Tumor combined immunotherapy system based on precise radiotherapy and application

Abstract

The application relates to the technical field of tumor treatment, and discloses a tumor combined immunotherapy system based on precise radiotherapy and application, wherein a PD-1 inhibitor is applied in the process of fast neutron radiotherapy, the treatment effect of the PD-1 inhibitor on cold tumors is improved, and a tumor treatment scheme with higher efficiency and smaller side effect is developed.

Description

Technical Field

[0001] This invention relates to the field of tumor treatment technology, specifically to a tumor combined with immunotherapy system based on precision radiotherapy and its application. Background Technology

[0002] The statements in this section provide only background information relevant to the disclosure of this application and may not constitute prior art.

[0003] Colorectal cancer (CRC) is the third most common malignant tumor worldwide and the second leading cause of cancer death globally. In China, the incidence of CRC has risen to second place and continues to rise, showing a trend towards affecting younger people. Although advancements in screening and surgical techniques have significantly reduced the mortality rate of CRC, the five-year survival rate for advanced-stage patients remains only 12%. Approximately 20%-25% of colorectal cancer patients are diagnosed with distant metastases at initial diagnosis, and among patients initially diagnosed with localized or locally advanced disease, about 50%-60% may progress to metastatic colorectal cancer after treatment. Treatment of metastatic colorectal cancer typically requires a combination of chemotherapy, targeted therapy, radiotherapy, and immunotherapy. However, most patients experience tumor recurrence within months. Due to limited treatment options, patients often face a lack of available therapies after first- and second-line treatments. Given the current challenges in treating colorectal cancer, its rapid progression, and the poor efficacy of subsequent treatments, exploring new and effective comprehensive treatment models and mechanisms to enable patients with metastatic colorectal cancer to receive lasting benefits has become an urgent problem to be solved in the field of oncology.

[0004] In recent years, immune checkpoint inhibitors (ICIs), represented by those targeting programmed cell death-1 (PD-1) and its ligand 1 (PD-L1), have made significant progress and breakthroughs in the treatment of various tumors, including non-small cell lung cancer, renal cell carcinoma, and melanoma. However, in colorectal cancer, ICI therapy is only effective for high-frequency microsatellite instability and mismatch repair deficient tumors, which account for only 3%-5% of all colorectal cancer patients. The vast majority of colon cancers exhibit microsatellite stability and intact mismatch repair, with their tumor microenvironment being immune desert, the so-called "cold tumor," making it difficult to benefit from ICI therapy. Single-cell studies suggest that compared to microsatellite instability, microsatellite stable colorectal cancer shows less cytotoxic T cell infiltration and weaker immune activation. Therefore, reshaping the tumor microenvironment and promoting intratumoral T cell infiltration has become key to improving the efficacy of immunotherapy against colon cancer.

[0005] Over the past two decades, radiotherapy technology has seen unprecedented leaps in progress. Traditional photon radiotherapy has reached a relative peak in efficacy, and further improvement and development are limited by the physical properties and biological effects of photons themselves. Due to its unparalleled biological advantages, high linear energy transfer (LET) particle therapy has emerged as a new option, with heavy ion and fast neutron therapy being the focus of attention in recent years. High LET radiation (such as fast neutron and heavy ion radiotherapy) releases more energy per unit pathway, leading to dense DNA damage and complex biological effects. Compared to conventional photon radiotherapy, high LET radiotherapy has a higher biological effect ratio, is more effective at killing tumor cells, and is particularly effective against radioresistant tumors (such as hypoxic tumors and recurrent cancers).

