Complementary Medicine, Peninsula Medical School, Universities of Exeter & Plymouth, Institute of Health & Social Care, Exeter, UK
Received 17 October 2003; revised 12 January 2004; accepted 15 January 2004
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ABSTRACT |
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Many cancer patients search the World Wide Web for information on complementary and alternative medicine. The aim of this study was to evaluate the quality of such information and identify the treatments most frequently discussed.
Materials and methods
We used a pre-tested search strategy to identify the websites that are most likely to be used by cancer patients and assessed them according to pre-defined criteria.
Results:
Thirty-two websites were included in this analysis. The quality of these sites was scored on a point system and varied between 8 and 14 points with a maximum of 14. Most sites issued recommendations for a plethora of treatments, which are typically not supported by sound scientific evidence. Three sites had the potential for harming patients through the advice issued. The most frequently discussed therapies were herbal medicines, diets and mindbody therapies.
Conclusion:
The most popular websites on complementary and alternative medicine for cancer offer information of extremely variable quality. Many endorse unproven therapies and some are outright dangerous.
Key words: alternative medicine, cancer, complementary medicine, Internet
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Introduction |
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The Internet has at the same time revolutionized the market regarding complementary and alternative medicine (CAM). The Pew Internet & American Life Project found in one of their surveys from 2001 that 48% of health seekers have looked for information about CAM [11]. Ethnic differences in choices of health information were assessed in a 2003 postal survey among 140 Caucasian, Japanese and non-Japanese Asians and Pacific Islander cancer patients [12]. Caucasian cancer patients preferred objective, scientific and up-to-date information obtained through medical journals from institutions, telephone information services and the Internet. Japanese patients tended to rely on sources from the media, including TV, newspapers, books, magazines and CAM providers. Non-Japanese Asians and Pacific Islanders mostly used person-to-person communication with physicians, social groups and other cancer patients.
Many cancer patients desperately seek knowledge about their condition and thus can be very vulnerable to misleading information. CAM products can easily be purchased on the Internet without prescription. This has previously led to at least one known fatality of a cancer patient [13]. The quality of websites on CAM for specific conditions varies; thus there is a need to raise public awareness about the issue [14]. We found reasons for concern regarding Internet-based recommendations on CAM for patients suffering from HIV/AIDS, diabetes, cancer and depression [1517]. Other studies have demonstrated poor content quality on websites about St Johns wort [18] and poor quality of general practice websites [19]. A recent survey on websites promoting specific CAM treatments for cancer concluded that there is a staggering amount of misinformation regarding CAM for cancer on the Internet [20].
The present study had two aims. Firstly, to assess the quality of popular websites on CAM for cancer. Secondly, to identify the most popular forms of CAM currently discussed via the Internet.
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Materials and methods |
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Each of these websites was evaluated according to the following criteria. First, the quality of the website based on the Sandvik score [22], which was developed based on the Health On the Net code (HON) [23] and validated in the field of urinary incontinence. The score ranges from 0 to 14 points where 14 stands for optimal quality. The authors defined a website with a total score of 05 points as poor, 610 points as medium and 1114 points as excellent quality (Table 1). Second, the reliability of the website based on whether it listed the HON code of approval [23]. Third, the risk each website could pose to patients, based on an overall score, and finally the type of CAM, distinguishing between curative, preventative or palliative cancer, depending on the context in which the CAM modality was discussed in.
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Two independent reviewers (HLW, KS) extracted the results and compared the data extraction sheets for each website and each criterion. Discrepancies were resolved by discussion with the third reviewer (EE). Extracted data was tabulated. Subsequently, the most frequently discussed therapies of CAM for the prevention, cure and supportive/palliative cancer care were identified.
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Results |
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Discussion |
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We carried out extensive literature searches in databases such as Medline, Cinahl, Amed, Psycinfo and Embase to assess the evidence of the top five CAM modalities suggested for preventative, curative and palliative cancer care in our study [24]. Our results show that coenzyme Q10 is one of the most frequently discussed cancer cures. Coenzyme Q10 has been associated with regression of breast cancer [25] and may stimulate the immune system [26]. To date, this evidence is far from compelling and does not seem to warrant a positive recommendation.
Shark cartilage has also been frequently recommended as a cancer cure. It is claimed to have anti-angiogenesis effects that may inhibit the growth of malignant cells, and preliminary non-clinical investigations supported this claim [27]. A preliminary phase II study suggested that high doses of Neovastat, a product derived from cartilage can increase survival time [28]. This finding, however, needs to be replicated in randomized controlled trials (RCTs). At present, there is insufficient evidence for shark cartilage to be used as a cancer treatment and the only published clinical study of shark cartilage for cancer failed to produce encouraging results [29].
