Detection of osseous metastases of the spine: Comparison of high resolution multi-detector-CT with MRI

Diagnostic accuracy of imaging modalities for detection of spinal metastases: a systematic review and meta-analysis

PURPOSE

Detecting spinal metastases is highly relevant in patients with oncological disorders as it can affect the staging and treatment of their disease. We aimed to evaluate the diagnostic performance of computed tomography (CT), magnetic resonance imaging (MRI), FDG positron emission tomography (PET)/CT, bone scintigraphy (BS), and single-photon emission computed tomography (SPECT) for spinal metastases detection.

METHODS

Medline, EMBASE, and Web of Science were systematically searched until March 2024 for diagnostic accuracy studies on spinal metastases detection (PROSPERO-registration: CRD42024540139). Data extraction and quality assessment using the QUADAS-2 tool were performed by two independent reviewers. Using bivariate random effects modeling, pooled sensitivities, specificities, and diagnostic odds ratios (DOR) were calculated, and hierarchical summary operating curves were constructed.

RESULTS

Twenty-five studies (49 datasets), encompassing 3102 patients were included. Per-patient pooled sensitivities of CT, MRI, PET/CT, BS and SPECT were 70%, 93%, 82%, 75%, and 84%, respectively. Pooled specificities were 74%, 85%, 75%, 92%, and 81%, respectively. Per-lesion pooled sensitivities of CT, MRI, PET/CT, BS and SPECT were 76%, 91%, 92%, 77%, and 92%, respectively. Pooled specificities were 91%, 94%, 85%, 52%, and 86%, respectively. MRI had the highest DOR in per patient and lesion analyses.

CONCLUSION

MRI had highest diagnostic accuracy for spinal metastases detection on patient and lesion level, suggesting a broader use in addition to the routine staging CT, at least in patients at high risk and where the detection of a spinal metastasis could alter therapy decisions. Herein, results should be considered with the limitations of each modality.

The Efficacy of a Multidisciplinary Approach and Diagnostic-Therapeutic Algorithm for Vertebral Metastases with Spinal Cord Compression

Background and Objectives: Metastatic spinal cord compression represents a substantial risk to patients, given its potential for spinal cord and/or nerve root compression, which can result in severe morbidity. This study aims to evaluate the effectiveness of a diagnostic-therapeutic algorithm developed at our hospital to mitigate the devastating consequences of spinal cord compression in patients with vertebral metastases. Materials and Methods: The algorithm, implemented in our practice in January 2022, is based on collective clinical experience and involves collaboration between emergency room physicians, oncologists, spine surgeons, neuroradiologists, radiation oncologists, and oncologists. To minimize potential confounding effects from the COVID-19 pandemic, data from the years 2019 and 2021 (pre-protocol) were collected and compared with data from the years 2022 and 2023 (post-protocol), excluding the year 2020. Results: From January 2022 to December 2023, 488 oncological patients were assessed, with 45 presenting with urgency due to suspected spinal cord compression. Out of these, 44 patients underwent surgical procedures, with 25 performed in emergency settings and 19 cases in elective settings. Comparatively, in 2019 and 2021, 419 oncological patients were evaluated, with 28 presenting with urgency for suspected spinal cord compression. Of these, 17 underwent surgical procedures, with 10 performed in emergency scenarios and 7 in elective scenarios. Comparing the pre-protocol period (years 2019 and 2021) to the post-protocol period (years 2022 and 2023), intrahospital consultations (commonly patients neurologically compromised) for spine metastasis decreased (105 vs. 82), while outpatient consultations increased remarkably (59 vs. 124). Discussion: Accurate interpretation of symptoms within the context of metastatic involvement is crucial for patients with a history of malignancy, whether presenting in the emergency room or oncology department. Even in the absence of a cancer history, careful interpretation of pain characteristics and clinical signs is crucial for diagnosing vertebral metastasis with incipient or current spinal cord compression. Early surgical or radiation intervention is emphasized as it provides the best chance to prevent deficits or improve neurological status. Preliminary findings suggest a notable increase in both the number of patients diagnosed with suspected spinal cord compression and the proportion undergoing surgical intervention following the implementation of the multidisciplinary protocol. The reduced number of intrahospital consultations (commonly patients neurologically compromised) and the increased number of visits of outpatients with vertebral metastases indicate a heightened awareness of the issue, leading to earlier identification and intervention before neurological worsening necessitating hospitalization. Conclusions: A comprehensive treatment planning approach is essential, and our multidisciplinary algorithm is a valuable tool for optimizing patient outcomes. The protocol shows potential in improving timely management of spinal cord compression in oncological patients. Further analysis of the factors driving these changes is warranted. Limitations: This study has limitations, including potential biases from the retrospective nature of data collection and the exclusion of 2020 data due to COVID-19 impact. To enhance the robustness of our results, long-term studies are required. Moreover, the single-center study design may limit the validity of the findings. Further multicenter studies would be beneficial for validating our results and exploring underlying factors in detail.

Treatment strategies in vertebral metastasis. Need for multidisciplinary committees from the perspective of the surgeon. Narration of literatura

Improvements in cancer diagnosis and treatment have improved survival. Secondarily, the number of patients who present a vertebral metastasis and the number with some morbidity in relation to these metastases also increases. Vertebral fracture, root compression or spinal cord injury cause a deterioration of their quality of life. The objective in the treatment of the vertebral metastasis must be the control of pain, maintenance of neurological function and vertebral stability, bearing in mind that in most cases it will be a palliative treatment. The treatment of these complications needs a multidisciplinary approach, radiologists, interventional radiologists, oncologists and radiation therapists, spine surgeons, but also rehabilitation or pain units. Recent studies show that a multidisciplinary approach of these patients can improve quality of life and even prognosis. In the present article, a review and reading of the literature on the multidisciplinary management of these patients is carried out.