[0006] Fast neutron therapy (FNT), representing high-LET radiation, possesses excellent properties similar to heavy ions and was one of the earliest particle beam therapies developed globally. Its unique radiobiological characteristics enable it to overcome multiple resistance mechanisms of tumor cells, particularly targeting hypoxic malignancies resistant to traditional photon beam therapy. Because FNT exhibits highly linear energy transfer, it can release a large amount of energy over a short distance, directly damaging DNA strands and causing irreparable double-strand breaks. It possesses a higher relative biological effect and a lower oxygen enhancement ratio, with weaker dependence on the cell cycle, and can effectively kill tumor cells even in hypoxic environments. In the last century, fast neutron therapy was considered a significant breakthrough in cancer treatment, primarily due to its direct killing effect on tumor cells. FNT has demonstrated excellent tumor-suppressing effects in the treatment of various tumor types, including salivary gland tumors, head and neck tumors, bone and soft tissue sarcomas. Studies have shown that for patients with inoperable non-small cell lung cancer, FNT shows better results than conventional photon radiotherapy (local control rate 16% vs 3%, P=0.02, overall survival rate 19% vs 6%, P=0.015).

[0007] Even so, the effectiveness of current single treatment methods remains low, and there is an urgent need to develop more efficient cancer treatment methods. Summary of the Invention

[0008] The purpose of this invention is to address the limitations and severe side effects of current traditional cancer treatments by providing a tumor-combined immunotherapy system and its application based on precision radiotherapy, thereby improving treatment efficiency and efficacy against cold-sensitive tumors. This study innovatively proposes combining low-dose fast neutron therapy with PD-1 inhibitors in patients with advanced colorectal cancer, exploring the synergistic effect of these two cutting-edge therapies. This approach overcomes the limitations of traditional monotherapy, providing a novel treatment strategy for the management of refractory colorectal cancer, and is expected to significantly improve treatment outcomes.

[0009] The technical solution of the present invention is as follows: This invention provides a tumor combined with immunotherapy system based on precision radiotherapy, including a fast neutron radiotherapy device and a PD-1 inhibitor injection device; during fast neutron radiotherapy, a PD-1 inhibitor is injected into the patient.

[0010] According to a preferred embodiment, the fast neutron radiotherapy uses low-dose fast neutrons.

[0011] In another aspect, the present invention provides the application of the tumor combined with immunotherapy system based on precision radiotherapy as described above in the treatment of tumors, wherein the tumor is a colon tumor or a lung tumor.

[0012] This invention provides a treatment method for tumors, comprising the following steps: using fast neutron radiotherapy to kill tumor cells, regulating the tumor microenvironment, activating the immune system, and promoting T cell chemotaxis into the tumor to treat the tumor.

[0013] According to a preferred embodiment, the fast neutron radiotherapy uses low-dose fast neutrons.

[0014] According to a preferred embodiment, the tumor is a colon tumor or a lung tumor.

[0015] Another aspect of the present invention provides a treatment method for tumors, comprising the following steps: treating tumors with fast neutron radiotherapy combined with a PD-1 inhibitor.

[0016] According to a preferred embodiment, the PD-1 inhibitor is administered via intravenous injection.

[0017] According to a preferred embodiment, the fast neutron radiotherapy uses low-dose fast neutrons.

[0018] According to a preferred embodiment, the tumor is a colon tumor or a lung tumor.

[0019] Another aspect of the present invention provides a radiotherapy regimen for enhancing tumor immunogenicity, comprising the following steps: radiotherapy using fast neutrons during the use of PD-1 inhibitor drugs.

[0020] According to a preferred embodiment, the PD-1 inhibitor drug is administered intravenously.

[0021] According to a preferred embodiment, the fast neutron radiotherapy uses low-dose fast neutrons.

[0022] Compared with existing technologies, the advantages of this invention are: 1. A novel tumor-combined immunotherapy system and its application based on precision radiotherapy: This study innovatively combines low-dose fast neutron radiotherapy with immunotherapy (PD-1 inhibitors), pioneering a new treatment approach for advanced colorectal cancer and overcoming the limitations of traditional single-treatment methods. This technological breakthrough not only advances tumor treatment technology but also lays a scientific foundation for developing more efficient and safer treatment regimens in the future. Through interdisciplinary collaboration, this research integrates the advantages of multiple fields such as radiotherapy, immunotherapy, and biotechnology, greatly promoting technological innovation. Furthermore, it deepens the understanding of tumor immune mechanisms, particularly in exploring distant tumor effects, providing important theoretical support for precision medicine.

