title: Clinical outcomes of stereotactic body radiotherapy for small lung lesions clinically diagnosed as primary lung cancer on radiologic examination.
abstract: OBJECTIVE
  Image-guided biopsy occasionally fails to diagnose small lung lesions, which are highly suggestive of primary lung cancer. The aim of the present study was to evaluate the outcome of stereotactic body radiotherapy (SBRT) for small lung lesions that were clinically diagnosed as primary lung cancer without pathologic confirmation.
  
  
  METHODS
  A total of 115 patients were treated with SBRT in 12 institutions. Tumor size ranged from 5 to 45 mm in diameter, with a median of 20 mm.
  
  
  RESULTS
  The 3-year and 5-year overall survival rates for patients with a tumor size < or =20 mm in diameter (n = 58) were both 89.8%, compared with 60.7% and 53.1% for patients with tumors >20 mm (n = 57) (p <0.0005), respectively. Local progression occurred in 2 patients (3.4%) with a tumor size < or =20 mm and in 3 patients (5.3%) with tumors >20 mm. Among the patients with a tumor size < or =20 mm, Grade 2 pulmonary complications were observed in 2 (3.4%), but no Grade 3 to 5 toxicity was observed. In patients with a tumor size >20 mm, Grades 2, 3, and 5 toxicity were observed in 5 patients (8.8%), 3 patients (5.3%), and 1 patient (1.8%), respectively.
  
  
  CONCLUSIONS
  In patients with a tumor < or =20 mm in diameter, SBRT was reasonably safe in this retrospective study. The clinical implications of the high local control rate depend on the accuracy of clinical/radiologic diagnosis for small lung lesions and are to be carefully evaluated in a prospective study.
authors.affiliation: Department of Radiology, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Inoue
authors.forename: Shinichi
authors.initials: S
authors.lastname: Shimizu
authors.forename: Rikiya
authors.initials: R
authors.lastname: Onimaru
authors.forename: Atsuya
authors.initials: A
authors.lastname: Takeda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Onishi
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Nagata
authors.forename: Tomoki
authors.initials: T
authors.lastname: Kimura
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Karasawa
authors.forename: Takuro
authors.initials: T
authors.lastname: Arimoto
authors.forename: Masato
authors.initials: M
authors.lastname: Hareyama
authors.forename: Eiki
authors.initials: E
authors.lastname: Kikuchi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shirato
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007564:Japan; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011859:Radiography; D016634:Radiosurgery / Q000009:adverse effects / Q000941:ethics; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome; D047368:Tumor Burden