Gigantism and Acromegaly Guidelines

Updated: Sep 05, 2017
  • Author: Alicia Diaz-Thomas, MD, MPH; Chief Editor: Sasigarn A Bowden, MD  more...
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Guidelines

Guidelines Summary

Guidelines for the diagnosis and treatment of acromegaly have been released by the following organizations:

  • American Association of Clinical Endocrinologists (AACE) (2011) [14]
  • The Endocrine Society (ENDO) (2014) [27, 28]  

Endocrine Society (ENDO) Guidelines

Diagnosis

Recommendations for diagnostic testing include [27] :

  • Measurement of IGF-1 levels in patients with typical clinical manifestations of acromegaly
  • Measurement of IGF-1 in patients without the typical clinical manifestations of acromegaly, but who have several of these associated conditions: sleep apnea syndrome, type 2 diabetes mellitus, debilitating arthritis, carpal tunnel syndrome, hyperhidrosis, and hypertension. 
  • Measurement of serum IGF-1 to rule out acromegaly in a patient with a pituitary mass
  • Use of random GH levels to diagnose acromegaly is recommended against
  • In patients with elevated or equivocal serum IGF-1 levels, diagnosis should be confirmed by a finding of lack of suppression of GH to <1 μg/L following documented hyperglycemia during an oral glucose load. 
  • Following biochemical diagnosis of acromegaly, an imaging study should be performed to visualize tumor size and appearance, as well as parasellar extent  
  • Magnetic resonance imaging (MRI) is the imaging modality of choice, followed by computed tomography (CT) scan when MRI is contraindicated or unavailable

Management of comorbidities and mortality risk

The following additional testing is recommended after diagnosis [27]

  • Evaluation for associated comorbidities: hypertension, diabetes mellitus, cardiovascular disease, osteoarthritis, and sleep apnea
  • All comorbidities should be monitored and rigorously managed
  • Screening colonoscopy for colon cancer 
  • Thyroid ultrasound if there is palpable thyroid nodularity
  • Assessment for hypopituitarism and hormone deficits

Treatment goals

Recommended therapeutic goals are as follows [27] :

  • Age-normalized serum IGF-1 value
  • Random GH < 1.0 μg/L 

Surgical Intervention

Key recommendations for surgical treatment include [27] :

  • Transsphenoidal surgery as the primary therapy in most patients
  • Repeat surgery should be considered if residual intrasellar disease is present following initial surgery
  • In select patients, preoperative medical therapy with somatostatin receptor ligands (SRLs) to reduce surgical risk from severe comorbidities
  • In a patient with parasellar disease making total surgical resection unlikely, surgical debulking to improve subsequent response to medical therapy
  • Measurement of IGF-1 level and a random GH at 12 weeks or later post-surgery; measure a nadir GH level after a glucose load in a patient with a GH greater than 1 μg/L
  • Perform an imaging study at least 12 weeks post-surgery to visualize residual tumor and adjacent structures;  MRI is the preferred study followed by CT scan when MRI is contraindicated or unavailable

Medical therapy

Key adjuvant medical therapy recommendations include [27] :

  • Patient with significant disease (ie, with moderate-to-severe signs and symptoms of GH excess and without local mass effects) should receive either a somatostatin-receptor ligand (SRL) or pegvisomant as the initial adjuvant medical therapy
  • Patient with only modest elevations of serum IGF-1 and mild signs and symptoms of GH excess should receive a trial of a dopamine agonist, usually cabergoline, as the initial adjuvant medical therapy '
  • Patients who cannot be cured by surgery, have extensive cavernous sinus invasion, do not have chiasmal compression, or are poor surgical candidates should receive SRL as primary therapy 
  • For patients with inadequate response to an SRL, pegvisomant or cabergoline should be added

Radiotherapy (RT)/Stereotactic Radiotherapy (SRT)

Recommendation for the use of radiation therapy include [27] :

  • Radiation therapy in the setting of residual tumor mass following surgery, and if medical therapy is unavailable, unsuccessful, or not tolerated
  • Stereotactic radiotherapy (SRT) should be performed over conventional radiation therapy unless the technique is not available, there is significant residual tumor burden, or the tumor is too close to the optic chiasm resulting in an exposure of more than 8 Gy

Management during pregnancy

The guidelines include the following recommendations for treatment during pregnancy [27] :

  • Discontinue long-acting SRL formulations and pegvisomant approximately 2 months before attempts to conceive;  use of short-acting octreotide as necessary until conception
  • During pregnancy, medical therapy only for tumor and headache control.
  • Monitoring GH and/or IGF-1 levels during pregnancy is not recommended