Issue link: https://www.e-digitaleditions.com/i/1482660
research focus 8 cannabis patient care | vol. 3 no. 3 cannapatientcare.com Overview of the Research on Cannabis for Pediatric Oncology B Y R U T H F I S H E R , P h D About Pediatric Oncology Cancer is one of the leading causes of death in children. While leukemia is the most common form of pediatric cancer, tumors of the central nervous system (CNS) are the leading causes of death in children with cancer (1). Cancer in children is rare (1). Unfortunately, its incidence has increased during the past 40 years, from about 13 cases per 100,000 children in 1975, to about 20 cases per 100,000 children in 2016 (2). Fortunately, however, the survival rate has dramat- ically improved, from about 10% during the 1970s to now up- wards of 90% (2). Pediatric oncology is different from adult oncology. The most notable difference is the frequencies in which differ- ent types of cancer occur in adults versus children. Specifical- ly, forms of cancer more common in adults include cancers of the lung, colon, pancreas, and breast. In contrast, cancer in children is overwhelmingly in the form of either leukemia or CNS tumors (1). Another important difference between adult and pediatric cancers is their respective causes. Much adult cancer is asso- ciated with "cumulative environmental exposures." In contrast, children haven't accumulated such exposures, so their can- cers tend to result more from genetic mutations or other forms of abnormal development. As a result, tumors from adults and children with similar tissue formations often have very differ- ent origins, and thus must be treated differently (1). Finally, children respond differently than adults to cancer treatments, such as chemotherapy (1). In short, children tend to suffer from different forms of can- cer than adults do, the causes of pediatric cancers are differ- ent from the causes of adult forms of cancer, and children re- spond differently to treatments. It follows that research and treatments that apply to adult cancers don't necessarily ap- ply to pediatric cancers; rather, pediatric cancer must be studied separately. Unfortunately, the small numbers of pa- tients, combined with the ethics associated with conducting research on children, makes it exceedingly difficult to study pediatric oncology. Studies of Cannabis for Pediatric Oncology Given the rarity of pediatric oncology, together with the ethics surrounding its study, it's no surprise that there are few studies in cannabis as a treatment for pediatric oncology, and those that do exist suffer from reliability or validity problems due to their small associated sample sizes. That said, let's consider what preclinical and clinical studies have discovered about cannabis as a treatment for pediatric oncology patients. Preclinical Studies Preclinical research on cannabis for pediatric oncology has established, first, that tumors with more cannabinoid receptors (CB1) at the time of diagnosis tended to shrink either on their own or in response to cannabis treatments. This suggests the endocannabinoid system is involved, and thus, that cannabis may act on tumors. Second, cannabinoids induce death in leukemia cells both in vitro and in vivo, and cannabis enhances the efficacy of leukemia chemotherapies. Third, tetrahydrocannabinol (THC) from both natural and synthetic sources has been shown to inhibit tumor growth. And last, THC and cannabidiol (CBD) have been shown to reduce cell viability, both in vitro and in vivo, in pediatric neuroblastoma (1,3). Clinical Studies Clinical research on cannabis for pediatric oncology has estab- lished, first, that cannabis may be more effective than either pla- cebo or conventional therapies in treating nausea and vomiting (1,3). Second, the experience of a pediatric oncology center in Israel using cannabis to treat patients found the majority (80%) of patients treated with cannabis reported "a high level of gen- eral satisfaction with the use of cannabis," specifically, "improved quality of sleep, appetite, and feeling better overall" with only "mild and short-term" side effects (4). Third, studies of dronabi- nol and nabilone, both synthetic forms of THC approved by the US Food and Drug Administration (FDA) for cancer-induced nau- sea and vomiting (CINV), have shown cannabis to be an effective treatment for CINV in children (5,6).