Abscopal effect of radiation on bone metastases of breast cancer: A case report

Molecular Changes in Breast Cancer Induced by Radiation Therapy

PURPOSE

Breast cancer treatments are based on prognostic clinicopathologic features that form the basis for therapeutic guidelines. Although the utilization of these guidelines has decreased breast cancer-associated mortality rates over the past three decades, they are not adequate for individualized therapy. Radiation therapy (RT) is the backbone of breast cancer treatment. Although a highly successful therapeutic modality clinically, from a biological perspective, preclinical studies have shown RT to have the potential to alter tumor cell phenotype, immunogenicity, and the surrounding microenvironment, potentially changing the behavior of cancer cells and resulting in a significant variation in RT response. This review presents the recent advances in revealing the complex molecular changes induced by RT in the treatment of breast cancer and highlights the complexities of translating this information into clinically relevant tools for improved prognostic insights and the revelation of novel approaches for optimizing RT.

METHODS AND MATERIALS

Current literature was reviewed with a focus on recent advances made in the elucidation of tumor-associated radiation-induced molecular changes across molecular, genetic, and proteomic bases. This review was structured with the aim of providing an up-to-date overview over the very broad and complex subject matter of radiation-induced molecular changes and radioresistance, familiarizing the reader with the broader issue at hand.

RESULTS

The subject of radiation-induced molecular changes in breast cancer has been broached from various physiological focal points including that of the immune system, immunogenicity and the abscopal effect, tumor hypoxia, breast cancer classification and subtyping, molecular heterogeneity, and molecular plasticity. It is becoming increasingly apparent that breast cancer clinical subtyping alone does not adequately account for variation in RT response or radioresistance. Multiple components of the tumor microenvironment and immune system, delivered RT dose and fractionation schedules, radiation-induced bystander effects, and intrinsic tumor physiology and heterogeneity all contribute to the resultant RT outcome.

CONCLUSIONS

Despite recent advances and improvements in anticancer therapies, tumor resistance remains a significant challenge. As new analytical techniques and technologies continue to provide crucial insight into the complex molecular mechanisms of breast cancer and its treatment responses, it is becoming more evident that personalized anticancer treatment regimens may be vital in overcoming radioresistance.

Effect of radiation dose rates and cisplatin on cytogenetic damage in rats receiving head-neck radiotherapy

BACKGROUND

We aimed to investigate effect of radiotherapy (RT) applications with different dose rates on cytogenetic damages, which focused on micronucleus (MN) formation, and evaluate how this damage varies by cisplatin in rats receiving head-neck RT.

MATERIAL AND METHODS

Thirty-six Sprague Dawley rats were divided into five groups. The first and second groups were irradiated at a dose rate of 300 monitor unit/minute (MU/min) and 600 MU/min, respectively. The third group was irradiated at a dose rate of 300 MU/min and given cisplatin. The fourth group was irradiated at a dose rate of 600 MU/min and given cisplatin. The fifth group received neither irradiation nor cisplatin (control group). One thousand polychromatic erythrocytes were scored, and MN frequency in polychromatic erythrocytes was determined for each rat.

RESULTS

There was a significant difference among five groups in terms of the number of MN (p: 0.001). The number of MN was significantly higher in the 600 MU/min + cisplatin group (fourth group) compared to the control group [9.5 (1.0-23.0) vs. 1.5 (1.0-2.0), respectively]. It was also significantly higher in 600 MU/min + cisplatin group (fourth group) compared to 300 MU/min group (first group) [9.5 (1.0-23.0) vs. 2.0 (1.0-3.0), respectively]. On the other hand, there was no significant difference among other groups.

CONCLUSIONS

Our findings suggest that RT given at a higher dose rate causes more cytogenetic damage, and this damage is increased by concurrent administration of cisplatin.

Immunotherapy and Radiotherapy Combinations for Sarcoma

Sarcomas are a heterogeneous group of bone and soft tissue tumors. Survival outcomes for advanced (unresectable or metastatic) disease remain poor, so therapeutic improvements are needed. Radiotherapy plays an integral role in the neoadjuvant and adjuvant treatment of localized disease as well as in the treatment of metastatic disease. Combining radiotherapy with immunotherapy to potentiate immunotherapy has been used in a variety of cancers other than sarcoma, and there is opportunity to further investigate combining immunotherapy with radiotherapy to try to improve outcomes in sarcoma. In this review, we describe the diversity of the tumor immune microenvironments for sarcomas and describe the immunomodulatory effects of radiotherapy. We discuss studies on the timing of radiotherapy relative to immunotherapy and studies on the radiotherapy dose and fractionation regimen to be used in combination with immunotherapy. We describe the impact of radiotherapy on the tumor immune microenvironment. We review completed and ongoing clinical trials combining radiotherapy with immunotherapy for sarcoma and propose future directions for studies combining immunotherapy with radiotherapy in the treatment of sarcoma.

