ESTRO 2024 - Abstract Book

S2156

Clinical - Upper GI

ESTRO 2024

Agrawal S, Mohan L, Mourya C, Neyaz Z, Saxena R.Radiological Downstaging with Neoadjuvant Therapy in Unresectable Gall Bladder Cancer Cases.Asian Pac J Cancer Prev. 2016;17(4):2137-40 Azizi AA, Lamarca A, Valle JW. Systemic therapy of gallbladder cancer: review of first line, maintenance, neoadjuvant and second line therapy specific to gallbladder cancer.Chin Clin Oncol. 2019 Aug;8(4):43.

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Digital Poster

Efficacy and safety of palliative radiotherapy during immunotherapy for metastatic esophageal cancer

Takeshi Fujisawa 1,2 , Hidenari Hirata 1,2 , Daisuke Kotani 3 , Hidehiro Hojo 1,2 , Masaki Nakamura 1,2 , Atsushi Motegi 1 , Shun Ichiro Kageyama 2 , Hidekazu Oyoshi 1 , Keiko Fukushi 1 , Yuzheng Zhou 1 , Kento Tomizaw 1 , Sadamoto Zenda 1,2 , Saori Mishima 3 , Takashi Kojima 3 , Tetsuo Akimoto 1,2 1 National Cancer Hospital East, Radiation oncology, Kashiwa-shi, Japan. 2 National Cancer Center, Radiation Oncology and Particle Therapy, Kashiwa-shi, Japan. 3 National Cancer Hospital East, Gastroenterology and Gastrointestinal Oncology, Kashiwa-shi, Japan

Purpose/Objective:

Anti-PD-1 antibody therapy has been established as a key standard treatment for patients with metastatic esophageal squamous cell carcinoma (ESCC). While anti-PD-1 antibody therapy provides prolonged overall survival as monotherapy in the second-line setting and in combination with chemotherapy or ipilimumab in the first-line setting, some patients who receive these treatments experience tumor-related symptoms, including dysphagia and pain. Palliative radiotherapy (RT) with or without cytotoxic chemotherapy is commonly used to improve tumor related symptoms in these populations. The duration of efficacy of palliative RT with or without cytotoxic chemotherapy has been reported to be as short as 3 – 4 months, indicating that much room for improvement exists in optimizing the effects of palliative RT. In the recent anti-PD-1 antibody treatment era, we hypothesized that palliative RT in combination with anti-PD-1 antibody therapy may demonstrate adequate efficacy for local disease control without increasing treatment-related toxicities. However, the efficacy and safety of palliative radiotherapy combined with anti-PD-1 antibody therapy in patients with metastatic ESCC remain unclear. Therefore, we conducted a retrospective study to clarify the efficacy and safety of palliative RT during anti-PD-1 antibody therapy.

Material/Methods:

We retrospectively reviewed the clinical records of patients with metastatic ESCC treated with palliative RT during or within 1 month after the last administration of anti-PD-1 antibody therapy at National Cancer Center Hospital East between January 2018 and April 2022. We evaluated local progression-free survival (LPFS), defined as the interval from the start of palliative RT to local progression in the irradiated field or any cause of death, as well as the local tumor response in the irradiated lesions in accordance with RECIST 1.1, overall survival (OS), and treatment-related adverse events graded by the CTCAE 5.0. We also evaluated PD-L1 expression immunohistochemically with the 28-8 antibody on tumor tissue samples obtained before palliative RT.