Endocrine Abstracts

Objective: Local tumor recurrence is common in adrenocortical carcinoma (ACC) and the most frequent cause for re-operation. Therefore, a concept for an adjuvant treatment is urgently needed. The role of radiotherapy in ACC has not been well defined and many authors have considered radiotherapy as ineffective. However, two studies with a small number of patients (n=3 and n=4, resp.) have suggested adjuvant radiation as an effective treatment to prevent recurrence in ACC^1,2.

Methods: We analyzed all patients from the German ACC Registry who have been treated by tumor bed radiation. Only patients treated with 40–54 Gy in an adjuvant setting (no macroscopic evidence for residual tumor after initial surgery) were included. 16 patients (stage I: 1, stage II: 9, stage III: 6) with median tumor diameter of 12.5±4.2 cm were matched with 16 patients for stage, R-status, adjuvant mitotane treatment, tumor size, and age.

Results: Local recurrence occurred in 2/16 patients in the radiation group and in 9/16 control patients (P<0.05). The probability to be free of local recurrence 5 years after surgery differed significantly (82% vs. 39%; P<0.05). However, in this small series overall survival was not significantly different between both groups (5-year survival: 46% in radiation group vs. 64% in controls; P=0.6). Acute adverse effects related to radiation therapy were mostly mild (gastrointestinal grade CTC I+II, erythma CTC I, and fatigue CTC II, wound healing CTC II in 10, 5, 4, and 1 patients, respectively). 1 patient developed a partial Budd-Chiari syndrome and 1 patient impaired renal function CTC I during follow up probably related to radiotherapy.

Conclusion: These data from the largest series of ACC patients treated with adjuvant tumor bed radiation suggest that radiation therapy is effective in reducing the high rate of local recurrence in ACC. However, no impact on long-term survival was demonstrated in this small patient sample.