Room: AAPM ePoster Library
Purpose: The purpose of this work is to investigate the potential of nanoparticles in enhancement of the abscopal effect, which generates an anti-tumor response to distant metastatic sites. Currently radiation therapy (RT) primarily focuses on treatment of localized tumors, but a large majority of cancer deaths have been shown to be caused by secondary metastases. Nanoparticles, such as gold nanoparticles (GNPs), have been shown to act as radiosensitizers. These were investigated to determine their potential for enhancing the abscopal effect, which could lead to new advancements in the future uses of RT to treat both localized tumors and distant metastases.
Methods: 18 female C57/BL6 mice were implanted with PY230 breast cancer cells, one subcutaneously and one orthotopically. Once tumors developed, mice were randomized. In the treatment group, the subcutaneous tumor was treated with combinations of 6Gy RT, GNPs, and Anti-CD40 as immunoadjuvant. Tumor sizes were measured to assess treatment response.
Results: The analysis of tumor measurements throughout the investigation showed that GNP+RT+AntiCD40 had best effect in tumor regression in both treated and non-treated tumors. 35 days after treatment in the treated tumor, control had 4.2 times higher tumor growth and RT had a 2.8 times higher tumor growth than RT+AntiCD40+GNP. 35 days after treatment in the non-treated tumor, control had 1.9 times higher tumor growth and RT had a 2.4 times higher tumor growth than RT+AntiCD40+GNP.
Conclusion: The enhancement of the abscopal effect is shown to be most visible when using RT+AntiCD40+GNP treatment. This warrants further study allowing for a more in-depth determination of the significance of GNPs functionalized with Anti-CD40 for boosting the abscopal effect. Advantages of using GNPs include potential to track distribution within the tumor volume including distribution of the Anti-CD40 or other immunotherapy drugs loaded on them.
Radiation Therapy, Image-guided Therapy