Partial surgical removal of growth hormone-secreting pituitary tumors enhances the response to somatostatin analogs in acromegaly

Annamaria Colao, Roberto Attanasio, Rosario Pivonello, Paolo Cappabianca, Luigi M. Cavallo, Giovanni Lasio, Alessandro Lodrini, Gaȩtano Lombardi, Renato Cozzi

Research output: Contribution to journalArticlepeer-review


Context: Surgery is a cornerstone in the treatment of acromegaly, but its efficacy in large, invasive tumors is scant. Objective: The objective of this study was to investigate whether partial surgical removal of GH-secreting pituitary tumors enhances the response rate to somatostatin analogs (SSA; sc octreotide, slow-release octreotide, and lanreotide). Design: This was a multicenter, open, retrospective study. Setting: The study was performed at university hospitals. Subjects and Methods: Eighty-six-patients (42 women and 44 men; age, 42 ± 14 yr) with acromegaly were studied. Interventions: Patients underwent two courses of octreotide, lanreotide, or slow-release octreotide treatments before and after surgery of at least 6 months. Main Outcome Measure: The main outcome measure was normal IGF-I levels for age. Results: Presurgical SSA treatment significantly decreased GH and IGF-I levels in all patients. GH levels were less than 2.5 μg/liter in 12 patients (14%); IGF-I levels normalized in nine (10%). After surgery, GH and IGF-I levels further decreased in all patients; tumor removal was greater than 75% in 50 (58%), 50.1-75% in 21 (24%), 25.1-50% in 10 (12%), and less than 25% in five patients (6%). Preoperatively, pituitary function was impaired in 12 patients (14%). Postsurgical SSA treatment lowered GH levels to less than 2.5 μg/liter in 49 (56%) and normalized IGF-I levels in 48 patients (55%). The success rate was significantly increased compared with that before surgery (P <0.0001). GH (r = -0.48; P <0.0001) and IGF-I levels (r = -0.38; P = 0.0003) after postsurgery SSA treatment correlated with the amount of tumor surgically removed. After surgery, pituitary function was impaired in 28 patients (32.6%) and was improved in 12 patients (13.9%). The cumulative prevalence of pituitary deficiency did not change during the study (normal function from 40 to 42%; deficiency from 60 to 58%). Conclusions: Surgical tumor removal (>75%) enhances the response to SSAs without impairing pituitary function. Our data indicate that surgical debulking has a significant place in the treatment algorithm of acromegaly.

Original languageEnglish
Pages (from-to)85-92
Number of pages8
JournalJournal of Clinical Endocrinology and Metabolism
Issue number1
Publication statusPublished - Jan 2006

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology, Diabetes and Metabolism


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