Consensus guidelines for postoperative stereotactic body radiation therapy for spinal metastases: results of an international survey

Earlier Radiation Is Associated with Improved 1-Year Survival After Metastatic Spine Tumor Surgery

OBJECTIVE

In patients undergoing metastatic spine surgery, we sought to 1) report time to postoperative radiation therapy (RT), 2) describe the predictive factors of time to postoperative RT, and 3) determine if earlier postoperative RT is associated with improved local recurrence (LR) and overall survival (OS).

METHODS

A single-center retrospective cohort study was undertaken of all patients undergoing spine surgery for extradural metastatic disease and receiving RT within 3 months postoperatively between January 2010 and January 2021. Time to postoperative RT was dichotomized at <1 month versus 1-3 months. The primary outcomes were LR, OS, and 1-year survival. Secondary outcomes were wound complication, Karnofsky Performance Status, and modified McCormick Scale (MMS) score. Regression analyses controlled for age, body mass index, tumor size, preoperative RT, preoperative/postoperative chemotherapy, and type of RT.

RESULTS

Of 76 patients undergoing spinal metastasis surgery and receiving postoperative RT within 3 months, 34 (44.7%) received RT within 1 month and 42 (55.2%) within 1-3 months. Patients with larger tumor size (β = -3.58; 95% confidence interval [CI], -6.59 to -0.57; P = 0.021) or new neurologic deficits (β = -16.21; 95% CI, -32.21 to -0.210; P = 0.047) had a shorter time to RT. No significant association was found between time to RT and LR or OS on multivariable logistic/Cox regression. However, patients who received RT between 1 and 3 months had a lower odds of 1-year survival compared with those receiving RT within 1 month (odds ratio, 0.18; 95% CI, 0.04-0.74; P = 0.022). Receiving RT within 1 month versus 1-3 months was not associated with wound complications (7.1% vs. 2.9%; P = 0.556) (odds ratio, 4.40; 95% CI, 0.40-118.0; P = 0.266) or Karnofsky Performance Status/modified McCormick Scale score.

CONCLUSIONS

Spine surgeons, oncologists, and radiation oncologists should make every effort to start RT within 1 month to improve 1-year survival after metastatic spine tumor surgery.

Antiresorptive Medications Prior to Stereotactic Body Radiotherapy for Spinal Metastasis are Associated with Reduced Incidence of Vertebral Body Compression Fracture

STUDY DESIGN

Retrospective Cohort.

OBJECTIVE

Antiresorptive drugs are often given to minimize fracture risk for bone metastases, but data regarding optimal time or ability to reduce stereotactic body radiotherapy (SBRT)-induced fracture risk is limited. This study examines the association between antiresorptive use surrounding spinal SBRT and vertebral compression fracture (VCF) incidence to provide information regarding effectiveness and optimal timing of use.

METHODS

Patients treated with SBRT for spinal metastases at a single institution between 2009-2020 were included. Kaplan-Meier analysis was used to compare cumulative incidence of VCF for those taking antiresorptive drugs pre-SBRT, post-SBRT only, and none at all. Cox proportional hazards and Fine-Gray competing risk models were used to identify additional factors associated with VCF.

RESULTS

Of the 234 patients (410 vertebrae) analyzed, 49 (20.9%) were taking bisphosphonates alone, 42 (17.9%) were taking denosumab alone, and 25 (10.7%) were taking both. Kaplan-Meier analysis revealed a statistically significant lower VCF incidence for patients initiating antiresorptive drugs before SBRT compared to those taking none at all (4% vs 12% at 1 year post-SBRT, P = .045; and 4% vs 23% at 2 years, P = .008). On multivariate analysis, denosumab duration (HR: .87, P = .378) or dose (HR: 1.00, P = .644) as well as bisphosphonate duration (HR: .98, P= .739) or dose (HR: .99, P= .741) did not have statistical significance on VCF incidence.

CONCLUSION

Initiating antiresorptive agents before SBRT may reduce the risk of treatment-induced VCF. Antiresorptive drugs are underutilized in patients with spine metastases and may represent a useful intervention to minimize toxicity and improve long-term outcomes.

Re-irradiation spine stereotactic body radiotherapy following high-dose conventional radiotherapy for metastatic epidural spinal cord compression: a retrospective study

PURPOSE

 We aimed to evaluate the efficacy and safety of re-irradiation stereotactic body radiation therapy (SBRT) in patients with metastatic epidural spinal cord compression (MESCC) following high-dose conventional radiotherapy.

