Medical Policy

This document addresses the use of nanoparticle-mediated thermal ablation to treat solid tumors. Nanoparticles are instilled into tumor tissue and then exposed to an energy source. Nanoparticle vibration induced by the energy source increases temperature to ablate the targeted tissue. Nanoparticle-mediated thermal ablation is purported to achieve homogeneous heat distribution in tumor tissue while protecting surrounding healthy tissue.

Note: For a high-level overview of this document, please see “Summary for Members and Families” below. 

Investigational and Not Medically Necessary:

Nanoparticle-mediated thermal ablation is considered investigational and not medically necessary for all indications.

This document describes clinical studies and expert recommendations, and explains why we do not consider nanoparticle-mediated thermal ablation to be clinically appropriate. The following summary does not replace the medical necessity criteria or other information in this document. The summary may not contain all of the relevant criteria or information. This summary is not medical advice. Please check with your healthcare provider for any advice about your health.

Key Information

Nanoparticle-mediated thermal ablation is a treatment being studied as a treatment for cancer. It uses very small particles, called nanoparticles, placed in or near a tumor. These particles are then heated using an outside energy source, such as a magnetic field or laser, and the heat destroys cancer cells. The goal is to heat and kill tumor cells while limiting harm to nearby healthy tissue. Some early studies suggest it may target tumors in a precise way, and it may be used along with other treatments like radiation. However, this treatment is still new and not well studied. It has only been tested in small groups, and there are no long-term results. Some people in studies had side effects, including swelling in the brain that caused symptoms like headaches and nerve problems, and some needed more surgery. Because of limited evidence and safety concerns, this treatment is not currently considered appropriate for routine use.

What the Studies Show

Researchers are studying this treatment using different types of nanoparticles and energy sources. One method uses magnetic fields to heat particles placed in tumors. In a small study of people with brain cancer, all participants developed swelling around the treated area. Several people had serious symptoms and needed steroids and surgery to remove the particles. Survival times varied, and the study was too small to show if the treatment improved health. Another approach uses gold-based nanoparticles and laser energy for prostate cancer. In a small study, many people had no cancer in the treated area after treatment, but the study was too small to prove that the treatment works in a wider population.

These studies were early phase trials and included only a small number of people. They were not designed to show clear benefit or long-term safety. Some trials have been stopped early, and others are still ongoing. Major medical societies do not address this treatment. Better studies are needed to know if nanoparticle-mediated thermal ablation improves health and is safe compared to standard treatments.

Is this clinically appropriate?

This treatment is not clinically appropriate because it has not been proven to improve health. Studies have been small and not designed to show clear benefit. Some people had harmful side effects, such as swelling and nerve problems that required more treatment or surgery. In addition, there are no large, high-quality studies with long-term results to confirm safety or effectiveness. Unproven treatments expose people to health risks without a demonstrated health benefit.

(Return to Description/Scope)

Summary

Nanoparticle-mediated thermal ablation is an emerging oncologic treatment approach that uses externally activated nanoparticles to generate localized hyperthermia and ablate tumor tissue. Evidence is limited to small, early-phase studies that are not powered to establish efficacy, with ongoing or terminated trials lacking sufficient long-term follow-up data to determine clinical outcomes. No major medical societies or clinical guidelines address this therapy, and the nanoparticles used are considered investigational devices by the FDA. Overall, the available evidence is insufficient to support safety, efficacy, or routine clinical use.

Description

Magnetic field induction ablation

Grauer and colleagues (2019) reported on 6 individuals with recurrent glioblastoma who underwent intracavitary thermotherapy with nanoparticles subjected to alternating magnetic fields. A total of 6 semi-weekly thermotherapy sessions were conducted using an alternating magnetic field applicator. Radiotherapy was given concurrently to the 4 individuals who were eligible for that treatment. Following tumor resection, the authors reported that the cavity walls were coated with 2 or 3 layers of NanoTherm particles (NanoTherm Therapeutics Inc., Wilmington, DE). Perifocal edema around the nanoparticle deposits developed in all participants approximately 2 to 5 months following treatment. This response resulted in headaches or worsening of pre-existing focal neurological deficits in 4 of the 6 study participants. These 4 individuals required treatment with high dose dexamethasone and additional surgery to remove the nanoparticles and the adjacent granulation tissue. Individuals treated at first recurrence (n=3) had a median overall survival (OS) of 23.9 months, The median OS in the individuals treated at the 2^nd or 4^th recurrence was 7.1 months. The authors concluded that a prospective phase I trial is warranted.

