Radiofrequency Ablation and Immunostimulant OK-432: Combination Therapy Enhances Systemic Antitumor Immunity for Treatment of VX2 Lung Tumors in Rabbits

Abstract

Combining RFA with local injection of immunostimulant OK-432 may lead to indirectly activation of systemic antitumor immunity.

Image-guided Tumor Ablation: Standardization of Terminology and Reporting Criteria—A 10-Year Update

“…Examples of this include modulating antitumor immunity after tumor ablation using vaccines or immunomodulatory agents (63). Yet, this area of research is too premature to provide a well-defined classification system.…”

Combination Radiofrequency Ablation and Local Injection of the Immunostimulant Bacillus Calmette–Guérin Induces Antitumor Immunity in the Lung and at a Distant VX2 Tumor in a Rabbit Model

“…RF ablation was performed under the same protocol in the RF-only and RF/BCG groups. An ablated area with more than a 3-mm ablative margin was confirmed on CT after RF ablation (10).…”

“…Isolation of the VX2 tumors and implantation into rabbits was performed as previously reported (10). Briefly, a single-cell suspension (2.5 Â 10 6 cells per milliliter) of VX2 tumor was prepared, and 0.2 mL of this suspension was injected via a coaxial 20-gauge needle through an 18-gauge needle that was inserted into the lower lobe of the left lung.…”

“…Enhanced antitumor immunity may be able to control systemic tumors. In previous experiments, the combination of RF ablation and local injection of OK-432 induced a systemic antitumor immunity and prolonged survival time (10) because OK-432 stimulates the maturation of DCs (10). Mycobacterium bovis bacillus Calmette-Guérin (BCG) is used to treat bladder cancer as an antineoplastic agent, and enhances immunity by promoting maturation of immature DCs (11).…”

Science to Practice: Can We Expand Focal Interventional Oncologic Ablation Treatments into an Effective Systemic Therapy?

“…Hamamoto et al (1) were able to demonstrate that combination therapy of a lung tumor by using radiofrequency ablation (RFA) with local injection of an immunostimulant, OK-432, resulted in improved survival when compared with other therapies tested in a VX2 rabbit model. In addition, not only was greater tumor regression seen in a second distant ear tumor implanted prior to the therapy, but also reduced tumor growth was seen when a second tumor implantation (ie, rechallenge) was attempted.…”