Occurrence of Malignant Tumours in the Acute Hepatic Porphyrias

Canadian guidance for diagnosis and management of acute hepatic porphyrias

Acute hepatic porphyrias (AHP) comprise four rare monogenic autosomal conditions. Each is linked to a deficiency of heme metabolizing enzymes. Common manifestations include severe abdominal pain, nausea, confusion, hyponatremia, hypertension, tachycardia, and neuropathy. Diagnosis is challenging due to a non-specific, variable presentation with symptoms mimicking other common conditions. Initial diagnosis of AHP can be made with a test for urinary porphobilinogen, δ-aminolevulinic acid and porphyrins using a single random (spot) sample. However, many patients have complications due to delays in diagnosis and management. A novel small interfering RNA-based agent, givosiran, has demonstrated efficacy in reducing acute attacks in a recent Phase III trial, leading to its approval for the management of AHP. Early diagnosis is crucial for the timely introduction of disease-modifying treatments that reduce impairments, enhance quality of life, and extend survival. In this guidance, we aim to improve awareness and outcomes of AHP by making recommendations about diagnosis, monitoring, and treatment in Canada.

Long-term complications in acute porphyria

New treatment options and low attack-related mortality have changed the life expectancy of patients with acute porphyria (AP) to that of the general population. Clinicians should therefore be aware of the long-term complications of AP, which typically include chronic neuropathy and encephalopathy, high blood pressure and porphyria-associated kidney disease. Patients have an increased risk of primary liver cancer (PLC), but no increased risk of non-hepatic cancers. Chronic pain occurs in patients with recurrent attacks, combined with chronic fatigue and nausea, leading to poor quality of life. Patients with sporadic attacks may also have chronic symptoms, which should be distinguished from mild recurrent attacks and treated appropriately. Sequels of acute polyneuropathy after an attack should be distinguished from ongoing chronic polyneuropathy, as the management is different. Overestimation of chronic neuropathy or encephalopathy caused by AP should be avoided, and other causes should be treated accordingly. Prevention of recurrent attacks is the best strategy for managing chronic comorbidities and should be actively accomplished. Hormonal interventions in female patients, or in severe cases, prophylactic givosiran or haematin, may be helpful before liver transplantation to prevent recurrent attacks. Regular monitoring can be personalised according to the patient's age, comorbidities and AP activity. Blood pressure, renal function and cardiovascular risk factors should be monitored annually in patients with previous symptoms. Appropriate medication and lifestyle management, including nutrition and hydration, are necessary to prevent complications. As PLC is common, especially in patients with acute intermittent porphyria, bi-annual surveillance after the age of 50 is important.

High disease burden and healthcare resource usage in patients with acute porphyria-A population-based analysis

BACKGROUND AND AIMS

Acute porphyria is a chronic recurrent disease with late diagnosis, heterogeneous clinical presentations and potentially devastating complications. The study aimed at providing real-world evidence on the natural course of acute porphyria, patient characteristics, disease burden, and healthcare utilization before diagnosis.

METHODS

This observational study used anonymized claims data covering 8 365 867 persons from German statutory health insurance, spanning 6 years (2015-2020). Patients with at least one diagnosis of acute porphyria during the index period (2019-2020) were classified into three groups by attack frequency. These findings were compared with two age- and sex-adjusted reference groups: the general population and fibromyalgia patients. Prevalence over the index period was calculated for all porphyria patients and those with active acute porphyria.

RESULTS

We revealed a prevalence of 79.8 per 1 000 000 for acute porphyria, with 12.9 per 1 000 000 being active cases. Acute porphyria patients, particularly with frequent attacks, demonstrated a higher comorbidity burden compared to the general population. Within the year before the recorded diagnosis, patients with acute porphyria required a median of 23.0 physician visits, significantly higher than the general population's 16.0. Additionally, 33.8% were hospitalized at least once during this period, a notably higher proportion than the general population (19.3%).