[Translated article] Treatment strategies in vertebral metastasis. Need for multidisciplinary committees from the perspective of the surgeon. Narration of literature

Improvements in cancer diagnosis and treatment have improved survival. Secondarily, the number of patients who present a vertebral metastasis and the number with some morbidity in relation to these metastases also increase. Vertebral fracture, root compression or spinal cord injury cause a deterioration of their quality of life. The objective in the treatment of the vertebral metastasis must be the control of pain, maintenance of neurological function and vertebral stability, bearing in mind that in most cases it will be a palliative treatment. The treatment of these complications needs a multidisciplinary approach, radiologists, interventional radiologists, oncologists and radiation therapists, spine surgeons, but also rehabilitation or pain units. Recent studies show that a multidisciplinary approach of these patients can improve quality of life and even prognosis. In the present article, a review and reading of the literature on the multidisciplinary management of these patients is carried out.

Spinal tumours: recommendations of the Polish Society of Spine Surgery, the Polish Society of Oncology, the Polish Society of Neurosurgeons, the Polish Society of Oncologic Surgery, the Polish Society of Oncologic Radiotherapy, and the Polish Society of Orthopaedics and Traumatology

PURPOSE

The purpose of these recommendations is to spread the available evidence for evaluating and managing spinal tumours among clinicians who encounter such entities.

METHODS

The recommendations were developed by members of the Development Recommendations Group representing seven stakeholder scientific societies and organizations of specialists involved in various forms of care for patients with spinal tumours in Poland. The recommendations are based on data yielded from systematic reviews of the literature identified through electronic database searches. The strength of the recommendations was graded according to the North American Spine Society's grades of recommendation for summaries or reviews of studies.

RESULTS

The recommendation group developed 89 level A-C recommendations and a supplementary list of institutions able to manage primary malignant spinal tumours, namely, spinal sarcomas, at the expert level. This list, further called an appendix, helps clinicians who encounter spinal tumours refer patients with suspected spinal sarcoma or chordoma for pathological diagnosis, surgery and radiosurgery. The list constitutes a basis of the network of expertise for the management of primary malignant spinal tumours and should be understood as a communication network of specialists involved in the care of primary spinal malignancies.

CONCLUSION

The developed recommendations together with the national network of expertise should optimize the management of patients with spinal tumours, especially rare malignancies, and optimize their referral and allocation within the Polish national health service system.

Imaging of metastatic epidural spinal cord compression

Metastatic epidural spinal cord compression develops in 5-10% of patients with cancer and is becoming more common as advancement in cancer treatment prolongs survival in patients with cancer (1-3). It represents an oncological emergency as metastatic epidural compression in adjacent neural structures, including the spinal cord and cauda equina, and exiting nerve roots may result in irreversible neurological deficits, pain, and spinal instability. Although management of metastatic epidural spinal cord compression remains palliative, early diagnosis and intervention may improve outcomes by preserving neurological function, stabilizing the vertebral column, and achieving localized tumor and pain control. Imaging serves an essential role in early diagnosis of metastatic epidural spinal cord compression, evaluation of the degree of spinal cord compression and extent of tumor burden, and preoperative planning. This review focuses on imaging features and techniques for diagnosing metastatic epidural spinal cord compression, differential diagnosis, and management guidelines.

State-of-the-Art Imaging Techniques in Metastatic Spinal Cord Compression

Metastatic Spinal Cord Compression (MSCC) is a debilitating complication in oncology patients. This narrative review discusses the strengths and limitations of various imaging modalities in diagnosing MSCC, the role of imaging in stereotactic body radiotherapy (SBRT) for MSCC treatment, and recent advances in deep learning (DL) tools for MSCC diagnosis. PubMed and Google Scholar databases were searched using targeted keywords. Studies were reviewed in consensus among the co-authors for their suitability before inclusion. MRI is the gold standard of imaging to diagnose MSCC with reported sensitivity and specificity of 93% and 97% respectively. CT Myelogram appears to have comparable sensitivity and specificity to contrast-enhanced MRI. Conventional CT has a lower diagnostic accuracy than MRI in MSCC diagnosis, but is helpful in emergent situations with limited access to MRI. Metal artifact reduction techniques for MRI and CT are continually being researched for patients with spinal implants. Imaging is crucial for SBRT treatment planning and three-dimensional positional verification of the treatment isocentre prior to SBRT delivery. Structural and functional MRI may be helpful in post-treatment surveillance. DL tools may improve detection of vertebral metastasis and reduce time to MSCC diagnosis. This enables earlier institution of definitive therapy for better outcomes.

Multidisciplinary Approach to Patients With Metastatic Spinal Cord Compression: A Diagnostic Therapeutic Algorithm to Improve the Neurological Outcome

Introduction

The morbidity associated with metastatic spinal disease is significant because of spinal cord and/or nerve root compression. The purpose of this paper is to define a diagnostic-therapeutic path for patients with vertebral metastases and from this path to build an algorithm to reduce the devastating consequences of spinal cord compression.

Materials and Methods

The algorithm is born from the experience of a primary care center. A spine surgeon, an emergency room (ER) physician, a neuroradiologist, a radiation oncologist, and an oncologist form the multidisciplinary team. The ER physician or the oncologist intercept the patient with symptoms and signs of a metastatic spinal cord compression. Once the suspicion is confirmed, the following steps of the flow-chart must be triggered. The spine surgeon takes charge of the patient and, on the base of the anamnestic data and neurological examination, defines the appropriate timing for magnetic resonance imaging (MRI) in collaboration with the neuroradiologist. From the MRI outcome, the spine surgeon and the radiation oncologist consult each other to define further therapeutic alternatives. If indicated, surgical treatment should precede radiation therapy. The oncologist gets involved after surgery for systemic therapy.

Results

In 2021, the Spine and Spinal Cord Surgery department evaluated 257 patients with vertebral metastasis. Fifty-three patients presented with actual or incipient spinal cord compression. Among these, 27 were admitted due to rapid progression of symptoms, neurological deficits and/or spine instability signs. The level was thoracic in 21 cases, lumbar in 4 cases, cervical in 1 case, sacral in 1 case. Fifteen were operated on, 10 of these programmed and 5 in emergency.

