Incidence and prognostic impact of recurrence in esophageal carcinoma patients achieving complete pathological response after neoadjuvant chemoradiotherapy or perioperative chemotherapy.

4069 Background: Esophageal carcinoma remains a global challenge, ranking 7th in cancer-related mortality. While the CROSS trial established neoadjuvant chemoradiotherapy (nCRT) as a standard of care with a 29% pathological complete response (pCR) rate, real-world data in diverse histological populations—particularly Squamous Cell Carcinoma (SCC)—are evolving. We aimed to evaluate the impact of pCR on Overall Survival (OS) and Disease-Free Survival (DFS) in a high-volume surgical cohort. Methods: A retrospective analysis of a prospective database was conducted for patients undergoing curative-intent esophagectomy at a tertiary cancer center (2019–2023). Inclusion: Patients receiving neoadjuvant therapy (nCRT or perioperative chemotherapy). Exclusion: Patients with upfront surgery, palliative resections, or incomplete records. Survival outcomes were analyzed using Kaplan-Meier curve. Results: Of 546 patients, 51% were male with a mean age of 44 ± 9 years. nCRT was the primary neoadjuvant modality (92.3%), followed by perioperative chemotherapy (7.7%). pCR was achieved in 54.8% of patients. At a median follow-up of 5 years, the overall recurrence rate was 27.1%; notably, only 28.3% of the pCR group experienced recurrence compared to the non-pCR group (p < 0.001). Recurrence patterns distant (48.6%), followed by locoregional (44.6%), and both (6.8%). The pCR group demonstrated superior survival outcomes: Mean OS: 57 ± 0.7 months vs 52 ± 1 months in non-pCR (p = 0.001); Mean DFS: 52 ± 1 months vs 35 ± 1 months in non-pCR (p < 0.001). Total study mortality was 8.4%. Conclusions: In this large South Asian cohort, pCR was achieved in over half of the patients following neoadjuvant therapy and served as a robust predictor of both OS and DFS. These findings reinforce pCR as a critical surrogate endpoint for long-term oncological success and suggest that tumor biology in this region may be particularly sensitive to multimodality protocols. Clinical characteristics and survival outcomes. Variable Value (n=546) Tumor Location Distal Esophagus: 52.6%Mid Esophagus: 25.3%Gastroesophageal Junction: 12.6% Histology Squamous Cell Carcinoma (SCC): 85.7%Adenocarcinoma: 14.3% Neoadjuvant Therapy Chemoradiotherapy (nCRT): 92.3%Chemotherapy: 7.7% Surgical Procedure McKeown Esophagectomy: 78.6%Ivor Lewis Esophagectomy:18.7%Trans-hiatal Esophagectomy: 2.7% Pathological Stage (TNM)I/II/III/IV 69.5% / 10.5% / 16.6% / 3.4% Resection Margin R0 (Negative): 95.1%R1 (Microscopic Positive): 4.9% Pathological Complete Response (pCR) Overall: 54.8%Squamous cell Carcinoma: 95.3%Adenocarcinoma: 4.6% Recurrence Overall Rate: 27.1%Recurrence within PCR group: 7.6% Overall Survival (Months) pCR = 57±0.7Residual Disease = 52±1 monthsp=0.001 Disease-Free Survival (Months) pCR = 52±1Residual Disease = 35±1p= <0.001