MATERIALS AND METHODS

 Twenty-one patients met the following eligibility criteria: with an irradiation history of 50 Gy2 equivalent dose in 2-Gy fractions (EQD2) or more, diagnosed MESCC in the cervical or thoracic spines, and treated with re-irradiation SBRT of 24 Gy in 2 fractions between April 2018 and March 2023. Prior treatment was radiotherapy alone, not including surgery. The primary endpoint was a 1-year local failure rate. Overall survival (OS) and treatment-related adverse events were assessed as the secondary endpoints. Since our cohort includes one treatment-related death (TRD) of esophageal perforation, the cumulative esophageal dose was evaluated to find the dose constraints related to severe toxicities.

RESULTS

 The median age was 68, and 14 males were included. The primary tumor sites (esophagus/lung/head and neck/others) were 6/6/7/2, and the median initial radiotherapy dose was 60 Gy2 EQD2 (range: 50-105 Gy2, 60-70/ > 70 Gy2 were 11/4). Ten patients underwent surgery followed by SBRT and 11 SBRT alone. At the median follow-up time of 10.4 months, 17 patients died of systemic disease progression including one TRD. No radiation-induced myelopathy or nerve root injuries occurred. Local failure occurred in six patients, with a 1-year local failure rate of 29.3% and a 1-year OS of 55.0%. Other toxicities included five cases of vertebral compression fractures (23.8%) and one radiation pneumonitis. The cumulative esophageal dose was recommended as follows: Dmax < 203, D0.035 cc < 187, and D1cc < 167 (Gy3 in biological effective dose).

CONCLUSION

 Re-irradiation spine SBRT may be effective for selected patients with cervical or thoracic MESCC, even with high-dose irradiation histories. The cumulative dose assessment across the original and re-irradiated esophagus was recommended to decrease the risk of severe esophageal toxicities.

Does Timing of Radiation Therapy Impact Wound Healing in Patients Undergoing Metastatic Spine Surgery?

INTRODUCTION

The impact of radiation on wound healing after metastatic spine surgery remains an active area of research. In patients undergoing metastatic spine surgery, we sought to (1) assess the relationship between preoperative and/or postoperative radiation on wound complications, and (2) evaluate the relationship between the timing of postoperative radiation and wound complications.

METHODS

A single-center, retrospective, cohort study of patients undergoing metastatic spine surgery was conducted from 2010 to 2021. The primary exposure variable was the use/timing of radiation. Radiation included both external beam radiotherapy (EBRT) and stereotactic body radiotherapy (SBRT). Patients were trichotomized into the following groups: (1) preoperative radiation only, (2) postoperative radiation only, and (3) no radiation. The primary outcome variable was wound complications, which was defined as dehiscence requiring reoperation, infection requiring antibiotics, or infection requiring surgical debridement. Multivariable logistic/linear regression controlled for age, tumor size, primary organ of origin, and the presence of other organ metastases.

RESULTS

A total of 207 patients underwent surgery for extradural spinal metastasis. Participants were divided into three groups: preoperative RT only (N = 29), postoperative RT only (N = 91), and no RT (N = 178). Patients who received postoperative RT only and no RT were significantly older than patients who received preoperative RT only (p = 0.009) and were less likely to be white (p < 0.001). No other significant differences were found in basic demographics, tumor characteristics, or intraoperative variables. Wound-related complications occurred in two (6.9%) patients with preoperative RT only, four patients (4.4%) in postoperative RT only, and 11 (6.2%) patients with no RT, with no significant difference among the three groups (p = 0.802). No significant difference was found in wound-related complications, reoperation, and time to wound complications between patients with preoperative RT only and no RT, and between postoperative RT only and no RT (p > 0.05). Among the postoperative-RT-only group, no difference in wound complications was seen between those receiving SBRT (5.6%) and EBRT (4.1%) (p > 0.999). However, patients who received preoperative RT only had a longer time to wound complications in comparison to those who received postoperative RT only (43.5 ± 6.3 vs. 19.7 ± 3.8, p = 0.004). Regarding timing of postoperative RT, the mean (SD) time to RT was 28.7 ± 10.0 days, with a median of 28.7 (21-38) days. No significant difference was found in time to postoperative RT between patients with and without wound complications (32.9 ± 12.3 vs. 29.0 ± 9.7 days, p = 0.391).

