Newly diagnosed high-risk malignant brain tumors with leptomeningeal dissemination in young children: A final update on Head Start II Regimen A2 intensified with high-dose methotrexate

Abstract

9552 Background: The prognosis for young children with newly diagnosed malignant brain tumors with leptomeningeal dissemination remains poor. From Jan 1997 to Mar 2003, “Head Start II” Regimen A2, intensified with high-dose methotrexate, was offered to this high-risk population. Methods: Eligibility: patients < 10 yrs of age; confirmed diagnosis of medulloblastoma (MB), primitive neuroectodermal tumor (PNET), ependymoma and choroid plexus carcinoma (CPC); and high-risk status as determined by neuroaxis dissemination. Patients with atypical teratoid/rhabdoid tumor (ATRT), regardless of stage, were also eligible. Treatment: 5 cycles of vincristine (0.05 mg/kg/week × 3 doses), cisplatin (3.5 mg/kg), etoposide (4 mg/kg/day × 2 days), cyclophosphamide (65 mg/kg/day × 2 days), and methotrexate (400 mg/kg) with leucovorin. Children without progressive disease (PD) by the end of induction underwent a single consolidation cycle (carboplatin, etoposide, thiotepa) with autologous stem cell rescue. Reduced dose RT (2340cGy CSI and focal boost) was reserved for any with residual disease at the end of induction or for the older patient (>6 yrs of age). Results: 40 patients were enrolled (MB, 22; PNET, 6; ependymoma, 5; AT/RT, 6; CPC, 1), med age at diagnosis 38 mos (range 5 to 119 mos). Significant toxicities of this intensified regimen included GI toxicities and infections. Among the entire cohort, there were 26 CR, 6 PR, 2 with stable disease and 4 with PD (and 2 toxic deaths), for a CR +PR response rate of 82%. For disseminated MB (4 M1; 2 M2; 16 M3), the CR rate alone is 77% (17/22). The 5-year EFS and OS for disseminated MB are 45% (95% CI, 24 % to 64%) and 54% (95% CI, 31% to 72%), respectively. Of note, 6/12 MB survivors (all M3) did not receive RT and all are NED >5 years from diagnosis. In addition, there are 3 AT/RT survivors, 12, 54 and 66 mos post-diagnosis who did not receive RT. Conclusions: This intensified regimen is feasible and tolerable. For patients with disseminated MB, the majority of whom had M3 disease at diagnosis, the impressive response rate and outcomes suggest that the addition of methotrexate is justified for future studies. Long- term neuropsychological outcomes are being studied at this time. No significant financial relationships to disclose.