Abstract
BACKGROUND: Surgical resection is the standard treatment for phaeochromocytoma (PCC). Current guidelines recommend an open approach for large tumours due to the increased risk of complications. This study aimed to characterize surgical outcomes for large (≥ 6 cm) and small (< 6 cm) PCCs and to identify factors that may improve postoperative outcomes. METHODS: This retrospective cohort study of patients undergoing adrenalectomy for PCC in 49 international centres between 2012 and 2022 compared patients with tumours < 6 cm in diameter and those with tumours ≥ 6 cm in diameter. Univariate, bivariate (dichotomous), and multivariate (multiple logistic and linear) analyses were used to evaluate outcomes and risk factors for complications. A secondary multivariable analysis evaluated factors, including operative approach, influencing outcomes for patients with tumours ≥ 6 cm. A 1:1 propensity score-matched (PSM) analysis was completed to control for age, sex, body mass index, and the Charlson Co-morbidity Index. RESULTS: Of the 2301 patients included in the analysis, 598 (26.0%) had PCCs with a diameter ≥ 6 cm. Patients with tumours ≥ 6 cm had a higher incidence of severe (Clavien-Dindo grade ≥ IIIa) postoperative complications (11.2% versus 4.8%; P < 0.001). Multivariable analysis revealed that tumour size ≥ 6 cm was an independent predictor of any complications (odds ratio (OR) 1.93; P < 0.001). Subanalysis of patients with tumours ≥ 6 cm demonstrated that laparoscopic (OR 0.33; P < 0.001) and robotic (OR 0.40; P = 0.038) adrenalectomy were independently associated with less morbidity than an open approach. PSM analysis revealed a mean 276.0-ml higher blood loss (95% confidence interval (c.i.) 138.9 to 413.0 ml; P < 0.001) and 2.9-point higher Comprehensive Complication Index (95% c.i. 0.6 to 5.3; P = 0.015) for patients with tumours ≥ 6 cm compared with patients with PCCs < 6 cm in diameter. Optimal cut-off analysis revealed that a tumour diameter of ≥ 5.8 cm was associated with increased complications. CONCLUSION: Patients undergoing adrenalectomy for PCCs ≥ 6 cm have a higher risk of severe complications than patients with smaller tumours. Despite this increased risk in patients with large (≥ 6 cm) tumours, minimally invasive surgery was independently associated with a reduced likelihood of complications. This study supports a minimally invasive approach in patients with large PCCs.