Dynamic postoperative prognosis and follow-up optimization for gastric cancer patients after neoadjuvant therapy: a multicenter retrospective study.

[BACKGROUND] Conditional survival (CS) estimates the probability of future survival based on time already survived. However, evidence regarding postoperative dynamic follow-up in gastric cancer patients after neoadjuvant therapy (NAT) remains limited. This study aimed to evaluate dynamic prognosis and optimize follow-up for locally advanced gastric cancer (LAGC) patients after NAT.

[METHODS] We retrospectively analyzed 997 LAGC patients who underwent NAT followed by radical gastrectomy across multiple Chinese centers. CS was used to evaluate the probability of surviving for Y years on top of having survived for X years. Prognostic factors for overall survival (OS) and recurrence-free survival (RFS) were identified by Cox regression and incorporated into a model predicting conditional probabilities at 1, 3, and 5 years after surgery. Patients were stratified into high- and low-risk groups using an optimal cut-off of 160 points derived from the RFS nomogram.

[RESULTS] The 3-year OS rate was 61.3%. CS increased with longer postoperative survival, with 3-year conditional overall survival (cOS3) rising from 62.2% at 1 year to 89.3% at 5 years. A similar trend was observed for 3-year conditional recurrence-free survival (cRFS3). Independent prognostic factors included preoperative CA19-9 level, tumor size, ypT stage, ypN stage, and perineural invasion (all P < 0.05). Recurrence analysis showed that 68.7% of high-risk patients experienced recurrence, with 91.9% of events occurring within 2 years.

[CONCLUSIONS] CS enables dynamic assessment of postoperative prognosis in patients with LAGC after NAT, underscoring the importance of intensified early follow-up to facilitate timely detection and intervention for recurrence.