Abscopal Effect on Bone Metastases from Solid Tumors: A Systematic Review and Retrospective Analysis of Challenge within a Challenge

BACKGROUND

Abscopal effect (AE) describes the ability of radiotherapy (RT) to induce immune-mediated responses in nonirradiated distant metastasis. Bone represents the third most frequent site of metastasis and an immunologically favorable environment for the proliferation of cancer cells. We revised the literature, searching documented cases of AE involving bone metastases (BMs) and evaluated the incidence of AE involving BMs in patients requiring palliative RT on BMs or non-BMs treated at our department.

METHODS

Articles published in the PubMed/MEDLINE database were selected using the following search criteria: ((abscopal effect)) AND ((metastases)). Patients with BMs, who underwent performed bone scintigraphy before and at least 2-3 months after RT, were selected and screened between January 2015 and July 2022. AE was defined as an objective response according to the scan bone index for at least one nonirradiated metastasis at a distance > 10 cm from the irradiated lesion. The primary endpoint was the rate of AE on BMs.

RESULTS

Ten cases experiencing AE of BMs were identified from the literature and eight among our patients.

CONCLUSIONS

The analysis performed here suggests the use of hypofractionated radiotherapy as the only triggering factor for AE of BMs through the activation of the immune response.

The abscopal effect: systematic review in patients with brain and spine metastases

Background

The abscopal effect is a rare phenomenon whereby local radiation induces a proposed immune-mediated anti-tumor effect at distant sites. Given the growing use of immunotherapies and systemic immune checkpoint inhibitors in neuro-oncologic practice, we aimed to review prior studies pertaining to this phenomenon in the context of tumor shrinkage both within the central nervous system as well as distant disease sites.

Methods

A systematic review in accordance with the PRISMA guidelines was conducted to identify all studies which assessed the abscopal effect in patients with treated metastatic cancer to the brain and/or spine. Articles were included if they reported the abscopal effect in patients (case studies) or if the abscopal effect was explicitly analyzed in case series with cohorts of patients with metastatic brain or spine tumors. Laboratory investigations and clinical trials investigating new therapies were excluded.

Results

Twenty reports met inclusion criteria [16 case reports, 4 case series (n = 160), total n = 174]. Case reports of the abscopal effect were in relation to the following cancers: melanoma (6 patients), breast cancer (3), lung adenocarcinoma (2), non-small-cell lung cancer (2), hepatocellular carcinoma (1), and renal cell carcinoma (1). Eleven patients had irradiation to the brain and 2 to the spine. Patients undergoing whole brain radiotherapy (6) had an average dose of 33.6 Gy over 8-15 fractions, and those undergoing stereotactic radiosurgery (5) had an average dose of 21.5 Gy over 1-5 fractions. One patient had radiation to the body and an intracranial abscopal effect was observed. Most common sites of extracranial tumor reduction were lung and lymph nodes. Ten case studies (57%) showed complete resolution of extra-CNS tumor burden. Median progression-free survival was 13 months following radiation. Four papers investigated incidence of abscopal effects in patients with metastatic melanoma to the brain who received immune checkpoint inhibitor therapy (n = 160); two papers found an abscopal effect in 35% and 52% of patients (n = 16, 21 respectively), and two papers found no evidence of abscopal effects (n = 61, 62).

Conclusions

Abscopal effects can occur following radiotherapy in patients with brain or spine metastases and is thought to be a result of increased anti-tumor immunity. The potential for immune checkpoint inhibitor therapy to be used in combination with radiotherapy to induce an abscopal effect is an area of active investigation.

A Patient-Level Data Meta-analysis of the Abscopal Effect

Purpose

The abscopal effect is defined when a form of local therapy causes tumor regression of both the target lesion and any untreated tumors. Herein cases of the abscopal effect were systematically reviewed and a patient-level data analysis was performed for clinical predictors of both duration of response and survival.