Discussion

Patients with a history of malignancy can present to the ER or to the oncology department with symptoms that must be correctly framed in the context of a metastatic involvement. Even when there is no previous cancer history, the patient's pain characteristics and clinical signs must be interpreted to yield the correct diagnosis of vertebral metastasis with incipient or current spinal cord compression. The awareness of the alert symptoms and the application of an integrated paradigm consent to frame the patients with spinal cord compression, obtaining the benefits of a homogeneous step-by-step diagnostic and therapeutic path. Early surgical or radiation therapy treatment gives the best hope for preventing the worsening, or even improving, the deficits.

Conclusions

Metastatic spinal cord compression can cause neurological deficits compromising quality of life. Treatment strategies should be planned comprehensively. A multidisciplinary approach and the application of the proposed algorithm is of paramount importance to optimize the outcomes of these patients.

Spinal metastasis: narrative reviews of the current evidence and treatment modalities

The treatment for spinal metastasis has evolved significantly during the past decade. An advancement in systemic therapy has led to a prolonged overall survival in cancer patients, thus increasing the incidence of spinal metastasis. In addition, with the improved treatment armamentarium, the prediction of patient survival using traditional prognostic models may have limitations and these require the incorporation of some novel parameters to improve their prognostic accuracy. The development of minimally-invasive spinal procedures and minimal access surgical techniques have facilitated a quicker patient recovery and return to systemic treatment. These modern interventions help to alleviate pain and improve quality of life, even in candidates with a relatively short life expectancy. Radiotherapy may be considered in non-surgical candidates or as adjuvant therapy for improving local tumour control. Stereotactic radiosurgery has facilitated this even in radioresistant tumours and may even replace surgery in radiosensitive malignancies. This narrative review summarizes the current evidence leading to the paradigm shifts in the modern treatment of spinal metastasis.

Finite Element Analysis of Osteoporotic and Osteoblastic Vertebrae and Its Association With the Proton Density Fat Fraction From Chemical Shift Encoding-Based Water-Fat MRI - A Preliminary Study

PURPOSE

Osteoporosis is prevalent and entails alterations of vertebral bone and marrow. Yet, the spine is also a common site of metastatic spread. Parameters that can be non-invasively measured and could capture these alterations are the volumetric bone mineral density (vBMD), proton density fat fraction (PDFF) as an estimate of relative fat content, and failure displacement and load from finite element analysis (FEA) for assessment of bone strength. This study's purpose was to investigate if osteoporotic and osteoblastic metastatic changes in lumbar vertebrae can be differentiated based on the abovementioned parameters (vBMD, PDFF, and measures from FEA), and how these parameters correlate with each other.

MATERIALS AND METHODS

Seven patients (3 females, median age: 77.5 years) who received 3-Tesla magnetic resonance imaging (MRI) and multi-detector computed tomography (CT) of the lumbar spine and were diagnosed with either osteoporosis (4 patients) or diffuse osteoblastic metastases (3 patients) were included. Chemical shift encoding-based water-fat MRI (CSE-MRI) was used to extract the PDFF, while vBMD was extracted after automated vertebral body segmentation using CT. Segmentation masks were used for FEA-based failure displacement and failure load calculations. Failure displacement, failure load, and PDFF were compared between patients with osteoporotic vertebrae versus patients with osteoblastic metastases, considering non-fractured vertebrae (L1-L4). Associations between those parameters were assessed using Spearman correlation.

RESULTS

Median vBMD was 59.3 mg/cm³ in osteoporotic patients. Median PDFF was lower in the metastatic compared to the osteoporotic patients (11.9% vs. 43.8%, p=0.032). Median failure displacement and failure load were significantly higher in metastatic compared to osteoporotic patients (0.874 mm vs. 0.348 mm, 29,589 N vs. 3,095 N, p=0.034 each). A strong correlation was noted between PDFF and failure displacement (rho -0.679, p=0.094). A very strong correlation was noted between PDFF and failure load (rho -0.893, p=0.007).

CONCLUSION

PDFF as well as failure displacement and load allowed to distinguish osteoporotic from diffuse osteoblastic vertebrae. Our findings further show strong associations between PDFF and failure displacement and load, thus may indicate complimentary pathophysiological associations derived from two non-invasive techniques (CSE-MRI and CT) that inherently measure different properties of vertebral bone and marrow.

Preconditioned water-fat total field inversion: Application to spine quantitative susceptibility mapping

PURPOSE

To (a) develop a preconditioned water-fat total field inversion (wfTFI) algorithm that directly estimates the susceptibility map from complex multi-echo gradient echo data for water-fat regions and to (b) evaluate the performance of the proposed wfTFI quantitative susceptibility mapping (QSM) method in comparison with a local field inversion (LFI) method and a linear total field inversion (TFI) method in the spine.

METHODS

Numerical simulations and in vivo spine multi-echo gradient echo measurements were performed to compare wfTFI to an algorithm based on disjoint background field removal (BFR) and LFI and to a formerly proposed TFI algorithm. The data from 1 healthy volunteer and 10 patients with metastatic bone disease were included in the analysis. Clinical routine computed tomography (CT) images were used as a reference standard to distinguish osteoblastic from osteolytic changes. The ability of the QSM methods to distinguish osteoblastic from osteolytic changes was evaluated.

RESULTS

The proposed wfTFI method was able to decrease the normalized root mean square error compared to the LFI and TFI methods in the simulation. The in vivo wfTFI susceptibility maps showed reduced BFR artifacts, noise amplification, and streaking artifacts compared to the LFI and TFI maps. wfTFI provided a significantly higher diagnostic confidence in differentiating osteolytic and osteoblastic lesions in the spine compared to the LFI method (p = .012).

CONCLUSION

The proposed wfTFI method can minimize BFR artifacts, noise amplification, and streaking artifacts in water-fat regions and can thus better differentiate between osteoblastic and osteolytic changes in patients with metastatic disease compared to LFI and the original TFI method.

