ESTRO 2024 - Abstract Book

S2202

Clinical - Upper GI

ESTRO 2024

1735

Digital Poster

SABR FOR LIVER DE NOVO, REPEAT, AND INDUCED OLIGOMETASTATIC DISEASE.

Miriam Torrisi 1,2 , Chiara Lucrezia Deantoni 1 , Laura Giannini 1,2 , Andrei Fodor 1 , Lucia Perna 3 , Sara Broggi 3 , Martina Midulla 1,2 , Roberta Tummineri 1 , Claudio Fiorino 3 , Najla Slim 1 , Paolo Passoni 1 , Antonella Del Vecchio 3 , Stefano Arcangeli 4,2 , Nadia Gisella Di Muzio 1,5 1 IRCCS Ospedale San Raffaele, Radioterapia, Milano, Italy. 2 Università degli studi Milano Bicocca, Radioterapia, Monza, Italy. 3 IRCCS Ospedale San Raffaele, Fisica Medica, Milano, Italy. 4 IRCCS San Gerardo dei Tintori, Radioterapia, Monza, Italy. 5 Università Vita Salute San Raffaele, Radioterapia, Milano, Italy

Purpose/Objective:

Non-surgical local ablative approaches for liver metastasis are increasingly used for patients (pts) not eligible for surgery. The role of Stereotactic Ablative Radiotherapy (SABR) in the management of oligometastatic cancer pts have been widely investigated confirming its safety and efficacy. Here we report our results based on the ESTRO EORTC definition of oligometastatic disease (OMD).

Material/Methods:

All pts with OMD treated at our institution with SABR from 02/2016- 02/2023, were retrospectively investigated. SABR was delivered with Helical Tomotherapy® (HT) or CyberKnife® (CK). For CK pts a median number of four (3-8) radiopaque gold fiducials were implanted before the treatment. All pts underwent contrast-enhanced simulation CT scan. Based on the metastatic disease history all pts were divided into 3 groups. Group 1 includes de-novo OMD (NOMD) (32 pts), group 2 repeat OMD (ROMD) (14 pts),and group 3 induced OMD (IOMD) (10 pts). Kaplan-Meyer estimate was used to report Overall survival (OS) and Local Relapse Free Survival (LRFS). Toxicity was registered according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0.

Results:

A total of 56 lesions in 40 pts were treated. Median age of the patients at diagnosis was 66 years (29-83). Median follow up was 14.5 months (0.6-81.9). Twenty-five lesions were treated with CK, the remaining 31 with HT. Median number of liver metastases/patient was 4 (1-6). Median GTV was 16.65 (0.3-631.7) cc. Median BED, calculated with tumor specific a/b coefficient, was 100 (59.5- 378) Gy. No ≥ G3 toxicities and radiation -induced liver disease (RILD) were recorded. OS at 6- and 12-months of NOMD, ROMD and IOMD were 90%, 84.6%, 80% and 73%, 75.2%, 70% (p=0.4), respectively. Six- and 12-month LRFS for NOMD, ROMD and IOMD was 85.9%, 100%, 100% and 85.9 %, 77.8% and 100%, respectively (p=0.48) (Figure 1).