Adrenocortical carcinoma: current and future therapeutic options
Martin Fassnacht1, Stefanie Hahner1, Sarah Johanssen1, Ann-Cathrin Koschker1, Marcus Quinkler2 & Bruno Allolio1
Adrenocortical carcinoma (ACC) is a rare and heterogeneous malignancy with incompletely understood pathogenesis and poor prognosis. Recent data from the German ACC Registry (n=377) demonstrate an overall 5-year survival of 46%. Survival is clearly stage-dependent (P<0.01) with a 5-year survival of 85% in stage 1, 56% in stage 2, 42% in stage 3, and 16% in stage 4, respectively.
In stages I III open surgery by an expert surgeon aiming at a R0 resection is the treatment of choice. However even after R0 resection, only 37% of the patients are disease-free after 5 years. Therefore, adjuvant treatment options are urgently needed. In a recent series including 177 patients from Italy and Germany, adjuvant mitotane prolonged significantly disease-free survival compared to observational follow-up. In addition, adjuvant radiotherapy of the tumor bed is a promising option to prevent local recurrence.
In tumor recurrence and metastatic disease, surgery should be considered if complete resection is feasible. In patients not amenable to surgery, mitotane (alone or in combination with cytotoxic drugs) remains the treatment of choice. Monitoring of drug levels (therapeutic range 1420 mg/l) is mandatory for optimum results. In advanced disease, the most promising therapeutic options (etoposide, doxorubicin, cisplatin plus mitotane and streptozotocin plus mitotane) are currently compared in an international phase III trial (www.firm-act.org). In 2006, we have administered EGFR inhibitors and VEGF antibody as salvage therapy in a small series of patients so far without significant success. However, in 2007 the Collaborative group for Adrenocortical Carcinoma Therapy (CO-ACT) will initiate three new trials for salvage therapies investigating two multi-targeted tyrosine kinase inhibitors and an IGF-1 receptor antibody, respectively, leading hopefully to improved clinical outcome. Future advances in the management of ACC will depend on a better understanding of the molecular pathogenesis of ACC facilitating the use of new targeted therapies.