Magnetic Resonance-Guided Focused Ultrasound Versus Conventional Radiation Therapy for Painful Bone Metastasis: A Matched-Pair Study

MR Imaging-Guided Focused Ultrasound for Breast Tumors

Breast tumors remain a complex and prevalent health burden impacting millions of individuals worldwide. Challenges in treatment arise from the invasive nature of traditional surgery and, in malignancies, the complexity of treating metastatic disease. The development of noninvasive treatment alternatives is critical for improving patient outcomes and quality of life. This review aims to explore the advancements and applications of focused ultrasound (FUS) technology over the past 2 decades. FUS offers a promising noninvasive, nonionizing intervention strategy in breast tumors including primary breast cancer, fibroadenomas, and metastatic breast cancer.

Update on musculoskeletal applications of magnetic resonance-guided focused ultrasound

Magnetic resonance-guided focused ultrasound (MRgFUS) is a noninvasive, incisionless, radiation-free technology used to ablate tissue deep within the body. This technique has gained increased popularity following FDA approval for treatment of pain related to bone metastases and limited approval for treatment of osteoid osteoma. MRgFUS delivers superior visualization of soft tissue targets in unlimited imaging planes and precision in targeting and delivery of thermal dose which is all provided during real-time monitoring using MR thermometry. This paper provides an overview of the common musculoskeletal applications of MRgFUS along with updates on clinical outcomes and discussion of future applications.

Image-Guided Energy Ablation for Palliation of Painful Bony Metastases-A Systematic Review

PURPOSE

To analyze the effectiveness of image-guided energy ablation techniques with and without concurrent therapies in providing palliative pain relief in patients with bone metastases.

MATERIALS AND METHODS

Ovid Embase, Ovid Medline, and Pubmed were searched from inception to April 14, 2023, using search terms related to bone lesions and MeSH terms regarding ablation therapy. English peer-reviewed primary articles were included that reported pain scores following image-guided energy-based ablation of bone metastases. Exclusion criteria included nonpalliative treatment, pain scores associated with specific treatment modalities not reported, and nonmetastatic bone lesions. Mean percentage reduction in pain score was calculated.

RESULTS

Of the 1,396 studies screened, 54 were included. All but 1 study demonstrated decreased pain scores at final follow-up. Mean reductions in pain scores at final follow-up were 49% for radiofrequency (RF) ablation, 58% for RF ablation and adjunct, 54% for cryoablation (CA), 72% for cryoablation and adjunct (CA-A), 48% for microwave ablation (MWA), 81% for microwave ablation and adjunct (MWA-A), and 64% for high-intensity focused ultrasound (US). Postprocedural adverse event rates were 4.9% for RF ablation, 34.8% for RF ablation and adjunct, 9.6% for CA, 12.0% for CA-A, 48.9% for MWA, 33.5% for MWA-A, and 17.0% for high-intensity focused US.

CONCLUSIONS

Image-guided energy ablation demonstrated consistently strong reduction in pain across all modalities, with variable postprocedural adverse event rates. Owing to heterogeneity of included studies, quantitative analysis was not appropriate. Future primary research should focus on creating consistent prospective studies with established statistical power, explicit documentation, and comparison with other techniques.

Comparison of Two Modern Survival Prediction Tools, SORG-MLA and METSSS, in Patients With Symptomatic Long-bone Metastases Who Underwent Local Treatment With Surgery Followed by Radiotherapy and With Radiotherapy Alone

BACKGROUND

Survival estimation for patients with symptomatic skeletal metastases ideally should be made before a type of local treatment has already been determined. Currently available survival prediction tools, however, were generated using data from patients treated either operatively or with local radiation alone, raising concerns about whether they would generalize well to all patients presenting for assessment. The Skeletal Oncology Research Group machine-learning algorithm (SORG-MLA), trained with institution-based data of surgically treated patients, and the Metastases location, Elderly, Tumor primary, Sex, Sickness/comorbidity, and Site of radiotherapy model (METSSS), trained with registry-based data of patients treated with radiotherapy alone, are two of the most recently developed survival prediction models, but they have not been tested on patients whose local treatment strategy is not yet decided.

