Clinical Implications of the Degree of Pancreatic Invasion in Ampulla of Vater Carcinoma.

Background: Ampulla of Vater carcinoma (AVC) stage T3 was subdivided according to the degree of pancreatic invasion into T3a (≤ 0.5 cm) and T3b (> 0.5 cm) by the 8th edition of the Union for International Cancer Control (UICC)/American Joint Committee on Cancer (AJCC) cancer staging system. However, the differences in clinicopathological features and survival outcomes between the two categories have not been well discussed.

Patients And Methods: We retrospectively analyzed 133 consecutive patients who underwent pancreatoduodenectomy for AVC at our institution between 2002 and 2020. Clinicopathological features and survival outcomes of patients with AVC were analyzed, with a focus on the depth of pancreatic invasion. In addition, the survival outcomes of patients with T3 AVC were compared with those of patients with resectable pancreatic head carcinoma (R-PhC) who underwent pancreatoduodenectomy during the same period.

Results: The overall survival (OS) in patients with T3b AVC (n = 12) was significantly worse than that in patients with T3a AVC (n = 39) [median survival time (MST) 9.2 vs. 74.5 months, p < 0.001). A multivariate analysis identified T3b tumor (hazard ratio 5.64, p = 0.009) as an independent prognostic factor. The OS of patients with T3a AVC was significantly better than that of patients with R-PhC who received adjuvant chemotherapy (n = 276, MST 35.0 months, p = 0.007). In contrast, the OS of patients with T3b AVC tended to be worse than that of patients with R-PhC managed without adjuvant chemotherapy, although this difference was not statistically significant (n = 163; MST, 17.5; p = 0.140).

Conclusions: AVC with > 0.5 cm invasion into the pancreas was associated with poor survival and represented advanced tumor progression to systemic disease.