Proposal for modification of the ENSAT staging system for adrenocortical carcinoma using tumor grade

Purpose Various staging systems for adrenocortical carcinoma (ACC) have been proposed. We hypothesized that incorporating tumor grade into the current European Network for the Study of Adrenal Tumors (ENSAT) staging system would improve the ability to more accurately predict time to recurrence and death. Methods A retrospective review of patients included in the University of Michigan ACC database from 2005 to 2009 was done; and stage, tumor grade, time to recurrence, and death were recorded and analyzed using the Cox regression and Kaplan-Meier survival curves. Results Ninety one patients had complete information for inclusion. The median follow-up was 24 months while the median time to recurrence was 4.1 months. There were 28 deaths; overall, tumor grade showed a significant difference in time to tumor recurrence (p=0.011) and time to death (p=0.004). Time to death among stage 2 patients separated into those with high- and low-grade tumors reached statistical significance (p=0.05), and notable but not statistically significant differences were identified in all stages. Based on tumor grade and survival curves, modifications to the current ENSAT staging system were made. Conclusion Tumor grade plays a significant role in the outcome of patients with ACC. High-grade tumors are associated with shorter disease-free intervals and shorter overall survival. The proposed modification of the ENSAT staging system allows for incorporation of tumor grade when predicting overall survival.