Complementary and alternative medicines, dietary manipulation and vitamin supplementation

Complementary and alternative medical (CAM) therapies are an extremely heterogeneous group of interventions that fall outside of the practices of conventional health care providers. Kara Kelly, in her review of the literature, noted that almost 1/3 of patients with cancer reported using CAM and the prevalence may be as high as 90% in some instances in children with cancer. The National Center for Complementary and Alternative Medicine in the US categorizes CAM into five groups. Nutritional interventions fall into the category of biologic therapies. Use of CAM nutritional interventions in children with cancer can be particularly problematic; challenging for children and their health care providers, risking compromised adherence to and even interference with conventional therapy. Biological variability and contamination of dietary supplements pose additional hazards. It is clearly important to establish trusting relationships with families so that open communication on the use of CAM can occur. Discussions on the quality of the evidence pertaining to safety and efficacy are essential. Cleary there are opportunities for definitive studies in the context of conventional clinical research. Examples include the use of antioxidants to limit toxicity, especially in the setting of hematopoietic stem cell transplantation in which the therapy is associated with depletion of anti-oxidant status. This setting also provides useful “testing ground” for clinical trials of other forms of CAM, especially those aimed at reducing mucositis and those claimed to provide nutritional benefits. CAM interventions are likely to have their most important role in supporting children through conventional chemotherapy and radiation therapy, especially for ameliorating toxicities for which there are insufficient conventional options. It is acknowledged that the use of CAM therapies empowers families in the care of their children with cancer. Working in concert with patient advocates and CAM practitioners is a constructive way forward in the necessary formal evaluation of the safety and efficacy of these products. Sheila Weitzman gave a comprehensive account of dietary “therapies” for cancer. It is clear that the incidence of some cancers in adults is affected by dietary components and that the lower incidences of these diseases in some parts of the world as compared to others can be attributed, at least in part, to different common dietary habits. Such observations have led to the nutritional guidelines of the American Cancer Society for cancer prevention. Claims that manipulation of the diet can cure malignant disease, however, remain unsupported by convincing evidence. Furthermore, many of these putative curative interventions are intolerable for children and some are frankly harmful. For the child with cancer, the focus of conventional supportive care should be on the provision of a well-balanced diet that meets the nutritional needs of the growing individual, with supplementation as required. In view of the 80% cure rate of childhood cancer today, it is important that nothing is given to the child which will interfere with the utilization and the efficacy of conventional therapy. Recognizing the widespread use of CAM, it is important for the practitioner to have an open dialogue with each family to ensure that there are no hidden agendas being pursued and that the reasonable use of non-harmful dietary interventions is supported. This approach may lead to indirect benefits such as the well-described placebo effect and an enhanced involvement of family members in the child's care. Such circumstances are worthy of further study. Ingrid Goh addressed the challenging issue of prenatal multi-vitamin supplementation and the occurrence of cancer in offspring. The rationale behind this area of research stems from the evidence in favor of a reduction in certain congenital anomalies associated with such supplementation. The evidence in support of cancer prevention is less clear. For example, some case-control studies suggest a significant protective effect with respect to brain tumors in children, while others do not. The complexity of interpretation is augmented in the recognition that supplements were in the form of multi-vitamins of varying compositions and the effect may vary with the timing of utilization during pregnancy. The balance of evidence in the case of acute lymphoblastic leukemia is in favor of a protective effect, perhaps attributable specifically to anti-oxidant components contained within these supplements, such as folic acid, vitamin C and vitamin E. A similar conclusion could be reached in the cases of neuroblastoma and retinoblastoma. The prospect of undertaking prospective, randomized studies is small. As the risks of judicious multi-vitamin supplementation in pregnancy are minimal the best practice is to encourage women to supplement with pre-natal multi-vitamins prior to and throughout pregnancy.

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