title: Outcome of four-dimensional stereotactic radiotherapy for centrally located lung tumors.
abstract: OBJECTIVE
  To assess local control, overall survival, and toxicity of four-dimensional, risk-adapted stereotactic body radiotherapy (SBRT) delivered while tracking respiratory motion in patients with primary and metastatic lung cancer located in the central chest.
  
  
  METHODS
  Fifty-eight central lesions of 56 patients (39 with primary, 17 with metastatic tumors) were treated. Fifteen tumors located near the esophagus were treated with 6 fractions of 8 Gy. Other tumors were treated according to the following dose escalation scheme: 5 fractions of 9 Gy (n = 6), then 5 fractions of 10 Gy (n = 15), and finally 5 fractions of 12 Gy (n = 22).
  
  
  RESULTS
  Dose constraints for critical structures were generally achieved; in 21 patients the coverage of the PTV was reduced below 95% to protect adjacent organs at risk. At a median follow-up of 23 months, the actuarial 2-years local tumor control was 85% for tumors treated with a BED >100 Gy compared to 60% for tumors treated with a BED ≤ 100 Gy. No grade 4 or 5 toxicity was observed. Acute grade 1-2 esophagitis was observed in 11% of patients.
  
  
  CONCLUSIONS
  SBRT of central lung lesions can be safely delivered, with promising early tumor control in patients many of whom have severe comorbid conditions.
authors.affiliation: Department of Radiation Oncology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam, The Netherlands. j.nuyttens@erasmusmc.nl
authors.forename: Joost J
authors.initials: JJ
authors.lastname: Nuyttens
authors.forename: Noelle C
authors.initials: NC
authors.lastname: van der Voort van Zyp
authors.forename: John
authors.initials: J
authors.lastname: Praag
authors.forename: Shafak
authors.initials: S
authors.lastname: Aluwini
authors.forename: Rob J
authors.initials: RJ
authors.lastname: van Klaveren
authors.forename: Cornelis
authors.initials: C
authors.lastname: Verhoef
authors.forename: Peter M
authors.initials: PM
authors.lastname: Pattynama
authors.forename: Mischa S
authors.initials: MS
authors.lastname: Hoogeman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D011879:Radiotherapy Dosage; D016896:Treatment Outcome; D047368:Tumor Burden