CONCLUSIONS

This study's findings, collected before the introduction of givosiran, as the first approved preventive therapy for acute porphyria in Europe, highlight the need for healthcare strategies and policies tailored to the complex needs of acute porphyria patients. The significant healthcare demands, heightened comorbidity burden, and increased healthcare system utilization emphasize the urgency of developing a comprehensive support infrastructure for these patients. Also, these acute porphyria real-world findings provide additional insights on disease characteristics in Germany.

[An overview of porphyrias]

Porphyrias are predominantly genetic metabolic disorders caused by dysregulation of specific enzymes in porphyrin-heme biosynthesis. The enzymatic dysfunction leads to formation and excretion of intermediate metabolic products in the form of porphyrins and/or their precursors δ‑aminolevulinic acid and porphobilinogen, which have cyto- and tissue-toxic properties. Clinically, porphyrias are extremely diverse, with symptoms ranging from skin changes on light-exposed areas of the body to potentially life-threatening neurovisceral attacks. Biochemical tests in urine, blood and stool are used for diagnosis, which can be supplemented by molecular genetic analyses. Treatment of the various forms of porphyria is complex and often requires close interdisciplinary cooperation between different medical specialties.

Liver transplantation and primary liver cancer in porphyria

The porphyrias are a heterogeneous group of metabolic disorders that result from defects in heme synthesis. The metabolic defects are present in all cells, but symptoms are mainly cutaneous or related to neuropathy. The porphyrias are highly relevant to hepatologists since patients can present with symptoms and complications that require liver transplantation (LT), and some porphyrias are associated with a high risk for primary liver cancer (PLC). Among the cutaneous porphyrias, erythropoietic protoporphyria (EPP) can lead to cholestatic liver failure where LT cures the liver disease but not the porphyria. In acute porphyria (AP), neurotoxic porphyrin precursors are produced in the liver and LT is a curative treatment option in patients with recurrent severe neuropathic attacks. Patients with AP, mainly acute intermittent porphyria, have a significantly increased risk for PLC that warrants surveillance and adequate follow-up of high-risk groups. LT is well established in both EPP with liver failure and AP with recurrent attacks, but most transplant centres have little porphyria experience and cooperation between transplant hepatologists, and porphyria experts is important in the often-difficult decisions on timing and management of comorbid conditions.

Porphyrin precursors and risk of primary liver cancer in acute intermittent porphyria: A case-control study of 188 patients

Acute intermittent porphyria (AIP) is a rare hereditary metabolic disease characterized by acute attacks and accumulation of the porphyrin precursors 5-aminolevulinic acid (ALA) and porphobilinogen (PBG). Patients with AIP have a high risk of primary liver cancer (PLC). We aimed to assess the association between porphyrin precursor excretion and the risk for PLC in patients with AIP. We studied 48 patients with AIP who developed PLC between 1987 and 2015 and 140 age and sex matched controls with AIP but no PLC. Data on all available urinary PBG and ALA samples collected from 1975 until 1 year before PLC diagnosis were analyzed and compared between cases and controls using logistic regression. Porphyrin precursor excretion was higher in patients with PLC (PBG median 7.9 [IQR 4.4-21.9] mmol/mol creatinine) than in controls (3.8 [1.2-9.8]) (adjusted odds ratio 1.07, 95% confidence interval: 1.02-1.12). None of the 28 patients with all registered samples below the upper limit of normal (ULN) developed PLC, and only one of the 45 patients with all samples <2× ULN developed PLC. Among non-PLC controls, ALA and PBG levels decreased after age 50-60 while an increasing trend was observed after age 65 among those who developed PLC. Increased urinary porphyrin precursors are associated with a high risk of developing PLC. Patients with normal levels appear to have a low risk while high or increasing ALA and PBG after age 65 indicates high risk, which should be considered in surveillance decisions.

