Long-term incidence of cancer after index treatment for symptomatic peripheral arterial disease - a health insurance claims data analysis

Background: Cancer as a concomitant condition in symptomatic peripheral arterial disease (PAD) patients could have an impact on further therapy and the long-term prognosis of these patients. Aim of this study was to investigate whether there is an increased incidence of cancer in PAD patients and to quantify the corresponding effect size. Materials and methods: Between January 1st, 2008 and December 31st, 2017, we analysed health insurance claims data from Germany's second-largest insurance fund, BARMER. Symptomatic PAD patients suffering from intermittent claudication (IC) or chronic limb-threatening ischaemia (CLTI) were stratified by gender at index treatment. PAD patients were then followed until an incident cancer diagnosis was recorded. To adjust for age and gender, standardized incidence ratios (SIR) were computed using the 2012 German standard population as reference. Results: 96,528 PAD patients (47% female, 44% IC, mean age 72 years) were included in the current study. When compared to the overall population, female and male PAD patients have a significantly increased risk of incident cancer of the lung (SIR 3.5 vs. 2.6), bladder (SIR 3.2 vs. 4.0), pancreas (SIR 1.4 vs. 1.6), and colon (SIR 1.3 vs. 1.3). During ten years of follow-up, some 7% of males and 4% of females developed lung cancer. For bladder, colon and pancreas cancer, the cumulative hazards were 1% vs. 3.2%, 2.2% vs. 2.8%, and 0.7% vs. 0.9%, respectively. Conclusions: Patients suffering from symptomatic PAD face a markedly higher risk for incident cancer in the long-term follow-up. The cancer risk increased continuously for certain types and PAD was strongly associated with cancer of the lung, bladder, pancreas, and colon. Taking these results into account, PAD patients could benefit from secondary and tertiary screening. These results also emphasize the impact of common risk factors such as tobacco smoke as target for health prevention.