ALTOPANC: Local ablative therapies in oligometastatic pancreatic adenocarcinoma—A bi-national French-Belgian retrospective study.

Abstract

728 Background: Oligometastatic disease (OMD) in pancreatic ductal adenocarcinoma (PDAC) is an emerging clinical entity. The limited extension of the disease prompt to explore the role of metastases-directed therapies (MDT); however, their actual survival and clinical benefits remain uncertain. Additional studies with larger effectives are needed to clarify the role of MDT in clinical practice. Methods: We conducted a retrospective multicenter, observational French-Belgian study to evaluate the impact of MDT on event-free survival (EFS) and overall survival (OS) in patients with OMD-PDAC. OMD was defined as metastases (mets) involving no more than 2 organ and ≤5 mets (Leonhardt CS. ESMO Open 2023). Eligible patients were adults with histologically confirmed PDAC who underwent a resection of the primary tumor, with concurrent or subsequent MDT of MDT. OS was defined as the delay from MDT to death from any cause; EFS was calculated from the date of MDT until radiologically confirmed disease progression, recurrence or death. The ALTOPANC score—based on known prognostic factors (CA 19-9 >90 U/mL, > 1 met, and non-pulmonary mets)—was correlated with OS and EFS. Results: Between 01/2011 and 12/2024, 155 patients with OMD-PDAC were included; 138 had metachronous metastases. Sites of mets included liver (n=71, 45%), lung (n=61, 39%), periaortic lymph nodes (n=13, 8%) and peritoneum (n=5, 3%). At time of the met's diagnosis, 107 patients (71%) had a single met, and 25 (17%) patients had presented two mets. After a median follow-up of 4.42 years, median EFS and median OS in the entire population were of 0.8 and 3,4 years respectively. MDT modalities consisted in surgery (n=69, 45%), radiotherapy (n=50, 32%), and thermoablation (n=36, 23%). In the multivariate Cox model, higher CA 19-9 level (HR = 1.29, 95% CI: 1.13–1.48, p = 0.0002) and the presence of 2 (HR = 2.54, 95% CI: 1.32–4.88, p <0.0001) or ≥3 treated mets (HR = 4.39, 95% CI: 2.18–8.84, p <0.0001) were independent adverse prognostic factors for OS. Thermoablation was independently associated with an improved OS compared to other technics (HR=0.51, 95%CI: 0.27–0.96, p =0.0127). The ALTOPANC score was significantly associated with EFS :2-year EFS rates were 53.1%, 23.8%, 8.3%, and 0% in patients with scores of 0, 1, 2, and 3, respectively (p < 0.001). A similar trend was observed for OS. Conclusions: 1) This real-world, study shows promising results of MDT in patients with OMD-PDAC, particularly thermoablation ; 2) among patients with favorable prognostic profile (low ALTOPANC score) may have the higher benefit. A prospective randomized study is warranted to confirm these results.