Association of Total Neoadjuvant Therapy with Favorable Clinical Outcomes in Patients with Locally Advanced Esophageal and Gastroesophageal Junction Adenocarcinomas (LA-GEJ CA).

231 Background: Both peri-operative chemotherapy and neoadjuvant chemoradiation have been shown to improve outcomes in patients (pts) with LA-GEJ CA compared to surgery alone. Rates of post-operative chemotherapy delivery remain suboptimal. Total neo-adjuvant therapy (TNT) in LA-GEJ CA - induction chemotherapy (IC) followed by concurrent chemoradiation (CRT) - may improve systematic delivery of neoadjuvant therapy and result in favorable clinical outcomes. Methods: We retrospectively reviewed medical records of 135 pts with LA-GEJ CA at our institution between 2/2007 and 11/2019; pertinent clinical data were abstracted with Institutional Review Board approval. Patients treated with IC and curative-intent CRT with ≥40 Gy dose of radiation for adenocarcinoma were included in this analysis (N = 59). Doublet or triplet IC regimens utilizing 5-Flurouracil(5-FU), Cisplatin/Oxaliplatin and Docetaxel were commonly administered while combinations of Carboplatin +Paclitaxel or 5-FU + Oxaliplatin were used in CRT. Clinical complete response (CCR) was defined as metabolic imaging and endoscopic biopsies negative for residual malignancy after completion of TNT. Patients were followed from diagnosis to recurrence and overall survival. Survival probabilities were estimated using the Kaplan-Meier method and compared between groups using a log-rank test. Results: Out of 59 evaluable pts, 69% were clinical stage T3, 71% were node positive. 37 pts (63%) underwent surgery, R0 resection rate was 89% (33/37), pathologic complete response (pCR) rate was 19% (7/37). Among the pts who did not undergo surgery, 41% (9/22) opted to forego surgery since they attained a CCR. For the entire cohort, median Disease-Free Survival (mDFS), median Overall Survival (mOS), and 3-yr OS were 2.4 yrs, 4.7 yrs, and 67% respectively. Pts who did not undergo surgery had a mDFS, mOS, and 3-yr OS of 1.5 yrs, 4.2 yrs, and 59% respectively. Median DFS, mOS, and 3-yr OS of patients who underwent surgery were 3.5 yrs, 5.8 yrs and 72% respectively. Patients who achieved a CCR and opted to forego surgery (N = 9) had a 3 -yr DFS of 42% vs 83% for pts (N = 7) who demonstrated a pCR after curative intent tri-modality therapy. (P = 0.0099) Interestingly, the same group that achieved CCR and opted out of surgery had 3yr OS of 89% vs 83% of those who demonstrated a pCR (p = 0.0042). Conclusions: TNT for pts with LA-GEJ CA is associated with high rates of R0 resection as well as excellent DFS and OS compared to historical controls, warranting prospective evaluation. The remarkable DFS and OS in patients who opted to forego surgery due to achieving CCR is reflective of the local and systemic control rendered by this approach. Careful characterization and close longitudinal follow-up of patients who achieve CCR may help identify a subgroup of LA-GEJ CA pts who may benefit from surgery sparing approaches.