than 9 hours (p=0.0108), and have increased insomnia (p<0.001), excessive sleepiness (p<0.001), depression (p<0.001), and anxiety (p<0.001) versus those without cancer.
The current findings may inform health care providers about the use of complementary and integrative practices and products by patients with cancer in an effort to manage symptoms of the disease. Additionally, these results may also be used to promote research to define the merits of the use of such complementary and integrative practices and products.
Patients are increasingly involved in many aspects of their own health care.1 With a growing interest in complementary and alternative medicine (CAM),1,2 cancer survivors are altering their dietary and physical activity regimens, as well as consuming supplements, with the goal of improving health-related quality of life (HQoL). CAM is defined by the National Center for Complementary and Alternative Medicine as “a group of diverse medical and health care systems, practices, and products that are not presently considered to be part of conventional medicine,”3 a definition that remains fluid as more complementary therapies become incorporated into conventional care (e.g., massage and acupuncture).4 Moreover, the expectations of society with regard to the conventional health care system are changing, with people more inclined to seek out and use CAM5,6 and 75% of U.S. adults having used at least one CAM modality for improved health at some point in their lifetime.7 According to the population-based 2007 National Health Interview Survey (NHIS), 38.3% of the U.S. population reported use of at least one CAM therapy in the last 12 months.8 U.S. adults made an estimated 354.2 million visits to CAM providers.9 In that same year, adults' out-of-pocket expenditures on use of CAM providers, CAM products, and CAM practices totaled $33.9 billion; the majority ($22 billion) was spent on CAM products and classes compared to $11.9 billion spent on CAM providers.9
Within the cancer patient population, CAM use is widespread and estimated to be as high as 64%.3,7,10,11 Predictors of higher CAM use by patients with cancer include female gender,3,7,11,12 stage of disease at diagnosis,7,11 age,4,12 higher education,4,12 higher income,4,12 race,7,12 and geographical location.7,11 Additionally, individuals living at a greater distance from health care providers may be more inclined to self-treat using CAM.7
Complementary modalities are utilized by patients with cancer in an effort to enhance the benefits of conventional treatments, including radiation and chemotherapy, as well as to improve overall well-being and HQoL.3,7,11,13,14 Use of CAM by patients with cancer is significantly associated with receiving multiple treatments, management of illness and treatment-related symptoms, improving survival, and decreasing recurrence,2,3,7,12 with patients using CAM during adjuvant chemotherapy, radiation therapy, palliative therapy, and phase I clinical trials.1 Additionally, data from the 2002 NHIS reveal that patients with cancer are more apt to utilize complementary modalities provided by a practitioner.12 The goals of the present study were to examine and describe the national patterns of CAM use with regard to services, practices, and products among individuals with cancer compared to those who did not report cancer, as well as the impact that HQoL symptoms (i.e., pain, insomnia, fatigue, and depression) experienced by patients with cancer have on CAM use.
Data from 23,370 adult respondents (aged 18 years and older) included in the 2007 NHIS were analyzed. Of the total sample, a subset of 1785 survey respondents was created based on their report of a previous cancer diagnosis.
The NHIS is an annual nationally representative survey designed by the National Center for Health Statistics of the Centers for Disease Control and Prevention to provide data on health and health care use in the United States. Two (2) CAM supplements, collected in 2002 and 2007, provide extensive data on the use of and expenditures for CAM providers, practices, and products. These supplements provide information related to factors in the CAM Health Care Model. Compared to the NHIS 2002 CAM supplement, the NHIS 2007 supplement expanded the number of CAM therapies (from 27 to 35), the number of diseases treated with CAM (from 73 to 81), and the list of CAM products (from 35 to 45), while the reference period for use of CAM products was reduced from 12 months to 30 days.8 The NHIS methodology employs a multistage sampling design that is representative of the U.S. “civilian noninstitutionalized population,” and has been described elsewhere.3,8,9 Protection of human subject confidentiality was assured through federal rules governing public use files and the oversight of the University of Virginia Health Sciences Research Institutional Review Board.
