Prognostic Factors Among Patients with Non-metastatic Adrenocortical Carcinoma

Background: Adrenocortical carcinoma (ACC) is a very rare and aggressive disease with limited systemic therapeutic options. Objectives: Treatment with adjuvant mitotane is common after resection of ACC; however, high-risk patients often experience early recurrence. The risk factors for recurrence after surgery were analyzed in patients with non-metastatic ACC. Methods: We retrospectively reviewed the medical records of 20 patients who were treated for ACC between 1994 and 2023 at Kansai Medical University Hospital or Kansai Medical University Medical Center in Osaka, Japan. We studied the recurrence-free survival (RFS) rates of a subset of 15 patients with non-metastatic ACC [European network for the study of adrenal tumors (ENSATs) stage I-III]. Statistical analyses included the Kaplan-Meier survival analysis and the Cox proportional hazard model. Results: Of the 15 patients with non-metastatic ACC, nine patients (60%) experienced recurrence. The median RFS was seven months, and all recurrences occurred within 24 months. In all cases, the site of recurrence was the lungs or liver. Univariate analysis showed that ENSAT stage III classification [hazard ratio (HR) 6.974, P = 0.007] was the only factor that made a statistically significant difference to RFS. Although five of the six ENSAT stage III patients took adjuvant mitotane, all experienced recurrence. Conclusions: In patients with non-metastatic ACC, a diagnosis of ENSAT stage III is the only factor that significantly affects RFS. In these patients, adjuvant mitotane is likely insufficient to prevent recurrence.