Cancer risk among pacemaker recipients in Denmark, 1982-1996

To address concerns about the potential carcinogenicity of pacemakers, we launched the first epidemiologic study of cancer incidence among pacemaker recipients. A nationwide cohort of 16,357 pacemaker recipients in Denmark from 1982 through 1996 was identified. The Danish Cancer Registry was used to identify all incident cancers within the cohort, with almost 75,000 person-years of observation. The cohort had a slight excess of cancer overall (SIR = 1.19, 95% confidence interval [95% CI, 1.1-1.2]). This was largely caused by an elevated SIR for multiple myeloma among men (SIR = 1.78,95% CI, 1.1-2.8), which increased to 2.60 (95% CI, 0.9-5.7) 5-9 years after implantation, and to a similarly increased SIR for kidney cancer among women (SIR = 2.05, 95% CI, 1.3-3.0), which increased to 3.39 (95% CI, 1.6-6.2) after a latency period of 5-9 years. An excess of urinary bladder cancer was also seen after 10 years. No excess risk was observed for breast cancer or sarcomas, although the SIRs for sarcomas tended to increase over time, based on small numbers. Our results are largely reassuring but, as pacemakers become more common and are implanted at earlier ages and as survival following implantation improves, the excesses of bladder cancer, multiple myeloma among men, and kidney cancer among women with long-term followup warrant further investigation.