Cushing's disease (CD) arises from pituitary-dependent glucocorticoid excess due to an ACTH-secreting corticotroph tumor. Genetic hits in oncogenes and tumor suppressor genes that afflict other pituitary tumor subtypes are not found in corticotrophinomas. Recently, a somatic mutational hotspot was found in up to half of corticotrophinomas in the USP8 gene that encodes a protein that impairs the downregulation of the epidermal growth factor receptor (EGFR) and enables its constitutive signaling. EGF is an important regulator of corticotroph function and its receptor is highly expressed in Cushing's pituitary tumors, where it leads to increased ACTH synthesis in vitro and in vivo. The mutational hotspot found in corticotrophinomas hyper-activates USP8, enabling it to rescue EGFR from lysosomal degradation and ensure its stimulatory signaling. This review presents new developments in the study of the genetics of CD and focuses on the USP8-EGFR system as trigger and target of corticotroph tumorigenesis.
Marily Theodoropoulou, Martin Reincke, Martin Fassnacht, and Masayuki Komada
Thomas Vanbrabant, Martin Fassnacht, Guillaume Assie, and Olaf Dekkers
Objective Adrenocortical carcinoma (ACC) is a malignancy with a poor prognosis. Many publications in ACC report on risk factors for a poor outcome; one risk factor studied is hormonal hypersecretion (cortisol, sex-hormones, steroid precursors, or aldosterone). The aim of this systematic review was to study the association between hormonal secretion and recurrence or mortality in ACC.
Design Systematic review and meta-analysis. We searched Pubmed, Embase and The Cochrane library (January 2018) for cohort studies examining the association between hormonal secretion on overall or recurrence-free survival in ACC.
Methods A random effects model meta-analysis was performed to obtain a weighted relative risk comparing cortisol-secreting and/or androgen-secreting ACCs to non-secreting tumours regarding overall and recurrence-free survival. Risk of bias assessment was performed for all studies included.
Result Nineteen publications were included representing a total of 3,814 patients. Most studies were generally considered low/intermediate risk of bias. Meta-analysis showed higher mortality risk for cortisol secreting ACCs, weighted relative risk 1.71 (95% CI 1.18-2.47) combining studies that adjusted for tumour stage; also a higher recurrence risk was found for cortisol producing ACCs, relative risk 1.43 (95% CI 1.18-1.73). Androgen secretion was not clearly associated with survival (RR 0.82, 95%CI 0.60-1.14).
This systematic review and meta-analysis shows that cortisol-secreting ACCs are associated with a worse overall survival; future research is needed to establish whether this association points to negative effects of cortisol action, whether it signifies a more aggressive ACC subtype or whether cortisol is merely a prognostic marker.
Stefanie Hahner, Martin Fassnacht, Fabian Hammer, Markus Schammann, Dirk Weismann, Immo Alex Hansen, and Bruno Allolio
Objective: A serine protease from rat adrenal cortex was recently characterized and named adrenal secretory protease (AsP). AsP is expressed in the adrenal cortex and is capable of cleaving pro-γ-melanocyte-stimulating hormone (1-76 N-terminus of pro-opiomelanocortin) into fragments that act as adrenal mitogens. AsP may therefore play a crucial role in adrenal growth and tumourigenesis. The aim of this study was to further characterize the human homologue of AsP and its possible role in adrenal tumourigenesis.
Methods and results: Starting with the rat cDNA sequence of AsP we detected high homology to the catalytic C-terminus of the human airway trypsin-like protease (HAT). Further analysis revealed that the HAT gene is the human homologue of a long splice variant of AsP, which we recently described as rat airway trypsin-like serine protease 1. In contrast to rodents, no short isoform of HAT was found in humans due to a stop codon in exon 6 which prevents the expression of a short isoform. While high expression of HAT mRNA was found in the trachea and in the gastrointestinal tract, expression in the adrenal was only very weak. RT-PCR and real-time PCR analysis revealed a complex tissue expression pattern of HAT, indicating a role for this protease in multiple tissues. We further investigated HAT expression in five normal adrenal glands, 15 adrenocortical adenomas (five hormonally inactive adenomas, five aldosterone-producing adenomas and five cortisol-producing adenomas), nine adrenocortical carcinomas, five phaeochromocytomas and two adrenal hyperplasias. Weak HAT expression was detectable in only two out of five normal adrenal glands, in one out of twenty-four adrenocortical tumours and four out of five phaeochromocytomas. However, the expression in the adrenal tissue was several orders of magnitude lower than in the trachea. In addition, we could not detect any HAT transcripts in a sample of fetal adrenal.
