title: Patterns of Disease Recurrence after SABR for Early Stage Non-Small-Cell Lung Cancer: Optimizing Follow-Up Schedules for Salvage Therapy.
abstract: BACKGROUND
  Stereotactic ablative radiotherapy is a guideline-recommended treatment for early stage non-small-cell lung cancer. We report on incidence and salvage of local recurrences (LR) and second primary lung cancers (SPLC) in a large series of patients with long-term follow-up, to generate data for evidence-based follow-up regimens.
  
  
  METHODS
  We excluded all patients with double tumors, TNM-stages other than T1-T2N0M0, biologically effective dose less than 100 Gy10 and previous treatment for the index tumor from our institutional database. LR was defined as recurrence in/adjacent to the planning target volume. A diagnosis of SPLC was determined using criteria described by Martini et al.
  
  
  RESULTS
  The 855 patients included had a median follow-up of 52 months. Forty-six patients developed LR after a median of 22 months (range 7-87 months). Actuarial local control rates at 3 and 5 years were 92.4% and 90.9%, respectively. Fifty-four percent had isolated LR and 13% had LR in combination with regional recurrences. Ten patients underwent radical salvage treatment; surgery (N = 6), high-dose radiotherapy (N = 3), or chemoradiation (N = 1). Median overall survival following LR was 13 months, but it was 36 months in patients who underwent radical salvage. A SPLC was diagnosed in 79 patients, after a median interval of 34 months. Actuarial cumulative incidences of SPLC at 3 and 5 years were 11.7% and 16.7%, respectively. Radical salvage for SPLC was performed in 63 patients (80%).
  
  
  CONCLUSIONS
  Both the timing of LR and persistent risk of SPLC serve as rationale for long-term follow-up using computed tomography scans in patients fit enough to undergo any radical treatment.
authors.affiliation: *Department of Radiation Oncology, and †Department of Pulmonary Diseases, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Naomi E
authors.initials: NE
authors.lastname: Verstegen
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Lagerwaard
authors.forename: Sayed M S
authors.initials: SM
authors.lastname: Hashemi
authors.forename: Max
authors.initials: M
authors.lastname: Dahele
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Slotman
authors.forename: Suresh
authors.initials: S
authors.lastname: Senan
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; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000628:therapy; D009367:Neoplasm Staging; D016609:Neoplasms, Second Primary / Q000000981:diagnostic imaging* / Q000628:therapy; D010347:Patient Care Planning; D016634:Radiosurgery / Q000379:methods*; D016879:Salvage Therapy; D015996:Survival Rate; D013997:Time Factors; D014057:Tomography, X-Ray Computed