Abstract 452P
Background
Many studies have used pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) as the primary endpoint for the short-term efficacy in gastric cancer, but whether it is a good indicator for overall survival is poorly understood.
Methods
A retrospective cohort study was conducted. Collect clinical and pathological data of 331 patients with locally advanced gastric cancer who achieved pathologic complete response after neoadjuvant therapy (pCR group) and non pathologic complete response patients (non-pCR group) who were strictly matched according to age, gender, clinical T stage, and N stage in a 1:1 ratio, admitted to 12 medical centers including Fudan University Affiliated Cancer Hospital in China from January 2018 to October 2023. Observation indicators: (1) Comparison of general clinical data, neoadjuvant treatment plans, cycles, and surgical outcomes between two groups. (2) Follow up. Postoperative adjuvant therapy, postoperative recurrence and metastasis, and survival status. The follow-up period is up to November 2023. The Kaplan Meier method was used to plot the survival curve and calculate the survival rate. The survival analysis was compared using the Log rank test.
Results
We found that serum oncological indicators, signet ring cell carcinoma, and neoadjuvant therapy pattern were closely related to pCR. Survival analysis found that patients with ypN0 in pCR, OS and DFS were significantly higher than non-pCR patients (both P<0.001). However, there was no statistically significant difference in OS (P=0.185) and DFS (P=0.108) between patients with ypN+ in pCR and non-pCR patients. In addition, there was no significant difference in OS and DFS between patients who received adjuvant chemotherapy after surgery and those who did not receive adjuvant chemotherapy in the pCR group (P>0.05).
Conclusions
pCR is an independent prognostic factor affecting OS and DFS in locally advanced gastric cancer after neoadjuvant therapy, but the survival benefits of pCR only exist in patients with ypT0N0, while patients with ypT0N+ cannot benefit from pCR. In addition, adjuvant chemotherapy may not improve the prognosis of pCR patients after neoadjuvant therapy.
Legal entity responsible for the study
The authors.
Funding
National Natural Science Foundation of China.
Disclosure
All authors have declared no conflicts of interest.