An international expert opinion statement on the utility of PET/MR for imaging of skeletal metastases

BACKGROUND

MR is an important imaging modality for evaluating musculoskeletal malignancies owing to its high soft tissue contrast and its ability to acquire multiparametric information. PET provides quantitative molecular and physiologic information and is a critical tool in the diagnosis and staging of several malignancies. PET/MR, which can take advantage of its constituent modalities, is uniquely suited for evaluating skeletal metastases. We reviewed the current evidence of PET/MR in assessing for skeletal metastases and provided recommendations for its use.

METHODS

We searched for the peer reviewed literature related to the usage of PET/MR in the settings of osseous metastases. In addition, expert opinions, practices, and protocols of major research institutions performing research on PET/MR of skeletal metastases were considered.

RESULTS

Peer-reviewed published literature was included. Nuclear medicine and radiology experts, including those from 13 major PET/MR centers, shared the gained expertise on PET/MR use for evaluating skeletal metastases and contributed to a consensus expert opinion statement. [18F]-FDG and non [18F]-FDG PET/MR may provide key advantages over PET/CT in the evaluation for osseous metastases in several primary malignancies.

CONCLUSION

PET/MR should be considered for staging of malignancies where there is a high likelihood of osseous metastatic disease based on the characteristics of the primary malignancy, hight clinical suspicious and in case, where the presence of osseous metastases will have an impact on patient management. Appropriate choice of tumor-specific radiopharmaceuticals, as well as stringent adherence to PET and MR protocols, should be employed.

Bone metastases from differentiated thyroid carcinoma: current knowledge and open issues

Bone represents the second most common site of distant metastases in differentiated thyroid cancer (DTC). The clinical course of DTC patients with bone metastases (BM) is quite heterogeneous, but generally associated with low survival rates. Skeletal-related events might be a serious complication of BM, resulting in high morbidity and impaired quality of life. To achieve disease control and symptoms relief, multimodal treatment is generally required: radioiodine therapy, local procedures-including surgery, radiotherapy and percutaneous techniques-and systemic therapies, such as kinase inhibitors and antiresorptive drugs. The management of DTC with BM is challenging: a careful evaluation and a personalized approach are essential to improve patients' outcomes. To date, prospective studies focusing on the main clinical aspects of DTC with BM are scarce; available analyses mainly include cohorts assembled over multiple decades, small samples sizes and data about BM not always separated from those regarding other distant metastases. The aim of this review is to summarize the most recent evidences and the unsolved questions regarding BM in DTC, analyzing several key issues: pathophysiology, prognostic factors, role of anatomic and functional imaging, and clinical management.

Multidisciplinary management of metastatic spine disease: initial symptom-directed management

In the past 2 decades, a deeper understanding of the cancer molecular signature has resulted in longer longevity of cancer patients, hence a greater population, who potentially can develop metastatic disease. Spine metastases (SM) occur in up to 70% of cancer patients. Familiarizing ourselves with the key aspects of initial symptom-directed management is important to provide SM patients with the best patient-specific options. We will review key components of initial symptoms assessment such as pain, neurological symptoms, and spine stability. Radiographic evaluation of SM and its role in management will be reviewed. Nonsurgical treatment options are also presented and discussed, including percutaneous procedures, radiation, radiosurgery, and spine stereotactic body radiotherapy. The efforts of a multidisciplinary team will continue to ensure the best patient care as the landscape of cancer is constantly changing.

Lactobacillus Fermentum ZS40 prevents secondary osteoporosis in Wistar Rat

Using retinoic acid to inducer, we successfully established a rat model of secondary osteoporosis and verified the preventive effect of Lactobacillus fermentum ZS40 (ZS40) on secondary osteoporosis. Serum biochemical indicators showed that ZS40 can effectively slow down bone resorption caused by retinoic acid, increase blood content of calcium, phosphorus, bone alkaline phosphatase, bone gla protein, and insulin-like growth factor 1, and decrease blood content of tartrate-resistant acid phosphatase (TRAP) 5b. qRT-PCR results showed that ZS40 could upregulate mRNA expressions of β-catenin, Wnt10b, Lrp5, Lrp6, Runx2, ALP, RANKL, and OPG, and downregulate mRNA expression of DKK1, RANK, TRACP, and CTSK in the rats' spinal cord. Results following TRAP staining showed that ZS40 could slow down retinoic acid-induced formation of osteoclasts. Micro-CT results showed that ZS40 could reduce Tb.Sp, increase BV/TV, Tb.N, Tb.Th, and ultimately increase bone mineral density of rats in vivo. These findings indicate that ZS40 might have a potential role in preventing retinoic acid-induced secondary osteoporosis in vivo.

Bone up on spinal osseous lesions: a case review series

Spinal osseous neoplasms are frequently encountered and can be challenging when present as solitary lesions. Familiarity with the range of benign and malignant spinal pathology can help the radiologist formulate a comprehensive differential diagnosis. This article focuses on the spectrum of extradural spinal tumors, accounting for the majority of primary spinal tumors, by comparing the epidemiology, pathophysiology, clinical presentation, and characteristic imaging appearance of these lesions. The discussion includes the commonly encountered benign lesions, such as vertebral venous vascular malformation and enostosis, as well as malignant lesions including metastases and lymphoma. The article also includes other less-encountered primary spinal tumors such as plasmacytoma, osteoid osteoma, osteoblastoma, giant cell tumor, eosinophilic granuloma, chordoma, chondrosarcoma, osteosarcoma, Ewing’s sarcoma, and angiosarcoma. Familiarity with the characteristic imaging features can help the radiologist reach an accurate diagnosis and obviate the need for unnecessary invasive procedures such as biopsy and surgery.

