Patients who have been diagnosed with cancer commonly use complementary and alternative medicine (CAM). In theory, CAM aims to enhance patients' quality of life (QoL) although little empirical data exist to support this proposition. The present study aimed to: (1) examine the use of CAM and the patterns of CAM use over time in patients with advanced cancer; (2) explore the reasons for CAM use and the changes over time; and (3) examine the impact of CAM use on the QoL of advanced cancer patients.
This longitudinal study followed-up every four to eight weeks 159 advanced cancer patients from notification to the Queensland Cancer Registry (QCR) of progressive disease until close to death using standardized protocols. The study collected both quantitative and qualitative data.
Overall, 60 (38%) respondents were using CAM at entry to the study, mostly vitamins, minerals and tonics, herbal remedies, and meditation, relaxation or yoga. About 60% of CAM users were utilising only one CAM system or modality, and 37% were receiving treatment from CAM practitioners (mainly medical practitioners offering CAM, reiki practitioners and naturopaths). The prevalence of CAM use increased to 52% over the study period. The majority of patients self-treated with CAM. Participants showed distinct patterns of CAM use over time and, accordingly, were grouped into three categories. Seventy-six (48%) participants were categorised as 'CAM non-users', 30 (19%) were categorised as 'irregular CAM users', and 53 (33%) respondents were categorised as 'regular CAM users'.
All 159 patients provided valid data at entry to the study and were included in the baseline analysis. For the follow-up analyses, valid data over the last year of life was obtained from 118 patients with available date of death. Longitudinal data on the rationale for CAM use and the QoL assessments were compared across the groups using date of death as the common baseline. The Generalised Estimating Equations (GEE) model was used to run these longitudinal models. A thematic analysis of the qualitative data was carried out to explore participants' understanding of QoL and their rationale for CAM use.
At entry to the study, regular CAM users were significantly younger and more likely to be either employed or not retired. Whereas both regular and irregular CAM users were significantly more likely to have no religious affiliation, CAM non-users were more likely to be either Protestant or to have other Christian (non-Catholic) affiliation. The three groups of participants did not differ significantly in any of the medical characteristics. There were no statistically significant differences in the use of conventional medicine across the CAM use groups.
At baseline, regular CAM users were significantly more dissatisfied with conventional medicine and more attracted to CAM. However, over the last year of life, CAM non-users reported significantly lower levels of perceived efficacy and greater need for personal control in the context of conventional cancer treatments. CAM use had no significant impact on the expected efficacy, perceived costs, or the loss of personal control in relation to these treatments. Regular CAM users who were diagnosed with gastrointestinal tract cancer were significantly more dissatisfied with conventional medicine than those with other cancer types. In addition, those regular users who did not use conventional medicine, who reported higher levels of subjective well-being or greater belief in curability were significantly more attracted to CAM. Those with lower income were significantly less attracted.
In terms of the QoL dimensions (subjective well-being and psychological distress), there were no significant differences across the CAM use groups over time. However, in terms of the QoL indicators, CAM non-users reported significantly higher levels of physical symptoms burden and lower levels of functional status compared to regular CAM users. Compared to irregular CAM users, regular users reported lower levels of affectionate support, lower positive social interaction, and lower levels of will to live.
CAM use is highly prevalent amongst patients with advanced cancer. There are significant differences over the last year of life between advanced cancer users and non-users of CAM in relation to the perceived efficacy of conventional medicine, the need for personal control in the decision-making process concerning cancer treatments, and some QoL indicators.