Ana Fernandez Ots1, Lois Browne2, Yaw Sinn Chin2, David Malouf3, Keith Wong2, Joseph Bucci2. 1. Radiation Oncology Department, St George Cancer Care Centre, NSW, Australia. Electronic address: anukiots@hotmail.com. 2. Radiation Oncology Department, St George Cancer Care Centre, NSW, Australia. 3. St George Urology Department, NSW, Australia.
Abstract
PURPOSE: To report the incidence of second primary cancer (SPC) after 125I brachytherapy (BT) for early prostate cancer in an Australian institution. METHODS AND MATERIALS: All the patients in our cohort had a cystoscopy before the implant. Data were prospectively collected on all subsequent SPC diagnoses. Standardized incidence ratios (SIRs) were calculated to compare data with the Australian population. Kaplan-Meier analysis was used to determine the actuarial second malignancy and pelvic malignancy rates and the death from SPC and from any cause. RESULTS: A total of 889 patients were followed up for a median of 4.16 (0-13) years with 370 (42%) patients having ≥5 years of followup. Sixty patients subsequently developed an SPC of which 11 were pelvic malignancies. The 5- and 10-year cumulative incidences were 1.3% (95% confidence interval [CI]: 0.6-3) and 3.3% (95% CI: 1-7) for any pelvic malignancy and 1% (95% CI: 0.4-2) and 2.6% (1-6) for bladder cancer, respectively. The SIR was significantly higher than expected for all bladder cancers at 2.9 (95% CI: 1-6) and close to significance (SIR, 3.0; 95% CI: 0.97-7) for bladder cancers within the first 5 years of followup in the subgroup analysis. On multivariate analysis, older age was associated with increased SPC risk and older age and positive smoking status were associated with increased overall mortality, mortality due to SPC, and mortality from second malignancy (p < 0.05). CONCLUSIONS: There may be a small increased risk of bladder SPC after prostate BT. A tendency toward a higher risk of bladder SPC after BT was found within the first 5 years of followup probably reflecting screening bias. Copyright Â
PURPOSE: To report the incidence of second primary cancer (SPC) after 125I brachytherapy (BT) for early prostate cancer in an Australian institution. METHODS AND MATERIALS: All the patients in our cohort had a cystoscopy before the implant. Data were prospectively collected on all subsequent SPC diagnoses. Standardized incidence ratios (SIRs) were calculated to compare data with the Australian population. Kaplan-Meier analysis was used to determine the actuarial second malignancy and pelvic malignancy rates and the death from SPC and from any cause. RESULTS: A total of 889 patients were followed up for a median of 4.16 (0-13) years with 370 (42%) patients having ≥5 years of followup. Sixty patients subsequently developed an SPC of which 11 were pelvic malignancies. The 5- and 10-year cumulative incidences were 1.3% (95% confidence interval [CI]: 0.6-3) and 3.3% (95% CI: 1-7) for any pelvic malignancy and 1% (95% CI: 0.4-2) and 2.6% (1-6) for bladder cancer, respectively. The SIR was significantly higher than expected for all bladder cancers at 2.9 (95% CI: 1-6) and close to significance (SIR, 3.0; 95% CI: 0.97-7) for bladder cancers within the first 5 years of followup in the subgroup analysis. On multivariate analysis, older age was associated with increased SPC risk and older age and positive smoking status were associated with increased overall mortality, mortality due to SPC, and mortality from second malignancy (p < 0.05). CONCLUSIONS: There may be a small increased risk of bladder SPC after prostate BT. A tendency toward a higher risk of bladder SPC after BT was found within the first 5 years of followup probably reflecting screening bias. Copyright Â