CONCLUSION

In patients undergoing metastatic spine surgery, a history of previous RT or postoperative RT did not significantly affect wound complications. However, those with previous RT prior to surgery had a longer time to wound complications than patients undergoing postoperative RT only. Moreover, timing of RT had no impact on wound complications, indicating that earlier radiation may be safely employed to optimize tumor control without fear of compromising wound healing.

An Update on the Management of Bone Metastases

PURPOSE OF REVIEW

Increasing life expectancy among patients with advanced cancer has placed a greater emphasis on optimizing pain control and quality of life. Concurrently, significant advancements in radiotherapy for bone metastases have permitted for dose escalation strategies such as stereotactic radiotherapy. This review aims to provide updated information on the management of bone metastases in light of these developments.

RECENT FINDINGS

We reviewed recent studies regarding the role and details of external beam radiotherapy for bone metastases, with emphasis on differences by treatment site as well as intention (palliative versus ablative for oligometastases). Conventional palliative radiotherapy remains a mainstay of management. While stereotactic radiotherapy may augment durability of pain relief and even survival time, there are significant questions remaining regarding optimal dosing and patient selection. Radiotherapy for bone metastases continues to evolve, particularly with increasing use of stereotactic radiotherapy. Future studies are needed to clarify optimal dose, fractionation, modality, and patient selection criteria among different radiotherapy approaches.

Emergency radiation therapy in modern-day practice: Now or never, or never again ?

Radiation therapy plays a fundamental role in oncological emergencies such as superior vena cava syndrome (SVCS) and metastatic epidural spinal cord compression (MESCC). These are two examples of critical complications of metastatic cancer in terms of pain and functional impact (respiratory and/or neurological). The aim of this review is to explore the current indications, treatment options and outcomes for emergency radiotherapy regarding to these complications.Regarding SVCS, studies are mostly retrospective and unanimously demonstrated a beneficial effect of radiotherapy on symptom relief. Spinal cord compression remains an indication for urgent radiotherapy, and should be combined with surgery when possible. The innovative stereotactic body radiotherapy (SBRT) showed promising results, however this technique requires small volumes and more time preparation and therefore is often unsuitable for SVCS and MESCC emergencies.This review concluded that radiotherapy has a central role to play within a multimodal approach for SVCS and MESCC treatment. Further prospective studies are needed to confirm the effectiveness of radiation and establish the criteria for selecting patients to benefit from this treatment option.

Oncologic and Functional Outcomes After Stereotactic Body Radiation Therapy for High-Grade Malignant Spinal Cord Compression

Purpose

Although surgical decompression is the gold standard for metastatic epidural spinal cord compression (MESCC) from solid tumors, not all patients are candidates or undergo successful surgical Bilsky downgrading. We report oncologic and functional outcomes for patients treated with stereotactic body radiation therapy (SBRT) to high-grade MESCC.

Methods and Materials

Patients with Bilsky grade 2 to 3 MESCC from solid tumor metastases treated with SBRT at a single institution from 2009 to 2020 were retrospectively reviewed. Patients who received upfront surgery before SBRT were included only if postsurgical Bilsky grade remained ≥2. Neurologic examinations, magnetic resonance imaging, pain assessments, and analgesic usage were assessed every 3 to 4 months post-SBRT. Cumulative incidence of local recurrence was calculated with death as a competing risk, and overall survival was estimated by Kaplan-Meier.

Results

One hundred forty-three patients were included. The cumulative incidence of local recurrence was 5.1%, 7.5%, and 14.1% at 6, 12, and 24 months, respectively. At first post-SBRT imaging, 16.2% of patients with initial Bilsky grade 2 improved to grade 1, and 53.8% of patients were stable. Five of 13 patients (38.4%) with initial Bilsky grade 3 improved to grade 1 to 2. Pain response at 3 and 6 months post-SBRT was complete in 45.4% and 55.7%, partial in 26.9% and 13.1%, stable in 24.1% and 27.9%, and worse in 3.7% and 3.3% of patients, respectively. At 3 and 6 months after SBRT, 17.8% and 25.0% of patients had improved ambulatory status and 79.7% and 72.4% had stable status.