Kyphoplasty in the treatment of occult and non-occult metastatic vertebral tumors

To compare the efficacy and safety of kyphoplasty (KP) in the treatment of occult metastatic vertebral tumors (OMVT) and non-occult metastatic vertebral tumors (MVT).From January 2013 to December 2017, 65 cases of occult metastatic vertebral tumors and 82 cases of metastatic vertebral tumors were selected and divided into 2 groups. After KP, they were followed up by a year of outpatient visits and telephone calls. The visual analogue scale (VAS) and Oswestry disability index (ODI) scores, the amount of bone cement injected, the change of vertebral height and the incidence of complications were recorded, compared and analyzed by SPSS software. t test was used to compare the differences between the same group of patients at different times and between the 2 groups of patients.In the OMVT group, the operation time was 24.52 ± 4.24 minutes, the fluoroscopy time was 10.18 ± 1.53 minutes and the volume of bone cement was 3.62 ± 0.93 ml. The VAS score decreased from 7.26 ± 01.08 preoperatively to 2.77 ± 0.93 postoperatively (P < .01). The ODI score decreased from 64.89 ± 9.05 preoperatively to 25.82 ± 4.63 postoperatively (P < .01). In the MVT group, the operation time was 26.63 ± 4.61 minutes, the fluoroscopy time was 11.04 ± 2.15 minutes and the volume of bone cement was 4.09 ± 1.10 ml. The VAS score decreased from 7.73 ± 0.94 preoperatively to 3.22 ± 0.80 postoperatively (P < .01). The ODI score decreased from 69.20 ± 7.14 preoperatively to 28.02 ± 4.40 postoperatively (P < .01). The vertebral height of MVT patients was significantly improved after operation (P < .01), but there was no difference in OMVT patients (P > .05).Occult metastatic vertebral tumors can be detected by Magnetic Resonance Imaging (MRI), and KP may be more effective and safer in the treatment of OMVT.

Imaging response assessment following stereotactic body radiotherapy for solid tumour metastases of the spine: Current challenges and future directions

Patients with metastatic disease are routinely serially imaged to assess disease burden and response to systemic and local therapies, which places ever-expanding demands on our healthcare resources. Image interpretation following stereotactic body radiotherapy (SBRT) for spine metastases can be challenging; however, appropriate and accurate assessment is critical to ensure patients are managed correctly and resources are optimised. Here, we take a critical review of the merits and pitfalls of various imaging modalities, current response assessment guidelines, and explore novel imaging approaches and the potential for radiomics to add value in imaging assessment.

Principles of Management of Spine Metastasis

BACKGROUND

With evolution of medicine, radiation therapy and surgical methods, cancer care has improved the quality of life for patients with improved survival and functional status in patients with skeletal metastasis. The most common site of skeletal metastases from other primary malignant neoplasms is the spine, hence, understanding the epidemiology of metastatic spine disease and its presentation is essential for developing a diagnostic and treatment strategy which eventually results in optimum care to reduce disease-related morbidity.

PURPOSE

With this review article we intend to describe an evidence-based review on the presentation, diagnosis and treatment of metastatic spinal disease.

METHODS

We reviewed the current available literature on management of spinal metastasis and have described a step wise evaluation and management strategy of metastatic spine disease.

CONCLUSION

The present review article addresses various aspects and related controversies related to evaluation, staging and treatment options in the management of spinal metastasis.

Effect of the types of pretreatment imaging modalities on the treatment response to palliative radiation for painful bone metastases from solid cancer: a single-center retrospective analysis

Background

Determining the appropriate gross tumor volume is important for irradiation planning in addition to palliative radiation for bone metastases. While irradiation planning is commonly performed using simulation computed tomography (CT), magnetic resonance imaging (MRI), bone scintigraphy, and ¹⁸fluorodeoxyglucose-positron emission tomography-CT (¹⁸FDG-PET-CT) are more sensitive for detecting bone metastasis and invasion areas. Therefore, this study evaluated whether pretreatment imaging modalities influenced the response to palliative radiation therapy (i.e., the irradiation effect) for painful bone metastases from solid malignant carcinomas.

Methods

Consecutive patients with painful bone metastases treated with palliative radiation between January 2013 and December 2017 at our institution were included. We retrospectively investigated the pretreatment images from the different imaging modalities (CT, MRI, bone scintigraphy, and ¹⁸FDG-PET-CT) obtained between 1 month before and the initiation of palliative radiation and determined the primary site of carcinoma, histological type, metastatic lesion type (osteolytic, osteoblastic, or mixed), pathological fracture, and metastatic site (vertebral or not). We then evaluated the relationship between these factors and treatment response. We defined “response” as the condition in which patients achieved pain relief or reduced the use of painkiller medicines.

Results

In total, 131 patients (78 men and 53 women) were included; the median age was 66 years (range, 24–89 years). Prescribed doses were 8–50 Gy/1–25 fractions with 2–8 Gy/fraction. Among the 131 patients, 105 were responders (response rate, 80%). The imaging modalities performed before irradiation were CT in 131 patients, MRI in 54, bone scintigraphy in 56, and ¹⁸FDG-PET-CT in 14. The Welch t-test and chi-square test showed no significant association between treatment response and each factor. Multiple logistic regression analysis including the imaging modality, metastatic site, and pathological fracture also showed no significant association with each factor.

Conclusions

There was no significant relationship between the type of pretreatment imaging and treatment response for painful bone metastases. Thus, setting the appropriate radiation field according to CT images and clinical findings could help avoiding further image inspection before palliative radiation for painful bone metastases.

Neuroimaging and Stereotactic Body Radiation Therapy (SBRT) for Spine Metastasis

Historically, management options for spinal metastases include surgery for stabilization and decompression and/or external beam radiation therapy (EBRT). EBRT is palliative in nature, as it lacks accurate targeting such that the prescribed radiation doses must be limited in order to maintain safety. Modern advancement in imaging and radiotherapy technology have facilitated the development of stereotactic body radiation therapy (SBRT), which provides increased targeted precision for radiation delivery to tumors resulting in lower overall toxicity, particularly to regional structures such as the spinal cord and esophagus, while delivering higher, more effective, and radically ablative radiation doses.Over the past decade, SBRT has been increasingly utilized as a method of treating spinal metastases either as the primary modality or following surgical intervention in both de novo and reirradiation setting. Numerous studies suggest that SBRT is associated with an 80% to 90% rate of 1-year local control across clinical scenarios. For example, studies of SBRT as the primary treatment modality suggest long-term local control rate of 80% to 95% for spinal metastases. Similarly, SBRT in the adjuvant setting following surgery is associated with local control rates ranging from 70% to 100%. Furthermore, because SBRT allows for lower dose to the spinal cord, it has also been used in patients who have had prior radiation therapy, with studies showing 66% to 93% local control in this scenario.

