The efficacy of octreotide LAR as firstline therapy for patients with newly diagnosed acromegaly is independent of tumor extension: predictive factors of tumor and biochemical response

Prolonged preoperative treatment of acromegaly with Somatostatin analogs may improve surgical outcome in patients with invasive pituitary macroadenoma (Knosp grades 1-3): a retrospective cohort study conducted at a single center

BACKGROUND

This study aimed to investigate preoperative somatostatin analogs (SSAs) treatment on the surgical outcome in patients with acromegaly.

METHODS

An analysis of 358 patients with acromegaly was conducted. The preoperative medical therapy group (81 patients) received SSA treatment for at least 3 months prior to surgery, while the primary surgery group (277 patients) underwent transsphenoidal surgery directly. Follow-up duration was ≥3 months. Tumor invasion was evaluated by magnetic resonance imaging (MRI) and classified according to the Knosp grading system.

RESULTS

Most patients were diagnosed with macroadenoma. Among all patients (Knosp grades 0-4), preoperative SSA therapy did not significantly improve the curative effect of surgery, according to the levels of growth hormone (GH) and/or insulin-like growth factor 1 (IGF-1) markers. In patients with macroadenoma (Knosp grades 1-3), the remission rates were significantly higher in the SSA group compared to the surgery group when considering GH (56.4% vs. 37.3%, P = 0.048) and IGF-1 (43.2% vs. 17.6%, P = 0.004). In the preoperative medical therapy group, long-term use of SSAs (>6 months) led to higher remission rates (GH, 72.2% vs. 51.0%; and IGF-1, 61.1% vs. 29.8%; P = 0.12 and 0.02, respectively].

CONCLUSIONS

The long-term preoperative SSAs treatment may improve the surgical curative rate in acromegalic patients with invasive macroadenomas (Knosp grades 1-3).

Surgical interventions and medical treatments in treatment-naïve patients with acromegaly: systematic review and meta-analysis

CONTEXT

Acromegaly is usually treated with surgery as a first-line treatment, although medical therapy has also been used as an alternative primary treatment.

OBJECTIVE

We conducted a systematic review and meta-analysis to synthesize the existing evidence comparing these two approaches in treatment-naïve patients with acromegaly.

DATA SOURCES

This study performed a comprehensive search in multiple databases, including Medline, EMBASE, and Scopus from early inception through April 2014.

STUDY SELECTION

The study used original controlled and uncontrolled studies that enrolled patients with acromegaly to receive either surgical treatment or medical treatment as their first-line treatment.

DATA EXTRACTION

Reviewers extracted data independently and in duplicates. Because of the noncomparative nature of the available studies, we modified the Newcastle-Ottawa Scale to assess the quality of included studies. Outcomes evaluated were biochemical remission and change in IGF-1 or GH levels. We pooled outcomes using the random-effects model.

DATA SYNTHESIS

The final search yielded 35 studies enrolling 2629 patients. Studies were noncomparative series with a follow-up range of 6-360 months. Compared with medical therapy, surgery was associated with a higher remission rate (67% vs 45%; P = .02). Surgery had higher remission rates at longer follow-up periods (≥ 24 mo) (66% vs 44%; P = .04) but not the shorter follow-up periods (≤ 6 mo) (37% vs 26%; P = .22) [Corrected].Surgery had higher remission rates in the follow-up levels of GH (65% vs 46%; P = .05). In one study, the IGF-1 level was reduced more with surgery compared with medical treatment (-731 μg/L vs -251 μg/L; P = .04). Studies in which surgery was performed by a single operator reported a higher remission rate than those with multiple operators (71% vs 47%; P = .002).

CONCLUSIONS

Surgery may be associated with higher remission rate; however, the confidence in such evidence is very low due to the noncomparative nature of the studies, high heterogeneity, and imprecision.

Preoperative octreotide treatment of acromegaly: long-term results of a randomised controlled trial

OBJECTIVE

Randomised studies have demonstrated a beneficial effect of pre-surgical treatment with somatostatin analogues (SSA) in acromegaly when evaluated early postoperatively. The objective of this study was to evaluate the long-term surgical cure rates.

METHODS

Newly diagnosed patients were randomised to direct surgery (n=30) or 6-month pretreatment with octreotide LAR (n=32). The patients were evaluated 1 and 5 years postoperatively. Cure was defined as normal IGF1 levels and by normal IGF1 level combined with nadir GH <2 mU/l in an oral glucose tolerance test, all without additional post-operative treatment. A meta-analysis using the other published randomised study with long-term analyses on preoperative SSA treatment was performed.

RESULTS

The proportion of patients receiving post-operative acromegaly treatment was equal in the two groups. When using the combined criteria for cure, 10/26 (38%) macroadenomas were cured in the pretreatment group compared with 6/25 (24%) in the direct surgery group 1 year postoperatively (P=0.27), and 9/22 (41%) vs 6/22 (27%) macroadenomas, respectively, 5 years postoperatively (P=0.34). In the meta-analysis, 16/45 (36%) macroadenomas were cured using combined criteria in the pretreatment group vs 8/45 (18%) in the direct surgery group after 6-12 months (P=0.06), and 15/41 (37%) vs 8/42 (19%), respectively, in the long-term (P=0.08).

