title: Technique, outcomes, and acute toxicities in adults treated with proton beam craniospinal irradiation.
abstract: BACKGROUND
  Proton craniospinal irradiation (p-CSI) has been proposed to reduce side effects associated with CSI. We evaluated acute toxicities and preliminary clinical outcomes in a series of adults treated with p-CSI.
  
  
  METHODS
  We reviewed medical records for 50 patients (aged 16-63 y) with malignancies of varying histologies treated consecutively with vertebral body-sparing p-CSI at MD Anderson Cancer Center from 2007 to 2011. Median CSI and total boost doses were 30.6 and 54 Gy. Forty patients received chemotherapy, varying by histology. Median follow-up was 20.1 months (range, 0.3-59).
  
  
  RESULTS
  Median doses to the thyroid gland, pituitary gland, hypothalamus, and cochleae were 0.003 Gy-relative biological effectiveness (RBE; range, 0.001-8.5), 36.1 Gy-RBE (22.5-53.0), 37.1 Gy-RBE (22.3-54.4), and 33.9 Gy-RBE (22.2-52.4), respectively. Median percent weight loss during CSI was 1.6% (range, 10% weight loss to 14% weight gain). Mild nausea/vomiting was common (grade 1 = 46%, grade 2 = 20%); however, only 5 patients experienced grade ≥2 anorexia (weight loss >5% baseline weight). Median percent baseline white blood cells, hemoglobin, and platelets at nadir were 52% (range, 13%-100%), 97% (65%-112%), and 61% (10%-270%), respectively. Four patients developed grade ≥3 cytopenias. Overall and progression-free survival rates were 96% and 82%, respectively, at 2 years and 84% and 68% at 5 years.
  
  
  CONCLUSIONS
  This large series of patients treated with p-CSI confirms low rates of acute toxicity, consistent with dosimetric models. Vertebral body-sparing p-CSI is feasible and should be considered as a way to reduce acute gastrointestinal and hematologic toxicity in adults requiring CSI.
authors: Corresponding Author: Anita Mahajan, MD, Department of Radiation Oncology, Unit 97, MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030. amahajan@mdanderson.org.
authors: Christian L
authors: CL
authors: Barney
authors: Aaron P
authors: AP
authors: Brown
authors: David R
authors: DR
authors: Grosshans
authors: Mary Frances
authors: MF
authors: McAleer
authors: John F
authors: JF
authors: de Groot
authors: Vinay
authors: V
authors: Puduvalli
authors: Susan L
authors: SL
authors: Tucker
authors: Cody N
authors: CN
authors: Crawford
authors: Mark R
authors: MR
authors: Gilbert
authors: Paul D
authors: PD
authors: Brown
authors: Anita
authors: A
authors: Mahajan
mesh_terms: D000293:Adolescent; D000328:Adult; D001932:Brain Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D003198:Computer Simulation; D061888:Craniospinal Irradiation / Q000009:adverse effects* / Q000379:methods*; D018572:Disease-Free Survival; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D009503:Neutropenia / Q000209:etiology*; D011379:Prognosis; D011522:Protons / Q000009:adverse effects*; D011878:Radiotherapy / Q000009:adverse effects*; D015996:Survival Rate; D055815:Young Adult
chemical_list: D011522:Protons
keywords: acute toxicity; craniospinal irradiation; proton therapy.