Occurrence of Malignant Tumours in the Acute Hepatic Porphyrias.

The porphyrias are a group of inherited metabolic diseases resulting from enzymatic deficiencies of specific haem biosynthetic enzymes. They can be classified as primarily acute and non-acute types. Clinically, the acute hepatic porphyrias (AHPs) are characterised by acute neurovisceral attacks. Patients with AHP may be at increased risk for development of hepatocellular carcinoma (HCC). However, systematic studies on the occurrence of other malignancies in patients with the AHPs have not been performed to date. Here, we studied the development of HCC and distinct malignant tumours in patients with the AHPs registered in a single European porphyria specialist centre. A questionnaire was designed and sent to all individuals (n = 122) diagnosed between 1970 and 2012 of whom a valid address was available (n = 82), requesting information on their personal and family history of cancer. Statistical analysis was performed to calculate incidence, prevalence and relative risk of HCC. To calculate confidence intervals, a Poisson distribution was assumed. Forty-nine patients (59.8%) returned a completed questionnaire. Overall, HCC was diagnosed in one female (2.1%), and the remaining patients reported on six distinct malignancies. We were able to confirm that HCC is an important complication in AHP. The patients in our cohort had an approximately 35-fold increased risk of developing HCC, similar to observations in other European countries. In addition, we detected colon, breast, uterine and thyroid cancer as well as lymphoma and a liver metastasis in patients with AHP. However, considering the small number of tumours and patients studied here, the data should be interpreted with caution, and further studies on cancer occurrence in AHP patients will require a multicentre setting.