Impact of pCR after Neoadjuvant Chemotherapy and Radical D2 Dissection in Locally Advanced Gastric Cancers: Analysis of 1001 Cases.

Background Advances in perioperative chemotherapy have improved outcomes in patients with gastric cancers (GC). This strategy leads to tumour downstaging and may result in a pathologic complete response (pCR). The study aimed to evaluate the predictors of pCR and determine the impact of pCR on long-term survival. Methods At the Department of Gastrointestinal and HPB Oncology at the Tata Memorial Centre, Mumbai, 1001 consecutive patients with locally advanced GCs undergoing radical resection following neoadjuvant chemotherapy from January 2005 to June 2022 were included. Results At a median follow-up of 61 months, the median OS was 53 months with a 5-year OS of 46.8%. Ninety-five patients (9.49%) realized a pCR. Non-signet and well-differentiated histology were associated with pCR. pCR was significantly associated with improved OS, 5-year OS 79.2% vs 43.2% (HR 0.30, p < 0.001). On multivariable analysis, the realization of pCR and completion of adjuvant chemotherapy had superior OS. Whereas, signet-ring histology, linitis-like tumors, and high lymph node ratio had adverse outcomes. Conclusion Tumour grade and signet-ring histology predict achievement of pCR in locally advanced GCs after neoadjuvant chemotherapy. Patients with pCR have significantly improved survival. Future neoadjuvant strategies should focus on enhancing pCR rates to improve overall outcomes.