Early Volumetric and Biochemical Effects of Embolization in Head and Neck Paragangliomas

Preoperative embolization is commonly performed for head and neck paragangliomas to reduce intraoperative bleeding; however, its early effects on tumor volume and catecholamine secretion remain unclear. We retrospectively reviewed 14 consecutive patients with head and neck paragangliomas who underwent embolization followed by surgical resection. Tumor volume was measured on contrast-enhanced T1-weighted imaging before and shortly after embolization. Serum and urinary norepinephrine levels were assessed in patients with catecholamine-secreting tumors. Post-embolization imaging was available for all 14 patients, and the mean interval between embolization and imaging was 4.1 ± 2.0 days. Mean tumor volume decreased by 10.5 ± 7.5% after embolization (p = 0.003). Among 5 patients with catecholamine-secreting tumors, tumor volume decreased by 11.2 ± 5.7% (p = 0.04). The mean interval between embolization and norepinephrine assessment was 3.0 ± 1.2 days. Serum and urinary norepinephrine levels decreased by 46.6 ± 12.5% (p = 0.04) and 22.2 ± 12.4%, respectively, although the latter did not reach statistical significance (p = 0.11). No significant correlation was observed between tumor volume reduction and changes in norepinephrine levels. Embolization for head and neck paragangliomas was associated with early tumor volume reduction and short-term decreases in norepinephrine levels, suggesting that embolization may contribute to early anatomical and biochemical changes beyond its traditional role as a preoperative adjunct.