Original articleHigh-dose intravenous vitamin C improves quality of life in cancer patients
Introduction
Various cancer symptoms cause profound changes in the quality of life (QOL) of patients. Because pain due to cancer is considered to occur in 70% or more of patients in the terminal stage, management of cancer pain is extremely important for maintenance and improvement of the QOL. Recently, “the World Health Organization (WHO) guidelines for cancer pain relief” have been accepted as the standard treatment for cancer pain, and many cancer patients seek alleviation from pain with appropriate use of opioids [1]. However, approaches to treating pain refractory to opioids and various distressing symptoms associated with cancer other than pain have not yet been sufficiently established.
While these limitations of conventional medical approaches are becoming widely recognized, there is a trend in seeking ideas to overcome limitations in complementary and alternative medicine (CAM) worldwide. The same trend has also been observed in Japan, and there is a high prevalence of CAM use in patients with advanced cancer, who expect that this therapy will help maintain and improve their QOL [2].
High-dose intravenous vitamin C (IVC) therapy, as a form of CAM for cancer, has been safely performed in the United States for at least 30 years [3], [4]. Several clinical studies have previously shown the clinical usefulness of oral and intravenous administration of high doses of vitamin C to cancer patients and that IVC may confer a survival benefit [5], [6]. However, because later studies have not confirmed the usefulness of vitamin C [7], [8], IVC was rarely administered in cancer care [9].
However, with growing worldwide interest in CAM in recent years, the usefulness of IVC has been actively re-evaluated. In 2005, the National Institute of Health and the National Cancer Institute of the United States jointly published a high-quality basic study, which showed that high vitamin C concentrations selectively exert anti-tumor effects on various cancer cells [10].
Moreover, it has been shown that patients with advanced cancer tend to have low blood concentrations of vitamin C [11]. Mayland et al., showed that blood vitamin C concentrations were low in 72% of 50 patients with advanced cancer and that low blood vitamin C concentrations correlated highly with short survival times.
Therefore, to examine the clinical usefulness of IVC in terms of QOL, we conducted a prospective observational study on changes in QOL due to IVC and evaluated its safety in cancer patients.
Section snippets
Methods
This study was designed as a multicenter, open-label, prospective, observational study and conducted with the approval of the ethics review committee of The Japanese College of Intravenous Therapy with which the participating institutions are affiliated.
Results
During the study period, 63 patients were enrolled. Three patients did not complete their participation in the study: 2 patients whose performance status (PS) was already 4 at enrollment became unable to continue outpatient visits because of disease progression and one patient was hospitalized to receive radiotherapy during the study period. Thus, only the data from 60 patients were used for the study. The characteristics of study patients are shown in Table 1.
In 57 of the study patients
Discussion
With the objective of examining the usefulness of high-dose IVC in improving the QOL of cancer patients, we conducted a multicenter prospective observational study and found that administration of IVC twice a week for 4 weeks significantly improved the QOL for cancer patients.
In recent years, the importance of providing palliative care to cancer patients in the early stage has been advocated worldwide, and clinical studies confirming the utility of this approach have also been reported [17].
Conclusion
We conducted a multicenter prospective observational study to examine the effects of high-dose IVC therapy on the QOL of cancer patients. Scores for both the global health status and functional scales of the EORTC-QLQ C30 showed significant improvement at 4 weeks of IVC therapy; further, subjective symptom scores, especially those for fatigue and insomnia, showed significant improvement. On the basis of these results, we propose that IVC can safely improve the QOL of cancer patients. IVC has
Conflict of interests
The authors have no potential conflicts of interest relevant to this study.
Acknowledgment
The authors acknowledge the active physician members of The Japanese College of Intravenous Therapy who registered and participated in this study.
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