Data files from the 2007 NHIS were merged and statistical analyses completed using SAS v.9.1 (SAS Institute, Cary, NC). These files included the household, sample adult, and adult alternative medicine files. Data were merged and sorted by the household, sample, and person-level variables. Data for individuals responding “yes” or “no” to the question of ever being diagnosed with cancer were included in the analysis. Frequency distributions of demographic variables were calculated using the final sample weighting variable. Chi-square tests were performed to analyze differences between those individuals with and without cancer. Regression analyses were performed to examine the influence of cancer status and report of symptoms on ever having used CAM.
Sociodemographic characteristics of the respondents are reported in Table 1. Those individuals who reported having been diagnosed with cancer were more likely to be older (p<0.001), female (p<0.001), non-Hispanic whites (p<0.001), unemployed (p<0.001), and single (p=0.0487) than those individuals without cancer.
The prevalence of ever having used a complementary therapy is reported in Table 2. Individuals with cancer reported a greater percentage of use of complementary therapies overall, with cancer status significantly associated with ever having used CAM (p<0.001). The five most common complementary practices and products used by individuals with cancer and controls were vitamin/mineral supplements (76.64% and 64.02%, respectively), prayer for self (68.85% and 53.19%, respectively), intercessory prayer (49.22% and 33.44%, respectively), chiropractic/osteopathic manipulation (34.60% and 22.07%, respectively), and herbal therapies (32.14% and 24.11%, respectively).
The most prevalent vitamins and minerals used in the past 12 months are reported in Table 3. A greater percentage of individuals with cancer (76.64%; p<0.001) reported use of vitamins and minerals than those without cancer (64.02%; p<0.001). Around 25% of individuals in both groups reported consumption of a calcium supplement. A greater percentage of individuals without cancer report use of a multivitamin (84.09%). The most prevalent herbal therapies used in the past 12 months are reported in Table 4 for individuals with and without cancer. The most common herbal supplement used by both individuals with and without cancer, respectively, were fish oil (44.38% and 38.33%), glucosamine (25.91% and 21.40%), garlic pills or gelcaps (15.72% and 11.23%), flaxseed oil (15.79% and 15.74%), and chondroitin (13.81% and 11.89%).
Hours of sleep and measures of HQoL over the past year are reported in Table 5. Individuals with cancer were more likely to sleep fewer than 7 hours (27.60%; p=0.0108) or greater than 9 hours (6.98%; p=0.0108), and have increased insomnia (31.04%; p<0.001), excessive sleepiness (15.60%; p<0.001), depression (15.77%; p<0.001), and anxiety (14.96%; p<0.001) versus those without cancer. When controlling for cancer status and hours of sleep, insomnia (p<0.001), fatigue (p=0.006), and anxiety (p<0.001) were predictive of CAM use. Data reflecting psychologic symptoms within the past 30 days are reported in Table 6. Individuals with cancer were more likely to feel sad, nervous, restless or fidgety, hopeless, that everything was an effort, and worthless than those without cancer (p<0.001). Increased symptoms were significantly associated with use of CAM therapies, after controlling for cancer status (p<0.001), with those individuals reporting higher rates of symptoms affecting HQoL more likely to use CAM than those with lower report of symptoms.
Use of complementary modalities by patients with cancer is common and similar in pattern to that of individuals without cancer in the general population, suggesting that the diagnosis of cancer alone may not be the motivation for the use of CAM (Table 2). However, a greater percentage of cancer survivors (i.e., those individuals self-reporting ever being diagnosed with cancer) utilize CAM therapies versus the general population. Both cancer survivors and individuals in the general population make considerable use of so-called “low/no cost” practices, such as meditation and deep breathing exercises, as well as other mind–body modalities. Additionally, use of natural products is very high among respondents, as is prayer, both by self and by others. Practices such as some mind–body modalities, natural products, and prayer may be easier to adopt for self-care and disease management, requiring less expense and time commitment than utilizing the services of a practitioner. The results of the current study are similar to findings reported by others using similar survey data.3,12,15 However, direct comparison of numbers with previous surveys should be done cautiously, given the differences in the sample population, the phrasing of questions, and the definition and types of CAM therapies included. What is unique about the current study is the analysis of symptoms affecting HQoL and the relationship to use of complementary practices and products.
