title: Proton SBRT for medically inoperable stage I NSCLC.
abstract: BACKGROUND
  The physical properties of proton beam radiation may offer advantages for treating patients with non-small-cell lung cancer (NSCLC). However, its utility for the treatment of medically inoperable stage I NSCLC patients with stereotactic body radiation therapy (SBRT) is unknown.
  
  
  METHODS
  Outcomes for patients with medically inoperable stage I NSCLC treated with proton SBRT were retrospectively analyzed. Proton SBRT was selected as the treatment modality based on pulmonary comorbidities (n = 5), prior chest radiation or/and multiple primary tumors (n = 7), or other reasons (n = 3). Treatments were administered using 2 to 3 proton beams. Treatment toxicity was scored according to common toxicity criteria for adverse events version 4 criteria.
  
  
  RESULTS
  Fifteen consecutive patients and 20 tumors were treated with proton SBRT to 42 to 50 Gy(relative biological effectiveness) in 3 to 5 fractions between July 2008 and September 2010. Treatments were well tolerated with only one case of grade 2 fatigue, one case of grade 2 dermatitis, three cases of rib fracture (maximum grade 2), and one case of grade 3 pneumonitis in a patient with severe chronic obstructive pulmonary disease. With a median follow-up of 24.1 months, 2-year overall survival and local control rates were 64% (95% confidence limits, 34%-83%) and 100% (83%-100%), respectively.
  
  
  CONCLUSIONS
  We conclude that proton SBRT is effective and well tolerated in this unfavorable group of patients. Prospective clinical trials testing the utility of proton SBRT in stage I NSCLC are warranted.
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02114, USA.
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Westover
authors.forename: Joao
authors.initials: J
authors.lastname: Seco
authors.forename: Judith A
authors.initials: JA
authors.lastname: Adams
authors.forename: Michael
authors.initials: M
authors.lastname: Lanuti
authors.forename: Noah C
authors.initials: NC
authors.lastname: Choi
authors.forename: Martijn
authors.initials: M
authors.lastname: Engelsman
authors.forename: Henning
authors.initials: H
authors.lastname: Willers
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016634:Radiosurgery / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome