Decreasing mortality and changes in treatment patterns in patients with acromegaly from a nationwide study

Insights into pituitary tumorigenesis: from Sanger sequencing to next-generation sequencing and beyond

Introduction: This review explores insights provided by next-generation sequencing (NGS) of pituitary tumors and the clinical implications.Areas covered: Although syndromic forms account for just 5% of pituitary tumours, past Sanger sequencing studies pragmatically focused on them. These studies identified mutations in MEN1, CDKN1B, PRKAR1A, GNAS and SDHx causing Multiple Endocrine Neoplasia-1 (MEN1), MEN4, Carney Complex-1, McCune Albright Syndrome and 3P association syndromes, respectively. Furthermore, linkage analysis of single-nucleotide polymorphisms identified AIP mutations in 20% with familial isolated pituitary adenomas (FIPA). NGS has enabled further investigation of sporadic tumours. Thus, mutations of USP8 and CABLES1 were identified in corticotrophinomas, BRAF in papillary craniopharyngiomas and CTNNB1 in adamantinomatous craniopharyngiomas. NGS also revealed that pituitary tumours occur in the DICER1 syndrome, due to DICER1 mutations, and CDH23 mutations occur in FIPA. These discoveries revealed novel therapeutic targets and studies are underway of BRAF inhibitors for papillary craniopharyngiomas, and EGFR and USP8 inhibitors for corticotrophinomas.Expert opinion: It has become apparent that single-nucleotide variants and small insertion/deletion DNA mutations cannot explain all pituitary tumorigenesis. Integrated and improved analyses including whole-genome sequencing, copy number, and structural variation analyses, RNA sequencing and epigenomic analyses, with improved genomic technologies, are likely to further define the genomic landscape.

Determinants of morbidities and mortality in acromegaly

Acromegaly is a systemic disease associated with increased morbidity, presenting cardiovascular, metabolic, respiratory, neoplastic, endocrine, articular and bone complications. Most of these comorbidities can be prevented or delayed with adequate disease treatment and, more recent studies with the use of modern treatments of acromegaly, have shown a change in the severity and prevalence of these complications. In addition, acromegaly is associated with increased mortality, but recent studies (especially those published in the last decade) have shown a different scenario than older studies, with mortality no longer being increased in adequately controlled patients and a change in the main cause of death from cardiovascular disease to malignancy. In this review, we discuss this changing face of acromegaly summarizing current knowledge and evidence on morbimortality of the disease. Arch Endocrinol Metab. 2019;63(6):630-7.

Metabolic Fingerprint of Acromegaly and its Potential Usefulness in Clinical Practice

Insulin-like growth factor-1 (IGF-1) and growth hormone (GH) levels are the main targets for monitoring acromegaly activity, but they are not in close relationship with the clinical course of the disease and the associated comorbidities. The present study was aimed at identifying metabolites that could be used as biomarkers for a better disease phenotyping. For this purpose, metabolic fingerprint using an untargeted metabolomic approach was examined in serum from 30 patients with acromegaly and 30 age-matched controls. Patients with acromegaly presented fewer branched-chain amino acids (BCAAs) compared to the control group (valine: 4.75 ± 0.87 vs. 5.20 ± 1.06 arbitrary units (AUs), p < 0.05; isoleucine: 2.54 ± 0.41 vs. 2.80 ± 0.51 AUs; p < 0.05). BCAAs were also lower in patients with active disease compared to patients with normal levels of IGF-1 with or without medical treatment. GH, but not IGF-1, serum levels were inversely correlated with both valine and isoleucine. These findings indicate that low levels of BCAAs represent the main metabolic fingerprint of acromegaly and that GH, rather than IGF-1, might be the primary mediator. In addition, our results suggest that the assessment of BCAAs could help to identify active disease and to monitor the response to therapeutic strategies.

Overall and Disease-Specific Mortality in Patients With Cushing Disease: A Swedish Nationwide Study

CONTEXT

Whether patients with Cushing disease (CD) in remission have increased mortality is still debatable.

OBJECTIVE

To study overall and disease-specific mortality and predictive factors in an unselected nationwide cohort of patients with CD.

DESIGN, PATIENTS, AND METHODS

A retrospective study of patients diagnosed with CD, identified in the Swedish National Patient Registry between 1987 and 2013. Medical records were systematically reviewed to verify the diagnosis. Standardized mortality ratios (SMRs) with 95% CIs were calculated and Cox regression models were used to identify predictors of mortality.

