title: Comorbidity as a predictor of overall survival in prostate cancer patients treated with external beam radiotherapy combined with HDR brachytherapy boosts.
abstract: BACKGROUND
  The risk stratification currently applied prior to curative treatment for localized prostate cancer (PC) does not take into account comorbidity or age. Therefore, we investigated the impact of comorbidity on overall survival (OS) in PC patients treated with external beam radiotherapy (EBRT) and high-dose rate (HDR) brachytherapy boost.
  
  
  METHODS
  At a single center, 611 consecutive patients diagnosed with localized PC from 1998 to 2004 underwent definitive EBRT (50 Gy) and HDR brachytherapy boosts (2 × 10 Gy) combined with neoadjuvant total androgen blockade. Comorbidity was assessed with the Charlson comorbidity score. The impact of risk factors on OS and disease-free survival (DFS) was calculated using Cox proportional hazard ratios. Risk groups were defined as follows: low-risk PC: PSA <10, WHO grade 1 and T stage 1; high-risk PC: PSA >20 and/or WHO grade 3 and/or T stage 3a; intermediate-risk PC representing patients who did not fit either the low- or high-risk PC group.
  
  
  RESULTS
  Mean age in the study cohort was 66.4 years, and 51% of the patients reported some degree of comorbidity. Divided into risk groups 8.2% were categorized as low-risk, 64% as intermediate-risk and 27.8% as high-risk PC. Overall 10-year survival was 72.2%, and 89% of the patients were relapse-free. In the univariate and multivariate analyses using Cox proportional hazard ratios, age, comorbidity and T stage were statistically significant predictors of OS: hazard ratios 1.56, 1.44 and 1.2 (p-values .002, .04 and .05), respectively. WHO grade, PSA at diagnosis, T stage and comorbidity were also significant predictors of DFS (p-values .0001, .0001, .009 and .003, respectively).
  
  
  CONCLUSIONS
  Comorbidity assessed with the Charlson score predicts OS in patients with localized PC treated with curative intent using combined EBRT and HDR brachytherapy boost, and should be considered when making decisions before radical treatment.
authors.affiliation: a Department of Oncology-Pathology , Karolinska Institutet , Stockholm , Sweden.|b Department of Oncology , Karolinska University Hospital , Stockholm , Sweden.
authors.forename: Marie
authors.initials: M
authors.lastname: Hjälm-Eriksson
authors.affiliation: a Department of Oncology-Pathology , Karolinska Institutet , Stockholm , Sweden.|b Department of Oncology , Karolinska University Hospital , Stockholm , Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Ullén
authors.affiliation: a Department of Oncology-Pathology , Karolinska Institutet , Stockholm , Sweden.|b Department of Oncology , Karolinska University Hospital , Stockholm , Sweden.
authors.forename: Hemming
authors.initials: H
authors.lastname: Johansson
authors.affiliation: c Department of Radiation Oncology , University of Minnesota , Minneapolis , Minnesota , USA.
authors.forename: Seymoure
authors.initials: S
authors.lastname: Levitt
authors.affiliation: a Department of Oncology-Pathology , Karolinska Institutet , Stockholm , Sweden.|b Department of Oncology , Karolinska University Hospital , Stockholm , Sweden.
authors.forename: Sten
authors.initials: S
authors.lastname: Nilsson
authors.affiliation: a Department of Oncology-Pathology , Karolinska Institutet , Stockholm , Sweden.
authors.forename: Karl-Mikael
authors.initials: KM
authors.lastname: Kälkner
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy; D000368:Aged; D001918:Brachytherapy / Q000401:mortality*; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000401:mortality*; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate