Combined chemotherapy and EUS-guided intra-tumoral 32-P implantation for locally advanced pancreatic ductal adenocarcinoma: a pilot study

AIM: This study evaluated clinical outcomes of combined chemotherapy and Endoscopic Ultrasound (EUS) guided intra-tumoral radioactive phosphorus-32 (32P OncoSil) implantation in locally advanced pancreatic adenocarcinoma (LAPC).

METHODS: Consecutive patients with a new histological diagnosis of LAPC were recruited over 20 months. Baseline CT and 18FDG PET-CT were performed and repeated after 12 weeks to assess response to treatment. Following 2 cycles of conventional chemotherapy, patients underwent EUS-guided 32P OncoSil implantation followed by a further six cycles of chemotherapy.

RESULTS: Twelve patients with LAPC (8M:4F; median age 69 years, IQR 61.5-73.3) completed the treatment. Technical success was 100% and no procedural complications were reported. At 12 weeks, there was a median reduction of 8.2cm3 (95% CI 4.95-10.85; p=0.003) in tumour volume, with minimal or no 18FDG uptake in 9 (75%) patients. Tumour downstaging was achieved in 6 (50%) patients, leading to successful resection in 5 (42%) patients, of which 4 patients (80%) had clear (R0) resection margins.

CONCLUSIONS: EUS guided 32P OncoSil implantation is feasible and well tolerated and was associated with a 42% rate of surgical resection in our cohort. However, further evaluation in a larger randomized multicenter trial is warranted. (32P funded by OncoSil Medical Ltd, equipment and staff funded by the Royal Adelaide Hospital, ClinicalTrials.gov number, NCT03003078).