Chemotherapy Combined With Radiation Therapy for Newly Diagnosed CNS AT/RT

OBJECTIVES:

Primary

• Determine the efficacy of intensive systemic and intrathecal chemotherapy and radiotherapy, in terms of medial survival, in children with newly diagnosed central nervous system atypical teratoid/rhabdoid tumors in comparison with historical outcomes from prior trials.

Secondary

• Determine the toxicity profile and tolerability of this regimen in these patients.
• Determine the chemosensitivity of these patients' tumors by Magnetic Resonance Imaging (MRI) after an attempt at maximum surgical resection after 2 courses of this regimen.
• Determine the predictive value of the INI-1 gene mutation in determining prognosis by comparing tumor samples from patients with vs without this mutation treated with this regimen.

STATISTICAL DESIGN: This was a single arm design evaluating median overall survival. The chosen historical control estimate of 7 months was based on 2 large multi-institutional studies in a similar setting and the alternative of 20.5 months based on a DFCI pilot study. There was 90% power to detect this improvement assuming 1-sided 0.10 alpha and 17 eligible patients. Sample size (n=20 patients) was inflated for expected 10-15% ineligible rate.

TREATMENT: Induction chemotherapy was required to be initiated within 50 days of the most definitive surgery.

• Central Nervous System (CNS)/intrathecal therapy: All patients with M0 disease receive triple intrathecal (IT) chemotherapy comprising methotrexate (MTX), cytarabine, and hydrocortisone on day 1 of weeks 1, 2, 4, 7, 13, 19, 27, 33, 39, 45, and 51 followed by oral or intravenous (IV) leucovorin calcium given 24 hours after each MTX dose. Patients with initially positive cerebrospinal fluid (CSF) cytology (M+) receive triple IT chemotherapy weekly until 2 consecutive CSF samples are negative for malignant cells.
• Pre-irradiation induction therapy (weeks 1-6): Patients receive vincristine IV on day 1 of weeks 1-6; cisplatin IV over 8 hours on day 1 and doxorubicin IV continuously over 48 hours beginning on day 2 of weeks 1 and 4; cyclophosphamide IV continuously over 72 hours beginning on day 2 of week 1; etoposide IV over 1 hour on days 1-3 of week 4; and filgrastim (G-CSF) subcutaneously (SC) beginning on day 6 of week 1 and day 4 of week 4 and continuing until blood counts recover.
• Induction chemoradiotherapy (weeks 7-12): Patients receive vincristine IV on day 1 of weeks 7-12; cisplatin IV over 8 hours on day 1, cyclophosphamide IV over 1 hour on day 2, etoposide IV over 1 hour on days 1-3 of weeks 7 and 10; and granulocyte-colony stimulating factor (G-CSF) subcutaneous (SC) daily beginning on day 4 of weeks 7 and 10 and continuing until blood counts recover. Patients with M0 disease and patients under 3 years of age with M+ disease undergo radiotherapy to the primary tumor daily on weeks 7-12. Patients 3 years of age and over with M+ disease undergo craniospinal irradiation (CSI) daily on weeks 7-12 until negative cerebral spinal fluid (CSF) cytology is achieved.
• Post-radiation induction therapy (weeks 13-18): Patients receive vincristine IV on day 1 of weeks 13 and 16; doxorubicin and cyclophosphamide as in pre-irradiation induction therapy beginning on day 1 of week 13; cyclophosphamide IV over 1 hour on days 1-3 of week 16; dactinomycin IV on days 1-5 of week 16; and G-CSF SC daily beginning on day 6 of weeks 13 and 16 and continuing until blood counts recover.
• Maintenance chemotherapy (weeks 19-42): Patients receive vincristine IV on day 1 of weeks 27, 33, and 39 and days 1 and 5 of weeks 30, 36, and 42; doxorubicin and cyclophosphamide as in pre-irradiation induction beginning on day 1 of weeks 27 and 33; doxorubicin IV over 15 minutes and dexrazoxane (DX) IV over 15 minutes on days 1 and 2 of week 39; cyclophosphamide IV over 1 hour on days 1-3 of weeks 30, 36, 39, and 42; dactinomycin IV on days 1-5 of weeks 30, 36, and 42 and on day 1 of weeks 19 and 23; oral temozolomide on days 1-5 of weeks 19 and 23; and G-CSF SC daily beginning on day 6 of weeks 19, 23, 30, 36, and 42, day 5 of weeks 27 and 33, and day 4 of week 39 and continuing until blood counts recover.
• Doxorubicin continuation therapy (for patients not receiving CSI and mediastinal radiotherapy)(weeks 45-51): Patients receive vincristine IV on day 1 of weeks 45, 48, and 51 and day 5 of week 48; doxorubicin IV over 15 minutes and DX IV over 15 minutes on days 1 and 2 of weeks 45 and 51; cyclophosphamide IV over 1 hour on days 1-3 of weeks 45, 48, and 51; dactinomycin IV on days 1-5 of week 48; and G-CSF SC daily beginning on day 4 of weeks 45 and 51 and day 6 of week 48 and continuing until blood counts recover.
• Non-doxorubicin continuation therapy (for patients receiving CSI or mediastinal radiotherapy)(weeks 45-51): Patients receive cyclophosphamide and G-CSF as in doxorubicin continuation therapy; vincristine IV on days 1 and 5 of weeks 45, 48, and 51; and dactinomycin IV on days 1-5 of weeks 45, 48, and 51.

Treatment continues in the absence of disease progression or unacceptable toxicity.