Abstract
BACKGROUND: Meticulous lymph node 6 station (LN#6) dissection is mandatory in pylorus-preserving gastrectomy (PPG), but can increase the risk of complications, such as postoperative delayed gastric emptying. With analyzing lymphatic spread patterns based on cross-sectional tumor location, we planned to predict the surgical burden of LN#6 dissection, balancing oncological safety and risk of postoperative complications. METHODS: We included consecutive PPG cases at Seoul National University Hospital (2007-2017) to assess the incidence, 5-year survival rate (5YSR), and 3-year recurrence-free survival (3RFS) of LN#6 metastasis. Cox regression analyzed the impact of LN#6 metastasis itself on 5YSR and 3RFS. The effect of tumor location among gastric middle-third tumors on LN#6 metastasis was evaluated. The therapeutic indices (TI) of LN#6 based on tumor location were calculated. RESULTS: Among 1070 PPG patients, 5YSR and 3RFS were 97.0% and 98.9%. LN#6 metastasis was found in 11 patients (1.03%), with 3 recurrences observed among them (3/11, 0.28%). LN#6 metastasis itself did not significantly affect 5YSR (p = 0.266) or 3RFS (p = 0.075). Tumor location showed a significant association for LN#6 metastasis (p = 0.015), with low body greater curvature (LB-GC) showing the highest prevalence (5/11, 45.45%). TI of LN#6 for LB-GC tumors was 3.76, while TI for low body lesser curvature (LB-LC) and midbody lesser curvature (MB-LC) tumors was 0.0. CONCLUSIONS: LN#6 metastasis is infrequent and does not affect 5YSR or 3RFS in PPG patients. Tumors in LB-GC demonstrated a higher tendency for lymphatic spread to LN#6, while those in lesser curvature demonstrated a lower spread, suggesting a reduced surgical burden for lesser curvature tumors. This study evaluated LN#6 metastasis in 1070 PPG patients, demonstrating low incidence and favorable oncological outcomes, supporting tailored LN#6 dissection for lesser curvature tumors to minimize complications without compromising safety.