QUESTIONS/PURPOSES

(1) Which of these two survival prediction models performed better in a mixed cohort made up both of patients who received local treatment with surgery followed by radiotherapy and who had radiation alone for symptomatic bone metastases? (2) Which model performed better among patients whose local treatment consisted of only palliative radiotherapy? (3) Are laboratory values used by SORG-MLA, which are not included in METSSS, independently associated with survival after controlling for predictions made by METSSS?

METHODS

Between 2010 and 2018, we provided local treatment for 2113 adult patients with skeletal metastases in the extremities at an urban tertiary referral academic medical center using one of two strategies: (1) surgery followed by postoperative radiotherapy or (2) palliative radiotherapy alone. Every patient's survivorship status was ascertained either by their medical records or the national death registry from the Taiwanese National Health Insurance Administration. After applying a priori designated exclusion criteria, 91% (1920) were analyzed here. Among them, 48% (920) of the patients were female, and the median (IQR) age was 62 years (53 to 70 years). Lung was the most common primary tumor site (41% [782]), and 59% (1128) of patients had other skeletal metastases in addition to the treated lesion(s). In general, the indications for surgery were the presence of a complete pathologic fracture or an impending pathologic fracture, defined as having a Mirels score of ≥ 9, in patients with an American Society of Anesthesiologists (ASA) classification of less than or equal to IV and who were considered fit for surgery. The indications for radiotherapy were relief of pain, local tumor control, prevention of skeletal-related events, and any combination of the above. In all, 84% (1610) of the patients received palliative radiotherapy alone as local treatment for the target lesion(s), and 16% (310) underwent surgery followed by postoperative radiotherapy. Neither METSSS nor SORG-MLA was used at the point of care to aid clinical decision-making during the treatment period. Survival was retrospectively estimated by these two models to test their potential for providing survival probabilities. We first compared SORG to METSSS in the entire population. Then, we repeated the comparison in patients who received local treatment with palliative radiation alone. We assessed model performance by area under the receiver operating characteristic curve (AUROC), calibration analysis, Brier score, and decision curve analysis (DCA). The AUROC measures discrimination, which is the ability to distinguish patients with the event of interest (such as death at a particular time point) from those without. AUROC typically ranges from 0.5 to 1.0, with 0.5 indicating random guessing and 1.0 a perfect prediction, and in general, an AUROC of ≥ 0.7 indicates adequate discrimination for clinical use. Calibration refers to the agreement between the predicted outcomes (in this case, survival probabilities) and the actual outcomes, with a perfect calibration curve having an intercept of 0 and a slope of 1. A positive intercept indicates that the actual survival is generally underestimated by the prediction model, and a negative intercept suggests the opposite (overestimation). When comparing models, an intercept closer to 0 typically indicates better calibration. Calibration can also be summarized as log(O:E), the logarithm scale of the ratio of observed (O) to expected (E) survivors. A log(O:E) > 0 signals an underestimation (the observed survival is greater than the predicted survival); and a log(O:E) < 0 indicates the opposite (the observed survival is lower than the predicted survival). A model with a log(O:E) closer to 0 is generally considered better calibrated. The Brier score is the mean squared difference between the model predictions and the observed outcomes, and it ranges from 0 (best prediction) to 1 (worst prediction). The Brier score captures both discrimination and calibration, and it is considered a measure of overall model performance. In Brier score analysis, the "null model" assigns a predicted probability equal to the prevalence of the outcome and represents a model that adds no new information. A prediction model should achieve a Brier score at least lower than the null-model Brier score to be considered as useful. The DCA was developed as a method to determine whether using a model to inform treatment decisions would do more good than harm. It plots the net benefit of making decisions based on the model's predictions across all possible risk thresholds (or cost-to-benefit ratios) in relation to the two default strategies of treating all or no patients. The care provider can decide on an acceptable risk threshold for the proposed treatment in an individual and assess the corresponding net benefit to determine whether consulting with the model is superior to adopting the default strategies. Finally, we examined whether laboratory data, which were not included in the METSSS model, would have been independently associated with survival after controlling for the METSSS model's predictions by using the multivariable logistic and Cox proportional hazards regression analyses.

