Introduction: Locally advanced unresectable pancreatic cancer (LAPC) has a dismal prognosis, with intratumoral therapies showing limited benefits. We assume that the dense stroma within these tumors hampers drug dispersion.
Aim: This study explores the efficacy of multisite intratumoral injections in improving a drug's distribution while minimizing its side effects.
Methods and results: In mice with orthotopic LAPC tumors, weekly intratumoral injections of oxaliplatin at four separate sites reduced the tumor growth by 46% compared with saline (p < 0.003). Oxaliplatin exhibited the greatest impact on the tumor microenvironment relative to gemcitabine, Abraxane, or their combination, with increased necrosis, apoptosis, fibroblasts, inflammation, and infiltrating lymphocytes (p < 0.008). When combined with intravenous FOLFIRINOX (FFX), multisite intratumoral oxaliplatin reduced the tumor weight by 35% compared with single-site injection (p = 0.007). No additional visible toxicity was observed even at a 10-fold occurrence of intratumoral treatment. This co-modality treatment significantly improved survival compared with other groups (p = 0.007).
Conclusions: Multisite intratumoral therapy in tandem with systemic treatment holds promise for reducing the tumor size and enhancing the overall survival in LAPC.
Keywords: EUS-FNA; LAPC; drug delivery; stroma.