Conclusions

We report the largest series to date of patients with high-grade MESCC treated with SBRT. The excellent local control and functional outcomes suggest SBRT is a reasonable approach in inoperable patients or cases unable to be successfully surgically downgraded.

Preoperative assessment and surgical indications: Separation surgery

Neurological compression occurs in 10%-20% of patients who develop spinal metastases. In the last decade, the evolution of oncological diagnostic and medical techniques, the change from conventional external radiation to radiosurgery and the new surgical instruments have meant that the treatment of these patients must be indicated in a personalized manner and by consensus, multidisciplinary way, in specific commissions. Today, the biological state of the patient, the presence of mechanical instability, the neurological assessment and degree of epidural compression, as well as the best prognostic categorization of the tumor, are established as decision factors prior to the indication of surgical treatment, treatment that has passed from a cytoreductive concept to that of a spinal cord release from tumor in order to ensure safe radiosurgery.

[Translated article] Preoperative assessment and surgical indications: Separation surgery

Neurological compression occurs in 10%-20% of patients who develop spinal metastases. In the last decade, the evolution of oncological diagnostic and medical techniques, the change from conventional external radiation to radiosurgery and the new surgical instruments have meant that the treatment of these patients must be indicated in a personalized manner and by consensus, multidisciplinary way, in specific commissions. Today, the biological state of the patient, the presence of mechanical instability, the neurological assessment and degree of epidural compression, as well as the best prognostic categorization of the tumor, are established as decision factors prior to the indication of surgical treatment, treatment that has passed from a cytoreductive concept to that of a spinal cord release from tumor in order to ensure safe radiosurgery.

Impact of Postoperative Stereotactic Body Radiation Therapy on Survival of Patients with Spinal Metastases in the Context of Additional Systemic Adjuvant Therapy

BACKGROUND

Stereotactic body radiotherapy (SBRT) has been established as a safe and effective treatment modality for control of long-term pain and tumor growth. However, few studies have investigated the efficacy of postoperative SBRT versus conventional external beam radiation therapy (EBRT) in extending survival within the context of systemic therapy.

METHODS

A retrospective chart review of patients who underwent surgery for spinal metastasis at our institution was conducted. Demographic, treatment, and outcome data were collected. SBRT was compared with EBRT and non-SBRT, and analyses were stratified by whether patients received systemic therapy. Survival analysis was conducted using propensity score matching.

RESULTS

Bivariate analysis in the nonsystemic therapy group revealed longer survival with SBRT compared with EBRT and non-SBRT. Further analysis also showed that primary cancer type and preoperative mRS significantly affected survival. Within patients who received systemic therapy, overall median survival for patients receiving SBRT was 22.7 months (95% confidence interval [CI] 12.1-52.3) versus 16.1 months (95% CI 12.7-44.0; P = 0.28) for patients who received EBRT and 16.1 months (95% CI: 12.2-21.9; P = 0.07) for patients without SBRT. Within patients who did not receive systemic therapy, overall median survival for patients with SBRT was 62.1 months (95% CI 18.1-unknown) versus 5.3 months (95% CI 2.8-unknown; P = 0.08) for patients with EBRT and 6.9 months (95% CI 5.0-45.6; P = 0.02) for patients without SBRT.

CONCLUSIONS

In patients who do not receive systemic therapy, treatment with postoperative SBRT may increase survival time compared with patients not receiving SBRT.

Dosimetric analysis on computed tomography myelography based treatment planning in stereotactic body radiotherapy for spinal metastases

This study aimed to quantitatively evaluate the influence of enhanced contrast on the CT myelography image of the spinal cord and/or cauda equina in addition to the target volume in spine SBRT treatment planning. In total, 19 patients who had previously undergone spine SBRT were randomly selected. The rigid image registration accuracy of CT myelography that aligned with the treatment planning CT was evaluated by calculating the normalized mutual information (NMI) and Pearson's correlation coefficient for the vertebral landmarks. At postregistration, the contrast-enhanced region of the CT myelography image was replaced with water-mass density, and the original treatment plan was recalculated on this image. For comparison, the dose was also recalculated on the contrast-enhanced CT myelography images. The NMI and Pearson's correlation coefficients for landmarks were 0.39 ± 0.12 and 0.97 ± 0.04, respectively. The mean D_0.035cc of the spinal cord and/or cauda equina on the CT myelography image with the contrast-enhanced region replaced by water-mass density showed -0.37% ± 0.64% changes compared with that of the treatment planning CT. Conversely, the mean D_0.035cc in contrast-enhanced CT myelography changed by -1.39% ± 0.51%. The percentage change in D_98% for the planning target volume was confirmed to be small by replacing the contrast-enhanced region with water-mass density (p < 0.01). The dose calculation of the target volume, spinal cord, and/or cauda equina using the CT myelography image that replaced the contrast-enhanced region with water-mass density could be a more appropriate procedure with less dose calculation uncertainty.

