Heat and Immunity Together: A Patient's Guide to Photothermal-Immunotherapy Combinations for Cancer

Table of Contents

• Key Points
• Why This Research Matters: The Cancer Treatment Gap
• Understanding Photothermal Therapy (PTT)
• How Heat Awakens the Immune System
• The IPTT Synergy: Combining Heat with Immunotherapy
• Photothermal Agents: The Heat Generators
• Inorganic Photothermal Agents
• Organic Photothermal Agents
• Biomaterials-Based and Hybrid Photothermal Agents
• Monitoring Treatment: Photoacoustic Imaging and AI
• Clinical Implications: What This Means for Patients
• Challenges Limiting Clinical Translation
• Recommendations and Future Directions
• Frequently Asked Questions
• Source Information

Key Points

• IPTT combines heat-based photothermal therapy with immune checkpoint inhibitors to kill tumor cells and activate the immune system.
• In animal models, some photothermal agents combined with immunotherapy achieved complete tumor elimination, but human data are lacking.
• Heat can convert immunologically 'cold' tumors to 'hot' ones, potentially improving response to immunotherapy.
• Light penetration depth, biocompatibility, and targeting precision remain major barriers to clinical use.
• IPTT is still in development; patients should consult their oncologist and consider clinical trials.

Why This Research Matters: The Cancer Treatment Gap

Cancer remains one of the world's most pressing health challenges. In 2022 alone, approximately 4,824,700 new cancer cases and 2,574,200 cancer-related deaths were reported in China. Globally, the World Health Organization estimates over 19 million new cancer cases and 10 million deaths occur every year.

A number of modifiable risk factors drive this disease. Tobacco use, alcohol consumption, chronic infections (such as hepatitis B virus, HBV, and human papillomavirus, HPV), obesity, and environmental carcinogens (cancer-causing substances) all contribute to tumor development. They do so through two key mechanisms: genomic instability (accumulation of DNA damage) and chronic inflammation (long-term, low-level inflammation that can promote cancer).

Current clinical treatments for cancer include surgery, radiotherapy (radiation), chemotherapy, immunotherapy, and targeted therapy. The introduction of immune checkpoint inhibitors (ICIs) has substantially reshaped how many malignant tumors are treated. ICIs are drugs that "release the brakes" on the immune system. They target key negative regulators of T cell activity by blocking inhibitory signaling pathways involving programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), and cytotoxic T lymphocyte-associated protein 4 (CTLA-4).

These agents have shown significant and durable clinical benefits in multiple cancer types, such as melanoma and non-small cell lung cancer. However, there is an important limitation: their effectiveness in solid tumors is often limited by hypoxic (oxygen-starved) microenvironments, which contribute to immunosuppression. In practical terms, many solid tumors are described as immunologically "cold," meaning they attract few immune cells and resist checkpoint inhibitor therapy. Additionally, the development of primary or secondary resistance remains a major clinical challenge.

Understanding Photothermal Therapy (PTT)

Photothermal therapy is a treatment modality that converts light into heat. It falls into two broad categories: traditional PTT, which heats tissue to 45 °C or above, and mild photothermal therapy (MPTT), which operates in a gentler 41–45 °C range.

To illustrate its clinical use: obstructive endobronchial carcinomas (tumors blocking the airways) can be effectively managed with photocoagulation ablation (heat-based destruction using light), while hepatic (liver) tumors can benefit from various forms of ablative therapy. MPTT has gained broader application in recent years precisely because it operates at lower, less damaging temperatures.

Each approach has trade-offs. Traditional PTT, operating at higher temperatures, is more effective at killing tumor cells. But it also causes more damage to surrounding normal tissues. MPTT is less damaging to normal tissues, yet correspondingly less effective at eradicating tumor cells directly. Instead, it is increasingly used as a regulatory mechanism — a way to modulate the immune environment rather than simply destroy tissue.

