Nanoshell Technology and Laser Ablation as a New Treatment for Mast Cell Disease

Photobiomodulation/Laser Therapy

Nanoshell Technology and Laser Ablation as a New Treatment for Mast Cell Disease

September 17 2023
Andrew J Rosenfeld, DVM, ABVP

By Andrew J Rosenfeld, DVM, ABVP

The use of laser light therapy (photobiomodulation) with specific light sensitive dyes for the treatment of specific types of tumors has been utilized for decades. There have been new discoveries of nano-particles made from noble elements such as gold that have an increased sensitivity to visible and near-infrared light absorption as compared to conventional laser phototherapy agents. The mechanism of action for these new particles as they enter the body by intravenous administration is to concentrate in tissue with altered vascular permeability, such as tumor masses. Then, when the nanoparticles are irradiated with laser light, electrons within the nanoparticles enter an excited state. The electron excitation releases the energy through heat production, causing an overheating of the regional tissue, local cell death, and destruction. The gold nanoparticles commonly utilized are gold nanospheres, nanorods, and nanocages, all of which have demonstrated an increased ability to absorb visual and near infrared light. The size and shape of the particles allow for vibration and spinning excitation, which further produces heat and necrosis to tissue when applying focused laser light to these areas.

Mast cell tumors account for 17.8 percent of all canine skin tumors diagnosed. The majority of these tumors reside in the skin or subcutaneous tissue. The breeds with the most concern of high-grade mast cell tumors overall are the Shar-Peis, Weimaraners, and Boxers. Prognosis can be controversial and dependent upon the location of the tumor. Treatment of mast cell tumors in canines commonly involves surgical excision, with the goal of obtaining microscopically tumor-free surgical margins. The veterinary researchers are divided as to poor prognosis: Certain veterinarians feel a poor prognosis comes with a diagnosis of a poorly differentiated tumor, whereas other investigators relate a poor prognosis associated with difficulties in performing surgery. Thus, the worse prognosis may be associated with the difficulty of applying an appropriate surgical procedure and incomplete tumor resection.

Companion Animal Health is now conducting clinical trials utilizing Nanotherapy in several tumor types and recently completed a pilot study with small mast cell tumors. These nanoparticles are made with a gold shell with a non-conducting silica core; their average size is 150 nanometers in diameter. The particles target cancerous tissue, including low grade mast cell tumors due to alterations in the endothelium of the blood supply of these masses. The tissue is then irradiated with focused infrared laser energy. Initial data from this study was presented at ACVIM in 2018 and revealed that 100% of patients all responded to Companion Nanotherapy, with 67% maintaining remission. The procedure was completed as a single treatment with very low rate of toxicity (See figures 1-8).

There are currently more formal study groups in progress at multiple trial sites looking at Companion Nanotherapy’s use in Oral Squamous Cell Carcinoma (Cats), Oral & Cutaneous Melanomas (Dogs), and Soft Tissue Sarcomas (Dogs). To date, this treatment modality has been used with over 130 dogs & cats with various types of tumors. All patients have shown a very low rate of toxicities/ complications thus far.

Given the current treatment options for low-grade cutaneous mast cell tumors to date, nanoshell therapy and photothermal ablation may offer patients a non-surgical one-time treatment option with limited to no complications. This treatment modality may allow veterinarians to shrink and stop tumor growth in patients that have masses in regions where surgery may not be as successful which, with limited surgical margins, may affect prognosis.

References

Xiaohua Huang & Prashant K. Jain & Ivan H. El-Sayed and Mostafa A. El-Sayed. Plasmonic photothermal therapy (PPTT) using gold nanoparticles. Lasers Med Sci (2008) 23:217–228. DOI 10.1007/s10103-007-0470-x

Anna Śmiech , Brygida Ślaska, Wojciech Łopuszyński, Agnieszka Jasik, Diana Bochyńska and Roman Dąbrowski. Epidemiological assessment of the risk of canine mast cell tumours based on the Kiupel two‑grade malignancy classification. Śmiech et al. Acta Vet Scand (2018) 60:70. https://doi.org/10.1186/s13028-018-0424-2

J. J. Thompson1, D. L. Pearl2, J. A. Yager3, S. J. Best3, B. L. Coomber4, and R. A. Foster. Canine Subcutaneous Mast Cell Tumor: Characterization and Prognostic Indices. Veterinary Pathology 48(1) 156-168

Milan Milovancev DVM, DACVS-SA, Katy L. Townsend BVSc (Hons) MS, DACVS-SA, Joanne L. Tuohy DVM, PhD, DACVS-SA, Elena Gorman DVM, MS, DACVP, Shay Bracha DVM,DACVIM(Oncology), Kaitlin M. Curran DVM,MS, DACVIM (Oncology), Duncan S. Russell BVMS (Hons), DACVP. Long-term outcomes of dogs undergoing surgical resection of mast cell tumors and soft tissue sarcomas: A prospective 2-year-long study. 2019 The American College of Veterinary Surgeons, Veterinary Surgery. 2020;49:96–105.

Dr. Lisa Parshley, PhD, DVM, DACVIM (Oncology). Nanoparticle and laser thermal ablation in canine low-grade mast cell tumor. Proceedings, ACVIM Forum, 2018. Olympia Veterinary Cancer Center, Olympia, WA, 2020.