OA03-RF01.01. Patterns and Predictors of Recurrence in Patients With Esophageal Cancer Who Achieve Pathological Complete Response to Multimodal Therapy

Topic Esophageal Cancer: Adjuvant and Neo-Adjuvant Therapies Background Neoadjuvant chemoradiotherapy (nCRT) and chemoimmunotherapy (nICT) are increasingly used for locally advanced esophageal squamous cell carcinoma. Although pathological complete response (pCR) is associated with favorable survival, nearly one third of pCR patients still experience recurrence. This study aimed to identify risk factors and recurrence patterns in this population. Methods We retrospectively reviewed 392 patients who achieved pCR after nCRT or nICT from two tertiary-referral centers between 1/2016 and 9/2023. Predictors and patterns of recurrence were evaluated using competing-risk models. Results The median follow-up time was 48.3 (interquartile range [IQR]: 41.9-60.7) months. A total of 61 patients (15.6%) developed disease recurrence with 37 after nCRT and 15 after nICT. The 2-year and 5-year cumulative incidence of recurrence in nCRT group was higher than that in the nICT group, showing 15% vs 8.9% and 23% vs 17%, respectively (P=0.032). Regarding specific sites of recurrence, nCRT group demonstrated a significantly increased cumulative incidence of distant recurrence than nICT group (P=0.002). After multivariable analysis, incomplete neoadjuvant therapy was independently predicting recurrence in nCRT group (adjusted hazard ratio[aHR] 2.86, P=0.005), whereas advanced cN stage (N2-3) was the only predictor significantly associated with relapse in nICT group (aHR 3.99, P=0.005). Conclusion Recurrence was not rare among patients who achieve pCR. Patterns of recurrence between nCRT and nICT were significantly differed, with higher incidence of distant recurrence found in nCRT. Factors predicting recurrence may alter in different modalities.