Risk for incident comorbidities, nonhepatic cancer and mortality in acute hepatic porphyria: A matched cohort study in 1244 individuals

The acute hepatic porphyrias (AHP) are associated with long-term complications such as primary liver cancer, hypertension, and chronic kidney disease. Data on other related comorbidities are scarce. In this register-based, matched cohort study, we assessed the risks of nonhepatic cancers, cardiovascular diseases, renal diseases, psychiatric disorders, and mortality in relation to porphyria type, sex, and biochemical disease activity. All patients in the Swedish porphyria register with a verified AHP diagnosis during 1987-2015 were included. The biochemical activity of acute intermittent porphyria was assessed using recorded maximal urinary porphobilinogen (U-PBG). Data on incident comorbidities and mortality were collected from national health registries. Cumulative incidences, rates, and hazards were compared to reference individuals from the general population, matched 1:10 by age, sex, and county. We identified 1244 patients with AHP with a median follow-up of 19 years. Health registries identified 149 AHP-subjects (12.0%) with nonhepatic cancer, similar to 1601 (13.0%) in the matched reference population (n = 12 362). Patients with AHP had a higher risk of kidney cancer (0.8% vs. 0.2%, p < 0.001), hypertension, and chronic kidney disease but no increase in risk for cardiovascular disease, except for cerebrovascular disease in patients with elevated U-PBG, (aHR = 1.40 [95% CI:1.06-1.85]). Mortality risk during follow-up was higher among patients with AHP (21% vs. 18%, p = 0.001), and associated with primary liver cancer, female sex, and biochemical activity. In conclusion, AHP is associated with an increased risk of kidney cancer, hypertension, chronic kidney disease, and mortality but not with cardiovascular disease or other nonhepatic cancers.

Reply to Lissing et al. Comment on "Ramai et al. Risk of Hepatocellular Carcinoma in Patients with Porphyria: A Systematic Review. Cancers 2022, 14, 2947"

We thank Dr. Lissing and colleagues for providing us with these helpful comments [...].

Comment on Ramai et al. Risk of Hepatocellular Carcinoma in Patients with Porphyria: A Systematic Review. Cancers 2022, 14, 2947

We read with interest this review by Ramai et al. [...].

Heterogeneous molecular behavior in liver tumors (HCC and CCA) of two patients with acute intermittent porphyria

INTRODUCTION

Acute intermittent porphyria (AIP) is a very rare (orphan) metabolic disorder of porphyrin biosynthesis which is characterized by elevated plasma and urine levels of 5-aminolevulinic acid (5-ALA) and porphobilinogen (PBG). Patients with this disorder which is caused by a germline mutation of the hydroxymethylbilan-synthase (HMBS)-gene have a high risk of primary liver cancer which may be determined by disease activity. The exact mechanism of carcinogenesis of this rare tumor is unknown, however.

MATERIALS AND METHODS

We analyzed paraffin-embedded formalin-fixed liver tumor and normal liver specimens of two female AIP patients treated at the Munich EPNET center. One patient had developed hepatocellular carcinoma (HCC), the other intrahepatic cholangiocarcinoma (CCA). Since biallelic inactivation of HMBS had been observed in one study, we used Sanger and next-generation sequencing with a 8 gene porphyria panel plus 6 potential modifier loci to search for mutations in DNA extractions.

RESULTS

In the patient with the HCC, we found a second inactivating mutation in the HMBS gene in the tumor but not in the adjacent normal liver tissue. No mutation could be found in the liver tissues of the patient with CCA, however.

CONCLUSIONS

Biallelic inactivation of HMBS or protoporphyrinogen-oxidase (PPOX), another enzyme of porphyrin biosynthesis, has been observed in patients with acute porphyrias and liver tumors. We could confirm this in our patient with HCC with a mutation in HMBS but not in the one with CCA. Since 5-ALA can be converted into carcinogenic substances such as 4,5-dioxovaleric acid (DOVA) or 3,6-dihydropyrazine-2,5-dipropanoic acid (= cyclic dimerization product of 5-ALA), local production of these metabolites in hepatic areas with complete loss of HMBS activity may contribute to liver carcinogenesis.