[0023] 2. Tumor combined immunotherapy system and application based on precision radiotherapy: Through combined therapy, a treatment method with excellent and significant therapeutic effects has been developed, which enhances the therapeutic effect of PD-1 inhibitors on cold tumors and broadens the application field of PD-1 inhibitors; providing new ideas for cancer treatment. Attached Figure Description

[0024] Figure 1 Flowchart for research on low-dose fast neutron radiotherapy; Figure 2 This is a flowchart of a study combining low-dose fast neutron radiotherapy with PD-1 inhibitors. Detailed Implementation

[0025] The specific embodiments listed in this invention are merely examples, and the invention is not limited to the specific embodiments described below. For those skilled in the art, any equivalent modifications and substitutions to the embodiments described below are also within the scope of this invention. Therefore, all equivalent transformations and modifications made without departing from the spirit and scope of this invention should be covered within its scope. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are commercially available conventional products. To better illustrate this invention, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this invention can be practiced even without certain specific details. In other embodiments, methods, means, equipment, and steps well known to those skilled in the art are not described in detail in order to highlight the main points of this invention.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Unless otherwise specified, all units used in this specification are International Standard Units (SI), and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors unavoidable in industrial production.

[0027] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0028] Experimental methods: (1) Cell culture CT26 cells (microsatellite stable, relatively resistant to PD-1 inhibitor treatment) or MC38 cells (microsatellite highly unstable, relatively sensitive to PD-1 inhibitor treatment) were cultured in DMEM medium containing 10% fetal bovine serum, 100 U / mL penicillin and streptomycin, and incubated at 37°C in a 5% CO2 incubator.

[0029] (2) Preparation of subcutaneous tumor-bearing mouse model 120 SPF-grade female BALB / c mice (6-8 weeks old, weighing 18-20 g) or 60 SPF-grade female C57BL / 6 mice (6-8 weeks old, weighing 18-20 g) were acclimatized for 7 days. CT26 cells or MC38 cells in the logarithmic growth phase were collected and prepared into a concentration of 5×10⁻⁶ cells using sterile PBS. 5 100 μL of cell suspension was injected subcutaneously into the right hind limb of mice after skin preparation and disinfection. Each mouse was inoculated with 100 μL to establish a tumor-bearing mouse model. Tumor formation was observed. The maximum long and wide diameters of the transplanted tumor were measured every other day using electronic calipers, and the volume was calculated as: Tumor volume = 0.5 × a × b², where a represents the maximum long diameter (mm) and b represents the maximum wide diameter (mm). Mouse weight was also recorded. The tumor was stopped when it reached 400 mm². 3 Then, proceed with subsequent experimental procedures.

[0030] (3) Grouping of tumor-bearing mice and radiotherapy Eligible tumor-bearing mice were randomly assigned to groups according to the study protocol. Except for the control group, all mice received radiotherapy. Mice were anesthetized with 40 mg / kg sodium pentobarbital and then fixed to a radiotherapy plate, with the tumor directly placed at the center of the irradiation area. The surrounding area was protected with boron-containing polyethylene plates to prevent radiation leakage. The neutron source energy of the device was 2.45 MeV, and the source-to-skin distance was set at 10 cm to ensure the effectiveness and safety of the treatment.

[0031] (4) Drug administration to mice Anti-PD-1 antibody (Bioxcell), 10 mg / kg, intraperitoneal injection, once every 3 days, for a total of 5 doses; In vivo cell blocking assay: anti-CD4 antibody or anti-CD8 (Bioxcell), 20 mg / kg, intraperitoneal injection, once every other day, from the start of group administration until the death of mice; anti-CXCR3 antibody (Bioxcell), 2.5 mg / kg, intraperitoneal injection, once every 3 days, for a total of 5 doses; anti-CCR5 antibody (Selleck), 0.01 mg / kg, once daily, from the start of group administration until the death of mice.