RESULTS

Of 502 identified patients with CD (n = 387 women; 77%), 419 (83%) were confirmed to be in remission. Mean age at diagnosis was 43 (SD, 16) years and median follow-up was 13 (interquartile range, 6 to 23) years. The observed number of deaths was 133 vs 54 expected, resulting in an overall SMR of 2.5 (95% CI, 2.1 to 2.9). The commonest cause of death was cardiovascular diseases (SMR, 3.3; 95% CI, 2.6 to 4.3). Excess mortality was also found associated with infections and suicide. For patients in remission, the SMR was 1.9 (95% CI, 1.5 to 2.3); bilateral adrenalectomy and glucocorticoid replacement therapy were independently associated with increased mortality, whereas GH replacement was associated with improved outcome.

CONCLUSION

Findings from this large nationwide study indicate that patients with CD have excess mortality. The findings illustrate the importance of achieving remission and continued active surveillance, along with adequate hormone replacement and evaluation of cardiovascular risk and mental health.

National acromegaly registries

Acromegaly is a rare disease, associated with multiple organs and systems damage. Thanks to implementation of registries, systematic data gathering, knowledge sharing and standardizing medical practices for optimal care greatly improved. Data concerning 19 national acromegaly registries are available, involving more than 16,000 patients. The weighted mean age of diagnosis is 45.2 years and seems stable over time. A macroadenoma is found in 75% of the cases. The proportion of patients operated (>80%) did not change along time. By contrast, use of radiotherapy has decreased while use of medical therapy increased. If judged on IGF-I levels, acromegaly is controlled in 61.3% of the patients. The disease control rate has improved over time. This is likely due to the development of medical treatment strategies. The collection of data about comorbidities in national registries is much less comprehensive than those about epidemiology, disease control or treatment strategies. The most reported comorbidities are arterial hypertension and diabetes. Data concerning mortality trends are controversial. It seems that cancer has become a leading cause of death in acromegaly patients in the last decade, period in which life expectancy improved, while cardiovascular mortality decreased. In conclusion, acromegaly registries offer a global view of the disease with no "a priori" assumptions. This is of outmost importance, because of the large amount of data and the huge number of associated comorbidities. This will help to establish guidelines for management of this rare disease.

Growth Hormone's Links to Cancer

Several components of the GH axis are involved in tumor progression, and GH-induced intracellular signaling has been strongly associated with breast cancer susceptibility in genome-wide association studies. In the general population, high IGF-I levels and low IGF-binding protein-3 levels within the normal range are associated with the development of common malignancies, and components of the GH-IGF signaling system exhibit correlations with clinical, histopathological, and therapeutic parameters in cancer patients. Despite promising findings in preclinical studies, anticancer therapies targeting the GH-IGF signaling system have led to disappointing results in clinical trials. There is substantial evidence for some degree of protection against tumor development in several animal models and in patients with genetic defects associated with GH deficiency or resistance. In contrast, the link between GH excess and cancer risk in acromegaly patients is much less clear, and cancer screening in acromegaly has been a highly controversial issue. Recent studies have shown that increased life expectancy in acromegaly patients who attain normal GH and IGF-I levels is associated with more deaths due to age-related cancers. Replacement GH therapy in GH deficiency hypopituitary adults and short children has been shown to be safe when no other risk factors for malignancy are present. Nevertheless, the use of GH in cancer survivors and in short children with RASopathies, chromosomal breakage syndromes, or DNA-repair disorders should be carefully evaluated owing to an increased risk of recurrence, primary cancer, or second neoplasia in these individuals.

The burden of disease for pituitary patients

Pituitary diseases are rare conditions with severe chronic multiorgan and multisystemic morbidity requiring complex multidisciplinary treatment and usually life-long drug treatment. Most cases are caused by functioning or non-functioning pituitary adenoma. From the patient's perspective, the burden of disease is caused by the tumour itself and associated compression symptoms, interventions, hormone excess and deficiencies, systemic manifestations of these endocrine abnormalities and general psychosocial issues that can manifest in patients with a chronic condition. In this review, patient burden is classified according to classic endocrine syndromes, with burden at diagnosis and after long-term remission, and also within the framework of value-based health care and the conceptual model of wellbeing. The recently developed patient-reported outcome measurement tool that helps to evaluate burden of patients is also discussed.

Acromegaly

Acromegaly is characterized by increased release of growth hormone and, consequently, insulin-like growth factor I (IGF1), most often by a pituitary adenoma. Prolonged exposure to excess hormone leads to progressive somatic disfigurement and a wide range of systemic manifestations that are associated with increased mortality. Although considered a rare disease, recent studies have reported an increased incidence of acromegaly owing to better disease awareness, improved diagnostic tools and perhaps a real increase in prevalence. Acromegaly treatment approaches, which include surgery, radiotherapy and medical therapy, have changed considerably over time owing to improved surgical procedures, development of new radiotherapy techniques and availability of new medical therapies. The optimal use of these treatments will reduce mortality in patients with acromegaly to levels in the general population. Medical therapy is currently an important treatment option and can even be the first-line treatment in patients with acromegaly who will not benefit from or are not suitable for first-line neurosurgical treatment. Pharmacological treatments include somatostatin receptor ligands (such as octreotide, lanreotide and pasireotide), dopamine agonists and the growth hormone receptor antagonist pegvisomant. In this Primer, we review the main aspects of acromegaly, including scientific advances that underlie expanding knowledge of disease pathogenesis, improvements in disease management and new medical therapies that are available and in development to improve disease control.

