title: Predictors of metastatic disease after prostate brachytherapy.
abstract: OBJECTIVE
  To identify predictors of metastatic disease after brachytherapy treatment for prostate cancer.
  
  
  METHODS
  All patients who received either brachytherapy alone (implant) or brachytherapy in combination with external beam radiation therapy for treatment of localized prostate cancer at The Mount Sinai Hospital between June 1990 and March 2007 with a minimum follow-up of 2 years were included. Univariate and multivariable analyses were performed on the following variables: risk group, Gleason score (GS), clinical T stage, pretreatment prostate-specific antigen level, post-treatment prostate-specific antigen doubling time (PSA-DT), treatment type (implant vs. implant plus external beam radiation therapy), treatment era, total biological effective dose, use of androgen deprivation therapy, age at diagnosis, and race. PSA-DT was analyzed in the following ordinate groups: 0 to 90 days, 91 to 180 days, 180 to 360 days, and greater than 360 days.
  
  
  RESULTS
  We included 1,887 patients in this study. Metastases developed in 47 of these patients. The 10-year freedom from distant metastasis (FFDM) rate for the entire population was 95.1%. Median follow-up was 6 years (range, 2-15 years). The only two significant predictors of metastatic disease by multivariable analyses were GS and PSA-DT (p < 0.001 for both variables). Estimated 10-year FFDM rates for GS of 6 or less, GS of 7, and GS of 8 or greater were 97.9%, 94.3%, and 76.1%, respectively (p < 0.001). Estimated FFDM rates for PSA-DT of 0 to 90 days, 91 to 180 days, 181 to 360 days, and greater than 360 days were 17.5%, 67.9%, 74%, and 94.8%, respectively (p < 0.001). Estimated 10-year FFDM rates for the low-, intermediate-, and high-risk groups were 98.6%, 96.2%, and 86.7%, respectively. A demographic shift to patients presenting with higher-grade disease in more recent years was observed.
  
  
  CONCLUSIONS
  GS and post-treatment PSA-DT are both statistically significant independent predictors of metastatic disease. Patients with a high GS and/or short PSA-DT have a higher likelihood of developing metastatic disease and should be considered for systemic therapy.
authors.affiliation: Department of Radiation Oncology, Mount Sinai School of Medicine, New York, NY 10029, USA. richard.stock@moutsinai.org
authors.forename: Kevin
authors.initials: K
authors.lastname: Forsythe
authors.forename: Ryan
authors.initials: R
authors.lastname: Burri
authors.forename: Nelson
authors.initials: N
authors.lastname: Stone
authors.forename: Richard G
authors.initials: RG
authors.lastname: Stock
mesh_terms: D000704:Analysis of Variance; D000726:Androgen Antagonists / Q000627:therapeutic use; D001918:Brachytherapy / Q000379:methods*; D003131:Combined Modality Therapy / Q000379:methods; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D010165:Palladium / Q000627:therapeutic use; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000188:drug therapy / Q000473:pathology* / Q000532:radiotherapy*; D011868:Radioisotopes / Q000627:therapeutic use; D012189:Retrospective Studies
chemical_list: D000726:Androgen Antagonists; D007457:Iodine Radioisotopes; D011868:Radioisotopes; D010165:Palladium; D017430:Prostate-Specific Antigen