Clinical Management of Pheochromocytomas: A Surgical Oncology Discussion

Understanding Pheochromocytomas

• 💡 Pheochromocytomas are rare neuroendocrine tumors originating from the adrenal medulla's chromaffin cells, secreting catecholamines like norepinephrine and epinephrine.
• 🎯 They account for 0.5-0.1% of hypertensive patients, with an annual incidence of 500-1500 cases in the US, peaking between ages 30-50.
• 🔑 The "rules of 10" (10% bilateral, 10% extra-adrenal, 10% malignant, 10% in children, 10% familial) apply primarily to sporadic cases; familial cases are more often bilateral.
• 🧬 Over 40% are associated with germline mutations (e.g., MEN2, SDH deficiency), making genetic testing crucial, especially in younger patients.

Diagnostic Workup and Imaging

• 🔍 Initial workup involves plasma-free fractionated metanephrines and normetanephrines, which are highly sensitive screening tools.
• 🧪 A confirmatory 24-hour urine test for fractionated metanephrines and normetanephrines is used if plasma tests are equivocal, offering higher specificity.
• ⚠️ It's critical to obtain lab testing before any tumor manipulation (biopsy or surgery) to prevent catecholamine surges.
• 📊 Imaging typically includes an adrenal protocol CT for masses >3 cm and >10 Hounsfield units, or an adrenal protocol MRI, where masses are bright on T2.
• 📍 MIBG scans and newer dotatate PET scans can help locate biochemically active tumors, especially if not clearly visible on standard CT.

Pre-operative Preparation and Pharmacologic Blockade

• ⚠️ Surgical resection can lead to labile blood pressure, arrhythmias, and tachycardia, necessitating multidisciplinary preparation.
• 💊 Pre-operative pharmacologic blockade typically starts with alpha-receptor blockade (e.g., doxazosin) for at least two weeks, aiming for systolic BP <120 mmHg and mild orthostasis.
• 🩺 If tachycardia persists after 3-4 days, a beta-blocker (e.g., metoprolol) can be added.
• 🧠 Selective alpha-blockers are preferred to avoid reflex tachycardia associated with non-selective agents.

Surgical Approaches and Considerations

• 🚀 Minimally invasive approaches (laparoscopic posterior retroperitoneal or transabdominal adrenalectomy) are generally recommended by NCCN guidelines.
• ⚠️ Open approaches may be considered for large tumors (>6-10 cm), invasive features, or high-risk mutations (e.g., SDHB).
• 🔪 The posterior retroperitoneal approach involves a prone position, while the transabdominal approach requires mobilizing abdominal structures.
• 💡 Cortical-sparing adrenalectomy is recommended for patients with bilateral pheochromocytomas, prior adrenalectomy, or MEN2 syndrome to reduce adrenal insufficiency.
• 🩺 Intraoperative ultrasound can help identify tumors and their relationship to the adrenal vein, crucial for preserving adrenal function during cortical-sparing procedures.
• 🤝 A strong collaboration with the anesthesia team is vital for managing hemodynamic fluctuations during surgery.

Post-operative Management and Surveillance

• 🏥 Patients typically have a short hospital stay (around 24 hours) after uneventful MIS adrenalectomy, unless hemodynamic instability or hormonal management is required.
• 📉 Post-operative risks include hypotension (due to residual blockade, hypovolemia) and, rarely, hypoglycemia.
• 🗓️ Surveillance per NCCN guidelines includes history/physical and plasma-free or 24-hour urine metanephrines/normetanephrines between 3-12 months, then annually for up to 10 years.
• ☢️ For metastatic disease, workup includes CT chest and dotatate/FDG PET CT, with treatment options like chemotherapy, radiation, or targeted therapies discussed in multidisciplinary tumor boards.