The 20th century saw striking advances in curing childhood cancer, primarily as a result of the discovery that broadly toxic chemotherapy agents could kill malignant cells. As a result, pediatric cancer, once a virtually incurable disease, now enjoys an overall long-term survival rate that tops 80 percent. In the 21st century, attention is turning to newer agents that promise to open additional, less toxic avenues to cure. As we mark Childhood Cancer Awareness Month 2015 throughout September, here are four things on the horizon for pediatric cancer.
Precision medicine. Treatment for cancers is now being transformed because we can genetically characterize an individual’s tumor, finding genetic changes that suggest specific targeted therapies. These therapies are developed for specific targets that may be implicated in a wide variety of pediatric and adult cancers.
A cancer’s biology, rather than its location in the body or the age of the patient, becomes the salient factor. Drugs that are proving effective at treating an adult lymphoma, for instance, can also treat a pediatric solid tumor with similar biologic characteristics. Likewise, a discovery in pediatric cancer can open new avenues of treatment for adult cancers. Still, there are barriers to overcome in bringing these discoveries to children with cancer. We need drugs in liquid form for young children, yet many drugs are being developed only as pills. We need preclinical testing in pediatric models and efficient early phase trials to establish the appropriate dosing for children. We must recognize that some pathways implicated in the development of a childhood cancer might be different from the pathways indicated in adult cancers, but there may still be crossover in terms of the therapeutic agents themselves. Pediatric cancers often involve changes in the epigenome — or in gene regulation — rather than mutations or abnormalities in gene sequencing. The question is can we use the same pathways being used in precision medicine to target epigenetic changes.
Immunotherapy. Immunotherapy is another new approach generating excitement in the treatment of pediatric and adult cancers. The Food and Drug Administration recently approved Unituxin™ (dinutuximab), an antibody agent for high-risk neuroblastoma, making it the first immunotherapy drug for pediatric cancer to earn FDA approval.
Meanwhile, promising pediatric trials are underway for an immunotherapy approach that genetically modifies a patient’s T-cells to recognize tumor cells in treatment-resistant leukemia. There is a lot of enthusiasm about similarly modifying the immune system’s T-cells to treat other cancers. Exciting advances are being made in adult oncology in immune checkpoint blockade therapy that uses drugs to teach a patient’s own immune system to recognize and reject tumor cells. Already there have been dramatic advances in melanoma outcomes and promising results in other adult-onset cancers. We are beginning to learn how to use this approach in pediatric cancers. There is also a lot of interest in looking at specific cancers whose genetic mutations may act as “neoantigens,” or new antigens, suggesting another potential avenue for immunotherapy.
Reducing toxicity. The improved cure rates that characterized the last half of the 20th century came at a cost, as chemotherapy and radiation often have long-term negative effects that appeared as more treated children survived into adulthood.
Many developed serious chronic conditions, including heart disease, infertility, and secondary malignancies. Since the late 20th century, we have increasingly sought ways to reduce the toxicity of treatment to maintain cure rates with fewer late effects. These efforts will continue. Both targeted therapies and immunotherapy are promising not only because of their potential curative powers but also because they are potentially less toxic than standard chemotherapy. Clinicians also continue to explore ways to reduce radiation, as well as to make it more targeted to the tumor and involve less normal tissue.
We will likely have information, in the years to come, that will predict who is at higher risk for specific toxicities. This may help clinicians, parents and patients make decisions about best therapies, factoring in not only the likelihood of cure but also issues around long-term quality of life.
Global health. The strides in improved cure rates in North America and Europe have often not reached the developing world. Meanwhile, as improved health care systems reduce the risk of childhood death from malnutrition, diarrhea, and infectious diseases, resources in developing countries can be directed toward the care of children with cancer.
Today, clinicians in the United States, Canada, and Europe are working with clinicians in Latin America, Africa and parts of Asia to improve outcomes. Because pediatric cancers are rare, pediatric oncology is a global community accustomed to collaborating internationally, which offers a good platform for a stronger focus on improving survival of childhood cancer globally. Understanding the patterns of cancer throughout the world and differences in incidence in different countries may bring insights into understanding the causes of childhood cancer, as well.
Lisa Diller is chief medical officer, Dana-Farber/Boston Children’s Cancer and Blood Disorders Center and director, David B. Perini Jr. Quality of Life Clinic.
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