Supplemental Table S8. Pheochromocytoma: Screening and diagnosis
Screening
Re-printed with permission of the Canadian Hypertension Education Program.
Biochemical screening tests for pheochromocytoma:
i. To screen for pheochromocytoma
  1. 24-hr urinary total metanephrines and catecholamines (sensitivity 90-95%) or 24-hr urine fractionated metanephrines (sensitivity of about 100%) should be measured. Concomitant measurement of 24-hr urine creatinine should also be performed to confirm accurate collection.
  2. Plasma free metanephrines and free normetanephrines, where available, may also be considered (sensitivity up to 99%).
  3. Urinary VMA measurements should not be used for screening.
ii. Keep in mind that potential false positives should be considered in the setting of:
  1. interfering drugs
  2. mild elevation of screening values (i.e., less than two-fold upper limit of normal)
  3. normal values on repeat testing
  4. only 1 abnormal biochemical test in the panel of assays
  5. atypical imaging results for pheochromocytoma
  6. a low pre-test probability of pheochromocytoma
iii. In the presence of borderline biochemical test results or potentially false positive results, repeat testing may be performed and/or the clonidine suppression test may be used. This should be done before imaging is requested to avoid identifying potential incidentalomas.
iv. Imaging should generally be only done after biochemical confirmation eg. CT, MRI, ± MIBG
Treatment
v. Definitive treatment is with surgical resection. Preoperative planning is recommended for blood pressure control and volume expansion:
  1. Alpha blockade should be started 10-14 days preoperatively. Typical options include oral phenoxybenzamine (a long-acting, non-selective, irreversible alpha- blocker), prazosin, or doxazosin.
  2. Other anti-hypertensives may be added as necessary but diuretics should be avoided if possible. Dihdydropyridine calcium channel blockers are most commonly used add on agents for blood pressure control. Oral beta-blockers may be considered after achieving adequate alpha blockade to control tachycardia and prevent arrhythmias during surgery.
  3. Volume replacement and liberal sodium intake should be encouraged as volume contraction is common in this condition. Intravenous volume expansion in the perioperative period is recommended to prevent postoperative shock.
  4. Immediately post-op, consider stopping anti-hypertensives. Patients may also need aggressive intravenous fluids post-op.
vi. Postoperatively, annual long-term follow-up is recommended with urinary or plasma metanephrines to screen for recurrence, especially in those with a genetic predisposition.
vii. Genetic testing should be considered for individuals <50 years of age and for all patients with multiple lesions, malignant lesions, bilateral pheochromocytomas, paragangliomas, or a family history of pheochromocytoma or paraganglioma.