Conclusion: Gene structure and tissue distribution of HAT, the human homologue of the rat adrenal secretory protease AsP, reveal major interspecies differences. The observation of very low expression levels in normal adrenal tissue and adrenocortical tumours casts doubt about a role for HAT in the physiological and pathological growth of adrenocortical cells.
Sebastian Wortmann, Marcus Quinkler, Christian Ritter, Matthias Kroiss, Sarah Johanssen, Stefanie Hahner, Bruno Allolio, and Martin Fassnacht
No standard therapy for advanced adrenocortical carcinoma (ACC) is established by any randomized trial but a consensus conference 2003 recommended mitotane as monotherapy or combined with etoposide, doxorubicin and cisplatin or with streptozotocin as first-line systemic therapy. However, there is no evidence for any therapy beneficial in patients failing these therapies. Therefore, we evaluated the effects of the anti-VEGF antibody bevacizumab plus capecitabine as salvage therapy in ACC.
Patients registered with the German ACC Registry with refractory ACC progressing after cytotoxic therapies were offered treatment with bevacizumab (5 mg/kg body weight i.v. every 21 days) and oral capecitabine (950 mg/m2 twice daily for 14 days followed by 7 days of rest) in 2006–2008. Evaluation of tumour response was performed by imaging according to response evaluation criteria in solid tumours every 12 weeks.
Ten patients were treated with bevacizumab plus capecitabine. None of them experienced any objective response or stable disease. Two patients had to stop therapy after few weeks due to hand-foot syndrome, and three patients died on progressive disease within 12 weeks. Other adverse events were mild (grade I–II). Median survival after treatment initiation was 124 days.
Bevacizumab plus capecitabine has no activity in patients with very advanced ACC. Hence, this regimen cannot be recommended as a salvage therapy.
Cristina L Ronchi, Matthias Kroiss, Silviu Sbiera, Timo Deutschbein, and Martin Fassnacht
Adrenocortical carcinoma (ACC) is not only a rare and heterogeneous disease but also one of the most aggressive endocrine tumors. Despite significant advances in the last decade, its pathogenesis is still only incompletely understood and overall therapeutic means are unsatisfactory. Herein, we provide our personal view of the currently available treatment options and suggest the following research efforts that we consider timely and necessary to improve therapy: i) for better outcome in localized ACCs, surgery should be restricted to experienced centers, which should then collaborate closely to address the key surgical questions (e.g. best approach and extent of surgery) in a multicenter manner. ii) For the development of better systemic therapies, it is crucial to elucidate the exact molecular mechanisms of action of mitotane. iii) A prospective trial is needed to address the role of cytotoxic drugs in the adjuvant setting in aggressive ACCs (e.g. mitotane vs mitotane+cisplatin). iv) For metastatic ACCs, new regimens should be investigated as first-line therapy. v) Several other issues (e.g. the role of radiotherapy and salvage therapies) might be answered – at least in a first step – by large retrospective multicenter studies. In conclusion, although it is unrealistic to expect that the majority of ACCs can be cured within the next decade, international collaborative efforts (including multiple translational and clinical studies) should allow significant improvement of clinical outcome of this disease. To this end, it might be reasonable to expand the European Network for the Study of Adrenal Tumors (ENSAT) to a truly worldwide international network – INSAT.
Usman Arshad, Max Taubert, Max Kurlbaum, Sebastian Frechen, Sabine Herterich, Felix Megerle, Stefanie Hamacher, Martin Fassnacht, Uwe Fuhr, and Matthias Kroiss
Objective: Mitotane is used for the treatment of adrenocortical carcinoma. High oral daily doses of typically 1- 6 g are required to attain therapeutic concentrations. The drug has a narrow therapeutic index and patient management is difficult because of a high volume of distribution, very long elimination half-life, and drug interaction through induction of metabolizing enzymes. The present evaluation aimed at the development of a population pharmacokinetic model of mitotane to facilitate therapeutic drug monitoring.
