Jae Seung Kang1, Ryota Higuchi2, Jin He3, Masakazu Yamamoto2, Christopher L Wolfgang3, John L Cameron3, Youngmin Han1, Donghee Son4, Seungyeon Lee4, Yoo Jin Choi1, Yoonhyeong Byun1, Hongbeom Kim1, Wooil Kwon1, Sun-Whe Kim5, Taesung Park6, Jin-Young Jang1. 1. Department of Surgery and Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea. 2. Department of Surgery, Institute of Gastroenterology, Tokyo Women's Medical University, Tokyo, Japan. 3. Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA. 4. Department of Mathematics and Statistics, Sejong University, Seoul, Korea. 5. Center for Liver and Pancreatobiliary Cancer, National Cancer Center, Gyeonggi-do, Korea. 6. Department of Statistics and Interdisciplinary Program in Biostatistics, Seoul National University, Seoul, Korea.
Abstract
BACKGROUND: The minimal required number of retrieved lymph nodes (MNRLNs) to enable accurate staging of distal bile duct (DBD) adenocarcinoma remains unclear. The three-tier 8th N staging system of the American Joint Committee on Cancer (AJCC) for DBD adenocarcinoma has been recently released. The present study is aimed at proposing the MNRLNs for accurate staging and validating the 8th N stage. METHODS: Between 1991 and 2015, patients with pathologically confirmed DBD adenocarcinoma who underwent pancreatoduodenectomy were enrolled. MNRLN was calculated via a log-rank test based on cut-off values. The concordance index (C-index) was utilized to compare the discrimination capability of the two- and three-tier N stages. RESULTS: A total of 780 patients were enrolled. Lymph node (LN) positivity and 5-year overall survival (5-YOS) rates stabilized and significant survival differences between node-negative and -positive patients were observed when ≥12 LNs were retrieved. 5-YOS rates between each 8th N stage significantly differ (N0 vs. N1, P = 0.037; N1 vs. N2, P = 0.003). The C-index of the 8th N stage was higher than that of the 7th (0.59 vs. 0.57). CONCLUSIONS: For accurate staging, at least 12 LNs should be retrieved. The three-tier N staging system is valid for clinical practice and has a more accurate prognostic predictability than the two-tier system.
BACKGROUND: The minimal required number of retrieved lymph nodes (MNRLNs) to enable accurate staging of distal bile duct (DBD) adenocarcinoma remains unclear. The three-tier 8th N staging system of the American Joint Committee on Cancer (AJCC) for DBD adenocarcinoma has been recently released. The present study is aimed at proposing the MNRLNs for accurate staging and validating the 8th N stage. METHODS: Between 1991 and 2015, patients with pathologically confirmed DBD adenocarcinoma who underwent pancreatoduodenectomy were enrolled. MNRLN was calculated via a log-rank test based on cut-off values. The concordance index (C-index) was utilized to compare the discrimination capability of the two- and three-tier N stages. RESULTS: A total of 780 patients were enrolled. Lymph node (LN) positivity and 5-year overall survival (5-YOS) rates stabilized and significant survival differences between node-negative and -positive patients were observed when ≥12 LNs were retrieved. 5-YOS rates between each 8th N stage significantly differ (N0 vs. N1, P = 0.037; N1 vs. N2, P = 0.003). The C-index of the 8th N stage was higher than that of the 7th (0.59 vs. 0.57). CONCLUSIONS: For accurate staging, at least 12 LNs should be retrieved. The three-tier N staging system is valid for clinical practice and has a more accurate prognostic predictability than the two-tier system.