RESULTS

Between the two models, only SORG-MLA achieved adequate discrimination (an AUROC of > 0.7) in the entire cohort (of patients treated operatively or with radiation alone) and in the subgroup of patients treated with palliative radiotherapy alone. SORG-MLA outperformed METSSS by a wide margin on discrimination, calibration, and Brier score analyses in not only the entire cohort but also the subgroup of patients whose local treatment consisted of radiotherapy alone. In both the entire cohort and the subgroup, DCA demonstrated that SORG-MLA provided more net benefit compared with the two default strategies (of treating all or no patients) and compared with METSSS when risk thresholds ranged from 0.2 to 0.9 at both 90 days and 1 year, indicating that using SORG-MLA as a decision-making aid was beneficial when a patient's individualized risk threshold for opting for treatment was 0.2 to 0.9. Higher albumin, lower alkaline phosphatase, lower calcium, higher hemoglobin, lower international normalized ratio, higher lymphocytes, lower neutrophils, lower neutrophil-to-lymphocyte ratio, lower platelet-to-lymphocyte ratio, higher sodium, and lower white blood cells were independently associated with better 1-year and overall survival after adjusting for the predictions made by METSSS.

CONCLUSION

Based on these discoveries, clinicians might choose to consult SORG-MLA instead of METSSS for survival estimation in patients with long-bone metastases presenting for evaluation of local treatment. Basing a treatment decision on the predictions of SORG-MLA could be beneficial when a patient's individualized risk threshold for opting to undergo a particular treatment strategy ranged from 0.2 to 0.9. Future studies might investigate relevant laboratory items when constructing or refining a survival estimation model because these data demonstrated prognostic value independent of the predictions of the METSSS model, and future studies might also seek to keep these models up to date using data from diverse, contemporary patients undergoing both modern operative and nonoperative treatments.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Focused Ultrasound and External Beam Radiation Therapy for Painful Bone Metastases: A Phase II Clinical Trial

Background Recent consensus statements and clinical trials have assessed the value of MRI-guided focused ultrasound surgery for pain palliation of bone metastases; however, a comparison with external beam radiation therapy (EBRT) has not been performed. Purpose To compare safety and effectiveness data of MRI-guided focused ultrasound and EBRT in the treatment of bone metastases. Materials and Methods Participants with painful bone metastases, excluding skull and vertebral bodies, were enrolled in a prospective open-label nonrandomized phase II study between January 2017 and May 2019 and underwent either MRI-guided focused ultrasound or EBRT. The primary end point was the overall response rate at 1-month following treatment, assessed via the numeric rating scale (NRS) for pain (0-10 scale, with zero meaning "no pain" and 10 meaning "the worst pain imaginable"). Secondary end points were improvements at 12-month follow-up in NRS and quality of life (QoL) measures, including the Brief Pain Inventory (BPI), QoL-Questionnaire Cancer-15 Palliative Care (QLQ-C15-PAL), and QoL-Questionnaire Bone Metastases-22 (QLQ-BM22) and analysis of adverse events. Statistical analyses, including linear regression, χ² test, and Student t test followed the per-protocol principle. Results Among 198 participants, 100 underwent MRI-guided focused ultrasound (mean age, 63 years ± 13 [SD]; 51 women), and 98 underwent EBRT (mean age, 65 years ± 14; 52 women). The overall response rates at 1-month follow-up were 91% (91 of 100) and 67% (66 of 98), respectively, in the focused ultrasound and EBRT arms (P < .001), and complete response rates were 43% (43 of 100) and 16% (16 of 98) (P < .001). The mean baseline NRS score was 7.0 ± 2.1 for focused ultrasound and 6.6 ± 2.4 for EBRT (P = .16); at 1-month follow-up, they were reduced to 3.2 ± 0.3 and 5.1 ± 0.3 (P < .001), respectively. QLQ-C15-PAL for physical function (P = .002), appetite (P < .001), nausea and vomiting (P < .001), dyspnea (P < .001), and QoL (P < .001) scores were lower in the focused ultrasound group. The overall adverse event rates were 15% (15 of 100) after focused ultrasound and 24% (24 of 98) after EBRT. Conclusion MRI-guided focused ultrasound surgery and external beam radiation therapy showed similar improvements in pain palliation and quality of life, with low adverse event rates. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Kelekis in this issue.

