Adjuvant therapy in adrenocortical carcinoma: prognostic factors and treatment options

Adrenocortical carcinoma (ACC) is a rare cancer with high recurrence rates and heterogeneous clinical behavior. The role of adjuvant therapy remains unclear because of the challenges in collecting high-quality data for a rare cancer. The current treatment recommendations and guidelines for adjuvant therapy are mostly derived retrospectively from national databases and the treatment outcomes of patients seen in referral centers. To better select patients for adjuvant therapy, multiple factors need to be considered including staging, markers of cellular proliferation (such as Ki67%), resection margins, hormonal function, and possibly genetic alterations of the tumor as well as patient-related factors such as age and performance status. Adjuvant mitotane remains the most commonly used adjuvant therapy in ACC based on clinical practice guidelines, though emerging data from ADIUVO trial (mitotane vs observation in low-risk ACC) suggest that mitotane use in low-risk patients may not be needed. An ongoing clinical trial (ADIUVO-2) is evaluating the role of mitotane vs mitotane combined with chemotherapy in high-risk ACC. The use of adjuvant therapy has been controversial but can be justified in select patients with positive resection margins or after the resection of localized recurrence. A prospective study is needed to study the role of adjuvant radiation in ACC as radiation is expected to help only with local control without impact on distant microscopic metastases. There are no recommendations or published data about using adjuvant immunotherapy in ACC, but this may be a future study after establishing the efficacy and safety profile of immunotherapy in metastatic ACC.