ESTRO 2024 - Abstract Book

S1897

Clinical - Mixed sites, palliation

ESTRO 2024

Stereotactic radiotherapy for liver oligometastases: a large real-world analysis

Pezzulla Donato 1 , Elvira Maria Lima 2 , Giuditta Chiliro 2 , Carmela Romano 3 , Silvia Reina 2 , Gabriella Macchia 1 , Giulia Panza 2 , Savino Cilla 4 , Alessio Giuseppe Morganti 5 , Francesco Cellini 2,6 , Maria Antnietta Gambacorta 2 , Francesco Deodato 1,6 1 Responsible Research Hospital, Radiation Oncology Unit, Campobasso, Italy. 2 Fondazione Policlinico Universitario Agostino Gemelli IRCCS, UOC di Radioterapia, Dipartimento di Scienze Radiologiche, Radioterapiche ed Ematologiche, Roma, Italy. 3 Responsible Research Hospital, Medical Physics, Campobasso, Italy. 4 Responsible Research Hospital, Medical Physics Unit, Campobasso, Italy. 5 IRCCS Azienda Ospedaliero, Universitaria di Bologna - Alma Mater Studiorum University of Bologna, Radiation Oncology, Department of Experimental, Diagnostic and Specialty Medicine - DIMES, Bologna, Italy. 6 Istituto di Radiologia, Università Cattolica del Sacro Cuore, Istituto di Radiologia, Roma, Italy

Purpose/Objective:

A large pooled real-world analysis of liver oligometastases treated by stereotactic radiotherapy (SBRT) was carried out.

Material/Methods:

The clinical and dosimetric data of patients who underwent stereotactic radiotherapy for liver metastases from several tumors were collected and analyzed in terms of efficacy and toxicity profile. In particular, the Local Control (LC), the Distant Metastases Free Survival (DMFS), the Disease-Free Survival (DFS), the Overall Survival (OS), and the Next Systemic Therapy Free Survival (NESTFS) rates were analyzed.

Results:

Data of 113 patients (M/F: 49/64), accounting for a total of 150 hepatic lesions, that were treated between March 2006 and February 2023 in two Italian centers were evaluated. The patients' median age was 67 years old (39-92) and 48 (42.5%) patients had at least one comorbidity, mainly cardiovascular ones (61.5%) and diabetes (24.4%). The main primary tumours were colorectal (36.7%) and breast (16.3%) ones. The majority of the lesions could be defined as induced (30.7%) or repeated oligoprogressive (12.7%) metastases according to the ESTRO/EORTC consensus on oligometastases classification1. 98 lesions were treated with more than one daily fraction and 50 Gy in 5 fractions (41.8%) was the most used fractionation. Among the 52 radiosurgery treatments, 28 Gy in a single fraction (26.9%) was the most represented schedule. The median Gross Tumour Volume was 6.3 cc (0.1-106.3), the median Planning Tumour Volume was 23.8 cc (2.9-207.8), and the median liver volume was 1319.7 cc (727.8-2421.2). More details on patient and lesion characteristics are reported in Table 1. At the time of analysis, the treatment response was evaluable in 147 lesions, registering a complete response in 32.0%, partial response in 17.0%, stable disease in 32.0%, and progressive disease in 19.0%. As per the toxicity profile, we registered only 2 acute toxicity cases higher than grade 2 (2 Grade 3 hepatic toxicities), while only one late toxicity cases were higher than grade 2 (1 Grade 4 bone toxicity). Actuarial LC, DMFS, DFS, OS, and NESTFS at one year were 75.8%, 37.7%, 34.9%, 78.7%, and 54.7% respectively; while actuarial LC, DMFS, DFS, OS, and NESTFS at two year were 52.1%, 24.9%, 21.9%, 51.3%, and 36.8% respectively. In terms of LC, patients who had no treatment interruption had statistically significant higher LC rates than those who had one or more days of treatment interruption (79.9% vs 69.0% at one year; p: 0.018). Finally, a