ESTRO 2024 - Abstract Book

S2179

Clinical - Upper GI

ESTRO 2024

Unlike reported trials from the West which predominantly consisted of adenocarcinoma histology, the common histology in the Asian belt is squamous cell carcinoma (2). In this retrospective study, we have analyzed the pathological complete response (pCR) rates, R0 resection rates, surgical morbidity, and survival rates following NACTRT in locally advanced operable esophageal cancers.

Material/Methods:

This was a single institution retrospective study where all patients with operable locally advanced esophageal cancer planned for NACTRT followed by surgery were screened and included. All patients were evaluated using baseline PET CECT and upper gastrointestinal endoscopy. NACTRT consisted of external beam radiotherapy to a dose of 41.4Gy in 23 fractions using volumetric modulated arc therapy (VMAT) along with concurrent chemotherapy consisting of concurrent taxane – platinum doublet. The patients were then reassessed for surgery after 4 weeks using PET CECT. The surgical approach and extent of lymph node dissection were based on the location of primary and nodal involvement. Patients were followed up with clinical and radiological investigations after treatment completion.

Results:

A total of 102 patients treated during 2021 – 2022 were screened and included in the study. The median age of the study population was 56 years with almost equal proportions of both sexes (49% males and 51% females). 51% of patients had mid-thoracic disease whereas 49% had predominantly lower esophageal cancer. 99% of the histology was squamous with 49% of patients having moderately differentiated SCC. 98% of patients had T3 stage and 97% of patients had N stage of N0-1. 100 out of the 102 patients completed the planned NACTRT. One patient died due to treatment-related complications and for the other patient, the radiotherapy was terminated at 36Gy following COVID-related treatment break. All patients were treated with the VMAT technique (100%) to a dose of 41.4Gy in 23 fractions once a day for 4.5 weeks (Mean radiotherapy treatment duration was 33 days) along with 5 cycles (63.7%) of concurrent paclitaxel and carboplatin. 96 patients (94.1%) underwent surgery subsequently. Four patients had distant disease progression on response assessment imaging, one patient was deemed inoperable due to esophageo-pleural fistula and one patient died during NACTRT. The mean interval between radiotherapy completion and surgery was 8.2 weeks. Two-field transthoracic total esophagectomy was the most common surgical procedure (83%). 98% of patients underwent R0 resection. The pCR rate in this study cohort was 59.4%. The Class III/IV Clavien Dindo classification was 27.1% and 7.3% respectively. The postoperative mortality was 2% with anastomotic leak being the most common complication (23%) which was mostly managed non-operatively. Other complications were vocal cord palsy (14.6%), pulmonary (13.5%), and cardiac (8.3%) complications and chylothorax (7.3%). The median follow-up was 18 months (IQR 11 – 24 months). 1-year and 2-year overall survival in the study population were 87.6% and 85.7%. The 1-year and 2-year DFS were 80.9% and 75.5%. The failure rates were 13.5% among the patients who underwent NACTRT followed by surgery with the most common pattern being locoregional failure (10.4%). The most common site of failure was nodal failure. However, only 2 out of 9 locoregional failures were in-field. Distant failures were seen in 6.3% of patients.

Conclusion: