A comparison of robotic and laparoscopic minimally invasive adrenalectomy for adrenal malignancies

Background: Although guidelines recommend open adrenalectomy for most resectable adrenal malignancies, minimally invasive adrenalectomies are performed. Robotic adrenalectomies have become more popular recently, but there is a paucity of literature comparing laparoscopic and robotic resections. Methods: Patients who underwent a planned minimally invasive adrenalectomy for adrenal malignancies (adrenocortical carcinoma, malignant pheochromocytoma, other carcinoma) were identified in the National Cancer Database. The primary outcome was the conversion rate from minimally invasive to open. Other post-operative outcomes and survival were compared. Results: 416 patients (76.5%) underwent a laparoscopic adrenalectomy and 128 (23.5%) underwent a robotic operation. Demographics and clinical characteristics were similar. Approximately 19% of tumors resected by a minimally invasive approach were > 10 cm. The intra-operative conversion rate was decreased among robotic adrenalectomies relative to laparoscopic on univariate (7.8% vs. 18.3%, p = 0.005) and multivariable (odds ratio 0.39, p = 0.01) analyses. Using marginal standardization, there was a stepwise increase in the conversion rate as tumor size increased (< 5, 5–10, > 10 cm) for laparoscopic (7.5%, 18.0%, 33.2%) and robotic (3.1%, 8.3%, 17.3%) adrenalectomies. Operations which required conversion had a greater margin positivity rate, greater length of stay, and an association with poor overall survival. Conclusion: In contrast to most clinical guidelines, minimally invasive adrenalectomies are being performed on large malignant tumors. A laparoscopic approach was associated with a greater conversion rate and subsequent poor outcomes. If a surgeon is not planning an open adrenalectomy, but adrenal malignancy is a possibility, robotic adrenalectomy may be the preferred approach for resectable adrenal tumors.