Risk Factors for Recurrence in Pancreatic Neuroendocrine Tumor and Size as a Surrogate in Determining the Treatment Strategy: A Korean Nationwide Study
Wooil Kwon, Jin‐Young Jang, Ki Byung Song, Dae Wook Hwang, Song Cheol Kim, Jin Seok Heo, Dong Wook Choi, Ho Kyoung Hwang, Chang Moo Kang, Yoo‐Seok Yoon, Ho‐Seong Han, Joon Seong Park, Tae Ho Hong, Chol Kyoon Cho, Keun Soo Ahn, Huisong Lee, Seung Eun Lee, Chi‐Young Jeong, Young Hoon Roh, Hee Joon Kim, Korean Pancreas Surgery Club
Abstract
INTRODUCTION: The prognostic factors of pancreatic neuroendocrine tumor (PNET) are unclear, and the treatment guidelines are insufficient. This study aimed to suggest a treatment algorithm for PNET based on risk factors for recurrence in a large cohort. METHODS: Data of 918 patients who underwent curative intent surgery for PNET were collected from 14 tertiary centers. Risk factors for recurrence and survival analyses were performed. RESULTS: The 5-year disease-free survival (DFS) rate was 86.5%. Risk factors for recurrence included margin status (R1, hazard ratio [HR] 2.438; R2, HR 3.721), 2010 WHO grade (G2, HR 3.864; G3, HR 7.352), and N category (N1, HR 2.273). A size of 2 cm was significant in the univariate analysis (HR 8.511) but not in the multivariate analysis (p = 0.407). Tumor size was not a risk factor for recurrence, but strongly reflected 2010 WHO grade and lymph node (LN) status. Tumors ≤2 cm had lower 2010 WHO grade, less LN metastasis (p < 0.001), and significantly longer 5-year DFS (77.9 vs. 98.2%, p < 0.001) than tumors >2 cm. The clinicopathologic features of tumors <1 and 1-2 cm were similar. However, the LN metastasis rate was 10.3% in 1-2-cm sized tumors and recurrence occurred in 3.0%. Tumors <1 cm in size did not have any LN metastasis or recurrence. DISCUSSION/CONCLUSION: Radical surgery is needed in suspected LN metastasis or G3 PNET or tumors >2 cm. Surveillance for <1-cm PNETs should be sufficient. Tumors sized 1-2 cm require limited surgery with LN resection, but should be converted to radical surgery in cases of doubtful margins or LN metastasis.