Efficacy of adjuvant radiotherapy of the tumor bed on local recurrence of adrenocortical carcinoma

Context: Local tumor recurrence is common in adrenocortical carcinoma (ACC) and is the most frequent cause for reoperation. Although radiotherapy is often considered ineffective in the treatment of ACC, the limited number of available studies does not support this statement. Objective: The objective of the study was investigation of adjuvant tumor bed irradiation in the treatment of ACC. Design: We performed a retrospective analysis. Patients: The German ACC Registry (n = 285) was screened for patients who had received tumor bed radiotherapy in an adjuvant setting (no macroscopic evidence for residual disease after surgery). Fourteen patients without distant metastases (World Health Organization stage I, one patient; stage II, seven; stage III, three; and stage IV, three) were matched with 14 patients for resection status, adjuvant mitotane treatment, stage, and tumor size. Median follow- up of patients still alive (n = 15) was 37 months. Main Outcome Measure: Survival without local recurrence and disease-free survival was the main outcome measure. Results: Local recurrence was observed in two of 14 patients in the radiotherapy group and in 11 of 14 control patients. The probability to be free of local recurrence 5 yr after surgery differed significantly [79% ( 95% confidence interval, 53 - 100) vs. 12% (0 - 30); P < 0.01]. However, disease-free and overall survival were not significantly different between the two groups. Acute adverse events related to radiotherapy were mostly mild. One patient developed a partial BuddChiari syndrome. Conclusion: These data from the largest series of ACC patients treated with adjuvant tumor bed irradiation suggest that radiotherapy is effective in reducing the high rate of local recurrence in ACC. A randomized trial in high-risk patients is needed to further evaluate the efficacy of radiotherapy as an adjuvant treatment option in ACC.