Efficacy and predictors of short-term first-generation somatostatin analog presurgical treatment in acromegaly: A hospital-based study of 237 cases

Medical treatment of acromegaly - When the tumor size matters: A narrative review

Medical treatment of acromegaly is generally positioned as a second line of treatment after pituitary adenoma surgery. With the rising availability and variety of medications for acromegaly increases our understanding of their effectiveness and safety. Volume of the published data on the impact of medical therapy on biochemical control of acromegaly, contrasts a relative lack of publications which comprehensively address pituitary tumor alterations under different drug modalities. Assessment of changes in GH-secreting adenoma volume is often overshadowed by clinicians' focus on GH and IGF-I levels during acromegaly treatment. Close analysis of studies published in the last two decades, reveals that both an increase and decrease in somatotropinoma volume are possible during treatment with any of available drugs for acromegaly. Changes in pituitary tumor size may arise from the biological nature of adenoma itself, independently of the administered medications. Therefore, an individual approach is necessary in the treatment of patients with acromegaly, based on repeated insight to their clinical, biochemical, pathological and imaging characteristics. In this review, we summarize and comment how pituitary tumor size is affected by the treatment with all currently available drugs in acromegaly: long-acting somatostatin receptor ligands of the first generation (octreotide LAR and lanreotide autogel) and the second generation (pasireotide-LAR), as well as pegvisomant (PEG) and cabergoline (CAB).

Germline AIP variants in sporadic young acromegaly and pituitary gigantism: clinical and genetic insights from a Han Chinese cohort

PURPOSE

Variants in the Aryl hydrocarbon receptor-interacting protein (AIP) gene have been identified in sporadic acromegaly and pituitary gigantism, especially in young patients, with a predisposition to aggressive clinical phenotype and poor treatment efficacy. The clinical characteristics of patients with sporadic acromegaly and pituitary gigantism as well as AIP variants in Han Chinese have been rarely reported. We aimed to identify AIP gene variants and analyze the clinical characteristics of patients with sporadic acromegaly and pituitary gigantism in Han Chinese.

METHODS

The study included 181 sporadic acromegaly (N = 163) and pituitary gigantism (N = 18) patients with an onset age of no more than 45 years old, who were diagnosed, treated, and followed up in Huashan Hospital. All 6 exons and their flanking regions of the AIP gene were analyzed with Sanger sequencing or NGS. The clinical characteristics were compared between groups with and without AIP variants.

RESULTS

Germline AIP variants were found in 15/181 (8.29%) cases. In patients with an onset age ≤30 years old, AIP variants were identified in 12/133 (9.02%). Overall, 13 variants were detected. The pathogenic (P) variants p.R304X and p.R81X were identified in four cases, with two instances of each variant. Six exon variants (p.C254R, p.K103fs, p.Q228fs, p.Y38X, p.Q213*, and p.1115 fs) have not been reported before, which were likely pathogenic (LP). Patients with P/LP variants had younger onset ages, a higher prevalence of pituitary gigantism, larger tumor volumes, and a higher percentage of Ki-67-positive cells in tumors. In addition, the group with P/LP variants showed a less significant reduction of GH levels in an acute octreotide suppression test (OST) [17.7% (0, 65.0%) vs. 80.5% (63.9%, 90.2%), P = 0.001], and a trend of less GH decrease after the 3-month treatment with long-acting somatostatin analogs (SSAs).

CONCLUSION

Germline AIP variants existed in sporadic Chinese Han acromegaly and pituitary gigantism patients and were more likely to be detected in young patients. AIP variants were associated with more aggressive tumor phenotypes and less response to SSA treatment.

Predicting Response to Medical Treatment in Acromegaly via Granulation Pattern, Expression of Somatostatin Receptors Type 2 and 5 and E-Cadherin

Resistance to first-generation somatostatin receptor ligand (fgSRL) treatment in acromegaly is common, making the identification of biomarkers that predict fgSRL response a desired goal. We conducted a retrospective analysis on 21 patients with acromegaly who underwent surgery and subsequent pharmacological treatment. Through immunohistochemistry (IHC), we assessed the expression of the somatostatin receptor subtypes SSTR2 and SSTR5, E-Cadherin, and cytokeratin granulation pattern (sparsely or densely). Patients were divided into responders and non-responders based on their biochemical response to fgSRL and/or the newer agent, Pasireotide, or the GH-blocker, Pegvisomant. Patients resistant to fgSRL (n = 12) exhibited lower SSTR2 and E-Cadherin expressions. Sparsely granulated tumors were more frequent in the non-responder group. SSTR2 (p = 0.024, r = 0.49) and E-Cadherin (p = 0.009, r = 0.64) positively correlated with the Insulin-like Growth Factor 1 (IGF-1) decrease after fgSRL, while SSTR5 (p = 0.107, r = -0.37) showed a trend towards negative correlation. SSTR5 positivity seemed to be associated with Pasireotide response, albeit the number of treated patients was too low (n = 4). No IHC markers correlated with Pegvisomant response. Our findings suggest that densely granulated tumors, with positive SSTR2 and E-Cadherin seem to be associated with favorable fgSRL responses. The strongest predictive value of the studied markers was found for E-Cadherin, which seems to surpass even SSTR2.