Nanoparticle-mediated thermal ablation has also been proposed as a treatment for prostate cancer, but there are no published studies to support this proposal. A single arm, prospective clinical trial using NanoTherm was begun in 2021 with the intent to evaluate this therapy in individuals with intermediate-risk prostate cancer under active observation (NCT05010759). The study was terminated due to inadequate enrollment and the sponsor’s changing direction.

The National Comprehensive Cancer Network Guidelines in Oncology (NCCN Guidelines^®) do not recommend nanoparticle-mediated thermal ablation as a treatment for any condition. There is insufficient published evidence to permit reasonable conclusions concerning the effect of nanoparticle-mediated thermal ablation for any condition.

Non-infrared light induction ablation

Rastinhad and associates (2019) published the results of a clinical pilot study which used gold nanoparticles and laser ablation to treat individuals with low- or intermediate-risk localized prostate cancer (n=16). Participants received an intravenous (IV) infusion of gold-silica nanoshells (GSN) that preferentially settled in the aberrant vasculature of the prostatic tumor. The prostate was then treated with a laser guided by magnetic resonance and ultrasound fusion imaging. The subablative laser dose did not harm tissue without GSN, but GSN excitation by the laser ablated the cancerous tissue. The full treatment was limited to 15 individuals. One individual dropped out after experiencing epigastric pain after the infusion of nanoparticles. Following treatment, these 15 participants had follow-up evaluation with imaging and/or biopsy at 48-72 hours, 3 months and 12 months post-procedure. At 3 months post-procedure, 60% of the participants were free of cancer in the ablation zone. At 12 months post-procedure, 86.7% of the participants were free of cancer in the ablation zone. There were no reported grade 3 or higher adverse effects (AEs). The authors note that this study was not powered to evaluate the efficacy of this treatment and cautioned that it would be premature to draw any conclusions about efficacy.

An open-label, multi-center, single-treatment pivotal study with up to 60 participants is currently underway. Participants in the study include those with low- to intermediate-risk localized prostate cancer with MRI visible and confirmed focal areas of prostate cancer. The study is set to follow-up with individuals for 12 months following treatment.

(Return to Description/Scope)

Nano-oncology therapies have been proposed as an alternative method to treat cancers. Nanomedicine techniques under investigation include therapies using nanocarriers introduced through the vascular system to deliver therapeutic agents to the targeted area. Thermal nanoparticle therapy consists of the placement of inorganic materials to the target area followed by the application of an external energy source to cause vibration and hyperthermia (Nirmala, 2023).

Therapy is thought to attack tumor cells through several mechanisms. The hyperthermia generated by nanoparticle vibration causes tumor cell death. Cancerous cells, which are more susceptible to hyperthermia-induced cell death due to their leaky vascular nature, makes them more susceptible to hyperthermic therapies than healthy cells. Hyperthermia also increases tumor cell susceptibility to concomitant therapies, such as radiation or chemotherapy. It has also been postulated that local hyperthermia precipitated by alternating magnetic fields using magnetic nanoparticles may induce an antitumor immune response and trigger antitumor immunity and increase sensitivity to chemotherapy and immunotherapy (Grauer, 2019; Mahmoud, 2018).

The NanoTherm therapy consists of 3 components: NanoTherm - a ferrofluid containing iron oxide particles, NanoActivator^®, the alternating magnetic field generator, and NanoPlan^®, the software that supports individual treatment plans. Following injection of NanoTherm, the individual receives 6 treatment sessions over the course of 3 weeks. At this time in the US, studies are focused on intermediate stage prostate cancer. The goal of this focal treatment of small lesions is to allow individuals to remain in active surveillance and avoid the side effects of more invasive treatment.

AuroLase^® Therapy (Nanospectra Biosciences, Houston TX) consists of nanoparticles with a gold metal shell and a non-conducting silica core that are delivered via IV and accumulate in the tumor. Due to the enhanced permeability and retention (EPR) effect, nanoparticles preferentially localize within tumors due to leaky tumor vasculature and impaired lymphatic drainage. When exposed to photonic laser energy, the particles convert the light to heat destroying the tumor and the supplying vascular system without affecting adjacent tissue. The AuroShell particles are considered an investigational device at this time.

Both therapies are considered investigational devices by the Food and Drug Administration (FDA) at this time.

Active Surveillance: Disease monitoring with expectation of curative treatment if there is progression.

NanoTherm particles: a colloidal suspension of amino silane coated with iron oxide nanoparticles suspended and distributed in 15 nm size particles.

Observation: Disease monitoring on a less intensive scale until symptoms develop or are thought to be imminent. Treatment may be curative or palliative.

The following codes for treatments and procedures applicable to this document are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services are Investigational and Not Medically Necessary:
For the following procedure codes, or when the code describes a procedure indicated in the Position Statement section as investigational and not medically necessary.

Peer Reviewed Publications:

1. Grauer O, Jaber M, Hess K, et al. Combined intracavitary thermotherapy with iron oxide nanoparticles and radiotherapy as local treatment modality in recurrent glioblastoma patients. J Neurooncol. 2019; 141(1):83-94.
2. Hao B, Wei L, Cheng Y, et al. Advanced nanomaterial for prostate cancer theranostics. Front Bioeng Biotechnol. 2022; 10:1046234.
3. Mahmoudi K, Bouras A, Bozec D, et al. Magnetic hyperthermia therapy for the treatment of glioblastoma: a review of the therapy's history, efficacy and application in humans. Int J Hyperthermia. 2018; 34(8):1316-1328.
4. Maier-Hauff K, Ulrich F, Nestler D, et al. Efficacy and safety of intratumoral thermotherapy using magnetic iron-oxide nanoparticles combined with external beam radiotherapy on patients with recurrent glioblastoma multiforme. J Neurooncol. 2011; 103(2):317-324.
5. Nirmala MJ, Kizhuveetil U, Johnson A, et al. Cancer nanomedicine: a review of nano-therapeutics and challenges ahead. RSC Adv. 2023; 13(13):8606-8629.
6. Rastinehad AR, Anastos H, Wajswol E, et al. Gold nanoshell-localized photothermal ablation of prostate tumors in a clinical pilot device study. Proc Natl Acad Sci U S A. 2019; 116(37):18590-18596.
7. Rodríguez F, Caruana P, De la Fuente N, et al. Nano-based approved pharmaceuticals for cancer treatment: present and future challenges. Biomolecules. 2022; 12(6):784.
8. Schwake M, Müther M, Bruns AK, et al. Combined fluorescence-guided resection and intracavitary thermotherapy with superparamagnetic iron-oxide nanoparticles for recurrent high-grade glioma: case series with emphasis on complication management. Cancers (Basel). 2022; 14(3):541.
9. Srinivasan ES, Liu Y, Odion RA, et al. Gold nanostars obviate limitations to laser interstitial thermal therapy (LITT) for the treatment of intracranial tumors. Clin Cancer Res. 2023; 29(16):3214-3224.
10. Taneja SS. Re: Gold nanoshell-localized photothermal ablation of prostate tumors in a clinical pilot device study. J Urol. 2020; 203(1):31.
11. Zhao J, Zhang C, Wang W, et al. Current progress of nanomedicine for prostate cancer diagnosis and treatment. Biomed Pharmacother. 2022; 155:113714.

Government Agency, Medical Society, and Other Authoritative Publications:

1. Nanospectra Biosciences, Inc. An extension study MRI/US fusion imaging and biopsy in combination with nanoparticle directed focal therapy for ablation of prostate tissue. NCT04240639. Last updated on May 18, 2023. Available at: https://clinicaltrials.gov/ct2/show/NCT04240639. Accessed on March 19, 2026.
2. NCCN Clinical Practice Guidelines in Oncology^®. ^©2026 National Comprehensive Cancer Network, Inc. For additional information visit the NCCN website: http://www.nccn.org/index.asp. Accessed on May 11, 2026.
   • Central Nervous System Cancers. V.1.2026. Revised April 24, 2026.
   • Prostate Cancer. V.5.2026. Revised January 23, 2026.

1. American Cancer Society. Prostate Cancer. Key Statistics for Prostate Cancer. Last revised January 13, 2026. Available at: https://www.cancer.org/cancer/prostate-cancer/about/key-statistics.html. Accessed on March 19, 2026.
2. National Cancer Institute (NCI). Cancer and Nanotechnology. Available at: https://www.cancer.gov/nano/cancer-nanotechnology. Accessed on March 19, 2026.

AuroLase
AuroShell
Nanomedicine
Nanoshells

The use of specific product names is illustrative only. It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available.

Applicable to Commercial HMO members in California: When a medical policy states a procedure or treatment is investigational, PMGs should not approve or deny the request. Instead, please fax the request to Anthem Blue Cross Grievance and Appeals at fax # 818-234-2767 or 818-234-3824. For questions, call G&A at 1-800-365-0609 and ask to speak with the Investigational Review Nurse.

Federal and State law, as well as contract language, including definitions and specific contract provisions/exclusions, take precedence over Medical Policy and must be considered first in determining eligibility for coverage. The member’s contract benefits in effect on the date that services are rendered must be used. Medical Policy, which addresses medical efficacy, should be considered before utilizing medical opinion in adjudication. Medical technology is constantly evolving, and we reserve the right to review and update Medical Policy periodically.

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