Inflammatory myofibroblastic tumor from molecular diagnostics to current treatment.

Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm with intermediate malignancy characterized by a propensity for recurrence but a low metastatic rate. Diagnostic challenges arise from the diverse pathological presentation, variable symptomatology, and lack of different imaging features. However, IMT is identified by the fusion of the anaplastic lymphoma kinase (ALK) gene, which is present in approximately 70% of cases, with various fusion partners, including ran-binding protein 2 (RANBP2), which allows confirmation of the diagnosis. While surgery is the preferred approach for localized tumors, the optimal long-term treatment for advanced or metastatic disease is difficult to define. Targeted therapies are crucial for achieving sustained response to treatment within the context of genetic alteration in IMT. Crizotinib, an ALK tyrosine kinase inhibitor (TKI), was officially approved by the US Food and Drug Administration (FDA) in 2020 to treat IMT with ALK rearrangement. However, most patients face resistance and disease progression, requiring consideration of sequential treatments. Combining radiotherapy with targeted therapy appears to be beneficial in this indication. Early promising results have also been achieved with immunotherapy, indicating potential for combined therapy approaches. However, defined recommendations are still lacking. This review analyzes the available research on IMT, including genetic disorders and their impact on the course of the disease, data on the latest targeted therapy regimens and the possibility of developing immunotherapy in this indication, as well as summarizing general knowledge about prognostic and predictive factors, also in terms of resistance to systemic therapy.

Real-world outcomes of metastatic clear cell sarcoma sequential chemotherapy.

Clear cell sarcoma is an ultra-rare chemoresistant subtype of soft tissue sarcoma. This retrospective analysis aimed to clarify the efficacy of palliative chemotherapy in CCS by assessing response rates, progression-free survival (PFS), and overall survival (OS) at a referral center. A retrospective analysis of palliative treatment was conducted on patients with CCS treated at the sarcoma unit from 1997 to 2023. Treatment responses were assessed using RECIST criteria, and the Kaplan-Meier method was used to calculate PFS and OS. The analysis covered 23 CCS chemotherapy-treated patients with 11 (47.8%) men. The median age at the palliative treatment start was 32 years (range 18-59). The median follow-up was 8.2 months. Four patients were referred to our centre for M1 disease, and 6 received perioperative chemotherapy and progressed during follow-up. In the first line, 14 patients received anthracycline-based chemotherapy (60.9%), five were treated with ifosfamide (HD-IFO), and four received other regimens. One patient (4.3%) achieved partial response (PR), and 12 patients (52.2%) achieved stable disease (SD) as the best response. Median PFS in 1 line was 2.79 months (95% CI: 2.04-8.38), and 1.76 months (95% CI: 0.72-6.97) in the second line. The median OS from first-line palliative chemotherapy was 8.2 months (95% CI: 6.2-14), and the second-line palliative chemotherapy mOS was 4.6 months (95% CI: 3.9-NA). Perioperatively anthracycline-pretreated worsened patients' median PFS in the M1 setting. Poor responses to conventional chemotherapy were observed in CCS, indicating a need for further clinical trials in this indication.

Challenges and solutions in 3D printing for oncology: a narrative review.

BACKGROUND AND OBJECTIVE: Oncology is increasingly adopting three-dimensional (3D) printing, a method of creating objects through additive manufacturing using various techniques and materials. This technology, divided into conventional 3D printing (using non-biological materials like thermoplastics or titanium) and bioprinting (involving living cells and tissues), has shown potential in surgical planning, implant creation, and radiotherapy. However, despite promising preclinical and clinical applications, its clinical integration faces challenges such as a lack of strong evidence, standardized guidelines, and detailed data on costs and scalability. This study reviews the current use of 3D printing in oncology, aiming to differentiate between practical and experimental applications, thereby guiding clinicians interested in incorporating this technology. METHODS: A literature search was conducted to gather comments, reviews, and preclinical and clinical studies focusing on the use of 3D printing in oncology, with publications dated before December 1, 2023. The search for pertinent studies involved utilizing PubMed and Google Scholar Review. The selection process for articles was based on a unanimous consensus among all authors. We excluded topics related to bioprinting and the technical nuances of 3D printing. KEY CONTENT AND FINDINGS: The review comprehensively describes the utilization of 3D printing in radiation oncology, surgical oncology, orthopedic oncology, medical oncology, hyperthermia, and patients' education. However, 3D printing faces several limitations that are related to unpredictable costs, difficult scalability, very complex regulations and lack of standardization. CONCLUSIONS: 3D printing is increasingly useful in oncology for diagnostics and treatment, yet remains experimental and case-based. Despite growing literature, it focuses mostly on pre-clinical studies and case reports, with few clinical studies involving small samples. Thus, extensive research is needed to fully evaluate its efficacy and application in larger patient groups.

What is the Optimal Treatment Strategy after Sarcoma R2 Surgery?

OPINION STATEMENT: Soft tissue sarcomas (STS) are rare tumours of mesenchymal origin, most commonly occurring in the extremity but also in the retroperitoneum. The curative treatment for STS is radical surgery with wide margins, in some cases in combination with perioperative radiotherapy and chemotherapy. Nonradical resection (R2) of STS has been an emerging issue in recent decades, as optimal subsequent management remains debatable. Similarly, there is still no consensus on optimal surgical margins. Combining multiple treatment modalities in adjuvant therapy can achieve local and distant control in patients following surgery with positive margins. Patients who have undergone nonradical resection therefore require additional surgical interventions, and adjuvant radiotherapy resulting in a better prognosis but a higher number of complications. Following non-radical treatment, patients with limb and trunk wall sarcomas and retroperitoneal sarcomas should also undergo increased oncological surveillance. Given the potential issues that may emerge in such clinical situations, it is crucial to up-date the current guidelines to enhance the long-term prognosis of these patients.

Dose-intensified stereotactic body radiotherapy for painful vertebral metastases: A randomized phase 3 trial.

BACKGROUND: The purpose of this randomised study was to determine whether dose-intensified stereotactic body radiotherapy (SBRT) for painful vertebral metastases results in increased rates of pain improvement compared with conventional external beam radiotherapy (cEBRT) (control) 6 months after treatment. METHODS: This randomized, controlled phase 3 trial was conducted between November 2016 and January 2023, when it was stopped early. Patients were eligible if they were aged 18 years or older; had one or two painful, stable, or potentially unstable vertebral metastases; and had a life expectancy of 1 year or longer according to the investigator's estimates. Patients received 48.5 grays (Gy) in 10 fractions (with epidural involvement) or 40 Gy in five fractions (without epidural involvement) in the SBRT group and 30 Gy in 10 fractions or 20 Gy in five fractions in the cEBRT group, respectively. The primary end point was an improvement in the pain score at the treated site by at least 2 points (on a visual analog scale from 0 to 10 points) at 6-month follow-up. Data were analyzed on an intention-to-treat and per-protocol basis. RESULTS: Of 214 patients who were screened for eligibility, 63 were randomized 1:1 between SBRT (33 patients with 36 metastases) and cEBRT (30 patients with 31 metastases). The median age of all patients was 66 years, and 40 patients were men (63.5%). In the intention-to-treat analysis, the 6-month proportion of patients who had metastases with pain reduction by 2 or more points was significantly higher in the SBRT group versus the control group (69.4% vs. 41.9%, respectively; two-sided p = .02). Changes in opioid medication intake relative to baseline were nonsignificant between the groups. No differences were observed in vertebral compression fracture or adverse event rates between the groups. CONCLUSIONS: Dose-intensified SBRT improved pain score more effectively than cEBRT at 6 months.

Regional hyperthermia for soft tissue sarcoma - a survey on current practice, controversies and consensus among 12 European centers.

PURPOSE: To analyze the current practice of regional hyperthermia (RHT) for soft tissue sarcoma (STS) at 12 European centers to provide an overview, find consensuses and identify controversies necessary for future guidelines and clinical trials. METHODS: In this cross-sectional survey study, a 27-item questionnaire assessing clinical subjects and procedural details on RHT for STS was distributed to 12 European cancer centers for RHT. RESULTS: We have identified seven controversies and five consensus points. Of 12 centers, 6 offer both, RHT with chemotherapy (CTX) or with radiotherapy (RT). Two centers only offer RHT with CTX and four centers only offer RHT with RT. All 12 centers apply RHT for localized, high-risk STS of the extremities, trunk wall and retroperitoneum. However, eight centers also use RHT in metastatic STS, five in palliative STS, eight for superficial STS and six for low-grade STS. Pretherapeutic imaging for RHT treatment planning is used by 10 centers, 9 centers set 40-43 °C as the intratumoral target temperature, and all centers use skin detectors or probes in body orifices for thermometry. DISCUSSION: There is disagreement regarding the integration of RHT in contemporary interdisciplinary care of STS patients. Many clinical controversies exist that require a standardized consensus guideline and innovative study ideas. At the same time, our data has shown that existing guidelines and decades of experience with the technique of RHT have mostly standardized procedural aspects. CONCLUSIONS: The provided results may serve as a basis for future guidelines and inform future clinical trials for RHT in STS patients.

Update on Dosing and Fractionation for Neoadjuvant Radiotherapy for Localized Soft Tissue Sarcoma.

OPINION STATEMENT: Neoadjuvant radiotherapy (RT) over 5-6 weeks with daily doses of 1.8-2.0 Gy to a total dose of 50-50.4 Gy is standard of care for localized high-grade soft tissue sarcomas (STS) of the extremities and trunk wall. One exception is myxoid liposarcomas where the phase II DOREMY trial applying a preoperative dose of 36 Gy in 2 Gy fractions (3-4 weeks treatment) has achieved excellent local control rates of 100% after a median follow-up of 25 months.Hypofractionated preoperative RT has been investigated in a number of phase II single-arm studies suggesting that daily doses of 2.75-8 Gy over 1-3 weeks can achieve similar oncological outcomes to conventional neoadjuvant RT. Prospective data with direct head-to-head comparison to conventional neoadjuvant RT investigating oncological outcomes and toxicity profiles is eagerly awaited.For the entire group of retroperitoneal sarcomas, RT is not the standard of care. The randomized multi-center STRASS trial did not find a benefit in abdominal recurrence-free survival by the addition of preoperative RT. However, for the largest histological subgroup of well-differentiated and grades I and II dedifferentiated liposarcomas, the STRASS trial and the post-hoc propensity-matched STREXIT analysis have identified a possible benefit in survival by preoperative RT. These patients deserve to be informed about the pros and cons of preoperative RT while the longer follow-up data from the STRASS trial is awaited.

Diagnostics and Treatment of Extrameningeal Solitary Fibrous Tumors.

Solitary fibrous tumors (SFT) are rare mesenchymal neoplasms that account for less than 2% of all soft tissue masses. In the latest WHO 2020 Classification of Soft Tissue Tumors, extrameningeal SFT was listed as intermediate (rarely metastasizing) or malignant neoplasms. Due to the lack of characteristic clinical features, their diagnosis and treatment remain challenging. The pathogenesis of SFT is often associated with the presence of fusions of the NAB2-STAT6 gene on the 12q13 chromosome. Cytoplasmic CD34 positive staining is considerably characteristic for most SFTs; less frequently, factor XII, vimentin, bcl-2, and CD99 are present. A key factor in the diagnosis is the prevalent nuclear location of STAT6 expression. Radical resection is the mainstay of localized SFTs. In the case of unresectable disease, only radiotherapy or radio-chemotherapy may significantly ensure long-term local control of primary and metastatic lesions. To date, no practical guidelines have been published for the treatment of advanced or metastatic disease. Classical anthracycline-based chemotherapy is applicable. The latest studies suggest that antiangiogenic therapies should be considered after first-line treatment. Other drugs, such as imatinib, figitumumab, axitinib, and eribulin, are also being tested. Definitive radiotherapy appears to be a promising therapeutic modality. Since standards for the treatment of advanced and metastatic diseases are not available, further investigation of novel agents is necessary.

A CT-based radiomics classification model for the prediction of histological type and tumour grade in retroperitoneal sarcoma (RADSARC-R): a retrospective multicohort analysis.

BACKGROUND: Retroperitoneal sarcomas are tumours with a poor prognosis. Upfront characterisation of the tumour is difficult, and under-grading is common. Radiomics has the potential to non-invasively characterise the so-called radiological phenotype of tumours. We aimed to develop and independently validate a CT-based radiomics classification model for the prediction of histological type and grade in retroperitoneal leiomyosarcoma and liposarcoma. METHODS: A retrospective discovery cohort was collated at our centre (Royal Marsden Hospital, London, UK) and an independent validation cohort comprising patients recruited in the phase 3 STRASS study of neoadjuvant radiotherapy in retroperitoneal sarcoma. Patients aged older than 18 years with confirmed primary leiomyosarcoma or liposarcoma proceeding to surgical resection with available contrast-enhanced CT scans were included. Using the discovery dataset, a CT-based radiomics workflow was developed, including manual delineation, sub-segmentation, feature extraction, and predictive model building. Separate probabilistic classifiers for the prediction of histological type and low versus intermediate or high grade tumour types were built and tested. Independent validation was then performed. The primary objective of the study was to develop radiomic classification models for the prediction of retroperitoneal leiomyosarcoma and liposarcoma type and histological grade. FINDINGS: 170 patients recruited between Oct 30, 2016, and Dec 23, 2020, were eligible in the discovery cohort and 89 patients recruited between Jan 18, 2012, and April 10, 2017, were eligible in the validation cohort. In the discovery cohort, the median age was 63 years (range 27-89), with 83 (49%) female and 87 (51%) male patients. In the validation cohort, median age was 59 years (range 33-77), with 46 (52%) female and 43 (48%) male patients. The highest performing model for the prediction of histological type had an area under the receiver operator curve (AUROC) of 0·928 on validation, based on a feature set of radiomics and approximate radiomic volume fraction. The highest performing model for the prediction of histological grade had an AUROC of 0·882 on validation, based on a radiomics feature set. INTERPRETATION: Our validated radiomics model can predict the histological type and grade of retroperitoneal sarcomas with excellent performance. This could have important implications for improving diagnosis and risk stratification in retroperitoneal sarcomas. FUNDING: Wellcome Trust, European Organisation for Research and Treatment of Cancer-Soft Tissue and Bone Sarcoma Group, the National Institutes for Health, and the National Institute for Health and Care Research Biomedical Research Centre at The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research.

Salvage re-irradiation in non-melanoma skin cancers: A multicenter analysis.

BACKGROUND AND PURPOSE: We conducted a multicentre real-world study to assess the outcomes of radical salvage re-irradiation for non-melanoma skin cancer (nMSC) recurrences following definitive or postoperative radiotherapy. MATERIALS AND METHODS: Data on patients treated between 2006 and 2022 with re-irradiation for nMSCs were retrospectively collected from five high-volume brachytherapy centers. The primary endpoint was local control (LC). Secondary endpoints included overall survival, progression-free survival, and adverse events (AEs). The Kaplan-Meier estimator and Cox Proportional-Hazards Model were utilised in the analysis. RESULTS: A total of 58 patients with a median age of 78.4 years with recurrences of previously irradiated nMSC in the head and neck region were included in the analysis. The majority had cutaneous basal cell carcinoma (BCC; 91.4%), and were irradiated with high-dose-rate brachytherapy (HDR-BT; 91.4%). The most common locations included the nasal region (36.2%) and external ear (18.9%). The 1-year LC was 73.1% and decreased to 41.7% at three years. The size of the re-irradiated lesion was the single independent prognostic factor in Cox analysis (per mm; HR 1.07; 95% CI 1.04-1.11; p < 0.001). Grade 3 or worse AEs were reported in 7 cases (12.1%). CONCLUSION: Re-irradiation for nMSCs, predominantly administered with brachytherapy for radiorecurrent BCC, is associated with high recurrence rates, and the risk of failure significantly increases with the size of the treated lesion. Re-irradiation could be an option for selected elderly patients with small, localised, inoperable recurrences after RT to achieve local control or defer systemic treatment; however, prospective trials are necessary to confirm its safety and efficacy.

Hyperthermia in the treatment of high-risk soft tissue sarcomas: a systematic review.

BACKGROUND: The therapy of high-risk soft tissue sarcomas (STS) remains an interdisciplinary challenge. Regional hyperthermia (RHT) sparked interest as it has been shown to improve overall survival when added to perioperative chemotherapy (CTX). However, questions arise on how RHT should be optimally integrated into current multi-modal therapies. MATERIALS AND METHODS: We performed a systematic literature review according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies written in English and focused mainly on radiative RHT and superficial hyperthermia were evaluated and included. Studies including patients below the age of 18, with metastatic disease or review articles, were excluded. RESULTS: We identified 15 clinical reports from 1990 until July 2022. Three articles combined RHT + CTX, and twelve focused on combined RHT + radiotherapy (RT) or neoadjuvant chemoradiotherapy (CRT). Most treatments were based on invasive thermometry, and less on magnetic resonance imaging (MRI)-based, noninvasive thermometry for STS of the extremities. Perioperative chemotherapy was used for the combination of RHT and CTX, mostly Ifosfamide-based. The effectiveness of RT appeared to be increased by RHT, especially with two RHT sessions/week. The trimodal simultaneous approach of neoadjuvant RHT and CRT was also feasible. No significant toxicity of RHT was reported. CONCLUSIONS: The gathered data strengthen the beneficial role of RHT in the multimodal setting. Further expert consensus and clinical trials are required to determine the optimal integration of RHT in treating STS.

A critical appraisal of the four systematic reviews and meta-analysis on stereotactic body radiation therapy versus external beam radiotherapy for painful bone metastases and where we go from here.

Radiotherapy is an important treatment modality for pain control in patients with bone metastases. Stereotactic body radiation therapy (SBRT), which allows delivering a much higher dose per fraction while sparing critical structures compared to conventional external beam radiotherapy (cEBRT), has become more widely used, especially in the oligometastatic setting. Randomized controlled trials (RCTs) comparing the pain response rate of SBRT and cEBRT for bone metastases have shown conflicting results, as have four recent systematic reviews with meta-analyses of these trials. Possible reasons for the different outcomes between these reviews include differences in methodology, which trials were included, and the endpoints examined and how they were defined. We suggest ways to improve analysis of these RCTs, particularly performing an individual patient-level meta-analysis since the trials included heterogeneous populations. The results of such studies will help guide future investigations needed to validate patient selection criteria, optimize SBRT dose schedules, include additional endpoints (such as the time to onset of pain response, durability of pain response, quality of life (QOL), and side effects of SBRT), and better assess the cost-effectiveness and trade-offs of SBRT compared to cEBRT. An international Delphi consensus to guide selection of optimal candidates for SBRT is warranted before more prospective data is available.

Predictive Biomarkers of Pathological Response to Neoadjuvant Chemoradiotherapy for Locally Advanced Soft Tissue Sarcomas.

BACKGROUND: Marginally resectable and unresectable soft tissue sarcomas (STS) remain a therapy challenge due to the lack of highly active treatment. The aim of the study was to identify a biomarker to predict the pathological response (PR) to preplanned treatment of these STSs. METHODS: In the phase II clinical trial (NCT03651375), locally advanced STS patients received preoperative treatment with a combination of doxorubicin-ifosfamide chemotherapy and 5 × 5 Gy radiotherapy. PR to the treatment was classified using the European Organization for Research and Treatment of Cancer-Soft Tissue and Bone Sarcoma Group recommendations. We have chosen HIF-1α, CD163, CD68, CD34, CD105, and γH2AFX proteins, rendering different biological phenomena, for biomarker study. RESULTS: Nineteen patients were enrolled and in four cases a good PR was reported. The high expression of HIF-1α before surgery showed a negative correlation with PR, which means a poor response to therapy. Furthermore, the samples after surgery had decreased expression of HIF-1α, which confirmed the correlation with PR. However, high expression of γH2AFX positively correlated with PR, which provides better PR. The high number of positive-staining TAMs and the high IMVD did not correlate with PR. CONCLUSIONS: HIF1α and γH2AFX could be potential biomarkers for PR prediction after neoadjuvant treatment in STS.

Appropriateness of the 30-day expected mortality metric in palliative radiation treatment: a narrative review.

BACKGROUND AND OBJECTIVE: The 30-day expected mortality rate is frequently used as a metric to determine which patients benefit from palliative radiation treatment (RT). We conducted a narrative review to examine whether its use as a metric might be appropriate for patient selection. METHODS: A literature review was conducted to identify relevant studies that highlight the benefits of palliative RT in timely symptom management among patients with a poor performance status, the accuracy of predicting survival near the end of life and ways to speed up the process of RT administration through rapid response clinics. KEY CONTENT AND FINDINGS: Several trials have demonstrated substantial response rates for pain and/or bleeding by four weeks and sometimes within the first two weeks after RT. Models of patient survival have limited accuracy, particularly for predicting whether patients will die within the next 30 days. Dedicated Rapid Access Palliative RT (RAPRT) clinics, in which patients are assessed, simulated and treated on the same day, reduce the number of patient visits to the radiation oncology department and hence the burden on the patient as well as costs. CONCLUSIONS: Single-fraction palliative RT should be offered to eligible patients if they are able to attend treatment and could potentially benefit from symptom palliation, irrespective of predicted life expectancy. We discourage the routine use of the 30-day mortality as the only metric to decide whether to offer RT. More common implementation of RAPRT clinics could result in a significant benefit for patients of all life expectancies, but particularly those having short ones.

Qualitative Study on Diversity, Equity, and Inclusion Within Radiation Oncology in Europe.

PURPOSE: Organizational culture plays a major role in prioritizing diversity, equity, and inclusion (DEI) objectives by aligning individual values of employees with organizational values. However, effective strategies to create an inclusive organizational culture, in which these values are aligned, remain unclear. The European Society for Radiotherapy and Oncology (ESTRO) launched a qualitative study, as a follow-up of the previous project on DEI that highlighted low levels of inclusion and work engagement among radiation oncology (RO) professionals in Europe. The aim of the present study was to gain an understanding of how DEI could be improved within RO departments by creating a more inclusive organizational culture. METHODS AND MATERIALS: A qualitative research study was conducted by enrolling RO professionals from 4 selected European countries through an open call on the ESTRO platform. Respondents who completed an online survey and met the inclusion criteria, such as experiencing low DEI levels at work, were invited for an online semistructured interview. Interview transcripts were analyzed thematically with an abductive approach via concepts in relation to "DEI," "work engagement," "organizational culture," and "professional values." RESULTS: Twenty-six eligible respondents from Great Britain, Italy, Poland, and Switzerland were interviewed. The thematic analysis identified cases in which limited engagement at work emerged when the personal values of RO professionals conflicted with dominant organizational values, hampering DEI. Three conflicts were found between the following personal versus organizational values: (1) self-development versus efficiency, (2) togetherness versus competition, and (3) people-oriented versus task-oriented cultures. CONCLUSIONS: Awareness of how organizational values can conflict with professionals' values should be raised to improve inclusion and engagement in the workplace. Additionally, efforts should be focused on tackling existing power imbalances that hamper effective deliberation on organizational- versus personal-value conflicts.

Validation of a novel risk score to predict early and late recurrence in solitary fibrous tumour.

BACKGROUND: Current risk models in solitary fibrous tumour (SFT) were developed using cohorts with short follow-up and cannot reliably identify low-risk patients. We recently developed a novel risk model (G-score) to account for both early and late recurrences. Here, we aimed to validate the G-score in a large international cohort with long-term follow-up. METHODS: Data were collected from nine sarcoma referral centres worldwide. Recurrence-free interval (RFi) was the primary endpoint. RESULTS: The cohort comprised 318 patients with localised extrameningeal SFTs. Disease recurrence occurred in 96 patients (33%). The estimated 5-year RFi rate was 72%, and the 10-year RFi rate was 52%. G-score precisely predicted recurrence risk with estimated 10-year RFi rate of 84% in low risk, 54% in intermediate risk and 36% in high risk (p < 0.001; C-index 0.691). The mDemicco (p < 0.001; C-index 0.749) and SalasOS (p < 0.001; C-index 0.674) models also predicted RFi but identified low-risk patients less accurate with 10-year RFi rates of 72% and 70%, respectively. CONCLUSIONS: G-score is a highly significant predictor of early and late recurrence in SFT and is superior to other models to predict patients at low risk of relapse. A less intensive follow-up schedule could be considered for patients at low recurrence risk according to G-score.

ESTRO ACROP guidelines for external beam radiotherapy of patients with complicated bone metastases.

This is the second part of the guidelines on the management of bone metastases. In the first part, the diagnosis and management of uncomplicated bone metastases have been addressed. Bone metastases may significantly reduce quality of life due to related symptoms and possible complications. The most common symptoms include pain and neurologic deficits. The most serious complications of bone metastases are skeletal-related events (SRE), defined as pathologic fracture, spinal cord compression, pain, or other symptoms requiring an urgent intervention such as surgery or radiotherapy. Diffuse bone metastases may lead to hypercalcaemia that can be fatal if untreated. The growing access to modern diagnostic tools allows early detection of asymptomatic bone metastases that could be successfully managed with local treatment if oligometastatic or systemic treatment for diffuse bone metastases to try to avoid the development of SRE.