title: Primary non-small cell lung cancer: review of frequency, location, and time of recurrence after radiofrequency ablation.
abstract: OBJECTIVE
  To review the recurrence patterns in patients with primary non-small cell lung cancer (NSCLC) treated with percutaneous image-guided radiofrequency (RF) ablation.
  
  
  METHODS
  This retrospective review was institutional review board approved and HIPAA compliant. Informed consent was waived. Data from all patients with primary NSCLC who underwent lung RF ablation from January 1998 to January 2008 were reviewed. Ninety-one patients were identified. Ten patients with no posttreatment imaging results and two patients with multiple treated lung cancers were excluded. There were 79 tumors in 79 patients (mean age, 75 years). Mean tumor size was 2.5 cm (range, 1-5.5 cm). Fifteen (19%) tumors were central, and 64 (81%) tumors were peripheral. Nineteen (24%) patients underwent adjuvant external beam radiation, and nine (11%) patients underwent concomitant brachytherapy. Correlation of computed tomography and positron emission tomography imaging studies with biopsy results, tumor size, location, and stage was performed. Patterns of recurrence were classified as local, intrapulmonary, nodal, mixed (local and nodal), and distant.
  
  
  RESULTS
  Forty-five (57%) patients demonstrated no evidence of recurrence at follow-up imaging (range, 1-72 months; mean, 17 months). Recurrence was seen in 34 (43%) patients (range, 2-48 months; mean, 14 months). Recurrence after RF ablation was local in 13 (38%), intrapulmonary in six (18%), nodal in six (18%), mixed in two (6%), and distant metastases in seven (21%) cases. Median disease-free survival was 23 months. Sex, tumor location, and radiation therapy were not associated with risk of recurrence. Increasing tumor size (P = .02) and stage (P = .007) were related to risk of recurrence.
  
  
  CONCLUSIONS
  The most common pattern of recurrence was local, which suggests that more aggressive initial RF ablation and adjuvant radiation may offer improvement in outcomes. Continued follow-up imaging is needed because new recurrences were seen throughout the 2 years following treatment.
authors.affiliation: Department of Diagnostic Imaging, Rhode Island Hospital, Warren Alpert Medical School of Brown University, 593 Eddy St, Providence, RI 02903, USA. mdbeland@gmail.com
authors.forename: Michael D
authors.initials: MD
authors.lastname: Beland
authors.forename: Elliot J
authors.initials: EJ
authors.lastname: Wasser
authors.forename: William W
authors.initials: WW
authors.lastname: Mayo-Smith
authors.forename: Damian E
authors.initials: DE
authors.lastname: Dupuy
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology* / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007472:Iohexol; D008175:Lung Neoplasms / Q000473:pathology* / Q000601:surgery*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D012189:Retrospective Studies; D012307:Risk Factors; D014055:Tomography, Emission-Computed; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D007472:Iohexol