Differentiation of Predominantly Osteoblastic and Osteolytic Spine Metastases by Using Susceptibility-weighted MRI

Purpose To evaluate the use of susceptibility-weighted MRI for the differentiation of predominantly osteoblastic and osteolytic spine metastases. Materials and Methods For this prospective study, 53 study participants (mean age, 54.5 years ± 14.3 [range, 22-88 years]; 27 men with a mean age of 55.3 years ± 12.7 [range, 22-72 years] and 26 women with a mean age of 53.8 years ± 15.7 [range, 23-88 years]) with clinically suspected spine metastases underwent imaging with standard MRI sequences, susceptibility-weighted MRI, and CT. Sensitivities and specificities of MRI sequences for the detection of predominantly osteoblastic and osteolytic metastases were determined by using CT as the reference standard. The metastases-to-vertebral body signal intensity ratio (MVR) was calculated to compare modalities. Phantom measurements were obtained to correlate bone densities between MRI sequences and CT. Results A total of 64 metastases (38 predominantly osteoblastic, 26 predominantly osteolytic) were detected. Susceptibility-weighted MRI achieved a sensitivity of 100% (38 of 38) and specificity of 96% (25 of 26) for predominantly osteoblastic metastases and a sensitivity of 96% (25 of 26) and specificity of 100% (38 of 38) for predominantly osteolytic metastases. Standard MRI sequences achieved a sensitivity of 89% (34 of 38) and specificity of 73% (19 of 26) for predominantly osteoblastic metastases and a sensitivity of 73% (19 of 26) and specificity of 92% (35 of 38) for predominantly osteolytic metastases. MVR measurements obtained with susceptibility-weighted MRI demonstrated a strong correlation with those obtained with CT (R² = 0.75), whereas those obtained with T1-weighted MRI, T2-weighted MRI, and turbo inversion-recovery magnitude MRI showed a weak to moderate correlation (R² = 0.00, R² = 0.35, and R² = 0.39, respectively). Susceptibility-weighted MRI showed a strong correlation with CT with regard to metastases size (R² = 0.91). In phantom measurements, susceptibility-weighted MRI enabled the reliable differentiation of different degrees of mineralization (R² = 0.92 compared with CT). Conclusion Susceptibility-weighted MRI enables the reliable differentiation between predominantly osteoblastic and osteolytic spine metastases with a higher accuracy than standard MRI sequences. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Schweitzer in this issue.

Imaging Advances in the Management of Kidney Cancer

New developments in cross-sectional imaging, including contrast-enhanced ultrasound, dual-energy computed tomography, multiparametric magnetic resonance imaging, single-photon emission computed tomography, and positron emission tomography, together with novel application of existing and novel radiotracers, have changed the landscape of renal mass characterization (ie, virtual biopsy) as well as the detection of metastatic disease, prognostication, and response assessment in patients with advanced kidney cancer. A host of imaging response criteria have been developed to characterize the response to targeted and immune therapies and correlate with patient outcomes, each with strengths and limitations. Recent efforts to advance the field are aimed at increasing objectivity with quantitative techniques and the use of banks of imaging data to match the vast genomic data that are becoming available. The emerging field of radiogenomics has the potential to transform further the role of imaging in kidney cancer management through eventual noninvasive characterization of the tumor histology and genetic microenvironment in single renal masses and/or metastatic disease. We review of the effect of currently available imaging techniques in the management of patients with kidney cancer, including localized, locally advanced, and metastatic disease.

Clinical management of spinal metastases-The Dutch national guideline

This article is a summary of the revised Dutch multidisciplinary evidence-based guideline 'Spinal metastases' (English translation available at: https://www.oncoline.nl/spinal-metastases) that was published at the end of 2015. This summary provides an easy-to-use overview for physicians to use in their daily practice.

The Use of Imaging in Management of Patients with Low Back Pain

Lower back pain (LBP) is one of the most common chief complaints encountered in primary care. Advanced imaging studies, including computerized tomography (CT) and magnetic resonance imaging (MRI), are frequently ordered in the setting of LBP. Structural abnormalities are commonly identified by CT and MRI in patients complaining of low back pain, however, these findings are also found in asymptomatic patients. In the past decade, multiple guidelines have been published to help providers identify patients in whom the use of advanced imaging is appropriate. In this article, we review common conditions associated with LBP that require advanced imaging along with their clinical and associated imaging findings.

Oncologic Mechanical Emergencies

Prevalence of cancer and its various related complications continues to rise. Increasingly these life-threatening complications are initially managed in the emergency department, making a prompt and accurate diagnosis crucial to effectively institute the proper treatment and establish goals of care. The following oncologic emergencies are reviewed in this article: pericardial tamponade, superior vena cava syndrome, brain metastasis, malignant spinal cord compression, and hyperviscosity syndrome.

Spine Stereotactic Body Radiotherapy: Indications, Outcomes, and Points of Caution

STUDY DESIGN

A broad narrative review.

OBJECTIVES

The objective of this article is to provide a technical review of spine stereotactic body radiotherapy (SBRT) planning and delivery, indications for treatment, outcomes, complications, and the challenges of response assessment. The surgical approach to spinal metastases is discussed with an overview of emerging minimally invasive techniques.

METHODS

A comprehensive review of the literature was conducted on the techniques, outcomes, and developments in SBRT and surgery for spinal metastases.

RESULTS

The optimal management of patients with spinal metastases is complex and requires multidisciplinary assessment from an oncologic team that is familiar with the shifting paradigm as a consequence of evolving techniques in surgery and stereotactic radiation, as well as new developments in systemic agents. The Spinal Instability Neoplastic Score and the epidural spinal cord compression (Bilsky) grading system are useful tools that facilitate communication among oncologic team members and can direct management by providing a baseline assessment of risks prior to therapy. The combined multimodality approach with "separation surgery" followed by postoperative spine SBRT achieves thecal sac decompression, improves tumor control, and avoids complications that may be associated with more extensive surgery.

