Linsky, Paul L.

Background/objectives: Improvements in esophageal adenocarcinoma (EAC) treatment have reduced mortality. While chemoradiation before surgery was previously a standard of care, updated guidelines recommend peri-operative chemotherapy without chemoradiation. Continued investigation into optimal non-operative treatment paradigms for patients who defer surgery or are not candidates for surgery and certain chemotherapy regimens is needed. The impact of induction chemotherapy prior to chemoradiation on survival and surgical outcomes remains unclear. This study assessed survival and surgical outcomes in a real-world cohort of EAC patients receiving induction chemotherapy before chemoradiation. Methods: This single-institution, IRB-approved, retrospective cohort study included patients with newly diagnosed stage II-IVb (oligometastatic for IVb) EAC who received definitive chemoradiation (radiation ≥ 40 Gy and two cycles of chemotherapy) +/− esophagectomy from 2007 to 2022. Patients receiving induction chemotherapy were compared to those who did not. Endpoints included survival and surgical outcomes. Results: A total of 141 EAC patients received definitive chemoradiation; 83 received induction chemotherapy before chemoradiation. Patients receiving induction chemotherapy were younger (p < 0.01) with slightly lower performance status (p = 0.27) and presented at a more advanced stage (p < 0.001). Median OS was 3.5 years in the induction chemotherapy group compared to 2.2 years (p = 0.10). There was no difference in pathologic complete response (p = 0.81), esophagectomy frequency (p = 0.87), or surgical downstaging between treatment groups (p = 0.84). Conclusions: In this real-world, single-institutional patient cohort investigating induction chemotherapy prior to chemoradiation in EAC, patients receiving induction chemotherapy did well but did not have a statistically significant improvement in survival outcomes or surgical outcomes. This study showed that significant numbers of real-world patients may not receive esophagectomy. Thus, prospective, randomized clinical trials are warranted to better delineate the efficacy and selection of patients for induction chemotherapy when non-operative approaches are favored.

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.