Diagnosis and treatment of adrenocortical carcinomas
Adrenocortical carcinoma (ACC) is a rare malignancy and most of the diagnostic and therapeutic strategies are not fully established according to criteria of evidence based medicine. However, pre-operatively a thorough endocrine work-up is strongly recommended (www.ensat.org/acc.htm). In addition an adequate visualization of the tumor and potential metastases is mandatory for best patient care. Computerized tomography and magnetic resonance imaging are currently equally effective when performed according to state of the art. Open adrenalectomy is treatment of choice for localized tumors. However, it is an open question whether minimal invasive surgery is an alternative in smaller ACCs. In most patients, adjuvant therapy with mitotane is recommended and some patients might benefit from additional radiotherapy of the tumorbed. In all patients regular staging every 3 months is recommended.
In addition to mitotane, cytotoxic drugs are standard treatment in advanced ACC. The best results have been reported for mitotane plus etoposide, doxorubicin and cisplatin (response rate: 49%; Berruti 2005). A response rate of 36% was published for mitotane and streptozotocin (Khan 2000). These two regimens are currently compared in a phase-III-trial. The calculated patient accrual (n=300) of this FIRM-ACT trial has been completed in 10/2009 and first results are available later in 2010. In contrast to earlier reports, ACC is not radio-resistant. Therefore, palliative radiotherapy may be used in symptomatic metastatic lesions.
The first experience using targeted therapies is disappointing. Gefitinib, sorafenib, erlotinib+gemcitabine, or bevacizumab+capecitabine exhibited only limited efficacy in pretreated patients. However, trials testing IGF1 receptor inhibitors or sunitinib are ongoing and will hopefully hold more promise.
Overall the prognosis of ACC is still poor and data from the German ACC Registry (n=584) indicate a 5-year survival rate of 47%. However, recent collaborative efforts (e.g. by the European adrenal network ENSAT) and international trials will advance the field in the near future.