A Study Comparing Two Carboplatin Containing Regimens for Children and Young Adults With Previously Untreated Low Grade Glioma

Low grade gliomas are the most common central nervous system (CNS) tumors in the pediatric population. They consist of a heterogeneous group of tumors that are classified as World Health Organization (WHO) grade I or II. This includes astrocytic, oligodendroglial, neuronal and mixed glial- neuronal tumors. The clinical behavior of these tumors varies according to location and histology. The cerebellum is the most common location for low grade gliomas, but they can also arise in the cerebrum, deep midline structures such as the hypothalamus, optic pathway and, less frequently, in the brainstem.

Although the etiology of most childhood LGG is unknown, patients with Neurofibromatosis type 1 (NF-1) are one rare group predisposed to developing CNS tumors. NF-1 is an inherited disorder that affects the nervous system, eyes and skin. In addition, children are at an increased risk for developing optic pathway and hypothalamic low grade gliomas. Fifteen to-20% of NF-1 patients will develop these tumors, and they account for up to 70% of the tumors seen in this location. In half of patients with NF-1 and an optic pathway tumor, the patients are not symptomatic and the mass is found incidentally. Many optic gliomas in NF-1 patients follow an indolent course and stabilize without intervention. Patients are most commonly treated when there is deterioration in their vision or a symptomatic increase in the tumor size. Although the event free survival (EFS) has been reported to be similar between NF1 and non-NF1 patients, overall survival is higher in NF1 patients.

Location, as it affects the extent of surgical resection, plays a key role in the prognosis of all patients with low grade gliomas. Complete surgical resection offers a 90% survival rate at 10 years with often no need for adjuvant chemotherapy or radiation. Unfortunately, a gross total resection is not always possible due to the location of the tumor and its proximity to vital structures in the brain. In patients with an incomplete resection, the 10 year EFS is up to 74% with radiation treatment. However, toxicity from radiation, especially in young children, is significant and includes neurocognitive delays, endocrinopathies, secondary malignancy, ototoxicity and vasculopathy. Therefore, most experts agree that the standard of care in young children is to treat low grade gliomas that require adjuvant therapy after surgical resection/biopsy, or whose tumors are not surgically resectable with chemotherapy first, in order to delay or avoid radiation. This is especially true in children with NF-1, where the risk of a secondary malignancy after radiation therapy can be as high as 50% in the lifetime of the child.

Inclusion criteria

• Tumor Diagnosis: Low grade gliomas
• Patients must be less than 21 years of age at study entry.
• Central nervous system tumor. Patients with primary spinal cord lesions. Patients with metastatic disease are also allowed.
• No previous therapy for the tumor with the exception of corticosteroids and surgery.
• Performance status:Karnofsky Performance Scale (KPS for > 16 yrs of age) or Lansky Performance Score (LPS for ≤ 16 years of age) ≥ 50 assessed within two weeks prior to registration
• Seizure disorder should be well controlled.
• Normal organ and marrow function
• Female patients of childbearing potential must not be pregnant or breast-feeding. Female patients who have menstruated and are of childbearing potential must have a negative serum or urine pregnancy test prior to enrollment.
• Patients of childbearing or child fathering potential must be willing to use a medically acceptable form of birth control, which includes abstinence, while being treated on this study and for 6 months after the last drug administration.
• Ability of subject or parent/guardian to understand and the willingness to sign a written informed consent/assent document. Informed consent/assent must be signed prior to registration on this study.
• Tissue blocks or slides must be sent. If tissue is unavailable, the study chair must be notified prior to enrollment.

Exclusion criteria

• Patients who are receiving any other investigational or chemotherapeutic agents will be excluded.
• Patients with known inability to return for follow-up visits or obtain follow-up studies required to assess for toxicity to therapy.
• Patients with Subepenydmal Giant Cell Astrocytomas are excluded. Patients with intrinsic brainstem tumors of the pons will be excluded from the study.
• History of hypersensitivity reactions attributed to compounds of similar chemical or biologic composition to platinum based chemotherapy.
• Patients with uncontrolled inter-current illness are excluded.
• Females who are pregnant or breast feeding are excluded.