2980 - Clinical Outcomes of Chemoradiotherapy Using Volumetric Modulated Arc Therapy (VMAT) for Locally Advanced Esophageal Cancer: A Single Institute Experience

M. M. Fareed¹, P. M. Shaikh Jr², S. M. Raza³, M. Abubakar³, N. Amjad³, A. Afzal⁴, H. Fatima⁵, M. Mughal⁶, and D. A. Clump II⁷; ¹West Virginia University School of Medicine, Morgantown, WV, ²Department of Radiation Oncology, West Virginia University, Morgantown, WV, ³Shaukat Khanum Memorial Cancer Hospital, Lahore, Pakistan, ⁴Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Punjab, Pakistan, ⁵King Abdulaziz Medical City, Riyadh, Saudi Arabia, ⁶University College London, London, United Kingdom, ⁷West Virginia University Department of Radiation Oncology, Morgantown, WV

Purpose/Objective(s): Locoregional failure is a crucial problem associated with trimodality treatment for locally advanced esophageal carcinomas. The goal of this study is to assess the oncological outcomes of preoperative chemoradiation (dose 45 to 50 Gy delivered by volumetric modulated arc therapy-VMAT) with platinum-based chemotherapy followed by esophagectomy in locally advanced esophageal carcinomas. Materials/

Methods: Patients with cT2-cT4 or node positive esophageal carcinomas who received trimodality treatment between 2017 till 2020 were analyzed retrospectively after approval from institutional board review. Age, sex, weight, stage, histology, grade, tumor location, TNM stage, dose, fractionation, use of induction and/or concurrent chemotherapy, surgery type and resection margins were included in the analysis. Primary end point was disease free and overall survival. Multivariate analysis (MVA) was performed to uncover factors influencing the endpoints.
Results: A total of 122 patients were included in the study. Mean follow-up was 13.4 months. Mean age was 47 years (Range 23—81). There were 55 males and 67 females. 99 patients had cT3 (82%) whereas 58 (47.5%) had cN1 disease. The most common histology was Squamous cell carcinoma,102 (83.6%) and the most common grade was moderate, 92 (75.4%). Most patients received induction (n=99, 81%) and concurrent chemotherapy (n=116, 95%). Concurrent chemoradiation with a dose of 50 Gray in 25 fractions with platinum-based chemotherapy was the most common regimen. Sixty-five patients were treated with definitive intent and did not receive surgery, and 57 patients were treated with pre-operative intent of whom 56 (98%) underwent surgery. The most common surgical method was 3-stage Esophagectomy that was performed in 40 (70% of pre-operative intent) patients. After chemoradiation, in the pre-operative group, R0 resection was achieved in 38 patients (66.7%). At 2-years, the overall survival significantly improved in pre-operative group compared to definitive group (72% vs 32%, p=0.001). Similarly, the disease-free survival was significantly improved in pre-operative group compared to definitive group (78% vs 52%, p=0.03) at 2-years. R0 resection and radiation dose of 50 Gy were associated with better overall survival on MVA. Disease recurrence was seen in 34 (27.9%) with local recurrence in 10 (8.2%), distant metastasis in 20 (16.4%) and both in 4 (3.3%).
Conclusion: Trimodality treatment with a standard preoperative radiation dose and chemotherapy yielded a high pathologic complete response rate, along with better 2-year disease free and overall survival. R0 resection and 50 Gy radiation dose are associated with better OS.