title: Unexpected long-term survival after low-dose palliative radiotherapy for non-small cell lung cancer.
abstract: BACKGROUND
  Many experienced oncologists have encountered patients with proven non-small cell lung cancer (NCLC) who received modest doses of palliative radiotherapy (RT) and who unexpectedly survived for > 5 years; some were apparently cured. We used a very large prospective database to estimate the frequency of this phenomenon and to look for correlative prognostic factors.
  
  
  METHODS
  Patients with histologically or cytologically proven NSCLC, treated with palliative RT to a dose of < or = 36 Gy, were identified from a prospective database containing details of 3035 new patients registered from 1984-1990.
  
  
  RESULTS
  An estimated 1.1% (95% confidence interval, 0.7-1.6%) of 2337 palliative RT patients survived for 5 or more years after commencement of RT, including 18 patients who survived progression-free for 5 years. Estimated median survival was 4.6 months. Five-year survivors had significantly better Eastern Cooperative Oncology Group performance status at presentation than non-5-year survivors (P = 0.024) and were less likely to have distant metastases (P = 0.020). RT dose did not appear to be a significant prognostic factor. Patients who survived 5 years without progression had an estimated 78% probability of remaining free from progression in the next 5 years.
  
  
  CONCLUSIONS
  Approximately 1% of patients with proven NSCLC survived for > 5 years after palliative RT, and many of these patients appeared to have been cured by a treatment usually considered to be without curative potential. Because of the potential for long-term survival, doses to late-reacting normal tissues should be kept within tolerance when prescribing palliative RT in NSCLC.
authors.affiliation: Department of Radiation Oncology, Peter MacCallum Cancer Center, Melbourne, Victoria, Australia. Michael.Macmanus@petermac.org
authors.forename: Michael P
authors.initials: MP
authors.lastname: Mac Manus
authors.forename: Jane P
authors.initials: JP
authors.lastname: Matthews
authors.forename: Morikatsu
authors.initials: M
authors.lastname: Wada
authors.forename: Andrew
authors.initials: A
authors.lastname: Wirth
authors.forename: Valentina
authors.initials: V
authors.lastname: Worotniuk
authors.forename: David L
authors.initials: DL
authors.lastname: Ball
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000532:radiotherapy*; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006304:Health Status; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D010166:Palliative Care; D011379:Prognosis; D016019:Survival Analysis; D013997:Time Factors