Experience of Spanish centers with echoendoscopically implanted ³² P microparticles associated with chemotherapy in locally advanced pancreatic adenocarcinoma.

4232 Background: Phosphorous 32 microparticle ( 32 P) brachytherapy delivered by echoendoscopy (EUS) represents an innovative therapy in pancreatic cancer (PC). The device to implant it is approved in unresectable locally advanced PC in combination with gemcitabine-based chemotherapy. Our aim is to present the preliminary efficacy and safety results of a series that brings together the experience of thirteen centres in Spain. Methods: After being assessed by a multidisciplinary committee, patients signed consent to receive intratumoural 32 P by EUS. Complications associated with intratumoural 32P injection via EUS, associated adverse events (AEs) and preliminary efficacy results (progression-free survival [PFS], distant and locoregional, and overall survival [OS]) were analysed. Results: Fifty one patients (32 females and 19 males; age 65.5 years [range 48, 84]; 36 ECOG 1 and 14 ECOG 0) with unresectable locally advanced PC (30 in head, 5 in uncinate, 5 in neck and 11 in body; tumour size 30.8 mm [range 12, 60]) were included. The median time from tumour diagnosis to procedure was 5.9 months [0, 28.9]. Twenty-four patients (47 %) had received at least one previous line of treatment; four had received two prior lines. Fifty patients (98%) received gemcitabine-based chemotherapy concomitant with intratumoural 32P (42 gemcitabine plus nabpaclitaxel; 8 gemcitabine monotherapy. There were two AEs related to 32P injection by EUS: G1 epigastric pain (1 patient) and G2 asthenia (1 patient). A total of 30 patients (58.8%) had chemotherapy-related AEs, with 8 cases of G3 neutropenia (1 febrile neutropenia) and/or G3 thrombopenia; 22 had G1-2 toxicities: neurotoxicity (5), asthenia (4), neutropenia (3), thrombopenia (2), anaemia (4), nausea (2), diarrhoea (2), anorexia (1), onycholysis (1), mucositis (1), and constipation (1). Seven patients (13,7%) underwent surgery after intratumoural treatment (5 R0 and 2 R1). With a median follow-up of 8.7 months after injection (range: 1.02 months to 40.77 months), 25 patients (49.2 %) have progressed, 19 of them distantly, and nine also locoregionally. The median PFS since 32P injection is 8.5 months (95% CI 5.3, 17). 33 patients are alive at the end of follow-up (64.7%) with a median OS since 32P injection of 15.6 months 95% CI [10.2, 26.9]. Conclusions: Our experience suggests that intratumoural 32P associated with gemcitabine-based chemotherapy is safe. Patients after 32P injection achieve long overall survival. Surgical rescue was achieved in a high percentages of initially unresectable cases.