Several challenges with PTT remain, including limited penetration depth of light into tissue, heterogeneous (uneven) heat distribution, off-target toxicity associated with conventional photothermal agents, and insufficient efficacy when PTT is used alone. When employed as a standalone therapy, PTT often leads to uneven heat distribution within tumor tissues, making complete tumor eradication difficult to achieve.

How Heat Awakens the Immune System

Heat does far more than kill cells directly. PTT stimulates the expression of heat shock protein (HSP) genes, raising HSP levels in the tumor microenvironment (the surrounding tissues, blood vessels, and immune cells that interact with a tumor). HSP inhibitors can bind to these HSPs, disrupting DNA damage signaling in tumor cells, inhibiting the S and G2 phases of the tumor cell replication cycle, and interfering with tumor cell proliferation and repair processes.

Beyond this direct effect, PTT also enhances the activity of antigen-presenting cells (immune cells that display pieces of tumor cells to other immune cells), promotes T cell infiltration (movement of killer T cells into the tumor), and increases the expression of PD-L1 on tumor cells.

Remarkably, PTT's heating effect is not confined to the targeted tumor site. It can induce an "abscopal effect," a phenomenon in which treating one tumor triggers a systemic immune response that attacks tumors elsewhere in the body. This makes PTT capable of producing synergistic antitumor effects when combined with immunotherapy.

By increasing HSP expression and activating the immune system, PTT regulates the immune state of the tumor microenvironment. Crucially, PTT creates what researchers call a type I tumor microenvironment, characterized by PD-L1 overexpression and an abundance of tumor-infiltrating lymphocytes (immune cells that have entered the tumor). This positions PTT as a promising complement that can enhance the efficacy of immune checkpoint inhibitors.

The IPTT Synergy: Combining Heat with Immunotherapy

Immunophotothermal therapy (IPTT) combines thermotherapy (heat treatment) and immunotherapy through a dual mechanism of "physical killing + immune activation." This approach addresses two major problems in cancer care: tumor heterogeneity (the fact that tumor cells vary greatly within a single patient) and immune escape (the ability of tumors to evade immune attack).

How exactly does the synergy work? Emerging evidence suggests that MPTT not only alleviates tumor hypoxia through vasodilation (widening of blood vessels), but also synergizes with immune checkpoint inhibitors by converting immunologically "cold" tumors into "hot" phenotypes — tumors that are visibly infiltrated by active immune cells.

When MPTT heats tumor tissue, it induces immunogenic cell death (ICD), a form of cell death that alerts the immune system. Dying tumor cells release tumor-associated antigens (TAAs, molecules that identify the tumor as foreign) and damage-associated molecular patterns (DAMPs, danger signals) such as calreticulin, ATP, and HMGB1. These signals activate dendritic cells, which migrate to lymph nodes and prime naïve CD8+ T cells into cytotoxic T lymphocytes (CTLs, "killer" cells that hunt down tumor cells).

MPTT also reduces immunosuppressive cell populations, including T regulatory cells and myeloid-derived suppressor cells, while promoting a pro-inflammatory microenvironment. Adding immune checkpoint inhibitors such as anti-PD-1 or anti-PD-L1 further enhances T cell infiltration and function. This combined effect, demonstrated by combining near-infrared (NIR) photoimmunotherapy with anti-PD-L1 and CTLA-4 antibodies, achieved complete responses (total tumor elimination) in multiple murine (mouse) cancer models.

A concrete example comes from a preclinical breast cancer model. A hydrogel loaded with molybdenum disulfide and the immune adjuvant R837 (called PVA-MoS2-R837, or PMR hydrogel) significantly inhibited the recurrence of postoperative breast cancer. Contemporary photothermal agent designs are overcoming historical limitations related to targeting precision and thermal control, ushering in an era in which IPTT could redefine clinical oncology.