Risk of Hepatocellular Carcinoma in Patients with Porphyria: A Systematic Review

Simple Summary

Porphyria is a metabolic condition which leads to reduced heme production. While it involves multiple organs systems, porphyria affecting the liver can lead to elevations in hepatic enzymes, progressive fibrosis, cirrhosis and eventually malignancy. Our study looked at the prevalence of liver cancer in patients with porphyria. Overall, we found that patients with porphyria are at increased risk of developing hepatic malignancy. As a result, patients with porphyria should undergo routine surveillance for detecting primary liver malignancy.

Abstract

Acute porphyrias are a group of metabolic disorders resulting in defective porphyrin synthesis and reduced heme production, which carries a risk of malignancy. Porphyrias are inborn defects in the heme biosynthesis pathway resulting in neurovisceral manifestations and cutaneous photosensitivity attacks with multi-systemic involvement. Its estimated prevalence nears 5 per 100,000 patients worldwide. Subclinical liver disease is common, which can progress into transaminitis, fibrosis, cirrhosis, and malignancy. However, data on the incidence of primary liver cancer are lacking. We aim to determine the risk of hepatocellular carcinoma (HCC) in patients with porphyria. A systematic review and pooled analysis were conducted through 2021 on studies assessing blood tests, imaging, cancer development, liver transplant, surgical resection, and outcomes in porphyria. In total, 19 studies, which included 7381 patients with porphyria (3476 females), were considered for the final review. In eight studies, alpha-fetoprotein levels were elevated between 200 and 1000 IU/mL. Of the total cohort of patients with porphyria, primary liver cancer was diagnosed in 351 patients (4.8%), of whom 243 (3.3% of the total) were found to have HCC. A subset of patients was found to have cholangiocarcinoma (n = 18; 0.3% of the total). Interestingly, advanced liver disease or cirrhosis was not a prerequisite for the formation of HCC in a small group of patients. Of the total cohort, 30 patients underwent liver resection, 48 patients underwent liver transplantation, and 327 patients died. Patients with porphyria are at risk of developing primary liver malignancy. Further studies should aim to develop diagnostic and prognostic models aimed at the early detection of HCC in porphyria.

Risk of primary liver cancer in acute hepatic porphyria patients: A matched cohort study of 1244 individuals

BACKGROUND

The acute hepatic porphyrias (AHP) are associated with a risk of primary liver cancer (PLC), but risk estimates are unclear, and what AHP characteristics that predict PLC risk are unknown. In this register-based, matched cohort study, we assessed the PLC risk in relation to biochemical and clinical porphyria severity, genotype, age, and sex.

METHODS

All patients in the Swedish porphyria register with acute intermittent porphyria (AIP), variegate porphyria (VP), or hereditary coproporphyria (HCP) during 1987-2015 were included. This AHP cohort was compared with age-, sex-, and county-matched reference individuals from the general population. National register-based hospital admissions for AHP were used to indicate the clinical severity. For AIP, the most common AHP type, patients were stratified by genotype and urinary porphobilinogen (U-PBG). Incident PLC data were collected from national health registers.

RESULTS

We identified 1244 individuals with AHP (1063 [85%] AIP). During a median follow-up of 19.5 years, we identified 108 incident PLC cases, including 83 AHP patients (6.7%) and 25 of 12,333 reference individuals (0.2%). The adjusted hazard ratio for AHP-PLC was 38.0 (95% confidence interval: 24.3-59.3). Previously elevated U-PBG and hospitalizations for porphyria, but not AIP genotype or sex, were associated with increased PLC risk. Patients aged >50 years with previously elevated U-PBG (n = 157) had an annual PLC incidence of 1.8%.

CONCLUSION

This study confirmed a high PLC risk and identified a strong association with clinical and biochemical AIP activity. Regular PLC surveillance is motivated in patients older than 50 years with a history of active AIP.

