European Porphyria Network (EPNET) for information, epidemiological data, quality and equity of service

Review of hepatocellular cancer, hypertension and renal impairment as late complications of acute porphyria and recommendations for patient follow-up

This review critically appraises the data emerging from small retrospective and prospective cohort studies suggesting that patients with the autosomal dominant acute porphyrias may be at increased risk of hepatocellular cancer (HCC), hypertension (HT) and renal impairment. The most striking finding is a marked excess risk of HCC in Swedish patients with acute intermittent porphyria (AIP). As Sweden has a relatively high prevalence of AIP due to a founder effect, it is uncertain to what extent the finding is generalisable to other populations or other acute porphyrias and whether early intervention through screening can improve outcomes. As yet there is no evidence for the cost-effectiveness of systematic surveillance for HCC in acute porphyria outside Sweden. Data from several populations also suggest a high prevalence of chronic sustained HT and renal impairment in AIP, but it is uncertain if this represents a true excess risk, in particular for asymptomatic patients. As these long-term complications are important and potentially treatable, a pragmatic recommendation is that symptomatic patients with acute porphyria should be offered specialist long-term follow-up and, for those aged >50 years, annual liver ultrasound may be considered following discussion of the likely risks and benefits. Opportunistic cardiovascular risk assessment can readily be incorporated into a structured annual review so that appropriate drugs safe for use in acute porphyria are prescribed promptly. As these diseases are rare, collaborative international epidemiological studies such as those being coordinated through the European Porphyria Network are essential to inform best clinical practice.