title: Oligometastases treated with stereotactic body radiotherapy: long-term follow-up of prospective study.
abstract: OBJECTIVE
  To analyze the long-term survival and tumor control outcomes after stereotactic body radiotherapy (SBRT) for metastases limited in number and extent.
  
  
  METHODS
  We prospectively analyzed the long-term overall survival (OS) and cancer control outcomes of 121 patients with five or fewer clinically detectable metastases, from any primary site, metastatic to one to three organ sites, and treated with SBRT. Freedom from widespread distant metastasis (FFDM) was defined as metastatic disease not amenable to local therapy (i.e., resection or SBRT). Prognostic variables were assessed using log-rank and Cox regression analyses.
  
  
  RESULTS
  For breast cancer patients, the median follow-up was 4.5 years (7.1 years for 16 of 39 patients alive at the last follow-up visit). The 2-year OS, FFDM, and local control (LC) rate was 74%, 52%, and 87%, respectively. The 6-year OS, FFDM, and LC rate was 47%, 36%, and 87%, respectively. From the multivariate analyses, the variables of bone metastases (p = .057) and one vs. more than one metastasis (p = .055) were associated with a fourfold and threefold reduced hazard of death, respectively. None of the 17 bone lesions from breast cancer recurred after SBRT vs. 10 of 68 lesions from other organs that recurred (p = .095). For patients with nonbreast cancers, the median follow-up was 1.7 years (7.3 years for 7 of 82 patients alive at the last follow-up visit). The 2-year OS, FFDM, and LC rate was 39%, 28%, and 74%, respectively. The 6-year OS, FFDM, and LC rate was 9%, 13%, and 65%, respectively. For nonbreast cancers, a greater SBRT target volume was significantly adverse for OS (p = .012) and lesion LC (p < .0001). Patients whose metastatic lesions, before SBRT, demonstrated radiographic progression after systemic therapy experienced significantly worse OS compared with patients with stable or regressing disease.
  
  
  CONCLUSIONS
  Select patients with limited metastases treated with SBRT are long-term survivors. Future research should address the therapeutic benefit of SBRT for these patients.
authors.affiliation: Department of Radiation Oncology, University of Rochester Medical Center, Rochester, NY 14642, USA. MTMilano@yahoo.com
authors.forename: Michael T
authors.initials: MT
authors.lastname: Milano
authors.forename: Alan W
authors.initials: AW
authors.lastname: Katz
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Paul
authors.initials: P
authors.lastname: Okunieff
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000556:secondary / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000401:mortality / Q000556:secondary / Q000601:surgery; D001932:Brain Neoplasms / Q000401:mortality / Q000556:secondary / Q000601:surgery; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000556:secondary / Q000601:surgery; D015179:Colorectal Neoplasms / Q000401:mortality / Q000473:pathology; D004938:Esophageal Neoplasms / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000401:mortality / Q000473:pathology; D006801:Humans; D008113:Liver Neoplasms / Q000401:mortality / Q000556:secondary / Q000601:surgery; D008175:Lung Neoplasms / Q000401:mortality / Q000556:secondary / Q000601:surgery; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000532:radiotherapy*; D011446:Prospective Studies; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D012509:Sarcoma / Q000401:mortality / Q000556:secondary / Q000601:surgery