Comparison of Survival Between ypStage and pStage in Gastric Cancer

In East Asia, the standard treatment for resectable advanced gastric cancer involves gastrectomy and postoperative adjuvant chemotherapy; nevertheless, neoadjuvant chemotherapy is also expected to improve survival rates. However, it remains unclear whether the same criteria can be used to select adjuvant chemotherapy for patients treated with neoadjuvant chemotherapy, or how survival varies between post-chemotherapy pathological Stage (ypStage) and pathological Stage without chemotherapy (pStage). This study evaluated the long-term outcomes of ypStage and pStage in gastric cancers and investigated the optimal intensity of adjuvant chemotherapy for patients who have received preoperative chemotherapy.

From January 2007 to November 2019, 1,585 patients underwent radical gastrectomy for gastric cancer at the Kanagawa Cancer Center. The patient background was adjusted by propensity score matching, and recurrence-free survival was compared between the two groups. In addition, a prognostic factor analysis was conducted for each yp/pStage.

The 5-year recurrence-free survival rates for yp/pStage I were 77.1% and 90.9%, respectively, with no significant difference (p=0.342). The 5-year recurrence-free survival rates for yp/pStage II were 50.4% and 69.1%, respectively, with no significant difference (p=0.062). The 5-year recurrence-free survival rates for yp/pStage III were 42.9% and 68.7%, respectively, with a significant difference observed (p=0.016). In the prognostic factor analysis for each stage, the presence or absence of preoperative chemotherapy was selected as an independent prognostic factor for yp/pStage I [hazard ratio (HR)=17.72; p=0.001] and yp/pStage II (HR=2.655, p=0.003).

ypStage tends to have a worse prognosis than pStage, and further development of multidisciplinary treatment is necessary.