What is the management approach for a patient with pheochromocytoma?

Management of Pheochromocytoma

The management of pheochromocytoma requires complete surgical resection (R0) as the mainstay of treatment, with mandatory preoperative alpha-adrenergic blockade for at least 10-14 days before surgery to prevent potentially life-threatening hypertensive crises during the procedure. 1

Diagnosis and Initial Assessment

• Biochemical testing: Measure plasma or urinary metanephrines and normetanephrines to confirm catecholamine excess
• Imaging: CT/MRI of abdomen, chest CT, and in selected cases functional imaging (FDG-PET)
• Genetic testing: Consider screening for hereditary syndromes as approximately 25% of pheochromocytomas are hereditary

Preoperative Management

Alpha-Adrenergic Blockade (Essential First Step)

1. Start alpha-blockade 10-14 days before surgery 1

   • Options:
     • Phenoxybenzamine: Non-selective, non-competitive α1 and α2 blocker
       • Starting dose: 10 mg twice daily
       • Adjust every 2-4 days until BP control achieved
       • Provides better intraoperative hemodynamic stability but causes more postoperative hypotension 2, 3
     • Doxazosin: Selective, competitive α1 blocker
       • Fewer side effects than phenoxybenzamine
       • May require additional antihypertensive medications 2

2. Blood pressure targets:

   • <130/80 mmHg while seated
   • Systolic BP >90 mmHg when standing 1

3. Additional medications if needed:

   • Calcium channel blockers (nifedipine) for refractory hypertension
   • Metyrosine to inhibit catecholamine synthesis in severe cases 1

Beta-Adrenergic Blockade

• Add only after adequate alpha-blockade to prevent tachycardia
• Never start beta-blockers before alpha-blockers (risk of hypertensive crisis due to unopposed alpha-stimulation) 1, 4
• Preferably use β1-selective blockers 1

Preoperative Volume Expansion

• High-sodium diet
• Administer 1-2 liters of saline 24 hours before surgery
• Use compressive stockings to reduce orthostatic hypotension 1

Surgical Management

• Surgery is the definitive treatment for pheochromocytoma 1

• Approach:

  • Laparoscopic adrenalectomy is safe and effective for small tumors (<8 cm) without invasiveness 1
  • Open surgery for larger or invasive tumors
  • Surgery should be performed in specialized centers with experience in adrenal surgery 1

• Cytoreductive (R2) resection may improve quality of life and survival in malignant pheochromocytoma by reducing tumor burden and controlling hormonal hypersecretion 1

Intraoperative Management

• Monitoring: Continuous arterial blood pressure, central venous pressure, ECG
• Management of hypertensive episodes:
  • Magnesium sulfate
  • Intravenous alpha-blockers (phentolamine)
  • Calcium channel blockers
  • Nitroprusside or nitroglycerin 1
• Management of tachycardia: Intravenous beta-blockers (esmolol) 1

Postoperative Management

• Monitor for hypotension (common after tumor removal)
• Watch for hypoglycemia after reduction of catecholamine levels 1
• Assess for complete tumor removal: Measure plasma/urinary metanephrines 2-8 weeks postoperatively 1

Management of Malignant Pheochromocytoma

For inoperable or metastatic disease:

1. Radiopharmaceuticals: 131I-MIBG therapy for patients with good uptake on diagnostic scans 1
2. Chemotherapy: Cyclophosphamide, vincristine, and dacarbazine (CVD) regimen 1
3. Wait-and-see approach for low tumor burden and asymptomatic malignant disease 1

Follow-up Protocol

• After successful surgery:

  • Biochemical testing 2-8 weeks postoperatively
  • Imaging at 3-6 months 1
  • Regular follow-up every 3-4 months for 2-3 years, then every 6 months 1
  • Continue surveillance for at least 10 years (lifelong for malignant disease) 1

• For inoperable disease:

  • Follow-up every 3-6 months during the first year, then adjust based on disease course 1

Common Pitfalls and Caveats

• Never start beta-blockers before alpha-blockers - can precipitate hypertensive crisis
• Don't underestimate preoperative preparation time - at least 10-14 days of alpha-blockade is needed
• Watch for postoperative hypotension - especially with phenoxybenzamine
• Consider lifelong surveillance - recurrence can occur even after 10 years
• Genetic testing is important - approximately 25% of cases are hereditary

By following this structured approach to management, the morbidity and mortality associated with pheochromocytoma can be significantly reduced, improving patient outcomes and quality of life.