[0032] (5) Sample collection On days 7, 10, and 14 after the start of radiotherapy, eight mice from each group were randomly selected for blood collection from the orbital venous plexus. Serum samples were stored at -20°C and tested promptly. Mice were euthanized, and tumor, lung, and spleen tissues were dissected and weighed. Part of the tumor, lung, and spleen were fixed in paraformaldehyde for subsequent morphological examination, while the remainder were flash-frozen in liquid nitrogen and stored at -80°C for subsequent biochemical, gene, and protein analysis.

[0033] (6) Calculation of tumor inhibition rate The tumor mass was removed, washed with saline, dried, and weighed. The tumor inhibition rate was calculated based on the ratio of the average tumor weight of each group to the average tumor weight of the control group.

[0034] (7) Calculation of organ index Weigh the lungs and spleen of each group of mice and calculate the organ index according to the formula: Organ index = organ weight / (mouse body weight - tumor weight).

[0035] (8) Detection of blood biochemistry related indicators Place the collected serum samples into the test cups according to the loading volume specified by the blood biochemistry analyzer for each indicator, and perform the tests according to the instructions of the purchased diagnostic kits. The indicators tested include: blood urea nitrogen, creatinine, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, albumin, and total protein.

[0036] (9) Histopathological examination The fixed mouse lung and spleen tissues were dehydrated sequentially, cleared with xylene, embedded in liquid paraffin, and sectioned. Staining was performed: dewaxing and hydration with xylene; cell nuclei were stained with hematoxylin for 5 minutes, rinsed with tap water to regain blue color; hydrochloric acid-alcohol separation was performed, followed by rinsing with tap water; lithium carbonate fixation was performed, followed by rinsing with tap water and observation under a microscope. If the staining was too light, hematoxylin counterstaining was performed, followed by re-separation and fixation; eosin staining was performed for 8 minutes, followed by rinsing with tap water; rehydration and clearing were performed: rehydration was performed in 95% ethanol (I), 95% ethanol (II), 100% ethanol (I), and 100% ethanol (II), followed by immersion in xylene (I) and xylene (II) for 1–2 minutes each for clearing; the sections were mounted with neutral resin, and pathological changes were observed under a microscope, with images acquired.

[0037] (10) Detection of the immune microenvironment 1) T cell detection: Detection of the proportion and function of CD4+ T cells (CD3+CD4+), Treg cells (CD4+CD25+FoxP3+), and CD8+ T cells (CD3+CD8+).

[0038] 2) Immunofluorescence staining: The expression of CD8+ T cells, Treg cells, NK cells, MDSCs cells and neutrophils in tumor tissue was detected using Ki67, CD31, CD8, CD16, CD163, FOXP3, LY6C and LY6G antibodies.

[0039] 3) Tumor tissue single-cell sequencing: completed using the second-generation sequencing platform of Mianyang 404 Hospital and Mianyang Normal University.

[0040] Experimental Research Process Reference Figure 1 and Figure 2 The flowchart shown.

[0041] Example 1: Tumor Combined Immunotherapy System Based on Precision Radiotherapy A tumor-based immunotherapy system based on precision radiotherapy includes a fast neutron radiotherapy device and a PD-1 inhibitor injection device; during fast neutron radiotherapy, a PD-1 inhibitor is injected into the patient.

[0042] The system coordinates the radiation dose of the fast neutron radiotherapy device, delivering low-dose fast neutron radiotherapy to patients according to their needs and the doctor's control; at the same time, it controls the injection of PD-1 inhibitors into patients, significantly enhancing the treatment effect of tumors.