Focused Ultrasound and RadioTHERapy for non-invasive palliative pain treatment in patients with bone metastasis: a study protocol for the three armed randomized controlled FURTHER trial

BACKGROUND

Cancer-induced bone pain (CIBP), caused by bone metastases, is a common complication of cancer and strongly impairs quality of life (QoL). External beam radiotherapy (EBRT) is the current standard of care for treatment of CIBP. However, approximately 45% of patients have no adequate pain response after EBRT. Magnetic resonance image-guided high-intensity focused ultrasound (MR-HIFU) may improve pain palliation in this patient population. The main objective of this trial was to compare MR-HIFU, EBRT, and MR-HIFU + EBRT for the palliative treatment of bone metastases.

METHODS/DESIGN

The FURTHER trial is an international multicenter, three-armed randomized controlled trial. A total of 216 patients with painful bone metastases will be randomized in a 1:1:1 ratio to receive EBRT only, MR-HIFU only, or combined treatment with EBRT followed by MR-HIFU. During a follow-up period of 6 months, patients will be contacted at eight time points to retrieve information about their level of pain, QoL, and the occurrence of (serious) adverse events. The primary outcome of the trial is pain response at 14 days after start of treatment. Secondary outcomes include pain response at 14 days after trial enrolment, pain scores (daily until the 21st day and at 4, 6, 12 and 24 weeks), toxicity, adverse events, QoL, and survival. Cost-effectiveness and cost-utility analysis will be conducted.

DISCUSSION

The FURTHER trial aims to evaluate the effectiveness and cost-effectiveness of MR-HIFU-alone or in combination with EBRT-compared to EBRT to relieve CIBP. The trial will be performed in six hospitals in four European countries, all of which are partners in the FURTHER consortium.

TRIAL REGISTRATION

The FURTHER trial is registered under the Netherlands Trials Register number NL71303.041.19 and ClinicalTrials.gov registration number NCT04307914. Date of trial registration is 13-01-2020.

High Intensity Focused Ultrasound for Treatment of Bone Malignancies-20 Years of History

High Intensity Focused Ultrasound (HIFU) is the only non-invasive method for percutaneous thermal ablation of tissue, with treatments typically performed either under magnetic resonance imaging or ultrasound guidance. Since this method allows efficient heating of bony structures, it has found not only early use in treatment of bone pain, but also in local treatment of malignant bone tumors. This review of 20 years of published studies shows that HIFU is a very efficient method for rapid pain relief, can provide local tumor control and has a very patient-friendly safety profile.

Early economic modeling of magnetic resonance image-guided high intensity focused ultrasound compared to radiotherapy for pain palliation of bone metastases

Introduction

Magnetic Resonance Image-guided High Intensity Focused Ultrasound (MR-HIFU) is a non-invasive treatment option for palliative patients with painful bone metastases. Early evidence suggests that MR-HIFU is associated with similar overall treatment response, but more rapid pain palliation compared to external beam radiotherapy (EBRT). This modelling study aimed to assess the cost-effectiveness of MR-HIFU as an alternative treatment option for painful bone metastases from the perspective of the German Statutory Health Insurance (SHI).

Materials and methods

A microsimulation model with lifelong time horizon and one-month cycle length was developed. To calculate the incremental cost-effectiveness ratio (ICER), strategy A (MR-HIFU as first-line treatment or as retreatment option in case of persistent pain or only partial pain relief after EBRT) was compared to strategy B (EBRT alone) for patients with bone metastases due to breast, prostate, or lung cancer. Input parameters used for the model were extracted from the literature. Results were expressed as EUR per quality-adjusted life years (QALYs) and EUR per pain response (i.e., months spent with complete or partial pain response). Deterministic and probabilistic sensitivity analyses (PSA) were performed to test the robustness of results, and a value of information analysis was conducted.

