Hepatocellular carcinoma in patients with acute hepatic porphyria: frequency of occurrence and related factors

Abstract

Background/aims: Previous retrospective studies have suggested an association between hepatocellular carcinoma and acute hepatic porphyrias. The incidence, the relative risk, the characteristics and the outcome of primary liver cancer were prospectively evaluated in patients with acute hepatic porphyrias; the molecular mechanism of carcinogenesis in these patients was also pointed out.

Methods: A cohort of 650 patients with acute hepatic porphyria was followed over 7 years. Standardized rate ratio was used to measure the relative risk of primary liver cancer after indirect standardization. Morphological and clinical aspects of primary liver cancer were investigated, and survival rates were calculated using the Kaplan-Meier method. Common etiological factors involved in liver carcinogenesis were screened. Excretion rates of porphyrin precursors, serum melatonin levels and mutations in the genes encoding for heme biosynthetic enzymes were studied.

Results: Hepatocellular carcinoma was found in four symptomatic and three asymptomatic patients (four female, three male). The overall standardized rate ratio was 36 (95% CI: 14-74). The 5-year disease-free survival was 43% in patients with hepatocellular carcinoma. Usual risk factors for primary liver cancer were not confounding factors. Hepatocellular carcinoma was not related to specific heme biosynthesis gene mutations. Heme precursors were significantly increased in porphyric patients with hepatocellular carcinoma, and serum melatonin levels were low.

Conclusions: Acute hepatic porphyrias are risk factors for hepatocellular carcinoma. Hepatic porphyrias should be sought in patients with hepatocellular cancer without obvious etiology, and a periodic screening for hepatocellular carcinoma should be evaluated in these patients. Genes encoding for heme biosynthetic pathway may not act as tumor suppressor genes. Chronic increased levels of delta aminolevulinic acid could lead to the generation of free radicals and subsequently to hepatic carcinogenesis.