Predictors of Response to Treatment with First-Generation Somatostatin Receptor Ligands in Patients with Acromegaly

BACKGROUND AND AIMS

Predictors of first-generation somatostatin receptor ligands (fgSRLs) response in acromegaly have been studied for over 30 years, but they are still not recommended in clinical guidelines. Is there not enough evidence to support their use? This systematic review aims to describe the current knowledge of the main predictors of fgSRLs response and discuss their current usefulness, as well as future research directions.

METHODS

A systematic search was performed in the Scopus and PubMed databases for functional, imaging, and molecular predictive factors.

RESULTS

A total of 282 articles were detected, of which 64 were included. Most of them are retrospective studies performed between 1990 and 2023 focused on the predictive response to fgSRLs in acromegaly. The usefulness of the predictive factors is confirmed, with good response identified by the most replicated factors, specifically low GH nadir in the acute octreotide test, T2 MRI hypointensity, high Somatostatin receptor 2 (SSTR2) and E-cadherin expression, and a densely granulated pattern. Even if these biomarkers are interrelated, the association is quite heterogeneous. With classical statistical methods, it is complex to define reliable and generalizable cut-off values worth recommending in clinical guidelines. Machine-learning models involving omics are a promising approach to achieve the highest accuracy values to date.

CONCLUSIONS

This survey confirms a sufficiently robust level of evidence to apply knowledge of predictive factors for greater efficiency in the treatment decision process. The irruption of artificial intelligence in this field is providing definitive answers to such long-standing questions that may change clinical guidelines and make personalized medicine a reality.

Self-reported symptoms in patients with acromegaly: a 6-month follow-up in a single neurosurgical center

Acromegaly is characterized by hypersecretion of growth hormone (GH) and insulin-like growth factor 1 (IGF-1), accompanied by a compromise in the perception of wellness. The Patient-Assessed Acromegaly Symptom Questionnaire (PASQ) is relevant to assessing signs and symptoms but is mainly used to evaluate the efficacy of a pharmacological intervention. To explore the perioperative variation in symptom severity, the divergence between subgroups stratified according to clinical outcomes or treatment modalities, and the interaction between symptom scores and clinical indices, we prospectively recruited 106 patients with acromegaly from 2016 to 2018. Oral glucose tolerance and GH tests were performed, and PASQ was administered before treatment and 6 months postoperatively. Patients were divided into active (n = 49) and remission (n = 57) groups according to postoperative GH and IGF-1 levels. PASQ scores and GH and IGF-1 levels decreased significantly postoperatively in both groups. A significantly higher preoperative headache score and greater extent of decrease in arthralgia were seen in the active and remission groups, respectively. No significant variation in PASQ scores was found between patients receiving surgery alone and those receiving preoperative somatostatin analogs. Preoperative fasting GH (GH0) levels were positively correlated with preoperative excessive perspiration. Further regression analyses validated the variation in GH0 as a noteworthy determinant of the extent of change in soft-tissue swelling, excessive perspiration, fatigue, and total PASQ scores. Patient-reported symptoms were substantially alleviated after surgery, independent of endocrine remission or use of preoperative somatostatin. A GH level decrease was a notable coefficient for PASQ scores.

Age, GH/IGF-1 levels, tumor volume, T2 hypointensity, and tumor subtype rather than proliferation and invasion are all reliable predictors of biochemical response to somatostatin analogue therapy in patients with acromegaly: A clinicopathological study

PURPOSE

To determine whether biochemical responses to long-acting forms of first-generation somatostatin analogue (SSA) therapy in patients with acromegaly could be predicted from baseline and postoperative hormone concentrations, and tumor radiological and histopathological characteristics.

METHODS

A total of 68 patients with acromegaly for whom postoperative SSA therapy was started were categorized according to their responses to treatment (SSA-responders vs. non-responders). The patients were compared based on their demographic characteristics, hormone levels, magnetic resonance imaging (MRI), and histopathological findings. Receiver-operating-characteristic (ROC) curves were constructed using the predictive factors that were significant in the univariate analysis to determinate the optimal cut-off values.

