Comparison of long term survival outcomes between D1+ and D2 lymph node dissection for ≥ pT2 or pN+ gastric carcinoma: A large scale case-control study using propensity score matching.

Background: D2 lymph node dissection (LND) is a widely performed as a standard procedure for advanced gastric cancer (AGC). However, there is little evidence supporting D2 over D1+ LND for gastric cancer treatment. This study compared the long-term outcomes of D2 and D1+ LND for AGC.

Methods: We retrospectively reviewed data on 1121 patients who underwent curative distal gastrectomy and had pathologic stage of ≥ pT2 or pN+. The patients were categorized into the D1+ and D2 LND groups, and long-term survival was compared in the original and propensity score matching (PSM) cohorts.

Results: Overall, 909 and 212 patients underwent D2 and D1+ LND, respectively. The D2 group showed more advanced stage and more frequently underwent open surgery. Postoperative morbidity was significantly higher in the D2 group (19.5% vs. 13.2%, p = 0.034); however, mortality or ≥ grade III complications did not significantly differ between the groups. The 5-year overall survival (OS) and disease-free survival (DFS) did not significantly differ between D2 and D1+ groups at the same stage. Multivariate analysis of prognostic factors revealed that the extent of LND did not significantly affect survival, after adjusting for tumor stage and other clinicopathological factors. In the PSM cohort, the D2 and D1 groups showed no significant difference in OS (p = 0.488) and DFS (p = 0.705).

Conclusions: Long-term survival with D1+ LND was comparable to that with D2 LND for ≥ pT2 or pN + gastric carcinoma. A large randomized trial is warranted to validate the optimal extent of LND for gastric carcinoma.