Dr. Roger Packer (Senior Medical Advisor for the Childhood Brain Tumor Foundation, Executive Director and Chairman of the Department of Neurology at Children’s National Medical Center in Washington DC, and a Founder of the International Society for Pediatric Neuro Oncology)
Hope…. of dramatically speeding up the process of investigations and therapy for childhood JPAs….is quite real,Ӕ assuming that research funds are raised.
Most brain tumor programs have not developed programs focused on childhood pilocytic astrocytomas (JPA). Without dedicated PLGA programs and monies…Ӕ, (because JPAs are biologically different than other childhood brain tumors and behave differently than other tumors), it is likely that advances in our understanding and treatment will be unfortunately slower than possible.
“Current treatments such as chemotherapeutic agents work in some children with low-grade astrocytomas but have significant potential long-term sequelae, including the potential development of secondary tumors and the immediate risk of bone marrow suppression with resultant infection and hemorrhage that can be life threatening.
“Although chemotherapy is usually an effective short-term treatment, its beneficial effects often last only three to five years and patients once again may need aggressive surgeries or radiotherapy, still at a time when their brain is developing and they are at risk for significant secondary neurologic compromise. For some children with childhood juvenile pilocytic astrocytomas that do not respond to standard chemotherapeutic agents such as carboplatin, vincristine, or temozolomide, treatment requires more aggressive therapy to control disease, with resultant increased risks. Other patients with so-called low-grade juvenile pilocytic astrocytomas will progress despite all these modalities of treatment, especially this subset of children with juvenile pilocytic astrocytomas that disseminate the nervous system early in the course of illness.
“For these reasons, more research is desperately needed to develop new means of treatment for juvenile pilocytic astrocytomas. At the present time, many of the newer agents are not being tested in PLGAs and there are few, if any, clinical studies open for children with PLGAs. In the biologic labs, they are often an afterthought, as they do not fit with other types of astrocytomas in their molecular genetics. Adult-oriented programs, including adult-oriented funding programs, are a great deal more likely to focus on the more common adult tumors – especially glioblastoma multiforme. Research in glioblastoma multiforme may have little connotation as regards a better understanding of childhood PLGAs.
“In fact, over the many years that I have been on committees evaluating funding for projects, those few projects which have been focused on PLGAs, have not been prioritized highly and are usually not funded. There are simply more people working on higher grade gliomas and medulloblastomas and, for a variety of reasons, the science in these types of tumors is a bit more advanced and certainly is more consistent with the studies being performed in a variety of different types of cancer.
To make a real difference in the management of childhood PLGAs, monies need to be earmarked for PLGA research and education.
Dr. KK Wong, PhD, Associate Professor UT MD Anderson Cancer Center
“Currently, no diagnostic tools exist to allow clinicians to distinguish PLGA that will be progressive or refractory. Thus observation has been recommended for children below 3 to 5 years of age even after incomplete resection. It is because the treatments for aggressive brain tumors in children often carry significant long-term consequences, therefore are not acceptable as a means to prevent recurrence in JPA that already have a high probability of cure. Ideally, clinicians would be able to distinguish early on between JPA that are likely to be cured and those that are likely to recur or progress.
Ferenc A. Jolesz, MD, Professor of Radiology, Vice Chairman for Research, and Director, Division of MRI and Image Guided Therapy Program at the Department of Radiology at Brigham and Women’s Hospital (a Harvard Medical School affiliate)
Radiologists, neurosurgeons and physicist at Boston’s Brigham and Women’s Hospital (a Harvard Medical School Affiliate) are treating adult brain tumors noninvasively using focused ultrasonic waves that are guided with Magnetic Resonance Imaging.
This way of treating deep-seated brain tumors without opening the skull may provide an optimal way to treat otherwise inoperable pediatric brain tumors. Some pediatric brain tumors despite their benign nature are not resectable surgically or treatable with ionizing radiation and deemed inoperable because the neurosurgeon cannot go through the surrounding vital functioning brain such as the brainstem.
Under MRI monitoring these tumors can be safely coagulated without the damage of the surrounding functioning brain tissue. Tumor ablation or coagulation is achieved by the localized heat which is the result of the absorption of focused sound waves by the targeted tumor tissue.
The FUS treatment advantage over radiation therapy is that ultrasound does not deliver ionizing radiation, so there is no maximum or cumulative dose. The FUS procedure, unlike radiation, can be repeated safely numerous times.
This is particularly advantageous to treat slowly growing benign tumors like pilocytic astrocytoma. It is possible to treat a patient multiple times to prevent the growth of the tumor even if it is cannot be completely eliminated.
Focused ultrasound will require refinement before it will be routinely useful for pediatric brain tumors but it has the promise of making a substantial change in the prognosis of pediatric brain tumors, especially those whichare presently inoperable.”