What is the initial treatment and surgical approach for pheochromocytoma?

Initial Treatment and Surgical Approach for Pheochromocytoma

Preoperative alpha-adrenergic blockade for at least 10-14 days before surgery is mandatory for all patients with pheochromocytoma, followed by complete surgical resection (R0) as the mainstay of potentially curative treatment. 1, 2

Preoperative Medical Management

Alpha-Blockade (First-Line)

• Start alpha-blockade when:

  • Normetanephrine levels are ≥2-fold the upper reference limit
  • Patient is symptomatic 2

• Alpha-blocker options:

  • Non-selective α-blocker: Phenoxybenzamine (40-80 mg/day) 3

    • Standard dose: 10 mg twice daily with adjustments every 2-4 days 1
    • Advantages: Better control of systolic blood pressure 4
    • Disadvantages: More postoperative hypotension, orthostatic hypotension, edema, nasal congestion 4

  • Selective α1-blockers: Doxazosin, prazosin, or terazosin 2

    • Advantages: Fewer side effects 4
    • Disadvantages: May require additional antihypertensive medications 4

Blood Pressure Targets

• Supine position: <130/80 mmHg
• Upright position: Systolic BP preferably >90 mmHg 1

Additional Medications

• Beta-blockers: Only add after adequate alpha-blockade if tachycardia persists 2

  • Never start beta-blockers before alpha-blockade (risk of hypertensive crisis) 1

• If target BP not achieved:

  • Add calcium channel blockers (nifedipine slow release)
  • Consider metyrosine 1

Surgical Approach

Surgical Planning

• Surgery should be performed in specialized centers with >10 adrenalectomies for adrenal tumors per year 1

• Surgical approach based on tumor size:

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

Perioperative Management

• Intraoperative hypertension management:

  • Magnesium sulfate
  • Intravenous α-adrenoreceptor antagonist (phentolamine)
  • Calcium antagonists
  • Nitroprusside or nitroglycerin 1

• Tachycardia management:

  • Intravenous β-adrenergic receptor blocker (esmolol) 1

• Prevention of postoperative hypotension:

  • Saline infusion the day before surgery 1
  • Aggressive treatment if hypotension occurs 1

• Postoperative monitoring:

  • Glucose levels (risk of hypoglycemia after catecholamine reduction) 1

Post-Surgical Follow-up

• Biochemical testing:

  • Plasma/urine metanephrines 8 weeks post-surgery 2

• Imaging:

  • 3-6 months post-surgery 2

• Long-term surveillance:

  • Continue for at least 10 years
  • Lifelong follow-up for genetic cases 2

Important Considerations and Pitfalls

1. Never start beta-blockers before adequate alpha-blockade - this can precipitate a hypertensive crisis due to unopposed alpha-adrenergic stimulation 1, 2

2. Inadequate preoperative alpha-blockade can lead to severe intraoperative hypertension, cardiac arrest, and surgical failure 5

3. Higher doses of alpha-blockers may be more effective in preventing intraoperative hemodynamic instability during tumor manipulation 6

4. Postoperative hypoglycemia is a risk after tumor removal due to sudden decrease in catecholamine levels 1

5. Multidisciplinary approach involving endocrinologists, surgeons, and anesthesiologists is essential for optimal outcomes 2

Despite the lack of randomized controlled trials, current evidence suggests that both phenoxybenzamine and selective alpha-blockers (doxazosin, prazosin) are effective for preoperative preparation, with slightly different side effect profiles and hemodynamic effects 7, 4.