What is the primary treatment approach for pheochromocytoma vs paraganglioma?

Primary Treatment Approach for Pheochromocytoma vs Paraganglioma

The primary treatment approach for both pheochromocytoma and paraganglioma is complete surgical resection (R0) following appropriate preoperative alpha-adrenergic blockade, with the specific surgical approach determined by tumor location and size. 1, 2

Preoperative Management

Alpha-Adrenergic Blockade

• Alpha-adrenergic blockade should be initiated at least 10-14 days before surgery 2
• Options include:
  • Non-selective α-blocker: Phenoxybenzamine (40-80 mg/day) 3
  • Selective α1-blockers: Doxazosin, prazosin, or terazosin 4
• Target blood pressure: <130/80 mmHg supine and >90 mmHg systolic when standing 2
• Titration to orthostatic hypotension may provide better intraoperative hemodynamic stability 5

Beta-Blockers

• Should ONLY be added after adequate alpha-blockade if tachycardia persists 2
• Never use beta-blockers alone (risk of hypertensive crisis due to unopposed alpha stimulation)

Volume Expansion

• Liberal salt and fluid intake during alpha-blockade preparation 6
• IV fluid administration may be necessary before surgery

Surgical Approach

Pheochromocytoma (Adrenal)

• Laparoscopic adrenalectomy for tumors <8 cm without invasion 2
• Open surgery for larger tumors (>5-6 cm) or with evidence of invasion 2

Paraganglioma (Extra-adrenal)

• Surgical approach varies based on location:
  • Head and neck paragangliomas (HNPGLs):
    • Surgical resection with particular attention to avoiding neurovascular structure damage 1
    • Stereotactic radiosurgery (SRS) is recommended as primary treatment for SDHD-related HNPGLs, especially in elderly patients or those with cranial neuropathies 1
  • Thoracic, para-aortic, and pelvic paragangliomas:
    • Open surgical approach is preferred to allow manual assessment of vascular wall invasion 1
    • En bloc removal provides best long-term outcomes 1

Treatment Approach Based on Tumor Type and Location

Head and Neck Paragangliomas

1. Primary treatment options:

   • Stereotactic radiosurgery (SRS) - preferred for SDHD-related HNPGLs 1
   • Surgical resection - for small tumors in young, healthy patients 1

2. Factors favoring SRS over surgery:

   • Elderly patients
   • Significant comorbidities
   • Cranial neuropathies
   • Contralateral lower cranial neuropathies
   • Multifocal disease involving bilateral vagal nerves 1

Adrenal Pheochromocytoma

1. Primary treatment: Complete surgical resection 1, 2
2. Approach:
   • Laparoscopic for small (<8 cm) non-invasive tumors
   • Open surgery for larger or invasive tumors 2

Extra-adrenal Paragangliomas (Non-Head/Neck)

1. Primary treatment: Complete surgical resection 1
2. Approach: Open surgery typically required to assess vascular invasion 1

Management of Metastatic Disease

First-line options:

• Radionuclide therapy based on imaging phenotype:
  • PRRT (peptide receptor radionuclide therapy) - preferred for SDHD-related metastatic disease 1
  • 131I-MIBG - if good uptake on diagnostic scan 1

Second-line options:

• Chemotherapy with cyclophosphamide, vincristine, and dacarbazine (CVD) for:
  • Rapidly progressing disease
  • High visceral tumor burden
  • Following progression after radionuclide therapy 1

Alternative options:

• Tyrosine kinase inhibitors (sunitinib) or temozolomide for:
  • Progressing tumors not eligible for radionuclide therapy
  • Following progression after radionuclide therapy or CVD 1

Post-Treatment Follow-up

• Plasma/urine metanephrines 8 weeks post-surgery 2
• Imaging at 3-6 months post-surgery 2
• Regular follow-up for at least 10 years, lifelong for genetic cases 2

Important Considerations

• Surgery should be performed in specialized centers with >10 adrenalectomies per year 2
• Perioperative hemodynamic management requires communication among multiple specialties 1
• Palliative debulking rarely provides long-term biochemical control 1