Photothermal Agents: The Heat Generators

Photothermal agents (PTAs) are the heat generators of this system. They absorb light energy at specific wavelengths, typically in the near-infrared (NIR) range, and efficiently convert it into heat, raising the local temperature at the tumor site to induce apoptosis (programmed cell death) or necrosis (cell death due to injury) of tumor cells.

Most PTAs absorb light within the NIR-I window (750–1000 nm), although some absorb in the red-light region (620–750 nm) and the NIR-II window (1000–1500 nm). The NIR-II region is of growing research interest because it exhibits lower light scattering and superior tissue penetration, meaning light can reach deeper tumors more effectively.

The elevated temperature produced by PTAs also promotes the release of tumor antigens and activates the host's antitumor immune response. An ideal PTA must possess four properties:

• High photothermal conversion efficiency (PCE) — the ability to convert absorbed light into heat
• Good biocompatibility — safety within the body
• Stability — resistance to degradation before reaching the target
• Functionalisable properties — the ability to attach targeting or drug molecules

PTA performance depends on several factors, including the wavelength of light absorption, material size, shape, and surface modifications. PCE, a key performance indicator, is closely linked to the size and shape of the material. For example, gold nanorods measuring 15 nm exhibit a PCE of 100%, whereas 100 nm gold nanorods achieve only approximately 45% efficiency. This dramatic difference shows how much engineering detail matters at the nanoscale.

PTAs reach tumors through two distinct strategies:

1. Passive targeting exploits the enhanced permeability and retention (EPR) effect. Tumor blood vessels are leaky, and lymphatic drainage is impaired, so nanoparticles accumulate preferentially in tumor tissue. Passive targeting is easy to prepare and widely applicable.
2. Active targeting involves conjugating PTAs to specific ligands (molecular "keys") that recognize and bind to receptors overexpressed on tumor cell surfaces. Active targeting offers superior precision and improved cellular internalization (uptake of the particle into cells).

PTAs fall into four main categories based on chemical composition and structure: inorganic PTAs, organic PTAs, biomaterials-based PTAs, and organic/inorganic hybrid systems.

Inorganic Photothermal Agents

Inorganic PTAs are nanomaterials (typically sized 1 to 1000 nanometers) that convert light energy into heat energy. They play a significant role in tumor therapy due to high performance and multifunctionality, though challenges with biocompatibility, degradation, and penetration depth remain. Their applications extend beyond medicine into energy and environmental sectors.

Metallic Nanomaterials

Metallic gold is the most commonly used raw material for metallic nanomaterials, prized for its unique surface plasmon resonance effect (the collective oscillation of electrons that produces strong light absorption), strong NIR absorption, high PCE, and good stability.

Unlike traditional gold nanophotothermal agents, silica (SiO2)-coated gold nanorods can precisely control temperature increases in tumor tissue (up to 45 °C). When combined with anti-PD-L1 therapy, these nanorods achieved a 100% complete response in treated models, meaning tumors disappeared entirely. Their PCE exceeds 90%, and their precise temperature control (41–43 °C) supports synergistic immunotherapy.

For drug-resistant solid tumors, CeO2@GNSs/Myr-HA demonstrates considerable potential. Its combination of nano-enzymatic catalysis, PTT, and chemotherapy allows precise photothermal ablation of tumor tissue via nanomaterial accumulation. It shows enhanced synergistic efficacy in inhibiting tumor proliferation. Gold-cerium star nanoparticles (Au-Ce star NPs) similarly achieve high PCE (above 85% at 808 nm laser) with enhanced localized surface plasmon resonance and nano-enzymatic activity.

Some modified metal nanoparticles offer dual targeting capabilities. Iron oxide nanoparticles modified by glucose oxidase (GOx) — designated Fe₃O₄@PDA-PEG-cRGD-AA@GOx — accelerate iron deposition, leading to iron-induced death (ferroptosis) of tumor cells. These particles also possess magnetic resonance imaging (MRI) capabilities, enabling imaging and therapy in one platform. Their PCE ranges from moderate to high (35–65% at 808 nm).