Acute Intermittent Porphyria: An Overview of Therapy Developments and Future Perspectives Focusing on Stabilisation of HMBS and Proteostasis Regulators

Acute intermittent porphyria (AIP) is an autosomal dominant inherited disease with low clinical penetrance, caused by mutations in the hydroxymethylbilane synthase (HMBS) gene, which encodes the third enzyme in the haem biosynthesis pathway. In susceptible HMBS mutation carriers, triggering factors such as hormonal changes and commonly used drugs induce an overproduction and accumulation of toxic haem precursors in the liver. Clinically, this presents as acute attacks characterised by severe abdominal pain and a wide array of neurological and psychiatric symptoms, and, in the long-term setting, the development of primary liver cancer, hypertension and kidney failure. Treatment options are few, and therapies preventing the development of symptomatic disease and long-term complications are non-existent. Here, we provide an overview of the disorder and treatments already in use in clinical practice, in addition to other therapies under development or in the pipeline. We also introduce the pathomechanistic effects of HMBS mutations, and present and discuss emerging therapeutic options based on HMBS stabilisation and the regulation of proteostasis. These are novel mechanistic therapeutic approaches with the potential of prophylactic correction of the disease by totally or partially recovering the enzyme functionality. The present scenario appears promising for upcoming patient-tailored interventions in AIP.

Hepatocellular carcinoma (HCC): Epidemiology, etiology and molecular classification

Hepatocellular carcinoma (HCC), the primary malignancy of hepatocytes, is a diagnosis with bleak outcome. According to National Cancer Institute's SEER database, the average five-year survival rate of HCC patients in the US is 19.6% but can be as low as 2.5% for advanced, metastatic disease. When diagnosed at early stages, it is treatable with locoregional treatments including surgical resection, Radio-Frequency Ablation, Trans-Arterial Chemoembolization or liver transplantation. However, HCC is usually diagnosed at advanced stages when the tumor is unresectable, making these treatments ineffective. In such instances, systemic therapy with tyrosine kinase inhibitors (TKIs) becomes the only viable option, even though it benefits only 30% of patients, provides only a modest (~3months) increase in overall survival and causes drug resistance within 6months. HCC, like many other cancers, is highly heterogeneous making a one-size fits all option problematic. The selection of liver transplantation, locoregional treatment, TKIs or immune checkpoint inhibitors as a treatment strategy depends on the disease stage and underlying condition(s). Additionally, patients with similar disease phenotype can have different molecular etiology making treatment responses different. Stratification of patients at the molecular level would facilitate development of the most effective treatment option. With the increase in efficiency and affordability of "omics"-level analysis, considerable effort has been expended in classifying HCC at the molecular, metabolic and immunologic levels. This review examines the results of these efforts and the ways they can be leveraged to develop targeted treatment options for HCC.

Acute hepatic porphyria and cancer risk: a nationwide cohort study

BACKGROUND

Acute hepatic porphyria (AHP) is considered to be a risk factor for primary liver cancer (PLC), but varying risk estimates have been published.

OBJECTIVES

Our aim was to investigate the risk of PLC and other cancers in persons with AHP using a nationwide cohort design. Given that greater numbers of women than men tend to have manifest and more severe AHP, a further aim was to investigate sex differences in this risk.

METHODS

The study sample consisted of all Norwegian residents aged 18 years or older during the period 2000-2011. Persons with AHP (n = 251) were identified through the Norwegian Porphyria Centre, and patients with a cancer diagnosis were identified by linkage to the Cancer Registry of Norway.

RESULTS

For persons with AHP, the annual incidence rate of PLC was 0.35%. PLC risk was substantially higher for individuals with an AHP diagnosis compared to the reference population [adjusted hazard ratio (aHR) 108, 95% confidence interval (CI) 56-207]. In a meta-analysis of published studies on PLC and AHP, including ours, women had a higher risk than men. In addition, our results suggested that persons with AHP may have increased risks of kidney (aHR 7.4, 95% CI 2.4-23.1) and endometrial cancers (aHR 6.2, 95% CI 2.0-19.3).