CONCLUSION

Spine SBRT is a highly effective treatment that is capable of delivering ablative doses to the target while sparing the critical organs-at-risk, chiefly the critical neural tissues, within a short and manageable schedule. At the same time, surgery occupies an important role in select patients, particularly with the expanding availability and expertise in minimally invasive techniques. With rapid adoption of spine SBRT in centers outside of the academic setting, it is imperative for the practicing oncologist to understand the relevance and application of these evolving concepts.

Anatomic and functional imaging in the diagnosis of spine metastases and response assessment after spine radiosurgery

Spine stereotactic radiosurgery (SSRS) has recently emerged as an increasingly effective treatment for spinal metastases. Studies performed over the past decade have examined the role of imaging in the diagnosis of metastases, as well as treatment response following SSRS. In this paper, the authors describe and review the utility of several imaging modalities in the diagnosis of spinal metastases and monitoring of their response to SSRS. Specifically, we review the role of CT, MRI, and positron emission tomography (PET) in their ability to differentiate between osteoblastic and osteolytic lesions, delineation of initial bony pathology, detection of treatment-related changes in bone density and vertebral compression fracture after SSRS, and tumor response to therapy. Validated consensus guidelines defining the imaging approach to SSRS are needed to standardize the diagnosis and treatment response assessment after SSRS. Future directions of spinal imaging, including advances in targeted tumor-specific molecular imaging markers demonstrate early promise for advancing the role of imaging in SSRS.

Spinal metastases: multimodality imaging in diagnosis and stereotactic body radiation therapy planning

Due to increased effectiveness of cancer treatments and increasing survival rates, metastatic disease has become more frequent compared to the past, with the spine being the most common site of bony metastases. Diagnostic imaging is an integral part of screening, diagnosis and follow-up of spinal metastases. In this article, we review the principles of multimodality imaging for tumor detection with respect to their value for diagnosis and stereotactic body radiation therapy planning for spinal metastases. We will also review the current international consensus agreement for stereotactic body radiation therapy planning, and the role of imaging in achieving the best possible treatment plan.

Radium-223 outcomes after multiple lines of metastatic castration-resistant prostate cancer therapy in clinical practice: implication of pre-treatment spinal epidural disease

BACKGROUND

Magnetic resonance imaging (MRI) is not routinely performed before initiating radium-223 to document spinal epidural disease. However, radium-223 decays to form α-particles with very short path lengths that may not reach the epidural space. Herein, we investigate the impact of baseline spinal epidural disease on metastatic castration-resistant prostate cancer (mCRPC) patients treated with radium-223.

METHODS

Between October 2013 to December 2014, 41 consecutive mCRPC patients at a large tertiary cancer center were prescribed radium-223 as part of standard of care. 29% of patients had pre-treatment epidural disease (posMRI), 27% had no epidural disease (negMRI), and 44% did not have a baseline MRI (noMRI). All patients had post-treatment spinal imaging. Actuarial survival times were calculated for overall survival (OS), spinal axis radiographic progression-free survival (spinePFS) and epidural progression-free survival (epiPFS) from time of first radium-223 treatment.

RESULTS

For patients with posMRI (n=12), noMRI (n=18) and negMRI (n=11) cumulative rates of development or worsening of epidural disease and/or high-grade cord compression at time of last follow-up were 83%, 44% and 9%, respectively (P=0.001). For the posMRI, noMRI and negMRI groups the median OS was 6.3 months, 12.6 months and not reached (P=0.01), the median spinePFS was 3.2 months, 4.8 months and not reached (P=0.01), and the median epiPFS was 3.2 months, 10.4 months and not reached (P=0.001). Completing less than six cycles of radium-223 was significantly associated with worse OS (P<0.0001), spinePFS (P=0.007) and epiPFS (P=0.01). Greater than or equal to twenty osseous lesions pre-treatment was significantly associated with worse spinePFS (P=0.001) and epiPFS (P=0.03).

CONCLUSIONS

In a heavily pre-treated small cohort, patients with baseline epidural disease frequently progressed to spinal cord compression and early cessation of radium-223 therapy. Studies are needed to determine the optimal timing of radium-223 with other mCRPC therapies given the predilection for epidural disease and treatment failure after multiple prior lines of mCRPC therapy.

Response assessment after stereotactic body radiotherapy for spinal metastasis: a report from the SPIne response assessment in Neuro-Oncology (SPINO) group

The SPine response assessment In Neuro-Oncology (SPINO) group is a committee of the Response Assessment in Neuro-Oncology working group and comprises a panel of international experts in spine stereotactic body radiotherapy (SBRT). Here, we present the group's first report on the challenges in standardising imaging-based assessment of local control and pain for spinal metastases. We review current imaging modalities used in SBRT treatment planning and tumour assessment and review the criteria for pain and local control in registered clinical trials specific to spine SBRT. We summarise the results of an international survey of the panel to establish the range of current practices in assessing tumour response to spine SBRT. The ultimate goal of the SPINO group is to report consensus criteria for tumour imaging, clinical assessment, and symptom-based response criteria to help standardise future clinical trials.

Neuroimaging of spine tumors

Intramedullary, intradural/extramedullary, and extradural spine tumors comprise a wide range of neoplasms with an even wider range of clinical symptoms and prognostic features. Magnetic resonance imaging (MRI), commonly used to evaluate the spine in patients presenting with pain, can further characterize lesions that may be encountered on other imaging studies, such as bone scintigraphy or computed tomography (CT). The advantage of the MRI is its multiplane capabilities, superior contrast agent resolution, and flexible protocols that play an important role in assessing tumor location, extent in directing biopsy, in planning proper therapy, and in evaluating therapeutic results. A multimodality approach can be used to fully characterize the lesion and the combination of information obtained from the different modalities usually narrows the diagnostic possibilities significantly. The diagnosis of spinal tumors is based on patient age, topographic features of the tumor, and lesion pattern, as seen at CT and MRI. The shift to high-end imaging incorporating diffusion-weighted imaging, diffusion tensor imaging, magnetic resonance spectroscopy, whole-body short tau inversion recovery, positron emission tomography, intraoperative and high-field MRI as part of the mainstream clinical imaging protocol has provided neurologists, neuro-oncologists, and neurosurgeons a window of opportunity to assess the biologic behavior of spine neoplasms. This chapter reviews neuroimaging of spine tumors, primary and secondary, discussing routine and newer modalities that can reduce the significant morbidity associated with these neoplasms.