Systemic Complications of Acromegaly and the Impact of the Current Treatment Landscape: An Update

Acromegaly is a chronic systemic disease with many complications and is associated with increased mortality when not adequately treated. Substantial advances in acromegaly treatment, as well as in the treatment of many of its complications, mainly diabetes mellitus, heart failure, and arterial hypertension, were achieved in the last decades. These developments allowed change in both prevalence and severity of some acromegaly complications and furthermore resulted in a reduction of mortality. Currently, mortality seems to be similar to the general population in adequately treated patients with acromegaly. In this review, we update the knowledge in complications of acromegaly and detail the effects of different acromegaly treatment options on these complications. Incidence of mortality, its correlation with GH (cumulative exposure vs last value), and IGF-I levels and the shift in the main cause of mortality in patients with acromegaly are also addressed.

Preoperative Noninvasive Radiomics Approach Predicts Tumor Consistency in Patients With Acromegaly: Development and Multicenter Prospective Validation

Background: Prediction of tumor consistency before surgery is of vital importance to determine individualized therapeutic schemes for patients with acromegaly. The present study was performed to noninvasively predict tumor consistency based on magnetic resonance imaging and radiomics analysis. Methods: In total, 158 patients with acromegaly were randomized into the primary cohort (n = 100) and validation cohort (n = 58). The consistency of the tumor was classified as soft or firm according to the neurosurgeon's evaluation. The critical radiomics features were determined using the elastic net feature selection algorithm, and the radiomics signature was constructed. The most valuable clinical characteristics were then selected based on the multivariable logistic regression analysis. Next, a radiomics model was developed using the radiomics signature and clinical characteristics, and 30 patients with acromegaly were recruited for multicenter validation of the radiomics model. The model's performance was evaluated based on the receiver operating characteristic (ROC) curve, area under the ROC curve (AUC), accuracy, and other associated classification measures. Its calibration, discriminating capacity, and clinical usefulness were also evaluated. Results: The radiomics signature established according to four radiomics features screened in the primary cohort exhibited excellent discriminatory capacity in the validation cohort. The radiomics model, which incorporated both the radiomics signature and Knosp grade, displayed favorable discriminatory capacity and calibration, and the AUC was 0.83 (95% confidence interval, 0.81-0.85) and 0.81 (95% confidence interval, 0.78-0.83) in the primary and validation cohorts, respectively. Furthermore, compared with the clinical characteristics, the as-constructed radiomics model is more effective in prediction of the tumor consistency in patients with acromegaly. Moreover, the multicenter validation and decision curve analysis suggested that the radiomics model was clinically useful. Conclusions: This radiomics model can assist neurosurgeons in predicting tumor consistency in patients with acromegaly before surgery and facilitates the determination of individualized therapeutic schemes.

Mortality in acromegaly decreased in the last decade: a systematic review and meta-analysis

OBJECTIVE

To compare the acromegaly mortality rates with those expected for the general population from studies published before and after 2008.

METHODS

We performed a systematic review and included observational studies in which the number of deaths observed in acromegaly was compared with the expected mortality for the general population mortality observed/expected (O/E). The following electronic databases were used as our data sources: EMBASE, MEDLINE and LILACS. From the observed and expected deaths, we recalculated all standardized mortality ratios (SMR) and their respective confidence intervals (95% CI), which were plotted in a meta-analysis using the software RevMan 5.3.

RESULTS

We identified 2303 references, and 26 studies fulfilled our eligibility criteria. From the 17 studies published before 2008, the mortality in acromegaly was increased, while from the nine studies published after 2008, the mortality was not different from the general population (SMR: 1.35, CI: 0.99-1.85). In six studies where somatostatin analogs (SAs) were used as adjuvant treatment, acromegaly mortality was not increased (SMR: 0.98, CI: 0.83-1.15), whereas in series including only patients treated with surgery and/or radiotherapy, mortality was significantly higher (SMR: 2.11; CI: 1.54-2.91). In studies published before and after 2008, the mortality was not increased in patients who achieved biochemical control, while it was higher in those with active disease. Cancer has become a leader cause of deaths in acromegaly patients in the last decade, period in which life expectancy improved.

CONCLUSION

Mortality in acromegaly is normalized with biochemical control and decreased in the last decade with the more frequent use of SAs as adjuvant therapy. Increased life expectancy has been associated with more deaths due to cancer.