Background: Adrenocortical carcinoma (ACC), a rare and aggressive malignancy, accounts for up to 14% of adrenal incidentalomas. The only chance of cure for ACC is diagnosis at an early stage; therefore, a main indication for adrenalectomy in patients with adrenal incidentaloma has been the potential risk of ACC. Recent studies suggest that this has led to earlier stage of ACC at diagnosis, more curative operations, and better survival.
Methods: We analyzed data on ACC from The National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database. Four equal time quartiles (1973-1979, 1980-1986, 1987-1993, and 1994-2000) were compared for changes in demographics, pathology, treatment, and cause-specific mortality.
Results: The average age was 51.2 years (range: 1-97), and 45.9% of patients were men. The average tumor size was 12 cm (range: 2-36 cm), and only 4.2% were < or = 6 cm. Most (88%) patients had surgical resection of their tumor, and external beam radiotherapy was used in only 12% of patients. Between the time quartiles compared (as well as annually), there was no significant difference at presentation in age at diagnosis, sex, race/ethnicity, tumor size, tumor grade, the frequency of distant metastasis, and overall TNM stage. Low tumor grade, lower stage of ACC, later time quartile, and surgical resection were associated with a lower cause-specific mortality by univariate analysis (P < or = 0.002) and by multivariate analysis (P < or = 0.031).
Conclusions: Although adrenal incidentalomas have become a common indication for adrenalectomy, this has not resulted in patients with ACC being diagnosed earlier or treated at a lower stage of disease at the national level. The most important predictors of survival in these patients are tumor grade, tumor stage, and surgical resection.