Results

Compared to strategy B, strategy A resulted in additional costs (EUR 399) and benefits (0.02 QALYs and 0.95 months with pain response). In the base case, the resulting ICERs (strategy A vs. strategy B) are EUR 19,845/QALY and EUR 421 per pain response. Offering all patients MR-HIFU as first-line treatment would increase the ICER by 50% (31,048 EUR/QALY). PSA showed that at a (hypothetical) willingness to pay of EUR 20,000/QALY, the probability of MR-HIFU being cost-effective was 52%. The expected value of perfect information (EVPI) for the benefit population in Germany is approximately EUR 190 Mio.

Conclusion

Although there is considerable uncertainty, the results demonstrate that introducing MR-HIFU as a treatment alternative for painful bone metastases might be cost-effective for the German SHI. The high EVPI indicate that further studies to reduce uncertainty would be worthwhile.

Minimally Invasive Interventional Procedures for Metastatic Bone Disease: A Comprehensive Review

Metastases are the main type of malignancy involving bone, which is the third most frequent site of metastatic carcinoma, after lung and liver. Skeletal-related events such as intractable pain, spinal cord compression, and pathologic fractures pose a serious burden on patients’ quality of life. For this reason, mini-invasive treatments for the management of bone metastases were developed with the goal of pain relief and functional status improvement. These techniques include embolization, thermal ablation, electrochemotherapy, cementoplasty, and MRI-guided high-intensity focused ultrasound. In order to achieve durable pain palliation and disease control, mini-invasive procedures are combined with chemotherapy, radiation therapy, surgery, or analgesics. The purpose of this review is to summarize the recently published literature regarding interventional radiology procedures in the treatment of cancer patients with bone metastases, focusing on the efficacy, complications, local disease control and recurrence rate.

A Few-Shot Learning Approach Assists in the Prognosis Prediction of Magnetic Resonance-Guided Focused Ultrasound for the Local Control of Bone Metastatic Lesions

Magnetic resonance-guided focused ultrasound surgery (MRgFUS) constitutes a noninvasive treatment strategy to ablate deep-seated bone metastases. However, limited evidence suggests that, although cytokines are influenced by thermal necrosis, there is still no cytokine threshold for clinical responses. A prediction model to approximate the postablation immune status on the basis of circulating cytokine activation is thus needed. IL-6 and IP-10, which are proinflammatory cytokines, decreased significantly during the acute phase. Wound-healing cytokines such as VEGF and PDGF increased after ablation, but the increase was not statistically significant. In this phase, IL-6, IL-13, IP-10, and eotaxin expression levels diminished the ongoing inflammatory progression in the treated sites. These cytokine changes also correlated with the response rate of primary tumor control after acute periods. The few-shot learning algorithm was applied to test the correlation between cytokine levels and local control (p = 0.036). The best-fitted model included IL-6, IL-13, IP-10, and eotaxin as cytokine parameters from the few-shot selection, and had an accuracy of 85.2%, sensitivity of 88.6%, and AUC of 0.95. The acceptable usage of this model may help predict the acute-phase prognosis of a patient with painful bone metastasis who underwent local MRgFUS. The application of machine learning in bone metastasis is equivalent or better than the current logistic regression.

A time-driven activity-based costing approach of magnetic resonance-guided high-intensity focused ultrasound for cancer-induced bone pain

OBJECTIVE

To determine resource consumption and total costs for providing magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) treatment to a patient with cancer-induced bone pain (CIBP).

METHODS

We conducted a time-driven activity-based costing (TD-ABC) of MR-HIFU treatments for CIBP from a hospital perspective. A European care-pathway (including a macro-, meso-, and micro-level) was designed to incorporate the care-delivery value chain. Time estimates were obtained from medical records and from prospective direct observations. To calculate the capacity cost rate, data from the controlling department of a German university hospital were allocated to the modules of the care pathway. Best- and worst-case scenarios were calculated by applying lower and upper bounds of time measurements.

