ESTRO 2025 - Abstract Book

S1838

Clinical – Upper GI

ESTRO 2025

Material/Methods:

Between 2015 and 2024, 18 patients (19 lesions) with histologic diagnosis of cholangiocarcinoma (intrahepatic: 14; extrahepatic:4; perihilar:1) were treated with SBRT in our center. Gender: 13 M, 5 F. Mean age: 76 y (95%CI: 71-81). TNM stage: most patients were T1-T2N0 (90%). All patients were treated in a Tomotherapy unit with abdominal compression and delineation of an ITV encompassing respiratory cycle movement of GTV. Mean PTV: 115 cc (95%CI: 63-167). Mean prescription dose: 46.3 Gy (range: 35-54). Mean dose per fraction: 12.1 (range: 7-18). Mean tumoral biologically effective dose (BED): 105 Gy 10 (range: 60-151). The dosimetric parameters and dose to healthy tissues are shown in figure 1. No patients received neoadjuvant or concomitant chemotherapy. Evaluation of response by RECIST criteria. Statistics: Student T test, Chi square, Kaplan-Meier. Results: After a mean follow-up of 17 months, the objective response was: CR: 3 p.(16%), PR: 8 p.(42%), SD: 6 p.(32%) and PD: 2 p.(11%). There was a non-significant trend toward reduction in tumor size after SBRT (mean post-SBRT size of 28 mm versus 35 mm; p=0.056). Patients who respond had a lower in-field relapse rate (0%, 50%, 16% and 100% for CR, PR, SD and PD, respectively) and lymph node metastases rate (0%, 37%, 0% and 100% for CR, PR, SD and PD, respectively). Only a few patients had elevated tumor marker levels (CEA: 2 p.(11%); CA199: 5 p.(28%). One- and 2-y TLRFS, HRFS, LNMFS, DMFS and OS were 62%, 61%, 69%, 91%, 62% and 52%,49%, 55%, 52%, 47%, respectively. Dose, BED, tumor size and tumor markers had no influence on either recurrence or survival. Toxicity was mild and limited to alteration of liver function tests. There was no grade 3-4 toxicity. Conclusion: In this series of elderly patients with nonsurgical cholangiocarcinoma, SBRT offers a good overall response and survival with an excellent tolerance. SBRT should be considered as a potential part of treatment in chemotherapy prospective trials.

Keywords: Cholangiocarcinoma, SBRT