Analysis of the efficacy and safety of extended lymph node dissection in gastric cancer surgery: association with dissection quantity, inflammatory response, and complications.

[OBJECTIVE] To evaluate the comparative efficacy and safety of standard lymphadenectomy (D2) versus extended lymphadenectomy (D2+) in gastric cancer surgery. Additionally, we explored the relationship between the number of dissected lymph nodes, the magnitude of postoperative inflammatory response, and long-term survival outcomes.

[METHODS] A retrospective cohort was conducted on clinical data from 421 patients diagnosed with gastric cancer and treated between April 2019 and January 2022. Among them, 189 underwent standard D2 dissection and 232 received extended D2+ lymph node dissection. All patients received neoadjuvant chemotherapy followed by radical gastrectomy. Baseline characteristics, intraoperative and postoperative outcomes, inflammatory markers including C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6), complication rates, and survival metrics (3-year overall survival (OS) and progression-free survival (PFS)) were compared between groups. Univariate and multivariate Cox proportional hazards models were applied to identify survival-associated factors. Kaplan-Meier survival curves were constructed for subgroup analysis by TNM (tumor-node-metastasis) stage.

[RESULTS] There were no significant differences in baseline characteristics between the D2 and D2+ groups (P > 0.05). Compared to the D2 group, the D2+ group exhibited significantly longer operative times, greater intraoperative blood loss, and more lymph nodes dissected (all P < 0.001), while the length of hospital stay remained similar between the two groups (P = 0.708). Postoperative levels of CRP, TNF-α, and IL-6 were significantly elevated in the D2+ group (all P < 0.001), correlating positively with the number of lymph nodes removed (all P < 0.001). The incidence of postoperative complications did not differ between groups (P > 0.05). Notably, the D2+ group demonstrated a superior 2-year OS rate (P = 0.002) and significantly improved 3-year OS in patients with stage II disease (P = 0.018). However, no significant differences were observed in 1-year OS (P = 0.067), 3-year OS (P = 0.699), or 3-year OS for stage III patients (P = 0.428). Multivariate Cox regression analysis identified extended D2+ dissection, younger age, lower TNM stage, and higher tumor differentiation as independent protective factors for PFS (all P < 0.05).

[CONCLUSION] Extended D2+ lymph node dissection improves survival outcomes, particularly in stage II gastric cancer patients, without increasing postoperative complication risk. However, it induces a more robust inflammatory response. These findings suggest that D2+ dissection should be selectively considered, weighing the oncological benefits against the potential inflammatory burden, particularly in stage II patients.