Radiation Oncology/Medulloblastoma/Protons

Proton Therapy in Medulloblastoma

Clinical Data

• Loma Linda; 2004 (2001-2003) PMID 15701271 -- "Reducing toxicity from craniospinal irradiation: using proton beams to treat medulloblastoma in young children." (Yuh GE, Cancer J. 2004 Nov-Dec;10(6):386-90.)
  • Retrospective. 3 children, M2-M3 medulloblastoma, treated with CSI. 36 CGE + 18 CGE PF boost. Cranium - opposed lateral fields. Spine - three matched PA fields
  • Outcome: Substantially reduced dose to cochlea and vertebral bodies; virtually no exit dose through thorax, abdomen, and pelvis.
  • Toxicity: acute side effect mild
  • Conclusion: Successful reduction of normal tissue irradiation

Treatment Planning

• PSI
  • 2nd cancers; 2002 PMID 12377335 -- "Potential reduction of the incidence of radiation-induced second cancers by using proton beams in the treatment of pediatric tumors." (Miralbell R, Int J Radiat Oncol Biol Phys. 2002 Nov 1;54(3):824-9.)
    • Treatment planning. 2 children, parameningeal rhabdomyosarcoma and medulloblastoma. Conventional photon vs. IMRT vs PT vs IMPT. Secondary cancer incidence estimated
    • Outcome: RMS: protons reduced expected incidence by > 2x over photons; MB protons reduced expected incidence by 8-15x over photons
    • Conclusion: Potential for significant reduction in secondary cancers with proton therapy
  • Supratentorial; 1997 PMID 9231669 -- "Potential role of proton therapy in the treatment of pediatric medulloblastoma/primitive neuroectodermal tumors: reduction of the supratentorial target volume." (Miralbell R, Int J Radiat Oncol Biol Phys. 1997 Jun 1;38(3):477-84.)
    • Treatment planning. 3 year old child with medulloblastoma. Photon whole brain (conventional 2 field) vs. hand-optimized photon brain (6 fields) vs. IMRT (9 fields) vs. proton (3 fields). Whole brain 30 Gy + posterior fossa/ventricle boost 10 Gy.
    • Outcome: both optimized photon plans only slightly worse than proton plan
    • Conclusion: Decrease in morbidity can be expected from protons and optimized photon plans compared to whole brain irradiation
  • Craniospinal; 1997 PMID 9240650 -- "Potential role of proton therapy in the treatment of pediatric medulloblastoma/primitive neuro-ectodermal tumors: spinal theca irradiation." (Miralbell R, Int J Radiat Oncol Biol Phys. 1997 Jul 1;38(4):805-11.)
    • Treatment planning. 2 year old child with neuroblastoma, undergoing CSI. Single posterior 6 MV photon field vs. single posterior 100 MeV proton field, 30 Gy
    • Outcome: Target (spinal dural sac) coverage comparable. Vertebral body V50% photons 100% vs. protons 20%. Heart dose V60% photons 60% vs. protons 0%
    • Conclusion: Potential role for proton therapy in decreasing OAR dose during CSI irradiation

Economics

• Sweden; 2005 PMID 15637691 -- "Cost-effectiveness of proton radiation in the treatment of childhood medulloblastoma." (Lundkvist J, Cancer. 2005 Feb 15;103(4):793-801.)
  • Markov simulation, children age 5 followed for tumor control and adverse events
  • Outcome: Proton therapy 23,600 cost saving, 0.68 additional QALY per patient. Biggest benefit due to reduction in IQ and GHD loss
  • Conclusion: Proton therapy can be cost-effective and cost-saving compared with conventional RT