ESTRO 2024 - Abstract Book

S1025

Clinical - Gynaecology

ESTRO 2024

1035

Digital Poster

18FDG-PET response after chemoradiation of cervical cancer: detection of oligo-metastatic disease

Ludovica Forlani 1,2 , Federica Medici 1,2 , Viola Laghi 1,2 , Johnny Ma 1,2 , Savino Cilla 3 , Gabriella Macchia 4 , Francesco Deodato 4,5 , Anna Myriam Perrone 1,6 , Pierandrea De Iaco 1,6 , Claudio Zamagni 7 , Paolo Castellucci 8 , Stefano Fanti 1,8 , Andrea Galuppi 2 , Alessandra Arcelli 2 , Martina Ferioli 9 , Silvia Cammelli 1,2 , Alessio Giuseppe Morganti 1,2 1 Department of Medical and Surgical Sciences (DIMEC), Oncology, Alma Mater Studiorum University of Bologna, Bologna, Italy. 2 Radiation Oncology, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy. 3 Medical Physics Unit, Gemelli Molise Hospital - Università Cattolica del Sacro Cuore, Campobasso, Italy. 4 Radiation Oncology, Gemelli Molise Hospital - Università Cattolica del Sacro Cuore, Campobasso, Italy. 5 Istituto di Radiologia Oncology, Università Cattolica del Sacro Cuore, Roma, Italy. 6 Gynecologic Oncology, IRCCS Azienda Ospedaliero Universitaria di Bologna, Bologna, Italy. 7 Oncology Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy. 8 Nuclear Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy. 9 Radiation Therapy Unit, Azienda USL-IRCCS of Reggio Emilia, Reggio Emilia, Italy

Purpose/Objective:

Concurrent chemoradiation (CRT) followed by brachytherapy (BRT) boost is the established treatment for locally advanced cervical cancer (LACC). Nevertheless, a notable fraction of patients experience pelvic recurrence or distant metastases following CRT-BRT. Efforts to enhance outcomes through adjuvant systemic treatments have yielded limited success in most trials, often due to their application without stratification based on the risk of treatment failure. Meanwhile, the availability of stereotactic body radiotherapy (SBRT) may present a second curative option for patients with early oligometastases. This analysis aims to assess whether post-CRT-BRT 18F FDG-PET/CT scans can: i) provide prognostic insights, ii) facilitate early identification of patients with oligometastatic disease as potential candidates for SBRT.

Material/Methods:

We retrospectively analyzed LACC patients treated in our institution from 2007 to 2021. All patients underwent definitive CRT plus BRT boost and received an 18F-FDG-PET/CT scan 2-3 months after treatment completion. Survival curves were calculated using the Kaplan-Meier method and compared with the log-rank test.

Results:

A total of 168 patients were included in the study. The findings, as summarized in Table 1 , revealed the following: Five-year overall survival rates were 89.5%, 0.0%, and 16.3% in patients with complete response (CR), partial response (PR), and no change/progressive disease (NC/PD) on the initial 18F-FDG-PET/CT after CRT-BRT, respectively (p<0.001). Notably, among patients experiencing disease progression but no local progressive/residual LACC on their first post-CRT-BRT 18F-FDG-PET/CT scan, 37.5% had only oligometastatic disease. Additionally, among patients with CR on their initial 18F-FDG-PET/CT after CRT-BRT, 18 eventually experienced treatment failure at subsequent follow-up evaluations. Encouragingly, 61% of these patients had only isolated nodal recurrences or distant oligometastases.