To overcome NIR-I's limited penetration for deep tumors, researchers are exploring NIR-II absorbers. Manganese-based BODIPY coordinated photo-immune nanoadjuvants (Mn-BDP Nas) deliver Mn²⁺ to tumors, achieve deep tissue penetration beyond 5 mm, and activate immunity by inducing immunogenic cell death through NIR-II laser irradiation at 1064 nm with PCE above 85%. Combined immunotherapy demonstrated significant therapeutic effects on primary B16F10 tumors and their lung metastases — a model of melanoma that has spread. This combines photothermal therapy with STING pathway activation (a cellular alarm system) and immunogenic cell death.

Carbon-Based Nanomaterials

Carbon-based nanomaterials, including graphene-based materials and carbon nanotubes, hold significant potential in oncology and antimicrobial therapy. Their intrinsic properties — low PCE, insufficient biocompatibility, poor targeting, and difficult in vivo clearance — have historically limited their effectiveness. Researchers have addressed these limitations by modifying them with various functionalized moieties (chemical groups).

A key success story involves short single-walled carbon nanotubes (SWCNTs) functionalized with polyethylene glycolated phospholipids. These nanotubes proved biologically non-toxic with extended circulation times, leading to complete tumor elimination in mice without toxic side effects. Their PCE exceeds 80% at 1064 nm with broad-spectrum NIR-I/II absorption.

The efficiency gain is striking: in side-by-side experiments with gold nanorods, these carbon nanotubes were injected at a 10-fold lower dose and irradiated with a 10-fold lower power, yet still achieved highly efficient tumor elimination.

Semiconductor Nanomaterials

Semiconductor nanomaterials such as bismuth sulfide and bismuth selenide possess NIR absorption bands suitable for light-to-heat conversion. They are of interest due to their low cost and ease of preparation. However, single-semiconductor materials often suffer common drawbacks of inorganic PTAs: poor biocompatibility, low degradability, and monofunctionality.

The limitations can be mitigated by adding a shell. Chitosan-coated hollow copper sulfide nanoparticles conjugated with CpG oligodeoxyribonucleotides (HCuSNP-CpG) demonstrated effective photothermal immunotherapy in a mouse breast cancer model, with a PCE of 60–75% at 808 nm. Notably, HCuSNPs can be cleared from the body after laser irradiation, directly addressing the poor biocompatibility concern that plagues many inorganic PTAs. The hollow structure also provides high drug-loading capacity.

Organic Photothermal Agents

Compared to inorganic PTAs, organic PTAs are less stable but offer meaningful advantages, including cancer-targeting capabilities, multifunctionality, good biosafety, and biodegradability.

Organic Small-Molecule PTAs

The prototype of this class is indocyanine green (ICG), a commonly used clinical NIR fluorescent dye that absorbs NIR light to produce heat. Its weakness is poor stability: it tends to aggregate and degrade in physiological environments, which diminishes the efficacy of PTT.

Newer designs address these weaknesses. Bionic nanoparticles containing elastin (called C12-TPAE-AL nanoparticles) suppress the π–π stacking-induced fluorescence quenching that limits many organic dyes, thereby enhancing NIR-II fluorescence brightness and achieving a PCE of 62.4%. This demonstrates the potential of organic PTAs for precise treatment of deep-seated tumors. Lipoprotein-mimicking nanoparticles loaded with cyanine dyes achieve over 85% PCE at 1064 nm, targeting gliomas (brain tumors).

Another example is PDI nanostructures (perylene diimide-based), which are biodegradable, offer PTT-photodynamic therapy (PDT) synergy, and achieve 50–70% PCE at 808 nm. Their limitation is poor water solubility and efficiency dependent on molecular stacking, but they show promise in photoacoustic imaging and immune synergy.