Methods: Appropriate dosing information, plasma concentrations (1137 data points) and covariates were available from therapeutic drug monitoring (TDM) of 76 adrenocortical carcinoma patients treated with mitotane. Using nonlinear mixed effects modeling, a simple structural model was first developed, with subsequent introduction of metabolic autoinduction. Covariate data were analyzed to improve overall model predictability. Simulations were performed to assess the attainment of therapeutic concentrations with clinical dosing schedules.
Results: A one-compartment pharmacokinetic model with first order absorption was found suitable to describe the data, with an estimated central volume of distribution of 6086 L related to a high interindividual variability of 81.5%. Increase in clearance of mitotane during treatment could be modeled by a linear enzyme autoinduction process. Body mass index was found to have an influence upon disposition kinetics of mitotane. Model simulations favor a high dose regimen to rapidly attain therapeutic concentrations, with the first TDM suggested on day 16 of treatment to avoid systemic toxicity.
Conclusion: The proposed model describes mitotane pharmacokinetics and can be used to facilitate therapy by predicting plasma concentrations.
Irina Bancos, Shrikant Tamhane, Muhammad Shah, Danae A Delivanis, Fares Alahdab, Wiebke Arlt, Martin Fassnacht, and M Hassan Murad
To perform a systematic review of published literature on adrenal biopsy and to assess its performance in diagnosing adrenal malignancy.
Medline In-Process and Other Non-Indexed Citations, MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trial were searched from inception to February 2016. Reviewers extracted data and assessed methodological quality in duplicate.
We included 32 observational studies reporting on 2174 patients (39.4% women, mean age 59.8 years) undergoing 2190 adrenal mass biopsy procedures. Pathology was described in 1621/2190 adrenal lesions (689 metastases, 68 adrenocortical carcinomas, 64 other malignancies, 464 adenomas, 226 other benign, 36 pheochromocytomas, and 74 others). The pooled non-diagnostic rate (30 studies, 2013 adrenal biopsies) was 8.7% (95%CI: 6–11%). The pooled complication rate (25 studies, 1339 biopsies) was 2.5% (95%CI: 1.5–3.4%). Studies were at a moderate risk for bias. Most limitations related to patient selection, assessment of outcome, and adequacy of follow-up. Only eight studies (240 patients) could be included in the diagnostic performance analysis with a sensitivity and specificity of 87 and 100% for malignancy, 70 and 98% for adrenocortical carcinoma, and 87 and 96% for metastasis respectively.
Evidence based on small sample size and moderate risk of bias suggests that adrenal biopsy appears to be most useful in the diagnosis of adrenal metastasis in patients with a history of extra-adrenal malignancy. Adrenal biopsy should only be performed if the expected findings are likely to alter the management of the individual patient and after biochemical exclusion of catecholamine-producing tumors to help prevent potentially life-threatening complications.
Stefanie Hahner, Melanie Loeffler, Benjamin Bleicken, Christiane Drechsler, Danijela Milovanovic, Martin Fassnacht, Manfred Ventz, Marcus Quinkler, and Bruno Allolio
Adrenal crisis (AC) is a life-threatening complication of adrenal insufficiency (AI). Here, we evaluated frequency, causes and risk factors of AC in patients with chronic AI.
In a cross-sectional study, 883 patients with AI were contacted by mail. Five-hundred and twenty-six patients agreed to participate and received a disease-specific questionnaire.
Four-hundred and forty-four datasets were available for analysis (primary AI (PAI), n=254; secondary AI (SAI), n=190). Forty-two percent (PAI 47% and SAI 35%) reported at least one crisis. Three hundred and eighty-four AC in 6092 patient years were documented (frequency of 6.3 crises/100 patient years). Precipitating causes were mainly gastrointestinal infection and fever (45%) but also other stressful events (e.g. major pain, surgery, psychic distress, heat and pregnancy). Sudden onset of apparently unexplained AC was also reported (PAI 6.6% and SAI 12.7%). Patients with PAI reported more frequent emergency glucocorticoid administration (42.5 vs 28.4%, P=0.003). Crisis incidence was not influenced by educational status, body mass index, glucocorticoid dose, DHEA treatment, age at diagnosis, hypogonadism, hypothyroidism or GH deficiency. In PAI, patients with concomitant non-endocrine disease were at higher risk of crisis (odds ratio (OR)=2.02, 95% confidence interval (CI) 1.05–3.89, P=0.036). In SAI, female sex (OR=2.18, 95% CI 1.06–4.5, P=0.035) and diabetes insipidus (OR=2.71, 95% CI 1.22–5.99, P=0.014) were associated with higher crisis incidence.
