The Role of Adjuvant Therapy in Duodenal Adenocarcinoma and Intestinal Subtype Ampullary Carcinoma after Curative Resection

Objective: Defining the role of adjuvant therapy in duodenal adenocarcinoma (DAC) and intestinal subtype ampullary carcinoma (iAC). Summary background data: DAC and iAC share a similar histological differentiation but the benefit of adjuvant therapy remains unclear. Methods: Patients undergoing curative-intent surgical resection for DAC and iAC between 2010 and 2021 at five high-volume centers were included. Patient baseline, perioperative and long-term oncological outcomes were evaluated. Statistical testing was performed with SPSS 25 (IBM). Results: A total of 136 patients with DAC and 171 with iAC were identified. Patients with DAC had more advanced tumors than those with iAC. Median overall survival (OS) in DAC patients was 101 months versus 155 months for iAC patients (P=0.098). DAC had a higher rate of local (14.1% vs. 1.2%, P<0.001) and systemic recurrence (30.4% vs. 3.5%, P<0.001). Adjuvant therapy failed to improve overall survival in all patients with DAC and iAC. For DAC, patients with perineural invasion, but not other negative prognostic factors had improved OS rates with adjuvant therapy (72 m vs. 44 m, P=0.044). IAC patients with N+ (190 m vs. 57 m, P=0.003), T3-4 (177 m vs. 59 m, P=0.050) and perineural invasion (150 m vs. 59 m, P=0.019) had improved OS rates with adjuvant therapy. Conclusion: While adjuvant therapy fails to improve OS in all patients with DAC and iAC in the current study, it improved overall survival in DAC patients with perineural invasion and in iAC patients with T3-4 tumors, positive lymph nodes, and perineural invasion.