Use of immunosuppression and subsequent cancer incidence: cohort study

Objective Evaluate the association between cancer incidence and immunosuppressive treatment in patients with ocular inflammatory disease (OID).Methods and analysis We performed a retrospective cohort study of patients from 10 US OID subspecialty practices. Patients with non-infectious OID were included; HIV-infected patients were excluded. Time-dependent exposure to drug classes (ie, antimetabolites, calcineurin inhibitors, alkylating agents, tumour necrosis factor (TNF) inhibitors) and drugs were evaluated. Cancer incidence was ascertained by linkage to 12 state cancer registries from 1996 to 2015. Cancer incidence was analysed using Cox regression survival analysis, using 0-year, 3-year and 5-year lags after immunosuppression began.Results The cancer incidence cohort comprised 10 872 individuals at risk of incident cancer and residing in one of the 12 states covered; 812 primary cancers were identified through cancer incidence tracing with median follow-up time of 10 years. Neither TNF inhibitor, antimetabolite, calcineurin inhibitor nor alkylating agent classes were associated with statistically significant increases in cancer incidence adjusting for covariates. We found statistically significant reduced hazards in the systemic inflammatory disease (SID)-including cohort for adalimumab and chlorambucil, increased hazards for tacrolimus and etanercept in the non-SID cohort and reduced hazards for methotrexate in both. Other immunosuppressive drugs were not associated with overall cancer incidence.Conclusions We found no increased risk of overall or site-specific cancer incidence associated with short-term (non-transplant) therapy with most commonly used immunosuppressive drug classes and many specific drugs. Further research may clarify potentially protective or harmful effects of specific agents that were not consistently associated with reduced or increased cancer incidence.Trial registration number NCT00116090.