Different prognostic effect of lymph node metastasis between remnant gastric cancers and primary proximal gastric cancers.

ABSTRACT

BACKGROUND: Although the dissected lymph node number in remnant gastric cancer (RGC) may be smaller than in primary proximal gastric cancer (PGC), altered lymphatic flow provides different metastatic patterns in lymph nodes, which could potentially give rise to prognostic differences between RGC and PGC with nodal metastasis. METHODS: Between 1993 and 2020, 2546 consecutive patients with gastric cancer underwent gastrectomy. Of these, 53 patients with RGC and 381 patients with PGC with pathologic TNM stage I-III gastric cancer underwent curative gastrectomy. We reviewed their hospital records retrospectively. RESULTS: The number of dissected lymph nodes was significantly smaller in patients with RGC than in patients with PGC (P < .001; RGC, 13.0 vs PGC, 34.5). Although the 5-year overall survival (OS) rate did not differ between RGC and PGC in all patients, the prognosis in each pathologic N (pN) stage of RGC was worse than that of PGC, suggesting that each lymph node metastasis has a greater prognostic effect in RGC. In particular, even with patients with pN1 (20.0%) or pN2 RGC (40.0%), their 5-year OS rates were poor and similar to those of patients with pN3 PGC (35.7%). The presence of lymph node metastasis in RGC (hazard ratio [HR], 4.41; 95% CI, 1.02-18.9; P = .045) was an independent and a similar prognostic impact in pN3 PGC (HR, 2.82; 95% CI, 1.57-5.07; P < .001). Lymph node metastasis in RGC more strongly affected peritoneal or lymph node recurrence rather than hematogenous recurrence. CONCLUSION: The presence of lymph node metastasis yielded a poorer prognosis in patients with RGC than patients with primary PGC. Patients with RGC with lymph node metastasis should be specifically targeted in an effort to improve their prognosis.