AC occurs in a substantial proportion of patients with chronic AI, mainly triggered by infectious disease. Only a limited number of risk factors suitable for targeting prevention of AC were identified. These findings indicate the need for new concepts of crisis prevention in patients with AI.
Robert Kopetschke, Mario Slisko, Aylin Kilisli, Ulrich Tuschy, Henri Wallaschofski, Martin Fassnacht, Manfred Ventz, Felix Beuschlein, Martin Reincke, Nicole Reisch, and Marcus Quinkler
Adrenal and extra-adrenal phaeochromocytoma are chromaffin cell-derived tumours that are discovered due to classical symptom triad with headache, sweating and palpitations combined with persistent or paroxysmal hypertension. However, an increasing proportion of phaeochromocytoma seems to be discovered incidentally upon abdominal imaging.
To specify the exact circumstances of discovery of adrenal and extra-adrenal phaeochromocytoma.
Design and patients
Four German endocrine centres participated in this retrospective study. Medical records of 201 patients with adrenal and extra-adrenal phaeochromocytoma who were diagnosed between 1973 and 2007 were analyzed.
The typical triad of symptoms was found only in 10% of cases. Ten percent of patients presented were without clinical symptoms and 6.1% were normotensive. Documented blood pressure peaks occurred in 44.1% of cases. In 24 patients (12.2%), phaeochromocytoma was malignant. Before 1985, <10% of cases were incidentally discovered, whereas thereafter the frequency was >25% (29.4% of the total study population). Patients with incidentally detected phaeochromocytoma were significantly older (53.1±1.9 vs 47.0±1.3 years; P<0.05) and often had less blood pressure peaks (37.0 vs 70.7%; P<0.001) than patients in whom the diagnosis was suspected on clinical grounds. Of phaeochromocytomas 94.4% were intra-adrenal tumours, of which 12.9% were bilateral. Bilateral tumours were significantly smaller than unilateral tumours (36.6±14.7 vs 52.5±34.3 mm; P<0.05), whereas extra-adrenal tumours had a mean diameter of 52.6±28.7 mm.
Owing to better availability and accessibility of imaging procedures, the number of incidentally discovered phaeochromocytoma is increasing and reaches nearly 30% in our study population. Every adrenal incidentaloma should be investigated for the presence of phaeochromocytoma.
Carmina Teresa Fuss, Marcus Treitl, Nada Rayes, Petr Podrabsky, Wiebke Kristin Fenske, Daniel Alexander Heinrich, Martin Reincke, Tim-Ole Petersen, Martin Fassnacht, Marcus Quinkler, Ralph Kickuth, and Stefanie Hahner
Objective: Adrenal vein sampling (AVS) represents the current diagnostic standard for subtype differentiation in primary aldosteronism (PA). However, AVS has its drawbacks. It is invasive, expensive, requires an experienced interventional radiologist, and comes with radiation exposure. However, exact radiation exposure of patients undergoing AVS has never been examined.
Design and Methods: We retrospectively analyzed radiation exposure of 656 AVS performed between 1999 and 2017 at four university hospitals. The primary outcomes were dose area product (DAP) and fluoroscopy time (FT). Consecutively the effective dose (ED) was approximately calculated.
Results: Median DAP was found to be 32.5 Gy*cm2 [0.3 – 3181] and FT 18 min [0.3 – 184]. The calculated ED was 6.4 mSv [0.1 – 636]. Remarkably, values between participating centers highly varied: Median DAP ranged from 16 to 147 Gy*cm2, FT from 16 to 27 min, and ED from 3.2 to 29 mSv. As main reason for this variation differences regarding AVS protocols between centers could be identified, such as number of sampling locations, frames per second, and the use of digital subtraction angiographies.
Conclusion: This first systematic assessment of radiation exposure in AVS not only shows fairly high values for patients, but also states notable differences amongst the centers. Thus, we not only recommend taking into account the risk of radiation exposure, when referring patients to undergo AVS, but also to establish improved standard operating procedures to prevent unnecessary radiation exposure.