Endocrine Abstracts

JOINT3913

Introduction: Mitotane has been considered a mainstay adjuvant treatment for patients at high risk of adrenocortical carcinoma (ACC) recurrence. However, the level of evidence is graded as low to moderate, as this recommendation is based on the results of retrospective studies. The present study aimed to analyse the long-term outcomes of patients with ACC (ENSAT stage I-III, Ki-67 > 10%) based on whether they were treated with mitotane in the adjuvant setting.

Materials and Methods: This retrospective, single-center study included 34 patients diagnosed with ACC who underwent R0 surgery. Postoperatively, 26 patients received adjuvant mitotane for 24 months (IQR 20-35; M+ group). Of the 8 patients who did not receive mitotane (M- group), one stopped after one month due to liver toxicity, one refused treatment, and six underwent surgery in a non-expert center where adjuvant mitotane was not advised. The main study outcomes included recurrence-free survival (RFS), overall survival (OS) and disease specific survival (DSS).

Results: There were no significant differences between the groups in terms of age (44 years vs. 50 years; P = 0.452), tumor size (98 mm vs. 100 mm, P = 0.791) and hormonal hypersecretion (77% vs. 24%; P = 0.067). Patients in the M+ group had longer RFS compared to those in the M- group (133 ± 18 months vs. 52 ± 17 months; P = 0.008). In contrast, no differences were observed between the groups in OS (142 ± 17 months vs. 151 ± 29 months; P = 0.941) or DSS (180 ± 13 months vs. 167 ± 28 months; P = 0.424).

Conclusion: Adjuvant mitotane is associated with a significant improvement in RFS in patients at high risk of ACC recurrence. However, no significant impact was observed on OS or DSS.