Background : The 8th edition of the American Joint Committee on Cancer (AJCC), in contrast to the previous editions, designates T4 and N2 categories as pivotal parameters in Stage Ⅲ pancreatic cancer, emphasizing the significance of regional lymph node metastasis. This study aims to determine the prognostic roles of each T4 and N2 category in patients with stage Ⅲ pancreatic cancer who underwent pancreatectomy.

Methods : Among 424 patients who underwent pancreatectomy for pancreatic cancer between 2004 and 2019, 106 patients were identified as Stage III. After excluding 16 patients who underwent neoadjuvant chemotherapy, 90 Stage III patients were selected for this study. Recurrence and survival outcomes were compared between the T4 and N2 categories.

Results : Among 90 Stage III patients, 12 (13.3%) were T4(any N) and 78 (86.7%) patients were T(1-3)N2. No significant differences were observed in overall survival (OS) (p=0.373) and disease-free survival (DFS) (p=0.414) between the two groups. Despite similar recurrence rates (T4: n=8, 66.7% vs. N2: n=62, 79.5%, p=0.323), T4 patients showed a tendency toward local recurrence (52.6% vs. 15.7% recurrence rate) while N2 patients had a higher likelihood of systemic recurrence (26.3% vs. 75% recurrence rate, p=0.003).When comparing T4N2 patients (n=6) and T(1-3)N2/T4N(0-1) patients (n=84), both groups had similar OS (p=0.136) and DFS (p=0.053).

Conclusions : In Stage III pancreatic cancer, there were no discernable difference of survival outcomes between T4(any N) and T(1-3)N2 groups. However, the distinct difference in recurrence patterns after surgery between the two groups suggests the need for tailored surveillance and treatments for stage Ⅲ pancreatic cancer.