Methods and Materials

The Population, Intervention, Control, Outcome, Study (PICOS) design approach, Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) literature selection process, and Meta-analysis of Observational Studies in Epidemiology (MOOSE) were used to find articles published before September 2019 in MEDLINE/PubMed and Google Scholar. Inclusion criteria were (1) population: patients with reported abscopal response; (2) intervention: documented treatment(s); (3) control: none; (4) outcomes: overall and progression-free survival; and (5) setting: retrospective case reports. Time from treatment until abscopal response and time from abscopal response until progression/death were calculated. Univariate and multivariate analyses were conducted for survival outcomes.

Results

Fifty studies (n = 55 patients) were included. Median age was 65 years (interquartile range [IQR], 58-70) and 62% were male. Fifty-four (98%) patients received radiation therapy, 34 (62%) received radiation therapy alone, 5 (9.1%) underwent surgery, 4 (7.3%) received chemotherapy, and 11 (20%) received immunotherapy. Median total dose was 32 Gy (IQR, 25.5-48 Gy) and median dose per fraction was 3 Gy (IQR, 2-7.2). Median time until abscopal response was 4 months (IQR, 1-5; min 0.5, max 24). At 5 years, overall survival was 63% and distant progression-free survival was 45%. No variables had statistical significance in predicting duration of response or survival.

Conclusions

Almost all reported cases of the abscopal response are after radiation therapy; however, there are no known predictors of duration of response or survival in this population.

Differential abscopal effect in extracranial and intracranial lesions after radiotherapy alone for vertebral bone metastasis of unknown primary: a case report

Background

The abscopal effect is a phenomenon in which a tumor located far from irradiated lesions regresses. We have experienced a case in which both intracranial and extracranial lesions showed an abscopal effect after radiotherapy for spinal metastases of unknown primary. We report the differential abscopal effect in extracranial and intracranial lesions.

Case presentation

A 57-year-old Japanese man was diagnosed with multiple lung nodules, bone metastases, and brain metastases. The results of pathological examination at the previous hospital he visited suggested adenocarcinoma of the lung. However, there was a possibility that the biopsy specimen was inadequate. Radiation therapy was performed on the ninth thoracic vertebra for a total dose of 39 Gy in 13 fractions because the lesion in the ninth thoracic vertebra was destructively extending. After thorough examination, the primary lesion could not be identified, and we made diagnosis of cancer of unknown primary. The patient did not want to receive systemic chemotherapy; however, all of the lesions except for the brain metastases had spontaneously shrunk 2 months after radiation therapy. Although the brain metastases had partially shrunk, whole-brain radiotherapy for a total dose of 36 Gy in 12 fractions was performed. Fifteen months after initial radiation therapy, the brain metastasis recurred, and Gamma Knife radiosurgery was additionally performed. The brain metastases disappeared after the radiosurgery. During a period of 30 months after radiation therapy for the ninth vertebra, the lesions of the trunk all maintained their shrinkage without systemic chemotherapy. Right cervical lymph node metastasis and brain metastases occurred 30 months after the initial radiation therapy. A biopsy of the right cervical lymph node led to the diagnosis of clear cell carcinoma. Although we considered additional radiation therapy or chemotherapy, the patient died 3 months after the progression of recurrence lesions.

Discussion and conclusions

We report a rare case in which radiotherapy alone for an extracranial metastatic lesion of a vertebra resulted in an abscopal effect on both extracranial and intracranial lesions. Notably, the abscopal effect in the intracranial lesions was weaker than that in the extracranial lesions.

Abscopal Effects in Metastatic Cancer: Is a Predictive Approach Possible to Improve Individual Outcomes?

Patients with metastatic cancers often require radiotherapy (RT) as a palliative therapy for cancer pain. RT can, however, also induce systemic antitumor effects outside of the irradiated field (abscopal effects) in various cancer entities. The occurrence of the abscopal effect is associated with a specific immunological activation in response to RT-induced cell death, which is mainly seen under concomitant immune checkpoint blockade. Even if the number of reported apscopal effects has increased since the introduction of immune checkpoint inhibition, its occurrence is still considered rare and unpredictable. The cases reported so far may nevertheless allow for identifying first biomarkers and clinical patterns. We here review biomarkers that may be helpful to predict the occurrence of abscopal effects and hence to optimize therapy for patients with metastatic cancers.

Macrophage contributes to radiation-induced anti-tumor abscopal effect on transplanted breast cancer by HMGB1/TNF-α signaling factors

Objectives: The roles of innate immunity including macrophages in radiation-induced abscopal effect (RIAE) are ambiguous. In this study, we evaluated the role of macrophage in RIAE and the interaction of cytokines in tumor microenvironment after irradiation.