Laetrile, according to our survey, enjoys somewhat of a renaissance. It contains the toxic compound amygdalin, which commonly occurs in the kernels of almonds, apricots, cherries, peaches and apples. Clinical trials and animal studies have found no relevant benefit for cancer patients [30, 31].
The Gersons diet, another frequently discussed cancer cure on the Internet, is also not supported by convincing evidence. One study retrospectively compared 5-year melanoma survival rates of Gerson patients to rates reported in the medical literature. A six-fold increase in the 5-year survival was calculated [32]. However, the study was methodologically too flawed to allow any firm conclusions.
Similarly, mistletoe is often advocated. Our own systematic review of all 10 RCTs of mistletoe found no good evidence for an effect of this therapy on cancer progression or quality of life [33]. Thus, none of the top five cancer cures discussed on the websites is supported by appropriate evidence.
Lycopene, a carotenoid, is derived from tomatoes and has been suggested as a preventative therapy for cancer. Research has shown that diets rich in fruits and vegetables are associated with a decreased risk of developing cancer [34]. The antioxidant characteristics of lycopene have been investigated in various observational studies with mixed results. A recent review concluded that current evidence could not be considered adequate support either for or against the use of lycopene in cancer prevention [35].
A meta-analysis evaluating the association between dietary ß-carotene intake and decreased risk of epithelial ovarian cancer included five observational studies with a total of 3782 cancer patients [36]. It was suggested that high dietary intake of ß-carotene may represent a protective factor for ovarian cancer development. However, the authors admit its magnitude is modest. In a randomized controlled study studying the protective effects of ß-carotene in smokers it was found that the intervention group had 15% lower level of thioether excretion, a possibly carcinogenic intermediate product of smoking [37]. However, no clear link between ß-carotene and the prevention of cancer has so far been shown.
Experimental studies suggest that the risk of prostate cancer can be reduced with the intake of long-chain n-3 polyunsaturated fatty acids. However, human data are insufficient for firm conclusions. One case-controlled study involved 317 prostate cancer cases and 480 age-matched community controls [38]. These examples show that some of the preventative strategies discussed on the evaluated sites are, in fact, backed up by promising, albeit not compelling evidence.
Various studies of CAM advocated on the evaluated websites have shown encouraging results in the palliative/supportive care of cancer patients. Meditation has been shown to improve quality of life in women with breast cancer [39]. The prevention of chemotherapy-related nausea and vomiting with the application of acupressure and acupuncture has been shown to be effective [40, 41]. Massage can decrease stress, anxiety, depression and pain in cancer patients [42]. Thus, there is at least some evidence to support some of the palliative CAM approaches discussed on the websites evaluated.
Our study of cancer websites has several limitations. Because of the potentially fast-changing nature of the information available on the Internet the results are, strictly speaking, only valid for the period December 2002 to January 2003, when the study was carried out. However, comparing the overall findings with those from our pilot study conducted about one year earlier, we find little evidence for the main problems related to cancer websites to change. Due to the chosen research methodology, the sample of websites included in this survey is relatively small and may therefore not be representative of the totality of information available to cancer patients. We have only assessed websites published in the English language. It is therefore possible that websites in other languages have different characteristics than the ones evaluated in our study.
With currently 600 million individuals worldwide accessing the Internet [1], the findings of our study have important implications. Public awareness about the usefulness of Internet information needs to be raised and the content of some websites needs to be further evaluated. Major cancer organizations and other impartial interest groups should investigate websites and create and administer a seal of approval, for safety and reliability, such as the HON code. In 2002 a UK expert committee drafted the BIOME Resource Evaluation guidelines to help evaluate information relating to CAM [43]. However, after having tested these guidelines on various CAM cancer websites for defining their appropriateness, levels of inconsistencies in the results indicated that the BIOME guidelines need to be further developed.
By showing that some CAM cancer websites provide misinformation, we do not mean to deny that cancer patients can feel empowered and have a more active social support by accessing (preferably reliable) health information on the Internet [44, 45]. We feel that raising Internet users awareness as to what a good website contains is an important and timely task for researchers and health-care providers. Future research needs to identify and assess a larger number of websites promoting CAM for cancer. It would also be interesting to know the number of cancer patients who use information from such sites or purchase CAM for cancer online.
In conclusion, our analysis has shown that many websites offering information on CAM for cancer are not as reliable as one would hope. In the interest of cancer patients we should find ways of minimizing the potential harm such misinformation may cause.
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Acknowledgements |
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FOOTNOTES |
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