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Title: Incidence of Second Malignancies in Prostate Cancer Patients Treated With Low-Dose-Rate Brachytherapy and Radical Prostatectomy

Purpose: To compare the second malignancy incidence in prostate cancer patients treated with brachytherapy (BT) relative to radical prostatectomy (RP) and to compare both groups with the cancer incidence in the general population. Methods and Materials: From 1998 to 2010, 2418 patients were treated with Iodine 125 prostate BT monotherapy at the British Columbia Cancer Agency, and 4015 referred patients were treated with RP. Cancer incidence was compared with the age-matched general population using standardized incidence ratios (SIRs). Pelvic malignancies included invasive and noninvasive bladder cancer and rectal cancer. Cox multivariable analysis was performed with adjustment for covariates to determine whether treatment (RP vs BT) was associated with second malignancy risk. Results: The median age at BT was 66 years and at RP 62 years. The SIR comparing BT patients with the general population was 1.06 (95% confidence interval [CI] 0.91-1.22) for second malignancy and was 1.53 (95% CI 1.12-2.04) for pelvic malignancy. The SIR comparing RP patients with the general population was 1.11 (95% CI 0.98-1.25) for second malignancy and was 1.11 (95% CI 0.82-1.48) for pelvic malignancy. On multivariable analysis, older age (hazard ratio [HR] 1.05) and smoking (HR 1.65) were associated with increased second malignancy risk (P<.0001). Radical prostatectomymore » was not associated with a decreased second malignancy risk relative to BT (HR 0.90, P=.43), even when excluding patients who received postprostatectomy external beam radiation therapy (HR 1.13, P=.25). Older age (HR 1.09, P<.0001) and smoking (HR 2.17, P=.0009) were associated with increased pelvic malignancy risk. Radical prostatectomy was not associated with a decreased pelvic malignancy risk compared with BT (HR 0.57, P=.082), even when excluding postprostatectomy external beam radiation therapy patients (HR 0.87, P=.56). Conclusions: After adjustment for covariates, BT patients did not have an increased second malignancy risk compared with RP patients. Further follow-up of this cohort is needed given the potential latency of radiation-induced malignancies.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ; ;  [1] ;  [2] ;  [5] ;  [6] ;  [1] ;  [2] ;  [7] ;  [1] ;  [2]
  1. Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia (Canada)
  2. (Canada)
  3. Department of Population Oncology, British Columbia Cancer Agency–Vancouver Centre, Vancouver, British Columbia (Canada)
  4. Faculty of Medicine, University of British Columbia, Vancouver, British Columbia (Canada)
  5. Department of Medical Physics, British Columbia Cancer Agency–Vancouver Centre, Vancouver, British Columbia (Canada)
  6. Department of Radiation Oncology, British Columbia Cancer Agency–Vancouver Centre, Vancouver, British Columbia (Canada)
  7. Department of Radiation Oncology, British Columbia Cancer Agency–Centre for the North, Prince George, British Columbia (Canada)
Publication Date:
OSTI Identifier:
22420484
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 90; Journal Issue: 4; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; BLADDER; BRACHYTHERAPY; BRITISH COLUMBIA; COMPARATIVE EVALUATIONS; DOSE RATES; EXTERNAL BEAM RADIATION THERAPY; HAZARDS; IODINE 125; NEOPLASMS; PATIENTS; POPULATIONS; PROSTATE; RECTUM; TOBACCO SMOKES