Significance of neoadjuvant downstaging in gastric adenocarcinoma

Neoadjuvant chemotherapy is established in the treatment of gastric adenocarcinoma. Histopathological regression may have important prognostic implications. There are little data comparing clinical outcomes of patients with gastric adenocarcinoma that received neoadjuvant treatment and those neoadjuvant naive. The aim of this study is to determine the impact of neoadjuvant chemotherapy upon prognosis of patients being treated for gastric adenocarcinoma.

Consecutive patients with gastric cancer from a single center between 2007 and 2017 were evaluated. Patients were treated with either a subtotal or total gastrectomy with D2 lymphadenectomy. Stage-by-stage comparison of the extent of pathological downstaging was conducted for patients who received neoadjuvant treatment (ypTNM) and those who did not (pTNM) using the TNM eighth edition.

Overall, 384 patients underwent gastrectomy, 141 patients received neoadjuvant chemotherapy, and 86 patients (58.1%) were downstaged. Downstaged patients had improved overall survival compared to patients who did not respond to neoadjuvant chemotherapy (not reported vs 66 months, P < .001). Downstaging by >3 stages was the strongest independent predictor of overall survival (hazard ratio: 0.17; 95% confidence interval 0.062-0.44). Overall survival was significantly better among patients in the ypTNM groups when a stage-by-stage comparison was performed with the pTNM group.

Pathological stage is a more accurate predictor of prognosis compared clinical stage with downstaged patients benefiting from lower recurrence rates and improved overall survival. Patients downstaged due to neoadjuvant chemotherapy may potentially have more favorable clinical outcomes compared to stage-matched patients who did not receive this.