Overall, we found that both the use of CAM products and visits to CAM practitioners by women diagnosed with breast cancer significantly increased from 1998 to 2005. In 2005, 81.9 percent of respondents reported using CAM (41 percent to help manage their breast cancer) compared to 66.7 percent in 1998, suggesting that in 2005 CAM use has become the "norm" in this patient population.
The observed increase in CAM use appears not to be explained by changing demographics in the breast cancer population. The two cohorts were approximately the same with respect to age and income levels. The differences in ethnicity, the percentage that were married, and the level of education appear not to be big enough to account for the increases in use. For example, a mean age difference of 3 years is unlikely to be clinically significant. The 2005 cohort reported less surgery, but more chemotherapy and more hormone therapy (e.g., tamoxifen) which may be a reflection of differences in stage of cancer at diagnoses; however since cancer stage information was not collected in 1998, it is not possible to assess this. The differences in conventional treatments may also be related to changes in therapeutic protocols for breast cancer that have occurred since 1998.
Overall, the biggest increases were seen in the percentage of women seeing bodywork practitioners (including massage therapists, but not chiropractors), TCM practitioners/acupuncturists, homeopaths and "others". This may be related to the fact that massage therapy and acupuncture are two of the CAM practices which are generally the most accepted by the medical profession [12
]. For example, many physicians use acupuncture in their practices [16
]. In addition, given that neither acupuncture nor massage involves taking anything orally, it is likely they are perceived to have fewer potential adverse effects or interactions with conventional cancer treatments than some other CAM therapies. So it is possible that conventional MDs are either recommending these options more often to patients or at least not discouraging patients from using them.
Perception of safety and perceived lack of drug interactions may also explain the increased use of homeopathy. In addition, the homeopathic community was under review by the Health Professions Regulation Advisory Council for consideration as a future regulated health profession in Ontario during 2005 when this survey was conducted [17
]. Although the council hearing did not receive much media attention at the time, it may partially explain the increased use of homeopathy reported here.
Overall, there was a significant increase in the use of herbal products such as garlic, ginger, ginseng and green tea and special foods/diets. Both green tea and special diets/foods are used by more than 10 percent of all women diagnosed with breast cancer specifically to help manage their breast cancer. A review of the evidence suggests that there may be an overall decreased risk of cancer associated with taking Asian ginseng (Panax ginseng
), garlic, green tea, soy, and tomatoes but research is extremely preliminary and in some cases contradictory. Also, the minimum dose associated with decreased cancer risk has not been clearly defined for any of the supplements or herbs [18
]. Although there is evidence that ginger may be useful in the management of chemotherapy-induced nausea, it is not clear exactly what dose or dosing schedule is best. It is also not clear what additional benefits ginger products have over and above conventional anti-nausea medications (fewer adverse effects are claimed) [18
]. There are currently no herbs with significant evidence of efficacy as cancer treatments [18
Our results also found the use of Essiac significantly decreased. Essiac has been used in Canada for over 70 years [20
]. In contrast to green tea and soy, which has received considerable media and scientific attention as possible cancer prevention agents, Essiac has received little notice and has no peer-reviewed clinical trials or encouraging animal studies demonstrating any significant beneficial effects. For example, our retrospective survey found that Essiac did not have a significant effect on either health related quality of life or mood states in women with breast cancer. Women in the study were taking low doses (total daily dose 43.6 ± 30.8 mL) of Essiac that corresponded to label directions found on most Essiac products, but appear unlikely to have significant pharmacological effects[11
] Thus, it appears at least in part, that women are using more natural health products that are receiving increased positive attention in the media and by the scientific community and decreasing those that have garnered little evidence or interest.
Several limitations of our study need to be addressed. As with any retrospective study recall bias is a possible limitation. In 1998, respondents were only asked if they had ever used CAM products or visited CAM therapies. Thus, although we can comment on what women in 2005 were using to help manage their breast cancer, it is not possible to compare this to women in 1998.
Both in 1998, and in 2005, the most up-to-date records from the Ontario Cancer Registry were used to select samples as close to diagnosis as possible. However, given the recent computerization of the Registry, the 2005 cohort was surveyed almost 12 months closer to their diagnosis of cancer than the 1998 cohort and thus may have been more active in using CAM products and therapies to manage the lingering side effects of conventional cancer treatments. It might also have been easier for these women to recall the CAM they had used in the more active symptom phase of the management of the cancer than the women surveyed in 1998. It is possible that the difference in time since diagnosis accounts for the changes in CAM use reported by the two cohorts.
We originally selected a random sample from the Ontario Cancer Registry; however we were only able to mail surveys to approximately one-half of the sample from 1998 and just over one-third of the sample in 2005 (see Figure ). Physicians declined to provide permission for women that were too ill or emotionally unstable to respond or were unable to speak English (less than ten percent of the original sample). The reason we were unable to contact most of the other women was our inability to obtain a response from the physicians we contacted to obtain permission to mail a survey to the patient. It is possible that physicians who did not respond had more negative attitudes toward CAM and may have influenced their patients not to take CAM than those who agreed to allow their patients to participate. Thus, our prevalence rates may be an over-estimate of the actual prevalence of CAM use in the population of women with breast cancer.