What is the initial treatment for active pheochromocytoma?

Treatment for Active Pheochromocytoma

The initial treatment for active pheochromocytoma requires immediate alpha-adrenergic blockade for at least 10-14 days before definitive surgical resection, which is the only curative therapy. 1, 2

Immediate Medical Management (Alpha-Blockade)

Alpha-adrenergic blockade must be initiated within 24-48 hours of diagnosis and continued for 10-14 days before any surgical intervention. 2, 3 This preoperative preparation is mandatory to prevent life-threatening hypertensive crises and arrhythmias during surgery. 1

Blood Pressure Targets

• Supine BP: <130/80 mmHg 1, 2, 4
• Standing systolic BP: >90 mmHg 1, 2, 4

Alpha-Blocker Options

Phenoxybenzamine (non-competitive, non-selective alpha-blocker):

• Standard starting dose: 10 mg twice daily, with adjustments every 2-4 days 1
• FDA-indicated specifically for pheochromocytoma 5
• May provide superior intraoperative hemodynamic stability compared to selective blockers 6, 7
• More pronounced postoperative hypotension and side effects (orthostatic hypotension, edema, nasal congestion) 6

Doxazosin (competitive, selective α1-blocker):

• May be equally effective with fewer side effects 1, 6
• Significantly lower cost compared to phenoxybenzamine 7
• Requires more frequent addition of other antihypertensive agents 6

Additional Medications

Beta-blockers (CRITICAL CAVEAT):

• NEVER initiate beta-blockers before adequate alpha-blockade is established 1, 2, 4
• Only add beta-blockers after alpha-blockade to control tachyarrhythmias 1, 2
• Starting beta-blockers first can precipitate fatal hypertensive crisis from unopposed alpha-adrenergic stimulation 2

Calcium channel blockers:

• Can be added if target BP not reached with alpha-blockers alone 1
• Nifedipine slow-release is commonly used 1
• May be used as monotherapy in cases with normal to mildly elevated BP 4

Metyrosine (alpha-methylparatyrosine):

• Catecholamine synthesis inhibitor 1
• Reserved for refractory cases or when surgery is contraindicated 8, 9
• Combination with alpha-blockade provides superior intraoperative hemodynamic control 9

Preoperative Preparation (Critical for Preventing Postoperative Hypotension)

Volume expansion is essential: 2, 4

• High-sodium diet during preoperative period 2, 4
• Administer 1-2 liters of saline 24 hours before surgery 2, 4
• Use compression stockings 2, 4

Definitive Treatment: Surgical Resection

Complete surgical extirpation (R0 resection) is the only curative treatment and should be performed after adequate medical preparation. 1, 2, 3

Surgical Approach

• Laparoscopic adrenalectomy is the preferred approach for most pheochromocytomas 2, 4, 3
• Open surgery reserved for: tumors >6 cm, high suspicion of malignancy, or local invasion 2, 4
• Surgery should only be performed in specialized centers with >10 adrenalectomies per year 1

Intraoperative Management

For hypertensive crises during surgery: 1, 4

• Magnesium sulfate 1, 4
• Phentolamine (IV alpha-blocker) 1, 4
• Calcium antagonists 1, 4
• Nitroprusside or nitroglycerin 1, 4

For tachycardia: 1, 4

• Esmolol (short-acting IV beta-blocker) 1, 4

CRITICAL CAVEAT: Labetalol should be avoided in pheochromocytoma as it has been associated with paradoxical acceleration of hypertension. 1

Postoperative Care

Monitor for hypoglycemia: 1, 2, 3

• Occurs commonly after sudden reduction in catecholamine levels 1, 2, 3
• Requires close glucose monitoring 1, 3

Treat postoperative hypotension aggressively: 1, 4, 3

• Should be anticipated and managed with fluid resuscitation 1, 3

Biochemical confirmation of cure: 2, 3

• Measure plasma or urine metanephrines at 2-8 weeks postoperatively 2, 3
• Imaging at 3-6 months to verify complete tumor removal 4

Long-Term Surveillance

Lifelong follow-up is mandatory due to 10-17% recurrence rate: 1, 3, 10

• Clinical and biochemical monitoring every 3-4 months for first 2-3 years, then every 6 months 3
• Continue surveillance for at least 10 years, as recurrence can occur decades later 1, 10

Critical Pitfalls to Avoid

• Never perform fine needle biopsy of suspected pheochromocytoma - can precipitate fatal hypertensive crisis 3
• Never start beta-blockers before alpha-blockade - causes unopposed alpha stimulation and hypertensive crisis 1, 2, 4
• Never proceed to surgery without adequate preoperative alpha-blockade - associated with perioperative mortality 1, 9
• Do not use labetalol for hypertensive emergencies in pheochromocytoma - can worsen hypertension 1