RESULTS

The macro-level care pathway consisted of eight modules (i.e., outpatient consultations, pretreatment imaging, preparation, optimization, sonication, post-treatment, recovery, and anesthesia). The total cost of an MR-HIFU treatment amounted to €5147 per patient. Best- and worst-case scenarios yielded a total cost of €4092 and to €5876. According to cost categories, costs due to equipment accounted for 41% of total costs, followed by costs with personnel (32%), overhead (16%) and materials (11%).

CONCLUSION

MR-HIFU is an emerging noninvasive treatment for alleviating CIBP, with increasing evidence on treatment efficacy. This costing study can support MR-HIFU reimbursement negotiations and facilitate the adoption of MR-HIFU as first-line treatment for CIBP. The present TD-ABC model creates the opportunity of benchmarking the provision of MR-HIFU to bone tumor.Key pointsMagnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is an emerging noninvasive treatment modality for alleviating cancer-induced bone pain (CIBP).From a hospital perspective, the total cost of MR-HIFU amounted to €5147 per treatment.This time-driven activity-based costing model creates the opportunity of benchmarking the provision of MR-HIFU to bone tumor.

Efficacy and safety of magnetic resonance-guided focused ultrasound for the treatment of painful bone metastases: a systematic review and meta-analysis

OBJECTIVE

To report the safety and efficacy of magnetic resonance-guided focused ultrasound (MRgFUS) in the treatment of painful bone metastases through a systematic review and meta-analysis of pain scores before and after MRgFUS treatment and post-treatment adverse events.

MATERIALS AND METHODS

A comprehensive literature search of PubMed and Embase databases was performed for studies evaluating the efficacy and/or safety of MRgFUS. The mean difference of pain scores (10-point visual analogue scale or numerical rating scale) between baseline and 1-month/3-month pain scores was collected and analyzed in a pooled meta-analysis. Post-treatment adverse events based on the Common Terminology Criteria for Adverse Events (CTCAE) grading were recorded and the pooled prevalence was calculated.

RESULTS

A total of 33 studies published between 2007 and 2019 were collected, resulting in a total sample size of 1082 patients. The majority of the studies were prospective with a reported follow-up period of 3 months. The pooled proportion of patients that achieved pain relief from MRgFUS (complete response or partial response [≥ 2-point improvement of pain score]) was 79% (95% CI 73-83%). The pooled 1-month and 3-month mean difference in pain score were - 3.8 (95% CI - 4.3; - 3.3) and - 4.4 (95% CI - 5.0; - 3.7), respectively. The overall rate of high-grade (CTCAE grade 3 or higher) and low-grade (CTCAE grade 2 or lower) MRgFUS-related adverse events were 0.9% and 5.9%, respectively.

CONCLUSION

MRgFUS is an effective procedure that is able to provide significant pain palliation for patients with symptomatic bone metastases with a favorable safety profile.

The Roles of Magnetic Resonance-Guided Focused Ultrasound in Pain Relief in Patients With Bone Metastases: A Systemic Review and Meta-Analysis

Objective

Cancer pain, the most common skeleton-related event of bone metastases, significantly disturbs patients' life. MRI-guided focused ultrasound (MRgFUS) is a therapeutic option to relieve pain; however, its efficacy and safety have not been fully explored. Therefore, we aim to conduct a meta-analysis on studies reporting MRgFUS for patients with bone metastases.

Methods

Randomized controlled trials (RCT) and non-RCTs on MRgFUS treatment for patients with bone metastases were collected using PubMed, MEDLINE In-Process (US National Library of Medicine), National Institutes of Health (US National Library of Medicine), Embase (Elsevier), Web of Science, CINAHL, and the Cochrane Library between August 2007 and September 2019. Data on quantitative pain assessment before/after MRgFUS, response rate, and complication were extracted and analyzed.

Results

Fifteen eligible studies with 362 patients were selected in this meta-analysis. The average pain score was 6.74 (95% CI: 6.30-7.18) at baseline, 4.15 (95% CI: 3.31-4.99) at 0-1 week, 3.09 (95% CI: 2.46-3.72) at 1-5 weeks, and 2.28 (95% CI: 1.37-3.19) at 5-14 weeks. Compared with baseline, the pain improvement at 0-1 week was 2.54 (95% CI: 1.92-3.16, p < 0.01), at 1-5 weeks was 3.56 (95% CI: 3.11-4.02, p < 0.01), and at 5-14 weeks was 4.22 (95% CI: 3.68-4.76, p < 0.01). Change from baseline in OMEDD at 2 weeks after treatment was -15.11 (95% CI: -34.73, 4.50), at 1 month after treatment was -10.87 (95% CI: -26.32, 4.58), and at 3 months after treatment was -5.53 (95% CI: -20.44, 9.38). The overall CR rate was 0.36 (95% CI: 0.24-0.48), PR rate was 0.47 (95% CI: 0.36-0.58), and NR rate was 0.23 (95% CI: 0.13-0.34). Among 14 studies including 352 patients, 93 (26.4%) patients with minor complications and 5 (1.42%) patients with major complications were recorded.

Conclusion

This meta-analysis identifies MRgFUS as a reliable therapeutic option to relieve cancer pain for patients with metastatic bone tumors with controllable related complications.

Current Overview of Treatment for Metastatic Bone Disease

The number of patients with bone metastasis increases as medical management and surgery improve the overall survival of patients with cancer. Bone metastasis can cause skeletal complications, including bone pain, pathological fractures, spinal cord or nerve root compression, and hypercalcemia. Before initiation of treatment for bone metastasis, it is important to exclude primary bone malignancy, which would require a completely different therapeutic approach. It is essential to select surgical methods considering the patient’s prognosis, quality of life, postoperative function, and risk of postoperative complications. Therefore, bone metastasis treatment requires a multidisciplinary team approach, including radiologists, oncologists, and orthopedic surgeons. Recently, many novel palliative treatment options have emerged for bone metastases, such as stereotactic body radiation therapy, radiopharmaceuticals, vertebroplasty, minimally invasive spine stabilization with percutaneous pedicle screws, acetabuloplasty, embolization, thermal ablation techniques, electrochemotherapy, and high-intensity focused ultrasound. These techniques are beneficial for patients who may not benefit from surgery or radiotherapy.

Musculoskeletal Oncologic Interventions: Proceedings from the Society of Interventional Radiology and Society of Interventional Oncology Research Consensus Panel

Musculoskeletal interventions are increasingly used with palliative and curative intent in the multidisciplinary treatment of oncology patients with bone and soft-tissue tumors. There is an unmet need for high-quality evidence to guide broader application and adoption of minimally invasive interventional technologies to treat these patients. Therefore, the Society of Interventional Radiology Foundation and the Society of Interventional Oncology collaborated to convene a research consensus panel to prioritize a research agenda addressing the gaps in the current evidence. This article summarizes the panel's proceedings and recommendations for future basic science and clinical investigation to chart the course for interventional oncology within the musculoskeletal system. Key questions that emerged addressed the effectiveness of ablation within specific patient populations, the effect of combination of ablation with radiotherapy and/or immunotherapy, and the potential of standardization of techniques, including modeling and monitoring, to improve the consistency and predictability of treatment outcomes.

Combining radiotherapy and focused ultrasound for pain palliation of cancer induced bone pain; a stage I/IIa study according to the IDEAL framework

•

Combined treatment of EBRT and MR-HIFU is feasible and well tolerated by patients.

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Clinical outcomes of combined treatment of EBRT and MR-HIFU are promising.

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Superiority of combined treatment over standard EBRT needs to be evaluated in a comparative study.

Background

Cancer induced bone pain (CIBP) strongly interferes with patient’s quality of life. Currently, the standard of care includes external beam radiotherapy (EBRT), resulting in pain relief in approximately 60% of patients. Magnetic Resonance guided High Intensity Focused Ultrasound (MR-HIFU) is a promising treatment modality for CIBP.

Methods

A single arm, R-IDEAL stage I/IIa study was conducted. Patients presenting at the department of radiation oncology with symptomatic bone metastases in the appendicular skeleton, as well as in the sacrum and sternum were eligible for inclusion. All participants underwent EBRT, followed by MR-HIFU within 4 days. Safety and feasibility were assessed, and pain scores were monitored for 4 weeks after completing the combined treatment.