In the current study, respondents with cancer were more likely to receive inadequate or excessive sleep, as well as to experience greater insomnia, fatigue, depressed mood, and anxiety over the course of the previous year (Table 5). Moreover, insomnia, fatigue, and anxiety were predictive of CAM use after controlling for hours of sleep and cancer status. Cancer survivors were more likely to be affected by increased psychologic symptoms associated with reduced HQoL in the past 30 days versus the general population (Table 6). These data are not surprising, given the unquestionably stressful nature of the diagnosis of cancer and its treatment, which results in symptoms including depression, anxiety, fatigue, sleep disturbances, and pain. These disease- and treatment-related symptoms are the impetus for many patients with cancer to combine conventional care with complementary modalities to improve HQoL.3,7,11,13,14
The most common categories of complementary modalities used by individuals with a self-reported diagnosis of cancer were natural products, including vitamins, minerals, and herbal therapies, and mind–body practices, including meditation, relaxation techniques, deep breathing exercises, yoga, t'ai chi, qigong, biofeedback, hypnosis, and energy healing therapies (Table 2). Research suggests that guided imagery may aid the reduction of cancer pain.16,17 Various types of meditation have been shown to improve quality of life in patients with cancer including improvements in mood, sleep quality, and perceived stress.18 Additionally, several studies report enhanced quality of life in patients with cancer, such as lower sleep disturbance, decreased stress symptoms, and changes in cancer-related immune cells after patients received relaxation, meditation, and gentle yoga therapy.19 Preliminary data suggest that biofield therapies such as Healing Touch and Reiki may increase quality of life in cancer and reduce pain and fatigue in patients with cancer.20
More than 50% percent of U.S. adults report taking dietary supplements regularly.21 Dietary intake of fruits and vegetables high in vitamin C, folate, and other antioxidants has been associated with reduced risk of various types of cancer in epidemiologic studies, particularly cancers of the mouth, esophagus, stomach, colon, lung, and breast.22,23 Vitamin C supplements have not been found to produce similar protective effects.24 Preliminary evidence surrounding the use of folate seems promising for decreasing the risk of breast, cervical, pancreatic, and gastrointestinal cancer.25 Currently there is insufficient evidence available to recommend folate supplementation for any type of cancer prevention or treatment. Data concerning supplementation with vitamin E are equivocal. There is preliminary evidence of the possible benefits of long-term vitamin E supplementation to reduce the risk of mortality in patients with bladder cancer;24 however, recent data from the Women's Health Study show no reduction in the development of cancer with the use of a natural-source vitamin E supplement taken daily.23 Additional research is necessary before a clear conclusion can be reached.
