Combined chemotherapy and endoscopic ultrasound-guided intratumoral 32P implantation for locally advanced pancreatic adenocarcinoma: a pilot study

Background: This study evaluated clinical outcomes of combined chemotherapy and endoscopic ultrasound (EUS)-guided intratumoral radioactive phosphorus-32 (³²P) implantation in locally advanced pancreatic adenocarcinoma (LAPC).

Methods: Consecutive patients with newly diagnosed LAPC were recruited over 20 months. Baseline computed tomography and ¹⁸F-2-fluoro-2-deoxy-D-glucose (¹⁸FDG) positron emission tomography-computed tomography were performed and repeated after 12 weeks to assess treatment response. Following two cycles of conventional chemotherapy, patients underwent EUS-guided ³²P implantation followed by six chemotherapy cycles.

Results: 12 patients with LAPC (median age 69 years [interquartile range 61.5-73.3]; 8 male) completed treatment. Technical success was 100 % with no procedural complications. At 12 weeks, median reduction in tumor volume was 8.2 cm³ (95 % confidence interval 4.95-10.85; P = 0.003), with minimal or no ¹⁸FDG uptake in nine patients (75 %). Tumor downstaging was achieved in six patients (50 %), leading to successful resection in five (42 %), including four R0 resections (80 %).

Conclusions: EUS-guided ³²P implantation was feasible, well tolerated, and resulted in a 42 % surgical resection rate. Further evaluation in a larger randomized multicenter trial is warranted.