Materials and Methods: Transplanted tumor of breast cancer cells in BalB/C mice, severe combined immunodeficiency (SCID) mice and non-obese diabetic (NOD)-SCID mice were irradiated with fractionation doses to observe anti-tumor abscopal effect. The underlying mechanism of RIAE was investigated by treating the mice with TNF-α inhibitor or macrophage depletion drug and analyzing the alteration of macrophage distribution in tumors. A co-culture system of breast cancer cells and macrophages was applied to disclose the signaling factors and related pathways involved in the RIAE.

Results: The growth of nonirradiated tumor was effectively suppressed in mice with normal or infused macrophages but not in mice with insufficiency/depletion of macrophage or TNF-α inhibition, where M1-macrophage was mainly involved. Investigation of the bystander signaling factors in vitro demonstrated that HMGB1 released from irradiated breast cancer cells promoted bystander macrophages to secret TNF-α through TLR-4 pathway and further inhibited the proliferation and migration of non-irradiated cancer cells by PI3K-p110γ suppression.

Conclusions: HMGB1 and TNF-α contributes to M1-macrophages facilitated systemic anti-tumor abscopal response triggered by radiotherapy in breast cancer, indicating that the combination of immunotherapy and radiotherapy may has important implication in enhancing the efficiency of tumor treatment.

The Abscopal Effect: Could a Phenomenon Described Decades Ago Become Key to Enhancing the Response to Immune Therapies in Breast Cancer?

Background

The term "abscopal effect" was defined in 1953. In oncology the term is used to describe systemic antitumor effects triggered by local irradiation (nontarget effect). Although the mechanism of the abscopal effect is not completely understood yet, it has been demonstrated that in situ tumor vaccination, and the resulting antitumor immune response, is one of the key factors.

Summary

The development of immune therapies has recently led to concepts combining local radiotherapy and immune therapy with the aim of enhancing the response to immune therapy by the immunological mechanisms summarized in the term abscopal effect. This concept has also been investigated in less immunogenic tumors such as breast cancer. Initial data are promising but the hypothesis that the combination of checkpoint inhibitors and local radiotherapy could be an effective combination in breast cancer has to be proven by ongoing trials. Substitution of local radiotherapy by local hyperthermia could be an option in selected cases.

Key Messages

Combination of checkpoint inhibitors with local radiation or hyperthermia in breast cancer is a promising approach and could enhance the response rates generated by immune therapy alone through the antitumor immune response initiated by the abscopal effect.

Research Progress and Existing Problems for Abscopal Effect

Radiation therapy plays a vital role in the treatment of tumours. In particular, the occurrence of the “abscopal effect” brings about a favourable turn for the treatment of patients with advanced metastatic malignant tumours. Because of the abscopal effect, non-irradiated areas are also treated. However, the abscopal effect occurs by chance, not through seeking. Although the abscopal effect has been studied enthusiastically, the desired result does not appear to be achieved. Moreover, its combination with immunotherapy appears to be overwhelming. There is an opinion that abscopal effect is difficult to achieve by irradiation of a single tumour, and irradiation of multiple or total lesions is advocated to increase the possibility of obtaining clinically meaningful outcomes. Obviously, there are still questions about the mechanism, condition and possibility underlying the occurrence of the abscopal effect. Can the abscopal effect truly change the future treatment strategy as the researchers expect? What are the current problems? This article reviewed the research in recent years to explore the progress and controversy surrounding the abscopal effect of radiation therapy.

Pure abscopal effect of radiotherapy in a salivary gland carcinoma: Case report, literature review, and a search for new approaches

We report the case of an 84-year-old woman with poorly differentiated non-small cell carcinoma of the right parotid who presented with headache, was found to have a primary right parotid gland cancer as well as metastatic disease, and underwent palliative radiotherapy to the primary site. The patient received no chemotherapy or immunotherapy, but both the primary site and several non-irradiated foci in the lungs regressed or completely resolved. The patient remained free of disease for about one year before progression. The case is a rare instance of abscopal regression of metastatic disease in the absence of pharmacologic immunomodulation. A literature review surveys the history of the abscopal effect of radiation therapy, attempts to understand the mechanisms of its successes and failures, and points to new approaches that can inform and improve the outcomes of radioimmunotherapy.

Abscopal Regressions of Lymphoma After Involved-Site Radiation Therapy Confirmed by Positron Emission Tomography

PURPOSE

Patients with abscopal regressions of lymphoma after palliative involved-site radiation therapy (ISRT), detected on sequential ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET), were identified by audit. A retrospective analysis was subsequently conducted to estimate the frequency of abscopal regression in follicular lymphoma (FL).

METHODS AND MATERIALS

Potential cases were identified at multidisciplinary lymphoma meetings and fulfilled these criteria: (1) palliative ISRT given for histologically confirmed lymphoma, (2) >2 lesions visualized on FDG-PET, (3) >1 unirradiated lesion(s) outside ISRT volume, (4) no systemic therapy delivered <2 months before radiation therapy or between radiation therapy and response assessment, (5) complete metabolic response (CMR) in ≥1 unirradiated lesions detected on serial FDG-PET/CT. All ISRT patients with FL treated in 2016 to 2018 were systematically reviewed.

RESULTS

Seven cases of abscopal regression were identified, including 4 patients with FL. In all cases, a CMR was apparent both within the ISRT volume and in ≥1 unirradiated lesions. One patient each was identified with mantle cell lymphoma (4 Gy in 2 fractions), Hodgkin lymphoma (20 Gy in 3 fractions, then 30 Gy in 15 fractions to the same volume), and Richter transformation of chronic lymphatic leukemia (30 Gy in 10 fractions). The 4 patients with FL received either 4 Gy in 2 fractions (n = 3) or 4 Gy followed 8 months later by 30 Gy in 15 fractions (n = 1). From 2016 to 2018, 29 courses of ISRT were prescribed for multifocal FL, after which 4 of 29 (13.8%) abscopal responses were detected, including in 4 of 9 (44.4%) patients with serial PET scans. Two patients, with relapsed disease after initial abscopal responses, experienced durable CMRs with immunotherapies.

CONCLUSIONS

In 4 of 7 cases, PET-detected abscopal regression of lymphoma occurred after 4 Gy, in 2 of 7 cases after repeated ISRT to the same volume, and in 2 of 7 was associated with subsequent complete response to immunotherapy, consistent with an immune basis for the abscopal effect. Abscopal regressions in FL appear to be more common than previously suspected.

Cancer immunotherapy with immunoadjuvants, nanoparticles, and checkpoint inhibitors: Recent progress and challenges in treatment and tracking response to immunotherapy

Chemotherapy, surgery, and radiation are accepted as the preferred treatment modalities against cancer, but in recent years the use of immunotherapeutic approaches has gained prominence as the fourth treatment modality in cancer patients. In this approach, a patient's innate and adaptive immune systems are activated to achieve clearance of occult cancerous cells. In this review, we discuss the preclinical and clinical immunotherapeutic (e.g., immunoadjuvants (in-situ vaccines, oncolytic viruses, CXC antagonists, device activated agents), organic and inorganic nanoparticles, and checkpoint blockade) that are under investigation for cancer therapy and diagnostics. Additionally, the innovations in imaging of immune cells for tracking therapeutic responses and limitations (e.g., toxicity, inefficient immunomodulation, etc.) are described. Existing data suggest that if immune therapy is optimized, it can be a real and potentially paradigm-shifting cancer treatment frontier.

Trends in the Abscopal Effect After Radiation to Spinal Metastases: A Systematic Review

While the abscopal effect has been previously described, the phenomenon has been poorly defined in the case of spinal metastases. This article is unique in that we present the first systematic review of the abscopal effect after radiation therapy to metastatic spinal cancer, especially since the spinal column represents one of the most common metastatic locations. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in the Enhancing the QUAlity and Transparency Of health Research (EQUATOR) resources, a systematic review identified relevant studies via a computer-aided search of MEDLINE and Embase. Ten publications that met the inclusion and exclusion criteria from the PRISMA flow diagram described a total of 13 patients, 76.9% of whom demonstrated image findings of the abscopal effect. In summary, important trends in the nine patients who experienced the abscopal effect in this review include higher doses of radiation and treatment with immunomodulators, both of which may help guide treatment paradigms for spinal metastases superimposed on diffuse metastatic disease. These trends, however, still warrant further investigations with experimental and clinical studies for a mechanistic understanding of the abscopal effect.

The Abscopal Effect of Stereotactic Radiotherapy and Immunotherapy: Fool's Gold or El Dorado?

An 'abscopal' effect if often used to refer to distant tumour regression after localised irradiation. Since the first report of the abscopal effect in the 1950s, well-documented cases with radiotherapy alone are very rare. It is widely accepted that the immune response plays an important role in the abscopal effect, although the mechanism is still unclear. With the recent success of cancer immunotherapy, there is growing interest in combining immunotherapy with radiotherapy to boost abscopal response rates. Compared with conventional radiotherapy, stereotactic ablative radiotherapy (SABR) not only delivers ablative dose to the tumour, but may also induce robust immune responses. In this review we examine studies that combine SABR and immunotherapy. We review the preclinical rationale for SABR and immunotherapy combinations, the case for and against abscopal effects, and the current landscape of clinical trials.

Bone density and pain response following intensity-modulated radiotherapy versus three-dimensional conformal radiotherapy for vertebral metastases - secondary results of a randomized trial

Background

This was a prespecified secondary analysis of a randomized trial that analyzed bone density and pain response following fractionated intensity-modulated radiotherapy (IMRT) versus three-dimensional conformal radiotherapy (3DCRT) for palliative management of spinal metastases.

Methods/materials

Sixty patients were enrolled in the single-institutional randomized exploratory trial, randomly assigned to receive IMRT or 3DCRT (30 Gy in 10 fractions). Along with pain response (measured by the Visual Analog Scale (VAS) and Chow criteria), quantitative bone density was evaluated at baseline, 3, and 6 months in both irradiated and unirradiated spinal bodies, along with rates of pathologic fractures and vertebral compression fractures.

Results

Relative to baseline, bone density increased at 3 and 6 months following IMRT by a median of 24.8% and 33.8%, respectively (p < 0.01 and p = 0.048). These figures in the 3DCRT cohort were 18.5% and 48.4%, respectively (p < 0.01 for both). There were no statistical differences in bone density between IMRT and 3DCRT at 3 (p = 0.723) or 6 months (p = 0.341). Subgroup analysis of osteolytic and osteoblastic metastases showed no differences between groups; however, mixed metastases showed an increase in bone density over baseline in the IMRT (but not 3DCRT) arm. The 3-month rate of the pathological fractures was 15.0% in the IMRT arm vs. 10.5% in the 3DCRT arm. There were no differences in pathological fractures at 3 (p = 0.676) and 6 (p = 1.000) months. The IMRT arm showed improved VAS scores at 3 (p = 0.037) but not 6 months (p = 0.430). Using Chow criteria, pain response was similar at both 3 (p = 0.395) and 6 (p = 0.732) months.

Conclusions

This the first prospective investigation evaluating the impact of IMRT vs. 3DCRT on bone density. Along with pain response and pathologic fracture rates, significant rises in bone density after 3 and 6 months were similar in both cohorts. Future randomized investigations with larger sample sizes are recommended.

Trial registration

NCT, NCT02832830. Registered 14 July 2016

Iodine-125 seed implantation combined with arterial chemoembolization therapy for pain palliation in metastatic bone cancer: a retrospective study

Bone metastases are the most common sites for malignant tumors. Patients who failed to respond to initial first-line treatment with bisphosphonates usually suffer from extreme pain. The aim of this study was to observe the efficacy of arterial chemoembolization combined with Iodine-125 seed implantation in the treatment of bone metastatic cancer pain. All 14 patients with metastatic bone tumor wo failed first-line treatment underwent arterial chemoembolization the day before the implantation of the particles. A computer stereoscopic TPS was used to design the treatment plans, the number and dose of particles required for implantation. Pain relief was evaluated using several parameters such as Visual Analog Scale (VAS) and Verbal Rating Scales (VRS). Pain intensity was measured pre-operation and 1-week, 1-month, 3-month after the treatment. Meanwhile, we also assessed tumor size using computer tomography (CT). Pain palliation was observed in 35.7% (5/14), 57.1% (8/14), and 78.6% (11/14) of all patients at 1-week, 1-month and 3-month post treatment. Likewise, our analysis showed that the combination therapy resulted in a significant decrease of VAS score (6.71 ± 0.49 before treatment vs 3.36 ± 0.40 at 3 month post treatment) and overall responding rate of 92.0% using VRS pain assessment. Consistently, tumor size was reduced from 42.16 ± 10.32 before treatment to 29.11 ± 8.73 at 3 months post treatment. No serious complications were detected. Our study demonstrate that the combination of arterial chemoembolization and ¹²⁵I particles resulted in evident pain relief and reduction of tumor burden, suggesting that the combination treatment could be a feasible and promising therapy for bone tumor management.