[0043] Example 2: Differences in the regulation of the tumor microenvironment by different low-dose fast neutron radiotherapy 1) Effect of low-dose fast neutron radiotherapy on immunogenic cell death in tumor cells. Mouse tumor cells (mouse colon cancer CT26 cells or mouse Lewis lung cancer cell line) were cultured in vitro and treated with different doses of fast neutron radiotherapy (0 Gy, 0.5 Gy, 1 Gy, 2 Gy, 4 Gy). Tumor cells and their culture supernatants were collected at 24 h, 48 h, and 72 h after radiotherapy. The expression of calreticulin, MHC-I, PD-L1, and co-stimulatory molecules (CD80, CD86) on the surface of tumor cells was detected by flow cytometry. The levels of soluble damage-associated molecular patterns (DAMPs) (HMGB1, ATP, IFNβ) in the culture supernatant were detected by ELISA.

[0044] 2) Effect of low-dose fast neutron radiotherapy on T cell sensitization. Mouse tumor cells were labeled with PKH dye and administered different doses of fast neutron radiotherapy. After co-culturing with mouse peripheral blood mononuclear cells (PBMCs) for 24 hours, the phagocytic process was observed using confocal microscopy to verify whether the PKH dye signal entered the immune cells. CFSE-labeled mouse T cells were added to the above co-culture system. After 24 hours, flow cytometry was used to detect the proportion of T cells and the degree of CFSE dilution (reflecting T cell proliferation) in the co-culture system.

[0045] 3) Effects of low-dose fast neutron radiotherapy on immune cell subsets in the tumor microenvironment. A mouse tumor-bearing model was established, and different doses of fast neutron radiotherapy were administered. Flow cytometry and immunofluorescence were used to detect the number of immune cells infiltrating the mouse tumor tissue, including T cells, B cells, dendritic cells, NK cells, regulatory T cells (Tregs), tumor-associated macrophages (TAMs), and bone marrow-derived immunosuppressive cells (MDSCs).

[0046] 4) Effects of low-dose fast neutron radiotherapy on immune-activating genes in the tumor microenvironment. A mouse tumor-bearing model was established, and mice were given different doses of fast neutron radiotherapy. Tumor tissues from each group of mice were collected at different time points after radiotherapy, and transcriptome sequencing was performed. The expression differences of immune-activating genes (including genes related to tumor antigen presentation, innate immunity, T cell activation, and cytokines) in tumor tissues of different groups were compared. The optimal fast neutron dose to promote T cell infiltration was determined based on T cell infiltration and immune-activating gene activation.

[0047] 5) Adoptive T-cell labeling experiment. A mouse tumor-bearing model was established, divided into a low-dose fast neutron radiotherapy group and a control group. CD3+ T cells (GFP+) from the spleen and lymph nodes of GFP mice were selected, expanded in vitro, and then reinfused into the tumor-bearing mice via the tail vein. Flow cytometry and immunofluorescence were used to detect the CD3+GFP+ T cells infiltrating the tumor tissue of the mice, confirming that low-dose fast neutron radiotherapy promotes T cell infiltration into the tumor.

[0048] Example 3: Mechanism study of low-dose fast neutron radiotherapy regulating T cell immune homing effect (cGAS-STING pathway) 1) In vitro experiments: After mouse tumor cells were treated with low-dose fast neutron radiotherapy in vitro, the expression of the cGAS-STING pathway, including IRF3, pIRF3, cGAS, TBK1, pTBK1, STING, pSTING, and IFNβ, was detected by Western blot; the expression of CXCL9, CXCL10, CXCL11, CCL3, CCL4, and CCL5 in tumor cells and culture supernatant was detected by RT-PCR and ELISA.

[0049] 2) In vitro transwell experiment: Mouse tumor cells were seeded into the lower chamber of a transwell and divided into a low-dose fast neutron radiotherapy group and a control group. T cells in the tumor tissue were sorted by magnetic beads and seeded into the upper chamber of the transwell immediately after the low-dose fast neutron radiotherapy. The number of T cells in the lower chamber was detected to determine the chemotactic ability of low-dose fast neutron radiotherapy on T cells.

