Abstract

Purpose
The aim of this study is to summarize cancer risk among patients with clinical indications of immunosuppressive and antineoplastic drugs in Korea, which are pharmaceuticals defined as group 1 by International Agency for Research on Cancer (IARC).
Materials and Methods
We conducted a nationwide population-based retrospective cohort study using the Korean National Health Insurance Service (NHIS) claims data from 2002 to 2018. Patients with clinical indications for group 1 pharmaceuticals from 2002 to 2017 were selected as baseline population, and followed up until 2018. Cox proportional hazards regression model was used to analyze the risk of cancer and dose-response relationship between group 1 pharmaceuticals and cancer.
Results
Azathioprine use increased the risk of skin and hematologic cancer (HR 4.63, 95% CI 2.91-7.39; HR 3.15, 95% CI 2.41-4.13). Cyclosporine use increased the risk of skin and hematologic cancer (HR 2.30, 95% CI 1.79-2.95; HR 2.96, 95% CI 2.59-3.40). Cyclophosphamide use increased the risk of bladder and hematologic cancer (HR 2.69, 95% CI 1.92-3.78; HR 3.83, 95% CI 3.20-4.59). Chlorambucil use increased the risk of hematologic cancer (HR 3.51, 95% CI 2.53-4.87) and melphalan use increased the risk of hematologic cancer (HR 16.31, 95% CI 13.41-19.85). Methoxsalen use increased the risk of skin cancer (HR 2.32, 95% CI 1.36-3.95).
Conclusion
Group 1 pharmaceuticals were associated with increased risk of cancer. The results are expected to help establish alternative clinical strategies and policies for patients with clinical indications of group 1 pharmaceuticals, by continuous risk analysis and discussions on the surveillance systems.

• Keywords: Group 1 pharmaceuticals, Immunosuppressive drugs, Antineoplastic agents, Skin neoplasms, Hematologic cancer