Canadian Urological Association Best Practice Report: Long-term surveillance following resection of pheochromocytoma.

Abstract

Background Pheochromocytoma is a tumor of the catecholamine-producing cells of the adrenal medulla. The incidence is estimated to be 1–2 cases per 100 000 individuals and they make up approximately 5% of incidental adrenal masses.1 Classical symptoms of pheochromocytomas include headache, episodic perspiration, tachycardia, flushing, nausea, and hypertension, although many tumors can be asymptomatic.1 These tumors can be sporadic or hereditary. 2 Familial cases account for up to 30% of tumors.3 Pheochromocytomas can also occur outside the adrenal gland, known as paragangliomas, in up to 25% of cases.4 About 10% of pheochromocytomas are malignant.5 Although there are several clinical and genetic factors associated with an increased risk of malignancy, at this time, there are no molecular, cellular, or histological criteria that can reliably differentiate benign from malignant disease.5 Therefore, malignancy is defined by the presence of clinical metastases. The most common sites for metastases are lymph nodes, bones, liver, and lungs.6 Evaluation of suspected pheochromocytoma begins with confirming a biochemical disturbance by measuring plasma-free metanephrines or urinary fractionated metanephrines, followed by computed tomography (CT) imaging. Once a pheochromocytoma is confirmed, complete surgical resection of the tumor is advised, preferably via laparoscopic or robot-assisted adrenalectomy. The full details regarding workup and treatment of pheochromocytomas is beyond the scope of this review, but there are recent published guidelines on this topic.7 Following surgery, patients are at risk for tumor persistence and recurrence. Despite an overall good prognosis, the disease can recur in up to 16% of patients within 10 years following surgery.8,9 Recurrences may be local or metastatic and have been reported up to 53 years post-initial resection, making long-term followup essential.10 Extra-adrenal disease, hereditary pheochromocytomas, right-sided tumors, bilateral tumors, and larger tumors are thought to be risk factors for recurrence. Currently, there is no consensus on the proper methodology for followup. There have been no randomized studies addressing optimal followup nor prospective registries to provide higher-quality evidence for this issue. Important clinical questions remain regarding duration of followup and which tests should be used to detect and monitor recurrences.