ESTRO 2024 - Abstract Book

S2276

Clinical - Upper GI

ESTRO 2024

2962

Digital Poster

Comparing pathological response in bulky and non-bulky esophageal cancer after neoadjuvant treatment

Dr Arya Bhanu 1 , Dr Anjali Pahuja 2 , Dr David K Simson 1 , Dr Varghese Antony 1 , Dr Souharda Lohani 1 , Dr Shilpa Pati 1 , Dr Sumit Goyal 1 , Dr Shivendra Singh 1 , Dr Munish Gairola 1 , Dr Jaskaran Singh sethi 1 1 Rajiv Gandhi Cancer Institute and Research center, Radiation Oncology, delhi, India. 2 Rajiv Gandhi Cancer Institute and Research center, Radiation Oncology, Delhi, India

Purpose/Objective:

CROSS trial, a landmark study in oesophagal cancer, has established the pivotal role of neoadjuvant chemoradiotherapy (NACTRT). Cancers with smaller volumes were included in this study. However, in India, the treatment volumes commonly encountered in clinical practice are more significant than this study protocol. Our study aims to compare the clinicopathological outcomes of bulky versus non-bulky disease to neoadjuvant concurrent chemoradiation.

Material/Methods:

This study is a retrospective analysis of all patients with squamous cell carcinoma who underwent neoadjuvant concurrent chemoradiation (NACT-RT) followed by radical surgery at our institute from November 2019 to May 2022. All patients should have undergone pre-treatment and post-treatment Positron Emission Tomography and CT (PET- CT) and Upper gastrointestinal endoscopy (UGIE). Patients under 18 years, who have adenocarcinoma histology and those who took incomplete treatment from our institute were excluded. They were treated with neoadjuvant chemoradiation with radiation therapy (RT) to a dose of 41.4 Gy in 23 fractions concurrent with weekly paclitaxel and carboplatin. Surgery was planned after 6 to 8 weeks. All patients were treated with the Intensity Modulated Radio Therapy (IMRT) technique under image guidance. The clinical and pathological correlation was noted. Patients who did not meet the CROSS eligibility criteria in tumour length and width (more than 8cm in length and 5 cm in maximum radial width) were defined as a bulky disease (BD), and those who had lesser dimensions than mentioned above were defined as non-bulky disease (NBD). Cinico-pathological parameters were compared between the two groups. All the statistical analysis was done using Statistical Package for Social Sciences (Version 28.0, Armonk, NY: IBM Corp).

Results:

Seventy-nine patients were included in our study. Among these patients, 31 (40%) had BD and 48 (60%) NBD. The mean Gross Tumor Volume (GTV), including volume of the primary disease and nodal disease, in BD was 87.9 cc, and in NBD was 39.5 cc (p=0.02). While the mean Planning Target Volume (PTV) in BD was 532.3cc, and in NBD was 319.9cc (p=0.16). The median age of patients in BD was 54 years (range: 29 - 68), whereas for NBD, it was 59.5 (range: 31 - 73). The mean reduction in PET SUV values in BD and NBD patients was 61.53% and 53.40% respectively (p=0.453). Out of the 31 BD patients, post-treatment UGIE after NACT-RT showed 21 patients (67.7%) with complete response (CR), whilst 36 out of 48 patients (75%) in the NBD had CR (p=0.48). Similarly, out of 31 BD patients, 18