Patterns of regional recurrence after curative D2 resection for stage III (N3) gastric cancer: Implications for postoperative radiotherapy

Background and purpose: To analyze patterns of regional recurrence after curative gastrectomy and D2 lymph node dissection in patients with stage III (N3) gastric cancer. Materials and methods: Between 2004 and 2008, 2918 patients with primary gastric cancer underwent D2 resection at a single institution. A retrospective review was performed on 382 patients in stage III with N3 disease. Of these, 357 patients (93.5%) received adjuvant chemotherapy. None of the patients received pre- or postoperative radiotherapy. Results: Median follow-up was 56.3 months. The 5-year regional failure free-survival (RFFS) rate was 63.6%. Regional failure (RF) as any component of first recurrence occurred in 91 patients (23.8%), with isolated regional failure occurring in 49 (12.8%). The most commonly involved lymph nodes were the No. 16b, No. 16a, No. 12, No. 14, No. 13, and No. 9 nodes. RFFS was adversely affected by advanced nodal stage (N3b vs. N3a). The 5-year progression-free survival rate was 32.1% and overall survival was 41.5%. Conclusion: The most prevalent nodal recurrence in patients with advanced gastric cancer was in the nodal basin outside the D2 dissection field. Our findings may help physicians construct a lymph node target volume for radiation treatment of gastric cancer after D2 dissection.