title: Stereotactic body radiation therapy can be used safely to boost residual disease in locally advanced non-small cell lung cancer: a prospective study.
abstract: OBJECTIVE
  To report the results of a prospective, single-institution study evaluating the feasibility of conventional chemoradiation (CRT) followed by stereotactic body radiation therapy (SBRT) as a means of dose escalation for patients with stage II-III non-small cell lung cancer (NSCLC) with residual disease.
  
  
  METHODS
  Patients without metastatic disease and with radiologic evidence of limited residual disease (≤5 cm) within the site of the primary tumor and good or complete nodal responses after standard CRT to a target dose of 60 Gy were considered eligible. The SBRT boost was done to achieve a total combined dose biological equivalent dose >100 Gy to the residual primary tumor, consisting of 10 Gy × 2 fractions (20 Gy total) for peripheral tumors, and 6.5 Gy × 3 fractions (19.5 Gy total) for medial tumors using the Radiation Therapy Oncology Group protocol 0813 definitions. The primary endpoint was the development of grade ≥3 radiation pneumonitis (RP).
  
  
  RESULTS
  After a median follow-up of 13 months, 4 patients developed acute grade 3 RP, and 1 (2.9%) developed late and persistent grade 3 RP. No patients developed grade 4 or 5 RP. Mean lung dose, V2.5, V5, V10, and V20 values were calculated for the SBRT boost, and none were found to significantly predict for RP. Only advancing age (P=.0147), previous smoking status (P=.0505), and high CRT mean lung dose (P=.0295) were significantly associated with RP development. At the time of analysis, the actuarial local control rate at the primary tumor site was 82.9%, with only 6 patients demonstrating recurrence.
  
  
  CONCLUSIONS
  Linear accelerator-based SBRT for dose escalation of limited residual NSCLC after definitive CRT was feasible and did not increase the risk for toxicity above that for standard radiation therapy.
authors.affiliation: Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA. jmfedd0@uky.edu
authors.forename: Jonathan
authors.initials: J
authors.lastname: Feddock
authors.forename: Susanne M
authors.initials: SM
authors.lastname: Arnold
authors.forename: Brent J
authors.initials: BJ
authors.lastname: Shelton
authors.forename: Partha
authors.initials: P
authors.lastname: Sinha
authors.forename: Gary
authors.initials: G
authors.lastname: Conrad
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: John
authors.initials: J
authors.lastname: Rinehart
authors.forename: Ronald C
authors.initials: RC
authors.lastname: McGarry
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000601:surgery* / Q000628:therapy; D059248:Chemoradiotherapy / Q000379:methods; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008168:Lung / Q000528:radiation effects; D008175:Lung Neoplasms / Q000473:pathology* / Q000601:surgery / Q000628:therapy; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual; D011446:Prospective Studies; D017564:Radiation Pneumonitis / Q000209:etiology / Q000473:pathology; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D011879:Radiotherapy Dosage; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects