Tailored surgery for large adrenal tumors: the minimally invasive to open (hybrid) approach.

Conversion from minimally invasive techniques to open surgery has mostly been considered as an undesirable event associated with intraoperative complications or poor preoperative planning. However, the impact of conversion to open surgery during adrenalectomy for large adrenal tumours remains unclear. This study investigates the outcomes of conversion from minimally invasive to open surgery for adrenal masses ≥ 60 mm with an additional focus on the identification of survival predictors in patients with large adrenocortical carcinoma (ACC). We retrospectively analyzed 97 patients who underwent unilateral adrenalectomy for tumours ≥ 60 mm. Patient characteristics, tumour features, surgical approaches, and outcomes were compared. Survival outcomes in ACC patients (n = 34) were assessed using Kaplan-Meier analysis, with prognostic factors evaluated via univariate Cox regression and Ridge Regression modeling. Of 97 patients, 41 (42%) underwent minimally invasive adrenalectomy (MIA), 40 (41%) open adrenalectomy (OA), and 16 (17%) required conversion to open surgery (hybrid adrenalectomy, HA). HA had a longer operative time (median 226.5 vs. 108.5 min; p < 0.001) and hospital stay (median 9 vs. 4 days; p < 0.001) compared to MIA but not OA (median 188 min; p = 0.102; 10 days; p = 0.519, respectively). Overall, complications were more frequent in HA (43.7%) than MIA (7.3%; p = 0.003) but similar to OA (37.5%; p = 0.897). Minor complications were more common in HA than MIA (31 vs. 7%; p = 0.032), while major complications were comparable (12.5 vs. 7.5%; p = 0.617). Tumours in HA cases more often showed vascular infiltration (p = 0.001) and required multivisceral resection (p = 0.002). ENSAT tumour stage (OS: HR = 4.66, p = 0.041; PFS: HR = 2.52, p = 0.005) and the S-GRAS score (OS: HR = 6.00; PFS: HR = 1.50) were significant survival predictors in ACC, whereas the operative technique was not. Conversion to open surgery increases minor complications compared to MIA but not OA. ENSAT tumour stage and S-GRAS score predict survival in ACC, while the surgical approach does not. Timely conversion should be performed to ensure oncological safety when needed.