[0050] 3) In vitro blocking experiment: After knocking out STING in SCLC cells with siRNA, the expression of the above chemokines was detected after low-dose fast neutron radiotherapy, clarifying that the expression of chemokines induced by low-dose fast neutron radiotherapy is related to the STING pathway.

[0051] 4) In vivo experiments: A mouse tumor-bearing model was established, divided into a low-dose fast neutron radiotherapy group and a control group. Western blot was used to detect the expression of the cGAS-STING pathway. ELISA and liquid-phase microarray were used to detect the expression of T cell-related chemokines in the tumor to clarify the upstream and downstream relationship between low-dose fast neutron radiotherapy and the cGAS-STING pathway.

[0052] 5) In vivo chemokine receptor blockade experiment: A mouse tumor-bearing model was established, and the low-dose fast neutron radiotherapy group was given CXCR3 inhibitors and CCR5 inhibitors for in vivo blockade. Flow cytometry and immunofluorescence were used to detect the changes in the number and function of CD4+ T cells and CD8+ T cells in the tumor after blockade. RT-PCR and ELISA were used to detect the changes in the expression of chemokines in the tumor tissue after blockade, so as to clarify the role of the CXCR3 and CCR5 axis in promoting T cell chemotaxis into the tumor by low-dose fast neutron radiotherapy.

[0053] Example 4: Efficacy and toxicity of low-dose fast neutron radiotherapy combined with PD-1 inhibitors 1) Establish a mouse model of high tumor burden of colon cancer, with a tumor volume of approximately 400 mmHg. 3At that time, they were randomly divided into 4 groups: control, αPD-1, low-dose fast neutron radiotherapy, and low-dose fast neutron radiotherapy + αPD-1 (n=20 / group). The dose of low-dose fast neutron radiotherapy was the optimal dose determined in (1), and the following experiments were conducted: ① Observe the growth and metastasis of mouse tumors in vivo using small animal microCT and animal in vivo imaging (mouse tumor cells carry luciferase), and record mouse survival; ② On days 14 and 21 after the start of treatment, tumor tissue, spleen and peripheral blood of mice were collected. Flow cytometry and immunofluorescence were used to detect the changes in the number and function of immune cells such as T cells, B cells, NK cells, Tregs, macrophages and their typing (not detected in peripheral blood), MDSCs and other immune cells in the above organs of mice in each group. ③Western blot was used to detect the expression of the cGAS-STING pathway in tumor tissues of each group, including the expression of IRF3, pIRF3, cGAS, TBK1, pTBK1, STING, pSTING, and IFNβ. ④RT-PCR and ELISA were used to detect the expression of CXCL9, CXCL10, CXCL11, CCL3, CCL4, and CCL5 in tumor tissues of each group; RNAseq was used to detect the expression of genes related to immune activation.

[0054] 2) Effects of combined therapy on the tumor immune microenvironment: The mice were grouped and treated as in 1). Tumor tissues from each group of mice were collected at different time points after radiotherapy, single-cell sequencing was performed, tumor microenvironment atlases were drawn, and the cell groups were analyzed.

[0055] 3) Toxicity observation of combined treatment: The mice were grouped and treated as in 1), and the weight changes of mice in each group were recorded. H&E staining, Masson staining and hydroxyproline detection were performed on the important organs and tissues of mice in each group to detect inflammation and fibrosis.

[0056] 4) In vivo re-inoculation experiment: For mice that achieved complete remission after combination therapy, tumor cells were re-inoculated into the contralateral lung. Mice that had not previously been inoculated with tumor cells were used as controls to observe the tumor formation rate and tumor growth, and to determine whether the combination therapy produced an immune memory effect.

[0057] 5) In vivo T cell blocking experiment: In the low-dose fast neutron radiotherapy + PD-1 inhibitor treatment group, CD4+ T cells and CD8+ T cells were blocked in vivo, and the tumor growth and survival changes in mice were observed. Flow cytometry and immunofluorescence were used to detect the changes in the number and function of various immune cells in the tumor after blocking, so as to clarify the important role of T cells in the combined treatment of low-dose fast neutron radiotherapy + PD-1 inhibitor.