Organic Polymer PTAs

Some organic polymeric materials, such as conjugated polymers and dendritic macromolecules (highly branched, tree-like molecules), can also serve as PTAs.

[The published article continues this section in its full text, describing additional developments, along with the following sections on biomaterials-based PTAs, hybrid materials, and clinical translation challenges.]

Biomaterials-Based and Hybrid Photothermal Agents

Beyond purely synthetic materials, the review catalogs PTAs built from biological materials and hybrid organic-inorganic systems. These designs aim to improve biocompatibility, natural targeting, and multifunctionality.

Biomaterials-Based PTAs

• AMNPs — biological nanoparticles with natural tumor-targeting ability and the capacity to penetrate the blood-brain barrier (the protective filter that blocks many drugs from reaching the brain). PCE exceeds 60% at 808 nm. They are being developed for IPTT of glioblastoma, an aggressive brain cancer.
• CuS@RBC — copper sulfide nanoparticles wrapped in red blood cell membranes. The membrane coating provides long circulation time and NIR-II imaging capability, with a PCE of 40–65%. Limitations include a complex membrane encapsulation process and relatively low drug loading.
• Engineered bacteria — living bacteria modified to carry photothermal payloads. They naturally target tumors and activate positive immune feedback loops. However, they suffer from poor stability, and their efficacy depends on bacterial survival after treatment. These are being explored for glioma (brain tumor) IPTT.

Organic/Inorganic Hybrid Materials

Hybrid systems combine materials to achieve what no single material can. Specific examples from the review include:

• Composite nanostimulators (CuS-based) — tri-functional systems offering synergistic effects with light-controlled release. Copper sulfide contributes roughly 32.6% of the photothermal effect. They are being developed for IPTT of primary and metastatic tumors.
• BMNS-PNFs — highly biocompatible nanocomposites with a PCE of 31.57% that cause mitochondrial damage in tumor cells. They specifically target lung cancer cell lines, including HCC2279 and PC9, representing a potential treatment for lung tumors.
• IR-7-lipo/HA-CpG — lipid-based nanoparticles combining the dye IR-7 with hyaluronic acid and the immune adjuvant CpG. PCE measured 20.6% ± 1.2% at 808 nm. They generate a dual inflammatory response with low systemic toxicity and are designed for unresectable tumors or surgically resected residual disease.
• MnBV@DP/cKNGRE NPs — dual-targeting nanoparticles with a PCE of 35.15% at 880 nm (1.0 W/cm² laser power). Their PCE positively correlates with laser power density and concentration. They remodel the tumor microenvironment and are in development for combination targeted therapy and IPTT of triple-negative breast cancer, with photoacoustic imaging capability.
• Ti3C2-MXene-Au nanocomposites — a 65% PCE at 808 nm, catalyzing generation of hydroxyl radicals (-OH, highly reactive molecules that damage tumors) with high biosafety. Applications span photoacoustic imaging, enzymatic dynamic therapy, and IPTT.

Monitoring Treatment: Photoacoustic Imaging and AI

As photothermal therapy increasingly integrates with immunotherapeutic strategies, the demand for precise, real-time imaging has grown. Photoacoustic imaging (PAI) — a technique that detects ultrasound waves generated when light-absorbing materials expand and contract — offers high-resolution insights into dynamic changes within the tumor microenvironment, especially when enhanced by nanophotonic agents.

Artificial intelligence (AI) further amplifies this capability by enabling automated image analysis, early prediction of therapeutic responses, and personalized adaptive treatment planning. The convergence of these technologies positions AI-augmented PAI as a promising platform for guiding and assessing immunotherapeutic interventions in clinical settings. For example, SPDI-based photothermal therapies have shown excellent results in lymph node localization and cancer imaging, enabling ultrasensitive early thrombus (blood clot) imaging and facilitating multimodal imaging-guided cancer therapy.