Stereotactic Body Radiation Therapy for Spinal Metastases: Benefits and Limitations

Progress in biological cancer characterization, targeted systemic therapies and multimodality treatment strategies have shifted the goals of radiotherapy for spinal metastases from short-term palliation to long-term symptom control and prevention of compilations. This article gives an overview of the spine stereotactic body radiotherapy (SBRT) methodology and clinical results of SBRT in cancer patients with painful vertebral metastases, metastatic spinal cord compression, oligometastatic disease and in a reirradiation situation. Outcomes after dose-intensified SBRT are compared with results of conventional radiotherapy and patient selection criteria will be discussed. Though rates of severe toxicity after spinal SBRT are low, strategies to minimize the risk of vertebral compression fracture, radiation induced myelopathy, plexopathy and myositis are summarized, to optimize the use of SBRT in multidisciplinary management of vertebral metastases.

Case report: L5 tomita En bloc spondylectomy for oligometastatic liposarcoma with post adjuvant stereotactic ablative radiotherapy

Introduction

Tomita En-bloc spondylectomy of L5 is one of the most challenging techniques in radical oncological spine surgery. A 42-year-old female was referred with lower back pain and L5 radiculopathy with a background of right shoulder liposarcoma excision. CT-PET confirmed a solitary L5 oligometastasis. MRI showed thecal sac indentation hence wasn't suitable for Stereotactic Ablative Radiotherapy (SABR) alone. The seeding nature of sarcoma prevents the indication of separation surgery hence excisional surgery is considered for radical curative treatment. This case report demonstrates dual-staged modified TES including the utilisation of novel techniques to allow for maximum radical oncological control in the era of SABR and lesser invasive surgery.

Methods

First-stage: Carbonfibre pedicle screws planned from L2 to S2AI-Pelvis, aligned, to her patient-specific rods. Radiofrequency ablation of L5 pedicles prior to osteotomy was performed to prevent sarcoma cell seeding. Microscope-assisted thecal sac tumour separation and L5 nerve root dissection was performed. Novel surgical navigation of the ultrasonic bone-cutter assisted inferior L4 and superior S1 endplate osteotomies. Second-stage: Vascular-assisted retroperitoneal approach at L4–S1 was undertaken protecting the great vessels. Completion of osteotomies at L4 and S1 to En-bloc L5: (L4 inferior endplate, L4/5 disc, L5 body, L5/S1 disc and S1 superior endplate). Anterior reconstruction used an expandable PEEK cage obviating the need for a third posterior stage. Reinforced with a patient-specific carbon plate L4–S1 promontory.

Results

Patient rehabilitated well and was discharged after 42 days. Cyberknife of 30Gy in 5 fractions was delivered two months post-op. Despite left foot drop, she's walking independently 9 months post-op.

Conclusion

These are challenging cases require a truly multi-disciplinary team approach. We share this technique for a dual stage TES and metal-free construct with post adjuvant SABR to achieve maximum local control in spinal oligometastatic disease. This case promotes our modified TES technique in the era of SABR and separation surgery in carefully selected cases.

Clinical evaluation of vertebral body replacement of carbon fiber-reinforced polyetheretherketone in patients with tumor manifestation of the thoracic and lumbar spine

PURPOSE

Radiolucent anterior and posterior implants by carbon fiber-reinforced polyetheretherketone (CFR PEEK) aim to improve treatment of primary and secondary tumors of the spine during the last years. The aim of this study was to evaluate clinical and radiological outcomes after dorsoventral instrumentation using a CFR PEEK implant in a cohort of patients representing clinical reality.

METHODS

A total of 25 patients with tumor manifestation of the thoracic and lumbar spine underwent vertebral body replacement (VBR) using an expandable CFR PEEK implant between January 2021 and January 2022. Patient outcome, complications, and radiographic follow-up were analyzed.

