What is the treatment for a growth hormone tumor?

Treatment of Growth Hormone-Secreting Pituitary Tumors

Surgery by an experienced pituitary neurosurgeon is the first-line treatment for growth hormone-secreting adenomas, even when complete surgical cure appears unlikely, as tumor debulking reduces GH burden and facilitates subsequent medical therapy. 1

Primary Treatment Approach

Surgical Management

• Transsphenoidal surgery should be offered as initial treatment to the majority of patients with GH-secreting adenomas, with the goal of normalizing growth velocity, preventing excessive height, suppressing IGF-1 to normal range, and preserving or restoring vision 1

• Surgical success rates in experienced pituitary neurosurgical centers achieve approximately 50% remission in children and adolescents with GH excess 1

• Even when complete remission is unlikely, tumor debulking significantly reduces circulating GH burden and improves response to subsequent medical therapy and/or radiotherapy 1

• Re-operation should be considered in patients with notable residual tumor who show inadequate response to somatostatin analogue therapy or experience considerable tumor regrowth 1

Pre-operative Medical Therapy

Consider pre-operative treatment with somatostatin analogues and/or GH receptor antagonists in specific circumstances: 1

• To rapidly control signs and symptoms and support perioperative airway management 1
• To reduce height velocity, particularly if pituitary surgery must be delayed 1
• Starting dose for pegvisomant is 10 mg daily, titrated until serum IGF-1 levels normalize 1

Post-Operative Medical Management

For Residual Disease After Surgery

Offer monotherapy or combination medical therapy for patients with post-operative residual disease 1

Somatostatin Analogues (First-Line Medical Therapy)

• Lanreotide is FDA-approved for long-term treatment of acromegalic patients with inadequate response to surgery and/or radiotherapy 2
• After 48 weeks of lanreotide treatment, 43% of acromegalic patients achieved normal age-adjusted IGF-1 concentrations, and 38% achieved both normal IGF-1 and GH ≤2.5 ng/mL 2
• Lanreotide effectively controls IGF-1 and GH levels, shrinks tumors (mean tumor volume reduction of 44%), and reduces acromegalic symptoms 3
• Densely granulated tumors respond better to somatostatin analogues (68.8% remission rate) compared to sparsely granulated tumors (28.6% remission rate) 4

Dopamine Agonists

• Cabergoline can be used alone in patients with mild GH excess, co-administered with somatostatin analogues when GH hypersecretion is inadequately controlled, or substituted when somatostatin analogues are poorly tolerated 1
• The GH-lowering effect of dopamine agonists is modest, and doses required in acromegaly are often high 1

GH Receptor Antagonist

• Pegvisomant normalizes serum IGF-1 levels in adequate doses and can suppress growth velocity, a clinical priority in patients with gigantism 1
• Start pegvisomant at 10 mg daily and titrate until serum IGF-1 levels normalize 1
• Sparsely granulated tumors not controlled with somatostatin analogues consistently respond to switching to, or adding, a GH receptor antagonist 4

Monitoring Treatment Efficacy

Assess efficacy of medical treatment by both auxological measurements (growth velocity, height) and serum levels of GH and IGF-1 1

• IGF-1 monitoring is necessary with repeat biochemical testing (oral glucose tolerance tests) and radiological assessment (MRI) if recurrence is suspected 1

Radiotherapy

Indications for Radiotherapy

Offer pituitary radiotherapy to patients with GH-secreting adenoma and uncontrolled tumor growth with incomplete surgical and medical response, except for patients with skull base fibrous dysplasia 1

Important Caveats About Radiotherapy

• Radiotherapy may take up to 10 years to be fully effective in suppressing GH, so medical therapy is required at least as a temporary measure 1
• After radiotherapy, offer intermittent dose reduction or withdrawal of medical therapy (1-3 months to allow drug clearance) to assess radiation efficacy on GH hypersecretion 1
• Hypopituitarism develops in approximately 20% at 5 years and 80% at 10-15 years post-radiotherapy, requiring lifelong monitoring 1
• Avoid radiotherapy in patients with McCune-Albright syndrome and skull base fibrous dysplasia due to increased risk of sarcomatous transformation 1

Special Populations and Genetic Syndromes

Syndromic Causes

Offer clinical evaluation for associated syndromic causes of somatotrophinomas, including McCune-Albright syndrome, Carney complex, MEN1, and X-linked acrogigantism 1

• In patients with genetic causes where the whole gland may be affected, selective adenomectomy, radical surgery, or hypophysectomy have all been described as surgical approaches 1
• GH-releasing hormone-secreting pancreatic tumors should be considered as a cause of GH excess in patients with MEN1 syndrome 1

Ectopic GHRH Syndrome

• Plasma GHRH levels are usually elevated in patients with peripheral GHRH-secreting tumors (carcinoid, pancreatic cell tumors) and are normal or low in patients with pituitary acromegaly 5
• Surgical resection of the tumor secreting ectopic GHRH should be the primary approach, with long-acting somatostatin analogues as preferred second-line therapy 5

Treatment Algorithm Summary

1. First-line: Transsphenoidal surgery by experienced pituitary neurosurgeon 1
2. If residual disease: Medical therapy with somatostatin analogues (first choice), dopamine agonists, or GH receptor antagonist (pegvisomant) as monotherapy or combination 1
3. If medical therapy fails and tumor growth continues: Radiotherapy (except in McCune-Albright syndrome with fibrous dysplasia) 1
4. Monitor continuously with IGF-1, GH levels, growth velocity measurements, and MRI surveillance 1