Clinical Implications: What This Means for Patients

For patients, this research points toward a future in which cancer treatment is less about "one-size-fits-all" therapies and more about precisely coordinated multimodal strategies.

The most immediate implication concerns patients whose tumors do not respond well to immunotherapy alone. Because PTT appears to convert immunologically "cold" tumors into "hot" ones — and because it induces immunogenic cell death that releases tumor antigens — it may act as an in-situ vaccine, educating the immune system to recognize and attack a patient's specific tumor without needing to identify antigens in advance.

Key physical findings from the review include:

• Silica-coated gold nanorods combined with anti-PD-L1 achieved a 100% complete response rate in animal models.
• PEGylated single-walled carbon nanotubes achieved complete tumor elimination in mice with no toxic side effects, at a 10-fold lower dose and power than gold nanorods.
• Mn-BDP nanoadjuvants treated both primary B16F10 tumors and lung metastases, showing activity against spread disease.
• PMR hydrogel significantly inhibited postoperative breast cancer recurrence in a preclinical model.

Several engineered systems also respond to their environment — pH-responsive release, glutathione-triggered degradation, and laser-dose-dependent activity — which could translate into fewer off-target side effects for patients.

Challenges Limiting Clinical Translation

Despite promising preclinical results, the review emphasizes several hurdles between the laboratory and the clinic.

Light penetration is a fundamental physical constraint, especially with NIR-I wavelengths. While NIR-II absorbs (1000–1500 nm) improve depth, the >5 mm penetration reported remains insufficient for many deep visceral tumors without interventional delivery.

Biocompatibility and clearance remain complex. Some inorganic materials persist in the body and their long-term safety is not yet verified; others, such as HCuSNPs, were specifically designed to be cleared after laser irradiation for this reason. A recurring limitation in the table of agents reviewed is that metabolic pathways are unknown and synthesis is complex.

Targeting precision and thermal control are improving but remain incomplete. Uneven heat distribution can leave tumor cells viable, and off-target toxicity from free-floating photothermal agents can damage normal tissues. The review also notes that predicting which patients will respond — and avoiding primary or secondary resistance to immune checkpoint inhibitors — requires further study.

The combination of multiple therapeutic functions in a single nanoparticle (photothermal, photodynamic, chemotherapy, immune modulation) increases complexity, and loading ratios, drug release kinetics, and manufacturing consistency are not yet standardized. Scale-up production of many of these sophisticated nanoplatforms has not been demonstrated.

Recommendations and Future Directions

The authors propose several directions to accelerate clinical translation.

1. Prioritize NIR-II photothermal agents, since the 1000–1500 nm window offers lower light scattering and superior tissue penetration — directly addressing the depth limitation of current photothermal therapy.
2. Design PTAs with built-in clearance mechanisms, such as hollow copper sulfide nanoparticles that are eliminated after laser irradiation, to resolve long-term biocompatibility concerns.
3. Standardize PCE measurement and reporting, since efficiency depends strongly on size, shape, surface modification, laser wavelength, and power density.
4. Integrate imaging and AI into photothermal-immunotherapy workflows, using photoacoustic imaging to monitor tumor microenvironment changes and AI algorithms to personalize adaptive treatment planning.
5. Develop active-targeting strategies that improve tumor-specific accumulation and cellular uptake, reducing off-target toxicity and enhancing efficacy at lower doses.
6. Test combination regimens systematically, examining optimal timing and sequencing of photothermal therapy with immune checkpoint inhibitors, given the evidence that PTT upregulates PD-L1 expression and therefore may prime tumors for ICI response.

For patients reading this today, the practical takeaway is this: the field is converging on treatments that are precision-guided, multi-mechanism, and increasingly personalized. While the promise of IPTT is exciting, it remains in clinical development — patients should discuss any novel combination therapies with their oncologist and consider clinical trials where appropriate.

Frequently Asked Questions

What is immunophotothermal therapy (IPTT)?