Several epidemiologic studies report that dietary omega-3 fatty acids or fish oil may reduce the risk of developing breast, colon, or prostate cancer;26 however, randomized controlled trials are necessary before a clear conclusion can be drawn regarding the benefit of omega-3 fatty acid supplements on cancer prevention and treatment. Initial human studies suggest that regular consumption of garlic, particularly unprocessed garlic, may reduce the risk of developing several types of cancer, including gastric and colorectal malignancies; however, garlic may alter levels of various anticancer drugs.27 Early studies suggest that ginseng may improve body weight, quality of life, and the immune response in patients with cancer, and a few studies report that ginseng taken by mouth may lower risk of developing some cancers, especially if ginseng powder or extract is used.28
Side-effects and interactions with chemotherapy are being increasingly reported with herb use,29 and concerns about potential interactions of complementary modalities with biomedical and pharmacologic treatment, safety, efficacy, cost, and establishment of scientific evidence are rising.7 Given that many botanical supplements lack basic and clinical research documentation and are not closely regulated, many supplements may be contaminated.21 Toxicity may result from high concentrations of active ingredients in a supplement versus the native form of the natural product. Moreover, there remains a lack of reliable dosage guidelines. Nearly two thirds of individuals reporting use of natural supplements are unaware of drug interactions and information concerning adverse effects, making the assumption that a lack of such information implies safety.30 Concern has been raised that antioxidants may interfere with some chemotherapy agents, such as alkylating agents, anthracyclines, or platinums, which can depend on oxidative damage to tumor cells for the desired anticancer effects. For example, folic acid could interfere with the anticancer effects of methotrexate.25 Studies on the effects of antioxidants on cancer therapies have yielded mixed results, with some reporting interference, others noting benefits, and most suggesting no significant interaction.31 Still, caution is recommended for people undergoing treatment with chemotherapy or radiation because it has been proposed that the use of high-dose antioxidants may interfere with the effectiveness of treatment.
The questions of the adult alternative health survey do have several limitations. Firstly, data are dependent upon a respondent's knowledge of complementary and alternative practices and products as well as a willingness to report use. Secondly, the cross-sectional nature of the data collection does not allow for the calculation of annual estimates of CAM use, limiting the ability to track changes in use over time, or to examine causal relationships between CAM use and diagnosis of disease. Moreover, it is not possible to know whether or not a respondent began using CAM before or after his or her diagnosis. Because no additional follow-up questions were asked concerning the impact of CAM approaches on symptoms associated with HQoL, this relationship cannot be evaluated. The authors do not assume that all patients with cancer have similar patterns of CAM use and believe that adopting or maintaining complementary practices and products is individualized and subject to a variety of factors. The results presented in the current article represent the use of CAM overall over the course of the previous year rather than the use of complementary practices and products for a particular disease or condition, in this case cancer. While questions were asked in the NHIS as to whether or not these therapies or products were used specifically for cancer, many of these data are missing and do not reflect the overall use of CAM by patients with cancer. For example, patients with cancer may not have used a complementary practice or product for cancer per se but may have used these modalities for a disease- or treatment-related condition, such as fatigue, sleep disturbance, or pain. These data are not captured by the NHIS. Moreover, assessing use of CAM practices and products by cancer site/type increases the amount of statistical comparisons used and reduces the sample size, especially with regard to less common cancers, such that significant findings may be simply a result of multiple comparisons and artifact. Additionally, the number of therapies included in the survey is limited and does not include all modalities that may be commonly used by patients with cancer, such as aromatherapy or creative therapies such as art therapy, music therapy, and journaling.32
A major strength of the NHIS data concerning complementary modalities is the collection of data from a nationally representative sample of U.S. adults. These data allow for the estimation of use of complementary modalities across a variety of subgroups within the general population, such as cancer survivors. The large sample size facilitates investigation of the associations between use of complementary therapies and a range of self-reported health characteristics. The results of the current study could potentially guide researchers in conducting future CAM intervention studies of those therapies most commonly used by patients with cancer, as well as more trials to examine the benefits, risks, chemopreventive properties, and/or antitumor activities of complementary practices and products. Additionally, these findings may inform health care providers about the use of complementary and integrative practices and products by patients with cancer in an effort to manage symptoms of the disease as well as other comorbidities by providing the most current national estimates of CAM use in patients with cancer. Health care providers need to assess patient use of complementary practices and products routinely, especially in the oncology setting, while increasing their knowledge of CAM to maximize positive patient outcomes.
The authors would like to thank Rochelle Jobes and Dr. Ada Jacox for their editorial assistance in the preparation of this article. This publication was made possible by grant numbers 5-T32-AT000052 and 5-K07-AT002943 from the National Center for Complementary and Alternative Medicine (NCCAM) at the National Institutes of Health. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of NCCAM.
No financial conflicts exist.