Prostate brachytherapy and second primary cancer risk: A competitive risk analysis - Abstract

Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.

University Medical Center Utrecht, Utrecht; Radboud University Nijmegen Medical Center, Nijmegen; Catharina Ziekenhuis, Eindhoven, the Netherlands.

 

 

To assess the risk of second primary cancer (SPC) after [125I]iodine prostate cancer brachytherapy compared with prostatectomy and the general population.

In a cohort consisting of 1,888 patients with prostate cancer who received monotherapy with brachytherapy (n = 1,187; 63%) or prostatectomy (n = 701; 37%), SPC incidences were retrieved by linkage with the Dutch Cancer Registry. Standardized incidence rates (SIRs) and absolute excess risks (AERs) were calculated for comparison.

A total of 223 patients were diagnosed with SPC, 136 (11%) after brachytherapy and 87 (12%) after prostatectomy, with a median follow-up of 7.5 years. The SIR for all malignancies, bladder cancer, and rectal cancer were 0.94 (95% CI, 0.78 to 1.12), 1.69 (95% CI, 0.98 to 2.70), and 0.90 (95% CI, 0.41 to 1.72) for brachytherapy and 1.04 (95% CI, 0.83 to 2.28), 1.82 (95% CI, 0.87 to 3.35), and 1.50 (95% CI, 0.68 to 2.85) for prostatectomy, respectively. Bladder SPC risk was significantly increased after brachytherapy for patients age 60 years or younger (SIR, 5.84; 95% CI, 2.14 to 12.71; AER, 24.03) and in the first 4 years of follow-up (SIR, 2.14; 95% CI, 1.03 to 3.94; AER, 12.24). Adjusted for age, the hazard ratio (brachytherapy v prostatectomy) for all SPCs combined was 0.87 (95% CI, 0.64 to 1.18).

Overall, we found no difference in SPC incidence between patients with prostate cancer treated with prostatectomy or brachytherapy. Furthermore, no increased tumor incidence was found compared with the general population. We observed a higher than expected incidence of bladder SPC after brachytherapy in the first 4 years of follow-up, probably resulting from lead time or screening bias. Because of power limitations, a small increased SPC risk cannot be formally excluded.

Written by:
Hinnen KA, Schaapveld M, van Vulpen M, Battermann JJ, van der Poel H, van Oort IM, van Roermund JG, Monninkhof EM.   Are you the author?

Reference: J Clin Oncol. 2011 Oct 24. Epub ahead of print.
doi: 10.1200/JCO.2011.35.0991

PubMed Abstract
PMID: 22025166

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