Radiation Oncology/Pilocytic Astrocytoma

Pilocytic Astrocytoma Juvenile Pilocytic Astrocytoma WHO Grade I tumors Well-circumscribed, enhancing lesions typically located in the cerebellum; many are Optic Pathway Gliomas Surgical resection alone results in favorable outcome, with 10-year OS >80% Proton Therapy Loma Linda; 2002 (1991-1997) 11977386 -- "Conformal proton radiation therapy for pediatric low-grade astrocytomas." (Hug EB, Strahlenther Onkol. 2002 Jan;178(1):10-7.) Retrospective. 27 patients, progressive or recurrent low-grade astrocytoma. Fractionated proton therapy 50.4-63 CGE in 1.8 CGE/fx. Mean F/U 3.3 years Outcome: LC 78%, OS 85% Toxicity: well tolerated; Moyamoya disease in one child with NF1; 6 patients with optic pathway tumors maintained/improved their vision Conclusion: Proton RT is safe and efficacious; longer term follow-up needed Adult Pilocytic Astrocytoma Uncommon Clinical presentation includes visual disturbances, seizures, and headaches. Papilledema common Favorable prognosis both in terms of survival and neurologic function Most remain stable after resection (gross or subtotal) only, and need no adjuvant RT with close follow-up It may be reasonable to offer RT in unresectable disease, especially if causing neurologic symptoms 10 year OS 95% Intergroup NCCTG/RTOG (1986-1994) Prospective. 20 adults with supratentorial pilocytic astrocytoma. If gross total (n=11) or subtotal (n=6) resection, observation. If biopsy only (n=3), RT 50.4 Gy to 2-cm edema margin 10 years; 2004 15001258 -- "Adult patients with supratentorial pilocytic astrocytomas: a prospective multicenter clinical trial." (Brown PD, Int J Radiat Oncol Biol Phys. 2004 Mar 15;58(4):1153-60.) Median F/U 10 years 10-year outcome: 95% alive. 1 patient died of unknown cause 2.1 years after enrollment; 1 patient progressed 1 month after enrollment and was salvaged with P-32 followed 1.5 years later by RT, now without evidence of progression at 9 years Conclusion: Favorable prognosis; don't need RT after gross total or subtotal resection