Validation and Proposal for Refining the AJCC 8th Edition Staging System for Duodenal Adenocarcinoma

Background: Studies focusing on Duodenal Adenocarcinoma (DAC) are scarce and the clinicopathological features, patient characteristics, and survival factors of DAC are unknown. The 8th edition of the AJCC staging system for DAC incorporated the change focusing on positive Lymph Node (LN) numbers. We compared the classification systems in the 7th and 8th editions, and evaluated the clinicopathological features of and survival factors for DAC. Methods: One hundred thirty-five DAC patients undergoing operations at As an Medical Center from 2000 to 2016 were restaged according to the AJCC 8th edition. Results: One hundred and five patients underwent potentially curative resection and 30 underwent palliative surgery. In patients undergoing potentially curative resection, the median overall and disease-free survival were 89.5 and 52.1 months, respectively. The recurrence rate was 40.0%, with the liver being the most common site of metastasis. Although the new staging system for DAC could predict the prognosis satisfactorily, there is no other major improvement. A multivariate analysis revealed LN metastasis and T4 stage were the survival factors. Conclusion: The AJCC 8th edition staging system has the appropriate ability to predict prognosis in DAC patients. However, the survival was mainly related to the T4 stage and the presence of LN metastasis. The simpler staging system emphasizing on the T4 stage and LN metastasis is recommended.