AUTHOR=Marques-Pamies Montserrat , Gil Joan , Valassi Elena , Hernández Marta , Biagetti Betina , Giménez-Palop Olga , Martínez Silvia , Carrato Cristina , Pons Laura , Villar-Taibo Rocío , Araujo-Castro Marta , Blanco Concepción , Simón Inmaculada , Simó-Servat Andreu , Xifra Gemma , Vázquez Federico , Pavón Isabel , García-Centeno Rogelio , Zavala Roxana , Hanzu Felicia Alexandra , Mora Mireia , Aulinas Anna , Vilarrasa Nuria , Librizzi Soledad , Calatayud María , de Miguel Paz , Alvarez-Escola Cristina , Picó Antonio , Sampedro Miguel , Salinas Isabel , Fajardo-Montañana Carmen , Cámara Rosa , Bernabéu Ignacio , Jordà Mireia , Webb Susan M. , Marazuela Mónica , Puig-Domingo Manel TITLE=Revisiting the usefulness of the short acute octreotide test to predict treatment outcomes in acromegaly JOURNAL=Frontiers in Endocrinology VOLUME=Volume 14 - 2023 YEAR=2023 URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2023.1269787 DOI=10.3389/fendo.2023.1269787 ISSN=1664-2392 ABSTRACT=Introduction

We previously described that a short version of the acute octreotide test (sAOT) can predict the response to first-generation somatostatin receptor ligands (SRLs) in patients with acromegaly. We have prospectively reassessed the sAOT in patients from the ACROFAST study using current ultra-sensitive GH assays. We also studied the correlation of sAOT with tumor expression of E-cadherin and somatostatin receptor 2 (SSTR2) .

Methods

A total of 47 patients treated with SRLs for 6 months were evaluated with the sAOT at diagnosis and correlated with SRLs’ response. Those patients whose IGF1 decreased to <3SDS from normal value were considered responders and those whose IGF1 was ≥3SDS, were considered non-responders. The 2 hours GH value (GH2h) after s.c. administration of 100 mcg of octreotide was used to define predictive cutoffs. E-cadherin and SSTR2 immunostaining in somatotropinoma tissue were investigated in 24/47 and 18/47 patients, respectively.

Results

In all, 30 patients were responders and 17 were non-responders. GH2h was 0.68 (0.25-1.98) ng/mL in responders vs 2.35 (1.59-9.37) ng/mL in non-responders (p<0.001). GH2h = 1.4ng/mL showed the highest ability to identify responders (accuracy of 81%, sensitivity of 73.3%, and specificity of 94.1%). GH2h = 4.3ng/mL was the best cutoff for non-response prediction (accuracy of 74%, sensitivity of 35.3%, and specificity of 96.7%). Patients with E-cadherin-positive tumors showed a lower GH2h than those with E-cadherin-negative tumors [0.9 (0.3-2.1) vs 3.3 (1.5-12.1) ng/mL; p<0.01], and patients with positive E-cadherin presented a higher score of SSTR2 (7.5 ± 4.2 vs 3.3 ± 2.1; p=0.01).

Conclusion

The sAOT is a good predictor tool for assessing response to SRLs and correlates with tumor E-cadherin and SSTR2 expression. Thus, it can be useful in clinical practice for therapeutic decision-making in patients with acromegaly.