CONCLUSION

This study does not prove a beneficial effect of SSA pre-surgical treatment, but in the meta-analysis a trend towards significance can be claimed. A potential favourable, clinically relevant response cannot be excluded.

Management options for persistent postoperative acromegaly

This article presents management options for the patient with acromegaly after noncurative surgery. The current evidence for repeat surgery, adjuvant medical therapy with somatostatin analogues, dopamine agonists, the growth hormone receptor antagonist pegvisomant, combination medical therapy, and radiotherapy in the context of persistent postoperative disease are summarized. The relative advantages and disadvantages of each of these treatment modalities are explored, and a general treatment algorithm that integrates these modalities is proposed.

Octreotide long-acting repeatable for acromegaly

Acromegaly remains a therapeutic challenge for the endocrinologist. Among the available therapeutic options, octreotide long-acting repeatable (Sandostatin(®) LAR(®), Novartis) plays a chief role, both as a primary therapy and as an adjuvant treatment after unsuccessful surgery. A plethora of papers and a meta-analysis have demonstrated its efficacy in: control of clinical picture; achievement of safe growth hormone and normal age-matched IGF-I levels (both factors associated with restoration of normal life expectancy) in 60-70% of patients; control of tumor volume (with real shrinkage in over half of cases); and halt or reversal of most acromegaly-associated comorbidities. Treatment is well tolerated in most patients and can be safely prolonged for many years if required.

Meta-analysis on the effects of octreotide on tumor mass in acromegaly

BACKGROUND

The long-acting somatostatin analogue octreotide is used either as an adjuvant or primary therapy to lower growth hormone (GH) levels in patients with acromegaly and may also induce pituitary tumor shrinkage.

OBJECTIVE

We performed a meta-analysis to accurately assess the effect of octreotide on pituitary tumor shrinkage.

DATA SOURCES

A computerized Medline and Embase search was undertaken to identify potentially eligible studies.

STUDY ELIGIBILITY CRITERIA

Eligibility criteria included treatment with octreotide, availability of numerical metrics on tumor shrinkage and clear definition of a clinically relevant reduction in tumor size. Primary endpoints included the proportion of patients with tumor shrinkage and mean percentage reduction in tumor volume.

DATA EXTRACTION AND ANALYSIS

The electronic search identified 2202 articles. Of these, 41 studies fulfilling the eligibility criteria were selected for data extraction and analysis. In total, 1685 patients were included, ranging from 6 to 189 patients per trial. For the analysis of the effect of octreotide on pituitary tumor shrinkage a random effect model was used to account for differences in both effect size and sampling error.

RESULTS

Octreotide was shown to induce tumor shrinkage in 53.0% [95% CI: 45.0%-61.0%] of treated patients. In patients treated with the LAR formulation of octreotide, this increased to 66.0%, [95% CI: 57.0%-74.0%). In the nine studies in which tumor shrinkage was quantified, the overall weighted mean percentage reduction in tumor size was 37.4% [95% CI: 22.4%-52.4%], rising to 50.6% [95% CI: 42.7%-58.4%] with octreotide LAR.

LIMITATIONS

Most trials examined were open-label and had no control group.

CONCLUSIONS

Octreotide LAR induces clinically relevant tumor shrinkage in more than half of patients with acromegaly.

The expression of E-cadherin in somatotroph pituitary adenomas is related to tumor size, invasiveness, and somatostatin analog response

CONTEXT

Appropriate cell-to-cell adhesion is fundamental for the epithelial phenotype of pituitary cells. Loss of the adhesion protein E-cadherin has been associated with invasiveness, metastasis, and poor prognosis in cancers of epithelial origin. In somatotroph adenomas, a variable and reduced expression of E-cadherin has been demonstrated. In addition, nuclear translocation of E-cadherin was found to correlate with pituitary tumor invasion.

OBJECTIVE

The objective was to examine the protein expression of E-cadherin in somatotroph pituitary adenomas in relation to adenoma size, invasiveness, and somatostatin analog (SMS) efficacy.

PATIENTS AND METHODS

Eighty-three patients were included, and 29 were treated preoperatively with SMS. Adenoma E-cadherin protein expression was analyzed by Western blot (61 patients) and immunohistochemistry (IHC) (80 patients) with antibodies directed against both extracellular and intracellular domains (IHC). The acute (direct surgery group) and long-term (preoperatively treated group) SMS responses were evaluated. Baseline tumor volume and invasiveness were measured on magnetic resonance imaging scans.

RESULTS

Membranous E-cadherin was lost in several adenomas. Nine of these were nuclear E-cadherin positive. The E-cadherin protein expression correlated negatively to tumor size and positively to acute SMS response. Low E-cadherin levels (preoperatively treated group only) and loss of membranous E-cadherin correlated to tumor invasiveness. The E-cadherin level correlated positively to tumor reduction after SMS treatment, and adenomas with nuclear E-cadherin staining had lower IGF-I reduction and tumor shrinkage. Preoperatively treated adenomas had reduced E-cadherin protein levels, but the IHC expression was unaltered.

CONCLUSION

Reduced E-cadherin expression may correlate to a dedifferentiated phenotype in the somatotroph pituitary adenomas.