RESULTS

The SSA-responders were significantly older (p = 0.041). Lower GH at diagnosis (p = 0.036), the postoperative 1st-week GH level (p = 0.027), baseline GH, insulin-like growth factor-1 (IGF-1) and IGF-1% upper limit of normal (ULN) (p = 0.001, p = 0.006, p = 0.023, respectively) were associated with biochemical response. T2-hypointensity and lower tumor volume were more common in the SSA-responders (p = 0.018, p = 0.03, respectively). Compared to sparsely granulated somatotroph tumors, densely granulated somatotroph tumors and other PitNETs causing GH excess including mammosomatotroph and mixed somatotroph and lactotroph tumors were more likely to respond to SSA therapy (p = 0.026, p = 0.03, respectively). The cut-off values generated by ROC curve analysis were GH at diagnosis of ≤8.8 ng/mL, GH at baseline of ≤2.69 ng/mL, IGF-1 at baseline ≤461.5 ng/mL, IGF-1% ULN at baseline ≤180.4%, and tumor volume of ≤1.11 cm³ (all p < 0.05). There were no differences between the groups in terms of tumor invasiveness, proliferative activity (mitotic count per 2 mm² and Ki-67 labeling index) and quantitative analyses of T2-weighted MRI.

CONCLUSION

This study underscores that advanced age, low baseline GH and IGF-1 at diagnosis, low tumor volume, densely granulated tumor subtype, and T2 hypointensity may help predict biochemical response to SSA therapy in cases of acromegaly. These variables should be assessed with utmost attention for all patients prior to SSA treatment. In cases of possible resistance to SSA therapy, therapeutic activity should be monitored more closely and other therapies should be administered immediately in the event of poor response.

Combination of transsphenoidal endoscopic surgery and presurgical somatostatin analogs in thyrotropin (TSH)-secreting pituitary adenomas: Treatment outcome and long-term remission at a single pituitary center

BACKGROUND

Thyrotropin (TSH)-secreting pituitary adenomas (TSHomas) account for an extremely rare group of pituitary adenomas. Few studies examined the sensitivity and efficacy of presurgical somatostatin analogs (SSAs) and described the long-term remission under such treatment modality. The aim of the present study was to assess the efficacy of presurgical SSA treatment and long-term remission after surgery.

METHODS

A retrospective cohort of 65 TSHoma patients who received endoscopic transsphenoidal pituitary surgery between 2011 and 2020 in a single pituitary center in China was established. Data were analyzed for sex differences and different types of SSA and ultimately to explore the hormonal cutoff for remission prediction.

RESULTS

TSHomas had a predominant female preference in this cohort (43 women vs. 22 men). Baseline FT3 was higher in men [7.543 ± 2.407 vs. 5.58 (4.99, 6.58), p = 0.019], which was consistent with its longer diagnosis time and larger tumor volume. The median medication time for hormonal control was 2. 5 days for short-acting SSA and 4. 0 weeks for long-term SSA. Patients with long-acting SSA had a shrinking maximum tumor diameter at a median of 1.0 (-1.6, 4.925) mm. Only 10 patients (15.38%) were not in complete remission among whom 8 patients were not en-bloc resected and 2 patients had tumor recurrence after 81.6 and 10. 7 months of complete removal. Postsurgical thyroid hormones (within 1 week) of TSH <0.094 μIU/ml were identified as the cutoff for remission using the ROC curve.

CONCLUSIONS

The combination of endoscopic transsphenoidal surgery and presurgical SSA TSHomas provided a higher long-term remission for TSHomas.

Treatment of acromegaly by rosiglitazone via upregulating 15-PGDH in both pituitary adenoma and liver

Rosiglitazone, a synthetic peroxisome proliferator-activated receptor γ (PPARγ) ligand, has been reported to reduce growth hormone (GH) and insulin-like growth factor-1 (IGF-1) in 10 patients with acromegaly. However, the mechanisms remain unknown. Here, we reveal that PPARγ directly enhances 15-hydroxyprostaglandin dehydrogenase (15-PGDH) expression, whose expression is decreased and negatively correlates with tumor size in acromegaly. Rosiglitazone decreases GH production and promotes apoptosis and autophagy in GH3 and primary somatotroph adenoma cells and suppresses hepatic GH receptor (GHR) expression and IGF-1 secretion in HepG2 cells. Activating the PGE2/cAMP/PKA pathway directly increases GHR expression. Rosiglitazone suppresses tumor growth and decreases GH and IGF-1 levels in mice inoculated subcutaneously with GH3 cells. The above effects are all dependent on 15-PGDH expression. Rosiglitazone as monotherapy effectively decreases GH and IGF-1 levels in all nineteen patients with active acromegaly. Evidence suggests that rosiglitazone may be an alternative pharmacological approach for acromegaly by targeting both pituitary adenomas and liver.