Prospective study evaluating the relative sensitivity of 18F-NaF PET/CT for detecting skeletal metastases from renal cell carcinoma in comparison to multidetector CT and 99mTc-MDP bone scintigraphy, using an adaptive trial design

BACKGROUND

The detection of occult bone metastases is a key factor in determining the management of patients with renal cell carcinoma (RCC), especially when curative surgery is considered. This prospective study assessed the sensitivity of (18)F-labelled sodium fluoride in conjunction with positron emission tomography/computed tomography ((18)F-NaF PET/CT) for detecting RCC bone metastases, compared with conventional imaging by bone scintigraphy or CT.

PATIENTS AND METHODS

An adaptive two-stage trial design was utilized, which was stopped after the first stage due to statistical efficacy. Ten patients with stage IV RCC and bone metastases were imaged with (18)F-NaF PET/CT and (99m)Tc-labelled methylene diphosphonate ((99m)Tc-MDP) bone scintigraphy including pelvic single photon emission computed tomography (SPECT). Images were reported independently by experienced radiologists and nuclear medicine physicians using a 5-point scoring system.

RESULTS

Seventy-seven lesions were diagnosed as malignant: 100% were identified by (18)F-NaF PET/CT, 46% by CT and 29% by bone scintigraphy/SPECT. Standard-of-care imaging with CT and bone scintigraphy identified 65% of the metastases reported by (18)F-NaF PET/CT. On an individual patient basis, (18)F-NaF PET/CT detected more RCC metastases than (99m)Tc-MDP bone scintigraphy/SPECT or CT alone (P = 0.007). The metabolic volumes, mean and maximum standardized uptake values (SUV mean and SUV max) of the malignant lesions were significantly greater than those of the benign lesions (P < 0.001).

CONCLUSIONS

(18)F-NaF PET/CT is significantly more sensitive at detecting RCC skeletal metastases than conventional bone scintigraphy or CT. The detection of occult bone metastases could greatly alter patient management, particularly in the context when standard-of-care imaging is negative for skeletal metastases.

Current trends in mini-invasive management of spine metastases

The spine is a frequent localization of primary tumours or metastasis involving posterior arch, pedicles and vertebra body, and often causing unsustainable pain. The management of spinal metastasis remains complex, including medical therapy (corticosteroids, chemotherapy), radiotherapy and surgical treatment, or the recent percutaneous mini-invasive approach. The target of all these treatments is to improve the quality of life of patients affected by this type of lesion. Diagnosis of spinal metastasis and then its treatment should be based on the combination of different elements: clinical evaluation, CT, MRI and nuclear medicine patterns, considering the age of the patient, known primary tumour, location of the lesions, single/multiple lesions, pattern of morphology (border, matrix, expansile character, soft tissue extension), density or signal intensity, oncologic instability and expectancy of life. The percutaneous mini-invasive approach for patients affected by secondary lesions involving the spine has as treatment goal of: (1) pain relief improving the quality of life; (2) stability treatment re-establishing the spinal biomechanics, alterated by bone destruction or deformity, preventing pathological fracture; and (3) an anti-neoplastic effect. The aim of this paper is to provide a comprehensive diagnostic and percutaneous approach to the bone metastatic spine lesions, identifying which metamer should be treated to improve patient quality of life, showing the importance of a multi-disciplinary approach to this problem.

CT-guidance interstitial (125)Iodine seed brachytherapy as a salvage therapy for recurrent spinal primary tumors

Background

Management of spinal neoplasms has relied on open surgery and external beam radiotherapy (EBRT). Although primary spinal tumors are rare, their treatment remains a pervasive problem. This analysis sought to evaluate the safety and efficacy of CT-guided ¹²⁵I seed brachytherapy for recurrent paraspinous and vertebral primary tumors.

Methods

From November 2002 to June 2014, 17 patients who met the inclusion criteria were retrospectively reviewed. 14 (82.4%) had previously undergone surgery, 15 (88.2%) had received conventional EBRT and 3 (17.6%) had chosen chemotherapy. The number of ¹²⁵I seeds implanted ranged from 7 to 122 (median 79) with specific activity of 0.5-0.8 mCi (median 0.7 mCi). The post-plan showed that the actuarial D₉₀ of ¹²⁵I seeds were 90–183 Gy (median 137 Gy). The follow-up period ranged from 2 to 69 months (median 19 months). The local control rate was calculated by the Kaplan-Meier method.

Results

For 5 Chondrosarcomas, the 1-, 2-, 3-year local control rates were 75%, 37.5%, and 37.5%, respectively, with a median of 34 months (range, 4–39 months). For 4 chordomas, the local control rate was 50% with a median follow-up of 13 months (range, 3–17 months). For 3 fibromatosis, all of them were survival without local recurrence at the end of follow-up. During the follow-up period, 35.3% (6/17) died from metastases, 17.6% (3/17) developed local recurrence by 8, 14 and 34 months while 64.7% (11/17) remained alive. 100% experienced pain relief and normal or improved ambulation, without more than Frankel grade 3 radiation myelopathy.

Conclusions

Percutaneous ¹²⁵I seed implantation can be an alternative or retreatment for recurrent spinal primary tumors.

Oncologic mechanical emergencies

Prevalence of cancer and its various related complications continues to rise. Increasingly these life-threatening complications are initially managed in the emergency department, making a prompt and accurate diagnosis crucial to effectively institute the proper treatment and establish goals of care. The following oncologic emergencies are reviewed in this article: pericardial tamponade, superior vena cava syndrome, brain metastasis, malignant spinal cord compression, and hyperviscosity syndrome.