Conditional Survival Rate of Patients Undergoing Gastrectomy with D2 Lymph Node Dissection After Neoadjuvant Chemotherapy: A Retrospective Study.

[BACKGROUND] The conditional survival rate is a dynamic estimation method that changes over time. Our research aimed to assesses the conditional disease-specific survival rate and conditional recurrence-free survival rate among patients who undergoing radical gastrectomy for gastric cancer after neoadjuvant chemotherapy.

[METHODS] This study included 260 patients who undergoing gastrectomy with D2 lymph node dissection after preoperative chemotherapy. The 2-year conditional disease-specific survival rate (CDS2) indicates that patients who have survived for x years after initial treatment will survive for another 2 years, calculated as follows: CDS2 = Disease-Specific Survival (DSS) ( + 2)/ Disease-Specific Survival (). Similarly, the 2-year conditional recurrence free survival rate (CRFS2) formula is as follows: CRFS2 = Recurrence-Free Survival (RFS) ( + 2)/ Recurrence-Free Survival (). Cox proportional risk regression analysis was used to identify factors related to DSS and RFS.

[RESULTS] The 1-, 3-, and 5-year actuarial DSS rates were 82%, 57.6%, and 50.7%, respectively. According to conditional disease-specific survival rate (CDS) estimation, the CDS2 of patients who have already survived for 1 year, 3 years, and 5 years is 70.2%, 88%, and 93.3%, respectively. The RFS actuarial rates for 1 year, 3 years, and 5 years were 73.1%, 52.5%, and 46.4%, respectively. According to conditional recurrence free survival rate (CRFS) estimation, the CRFS2 of patients who survived for 1 year, 3 years, and 5 years without recurrence was 71.8%, 88.4%, and 100%, respectively. Lymph vessel infiltration, ypN stage, tumor differentiation, TRG grading, and surgical type are risk factors for DSS and RFS.

[CONCLUSION] The CDS and CRFS of patients undergoing gastrectomy with D2 lymph node dissection after neoadjuvant chemotherapy demonstrate gradual increase over time. Patients with adverse tumor characteristics exhibited the most substantial improvement in both CDS and CRFS.