Results

Six patients were enrolled. Median age was 67 years, median lesion diameter was 56,5 mm. In all patients it was logistically possible to plan and perform the MR-HIFU treatment within 4 days after EBRT. All patients tolerated the combined procedure well. Pain response was reported by 5 out of 6 patients at 7 days after completion of the combined treatment, and stabilized on 60% at 4 weeks follow up. No treatment related serious adverse events occurred.

Conclusion

This is the first study to combine EBRT with MR-HIFU. Our results show that combined EBRT and MR-HIFU in first-line treatment of CIBP is safe and feasible, and is well tolerated by patients. Superiority over standard EBRT, in terms of (time to) pain relief and quality of life need to be evaluated in comparative (randomized) study.

Proton Resonance Frequency Shift Thermometry: A Review of Modern Clinical Practices

Magnetic resonance imaging (MRI) has become a popular modality in guiding minimally invasive thermal therapies, due to its advanced, nonionizing, imaging capabilities and its ability to record changes in temperature. A variety of MR thermometry techniques have been developed over the years, and proton resonance frequency (PRF) shift thermometry is the current clinical gold standard to treat a variety of cancers. It is used extensively to guide hyperthermic thermal ablation techniques such as high-intensity focused ultrasound (HIFU) and laser-induced thermal therapy (LITT). Essential attributes of PRF shift thermometry include excellent linearity with temperature, good sensitivity, and independence from tissue type. This noninvasive temperature mapping method gives accurate quantitative measures of the temperature evolution inside biological tissues. In this review, the current status and new developments in the fields of MR-guided HIFU and LITT are presented with an emphasis on breast, prostate, bone, uterine, and brain treatments. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.

Prognostic and predictive factors for clinical and radiographic responses in patients with painful bone metastasis treated with magnetic resonance-guided focused ultrasound surgery

Background: Magnetic resonance-guided focused ultrasound surgery (MRgFUS) is an alternative local therapy for patients with painful bone metastasis. However, little is known about the prognostic and predictive factors of MRgFUS in treating bone metastasis. Materials and methods: This retrospective study analyzed the performance status, treated site, pretreatment pain score, pretreatment tumor volume and lesion coverage volume factor (CVF) of 31 patients who underwent MRgFUS. A numerical rating scale for pain was used at the same time to assess the clinical response. Radiographic responses were evaluated using a modified version of The University of Texas MD Anderson Cancer Center criteria and reference to the MR imaging or computed tomography scans obtained 3 months after treatment. Univariate and multivariate logistic regression analyses were conducted to examine the effect of variables on clinical and radiographic responses. Results: The overall clinical response rate was 83.9% and radiographic response rate was 67.7%. Multivariate logistic regression analysis revealed that the better pretreatment Karnofsky performance status (KPS) (odds ratio: 1.220, 95% confidence interval (CI): 1.033-1.440; p = 0.019) was significantly associated with a more positive clinical response, and that the lesion CVF (odds ratio: 1.183, 95% CI: 1.029-1.183; p = 0.0055) was an independent prognostic factor for radiographic responses. The radiographic response of patients with lesion CVF ≥70% and CVF <70% were 91.7% and 52.6%, respectively (p = 0.0235). Conclusion: The pretreatment KPS was an independent prognostic factor for clinical responses, and lesion CVF was an independent prognostic factor for radiographic responses.

Contemporary Management of Appendicular Skeletal Metastasis by Primary Tumor Type

Skeletal metastases exert a profound effect on patients and society, and will be encountered by most orthopedic surgeons. Once a primary malignancy is diagnosed, multidisciplinary management should focus on maximizing the quality of life while minimizing disease- and treatment-related morbidity. This may be best achieved with discerning attention to the unique characteristics of primary cancer types, including pathologic fracture healing rates, longevity, and efficacy of adjuvant therapies. Some lesions may respond well to nonsurgical measures, whereas others may require surgery. A single surgical intervention should allow immediate unrestricted activity and outlive the patient. In certain scenarios, a therapeutic benefit may be provided by excision with a curative intent. In these scenarios, or when endoprosthetic reconstruction is necessary, patients may be best referred to an orthopedic oncologist.