Abstract
Objective: To estimate the incidence of cancer among patients with ankylosing spondylitis (AS) and compare this risk with that of the general population.
Method: We obtained data from Taiwan’s National Health Insurance database on 19 289 patients with a first diagnosis of AS registered between 2000 and 2012 with no history of cancer before the diagnosis of AS. Standardized incidence ratios (SIRs) for all cancers and for site-specific cancers were used to assess whether AS was associated with an increased risk of cancer.
Results: During the follow-up period, 485 patients developed cancer. The incidence rate was therefore 256.3 per 100 000 person-years. Compared with the general population, patients with AS had an increased risk of cancer [SIR 1.33, 95% confidence interval (CI) 1.20–1.47]. The SIR of cancer was higher in older patients; the risk increased from 8 years after initial diagnosis. Among solid tumours, the risk of melanoma was the highest (SIR 4.64, 95% CI 1.93–11.15), followed by prostate (SIR 2.53, 95% CI 2.01–3.19), thyroid (SIR 2.09, 95% CI 1.45–3.00), and bone cancer (SIR 2.00, 95% CI 1.01–3.99). Among haematological cancers, the risk of leukaemia was the highest (SIR 1.94, 95% CI 1.21–3.12). By contrast, the risks of oesophageal and oral cancers decreased in patients with AS.
Conclusion: This nationwide population-based cohort study demonstrated that patients with AS in Taiwan are at an increased risk of cancer, particularly melanoma; prostate, thyroid, and bone cancers; and haematological malignancies.
Acknowledgements
We would like to thank the Ministry of Science and Welfare (103-2314-B-182A-070-MY2, 103-2314-B-182-043-MY2) and the CGMH (CMRPG3F0841, CORP3E0141, CORPG3G0251, CORPG3H0071, CORPG3J0191) for financially supporting this study, as well as the Graduate Institute of Clinical Medical Sciences at Chang Gung University for their methodological assistance. This study was based, in part, on data from the NHI database, provided by the National Health Insurance Administration (NHIA), Ministry of Health and Welfare (MoHW), and managed by the National Health Research Institutes, Taiwan. The interpretations and conclusions contained herein do not represent the opinions of the NHIA, MoHA, or the National Health Research Institutes, Taiwan.
Disclosure statement
No potential conflict of interest was reported by the authors.