CONCLUSIONS

Our findings confirmed a substantially higher risk of PLC associated with AHP compared to the general population. In a meta-analysis, the risk was shown to be greater for women than men. The novel findings of a moderate to substantial association between AHP and kidney and endometrial cancers should be investigated further.

Hepatic porphyria: A narrative review

Porphyrias are a group of metabolic disorders, which result from a specific abnormality in one of the eight enzymes of the heme biosynthetic pathway. These have been subdivided based on the predominant site of enzyme defect into hepatic and erythropoietic types and based on clinical presentation into acute neurovisceral and cutaneous blistering porphyrias. This review focuses on hepatic porphyrias, which include acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP), aminolevulinic acid dehydratase deficiency porphyria (ADP), and porphyria cutanea tarda (PCT). Of these, AIP and ADP are classified as acute porphyria, PCT as cutaneous, while VP and HCP present with both acute and cutaneous clinical manifestations. Porphobilinogen levels in a spot urine sample is the initial screening test for the diagnosis of acute hepatic porphyria, and plasma with spot urine porphyrin levels is the initial screening test to approach patients suspected of cutaneous porphyria. Specific biochemical porphyrin profile for each porphyria helps in determining the specific diagnosis. Pain relief and elimination of triggering agents are the initial steps in managing a patient presenting with an acute attack. Intravenous glucose administration terminates the mild episode of acute porphyria, with intravenous hemin needed for management of moderate to severe episodes. Liver transplantation is curative and may be needed for patients with a life-threatening acute porphyria attack or for patients with recurrent acute attacks refractory to prophylactic treatment. Of the cutaneous porphyrias, PCT is the most common and is frequently associated with a combination of multiple susceptibility factors such as alcohol use, smoking, hepatitis C virus infection, HIV infection, estrogen use, and mutations of the hemochromatosis gene. Regular phlebotomy schedule and low-dose hydroxychloroquine are effective and safe treatment options for management of PCT.

Population attributable fractions of risk factors for hepatocellular carcinoma in the United States

BACKGROUND

Hepatocellular carcinoma (HCC) incidence has been increasing in the United States for several decades; and, as the incidence of hepatitis C virus (HCV) infection declines and the prevalence of metabolic disorders rises, the proportion of HCC attributable to various risk factors may be changing.

METHODS

Data from the Surveillance, Epidemiology, and End Results-Medicare linkage were used to calculate population attributable fractions (PAFs) for each risk factor over time. Patients with HCC (n = 10,708) who were diagnosed during the years 2000 through 2011 were compared with a 5% random sample of cancer-free controls (n = 332,107) residing in the Surveillance, Epidemiology, and End Results areas. Adjusted odds ratios (ORs) and PAFs were calculated for HCV, hepatitis B virus (HBV), metabolic disorders, alcohol-related disorders, smoking, and genetic disorders.

RESULTS

Overall, the PAF was greatest for metabolic disorders (32%), followed by HCV (20.5%), alcohol (13.4%), smoking (9%), HBV (4.3%), and genetic disorders (1.5%). The PAF for all factors combined was 59.5%. PAFs differed by race/ethnicity and sex. Metabolic disorders had the largest PAF among Hispanics (PAF, 39.3%; 95% confidence interval [CI], 31.9%-46.7%) and whites (PAF, 34.8%; 95% CI, 33.1%-36.5%), whereas HCV had the largest PAF among blacks (PAF, 36.1%; 95% CI, 31.8%-40.4%) and Asians (PAF, 29.7%; 95% CI, 25.9%-33.4%). Between 2000 and 2011, the PAF of metabolic disorders increased from 25.8% (95% CI, 22.8%-28.9%) to 36% (95% CI, 33.6%-38.5%). In contrast, the PAFs of alcohol-related disorders and HCV remained stable.

CONCLUSIONS

Among US Medicare recipients, metabolic disorders contribute more to the burden of HCC than any other risk factor, and the fraction of HCC caused by metabolic disorders has increased in the last decade. Cancer 2016;122:1757-65. Published 2016. This article is a U.S. Government work and is in the public domain in the USA..