[0058] 6) In vivo chemokine receptor blocking experiment: In the low-dose fast neutron radiotherapy + PD-1 inhibitor treatment group, CXCR3 and CCR5 chemokine receptors were blocked in vivo. The changes in tumor growth and survival in mice were observed. Flow cytometry and immunofluorescence were used to detect the changes in the number and function of CD4+ T cells and CD8+ T cells in tumor tissue after blocking, so as to clarify the important role of chemokine-mediated T cell chemotaxis in the combined treatment of low-dose fast neutron radiotherapy + PD-1 inhibitor.

[0059] 7) Using STING knockout tumor cells, mice were grouped and treated as in 1). The growth and survival of mouse tumors were observed. Flow cytometry and immunofluorescence were used to detect changes in various immune cells such as T cells in the tumor. RT-PCR and ELISA were used to detect changes in the expression of chemokines in the tumor to clarify the effect of the STING pathway on T cell chemotaxis and its important role in the combined treatment of low-dose fast neutron radiotherapy and PD-1 inhibitor.

[0060] Example 5: Distant effects of low-dose fast neutron radiotherapy combined with PD-1 inhibitors 1) Distant effects of low-dose fast neutron radiotherapy combined with PD-1 inhibitors: Dual tumor-bearing mice were established and randomly divided into four groups: control group, PD-1 inhibitor group, low-dose fast neutron radiotherapy group, and low-dose fast neutron radiotherapy + PD-1 inhibitor group. The growth, toxicity, and overall survival (n=15 / group) of distant tumors (untreated side) were compared among the four groups. Distant tumor tissues were collected from each group, and the intratumoral immune microenvironment was detected using liquid-phase microarray and single-cell sequencing to clarify that low-dose fast neutron radiotherapy combined with PD-1 inhibitor can promote the distant effect.

[0061] 2) Exploration of multi-site low-dose fast neutron radiotherapy combined with PD-1 inhibitors: A mouse dual-tumor model was established to observe the differences in tumor growth, toxicity, and overall survival between the dual-tumor low-dose fast neutron radiotherapy + PD-1 inhibitor group and the single-tumor low-dose radiotherapy + PD-1 inhibitor group.

[0062] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A tumor combined with immunotherapy system based on precision radiotherapy, characterized in that, Including fast neutron radiotherapy devices and PD-1 inhibitor injection devices; During fast neutron radiotherapy, patients are injected with PD-1 inhibitors.

2. The tumor combined with immunotherapy system based on precision radiotherapy according to claim 1, characterized in that, The fast neutron radiotherapy uses low-dose fast neutrons.

3. The application of the tumor combined with immunotherapy system based on precision radiotherapy as described in claim 1 or 2 in tumor treatment, characterized in that, The tumor is either a colon tumor or a lung tumor.

4. A treatment method for tumors, characterized in that, Includes the following steps: Using fast neutron radiotherapy combined with PD-1 inhibitors to treat tumors.

5. A method for treating tumors according to claim 4, characterized in that, The PD-1 inhibitor is administered via intravenous injection.

6. A method for treating tumors according to claim 4, characterized in that, The fast neutron radiotherapy uses low-dose fast neutrons.

7. A method for treating tumors according to claim 4, characterized in that, The tumor is either a colon tumor or a lung tumor.

8. A radiotherapy method for enhancing tumor immunogenicity, characterized in that, Includes the following steps: Fast neutrons are used for radiotherapy during the use of PD-1 inhibitor drugs.

9. A radiotherapy method for enhancing tumor immunogenicity according to claim 8, characterized in that, The PD-1 inhibitor drug is administered intravenously.

10. A radiotherapy method for enhancing tumor immunogenicity according to claim 9, characterized in that, The fast neutron radiotherapy uses low-dose fast neutrons.

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