IPTT combines heat-based photothermal therapy with immune checkpoint inhibitors. Photothermal agents absorb near-infrared light and convert it to heat, killing tumor cells while activating the immune system. This dual approach aims to turn immunologically 'cold' tumors into 'hot' ones, potentially overcoming limitations of immunotherapy alone. It remains in clinical development.

How does heat awaken the immune system?

Heat from photothermal therapy stimulates heat shock protein genes, enhances antigen-presenting cell activity, promotes T cell infiltration into tumors, and increases PD-L1 expression on tumor cells. It can also trigger an abscopal effect, where treating one tumor prompts a systemic immune response attacking tumors elsewhere. This creates a type I tumor microenvironment that may enhance checkpoint inhibitor efficacy.

What are photothermal agents and how do they work?

Photothermal agents absorb light, typically near-infrared, and convert it into heat to raise local tumor temperature, causing cell death. They reach tumors via passive targeting (leaky tumor blood vessels) or active targeting (molecules binding to tumor receptors). Ideal agents have high heat-conversion efficiency, good biocompatibility, stability, and functionalisable properties.

What were the results in animal models?

In preclinical models, silica-coated gold nanorods combined with anti-PD-L1 achieved 100% complete tumor responses. PEGylated single-walled carbon nanotubes eliminated tumors in mice with no toxic side effects, using a 10-fold lower dose and power than gold nanorods. A hydrogel significantly inhibited postoperative breast cancer recurrence in a preclinical model. These are animal studies, not human trials.

What are the main challenges limiting clinical translation?

Light penetration is limited, especially with NIR-I wavelengths; even NIR-II achieves only about 5 mm depth, insufficient for deep tumors. Biocompatibility and clearance of some inorganic materials remain unverified. Targeting precision and heat control are incomplete, risking off-target damage. Predicting patient response and overcoming immunotherapy resistance require further study. Scale-up production is not yet demonstrated.

How is treatment monitored during IPTT?

Photoacoustic imaging detects ultrasound waves generated when light-absorbing materials expand and contract, providing high-resolution insights into tumor microenvironment changes. Artificial intelligence can automate image analysis, predict therapeutic responses early, and help personalize adaptive treatment planning. This combination is being explored to guide and assess immunotherapeutic interventions in clinical settings.

What does this mean for patients right now?

IPTT is still in clinical development. The research points toward future precision-guided, multi-mechanism treatments, but it is not yet available in routine care. Patients should discuss any novel combination therapies with their oncologist and consider clinical trials where appropriate. No IPTT regimen is currently approved for standard cancer treatment.

If I have a solid tumor that hasn't responded to immunotherapy, when should I ask about a second opinion on photothermal-immunotherapy combinations?

Immunophotothermal therapy is still in clinical development, so it is not yet a standard option. A second opinion is worth seeking when a solid tumor is immunologically "cold" or has developed resistance to checkpoint inhibitors, since heat-based photothermal therapy may convert cold tumors into hot ones and induce immunogenic cell death. Because photothermal agents, light penetration, and clearance remain unresolved, an independent review can clarify whether a clinical trial is appropriate. Diagnostic Detectives Network provides independent expert second opinions.

Source Information

Original article title: Emerging photothermal agents combined with immunotherapy for cancer treatment.

Authors: Xu T, Yang X, Chen X, Wang Q, Ye J, You C, Zhu J, Gui Y.

Affiliation: Department of Oncology, Affiliated Hospital of North Sichuan Medical College, Nanchong 637000, Sichuan, China

Journal: Discover Oncology (2025) 16:1936

DOI: https://doi.org/10.1007/s12672-025-03669-8

Article type: Open Access Review

License: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License

Note: This patient-friendly article is based on peer-reviewed research. It is intended for educational purposes and does not constitute medical advice. Patients should consult their healthcare providers regarding treatment decisions.