RESULTS

A consecutive series aged 65.8 ± 14.7 (27.6-91.2) years were treated at 37 vertebrae of tumor manifestation, including two cases (8.0%) of primary tumor as well as 23 cases (92.0%) of spinal metastases. Overall, 26 cages covering a median of 1 level (1-4) were implanted. Duration of surgery was 134 ± 104 (65-576) min, with a blood loss of 792 ± 785 (100-4000) ml. No intraoperative cage revision was required. Surgical complications were reported in three (12.0%) cases including hemothorax in two cases (one intraoperative, one postoperative) and atrophic wound healing disorder in one case. In two cases (8.0%), revision surgery was performed (fracture of the adjacent tumorous vertebrae, progressive construct failure regarding cage subsidence). No implant failure was observed.

CONCLUSION

VBR using CFR PEEK cages represents a legitimate surgical strategy which opens a variety of improvements-especially in patients in need of postoperative radiotherapy of the spine and MRI-based follow-up examinations.

Implementation of triggered kilovoltage imaging for stereotactic radiotherapy of the spine for patients with spinal fixation hardware

Background and purpose

Mitigation of intrafraction motion (IM) is valuable in stereotactic radiotherapy (SRT) radiotherapy where submillimeter accuracy is desired. The purpose of this study was to investigate the application of triggered kilovoltage (kV) imaging for spine SRT patients with hardware by correlating kV imaging with patient motion and summarizing implications of tolerance for IM based on calculated dose.

Materials and methods

Ten plans (33 fractions) were studied, correlating kV imaging during treatment with pre- and post-treatment cone beam computed tomography (CBCT). Images were taken at 20-degree gantry angle intervals during the arc-based treatment. The contour of the hardware with a 1 mm expansion was displayed at the treatment console to manually pause treatment delivery if the hardware was visually detected outside the contour. The treatment CBCTs were compared using retrospective image registration to assess the validity of contour-based method for pausing treatment. Finally, plans were generated to estimate dose volume objective differences in case of 1 mm deviation.

Results

When kV imaging during treatment was used with the 1 mm contour, 100 % of the post-treatment CBCTs reported consistent results. One patient in the cohort exhibited motion greater than 1 mm during treatment which allowed intervention and re-setup during treatment. The average translational motion was 0.35 mm. Treatment plan comparison at 1 mm deviation showed little differences in calculated dose for the target and cord.

Conclusions

Utilizing kV imaging during treatment is an effective method of assessing IM for SRT spine patients with hardware without increasing treatment time.

Radiation myelopathy following stereotactic body radiation therapy for spine metastases

PURPOSE

Stereotactic body radiation therapy (SBRT) is now considered a standard of care treatment option in the management of spine metastases. One of the most feared complications of spine SBRT is radiation myelopathy (RM).

METHODS

We provided a narrative review of RM following spine SBRT based on review of the published literature, including data on spinal cord dose constraints associated with the risk of RM, strategies to mitigate the risk, and management options for RM.

RESULTS

There are limited published data of cases of RM following spine SBRT with detailed spinal cord dosimetry. The HyTEC report provided recommendations for the point maximal dose (Dmax) for the spinal cord that is associated with a < 5% risk of RM for 1-5 fractions spine SBRT. In the setting of spine SBRT reirradiation after previous conventional external beam radiation therapy (cEBRT), factors associated with RM are: SBRT spinal cord Dmax, cumulative spinal cord Dmax, and the time interval between previous RT and SBRT reirradiation. There are various strategies to mitigate the risk of RM, including accurate delineation of the spinal cord (or thecal sac), strict adherence to the recommended spinal cord dose constraints, and robust treatment immobilisation set-up and delivery. Limited effective treatment options are available for patients who develop RM, and these include corticosteroids, hyperbaric oxygen, and bevacizumab; however, none have been supported by high quality evidence.

CONCLUSION

RM is a rare but devastating complication following SBRT for spine metastases. There are strategies to minimise the risk of RM to ensure safe delivery of spine SBRT.

A Multimodal Clinical Approach for the Treatment of Bone Metastases in Solid Tumors

Context

Bone metastasis (BM) is a frequent complication of cancer, representing the third most common site of secondary spread in solid cancers behind the lung and liver. Bone metastasis is found in up to 90% of prostate and breast cancer patients. They can cause significant complications, such as pathological fractures and paralysis of the spine, which decrease daily functioning and quality of life (QoL) and worsen prognosis. The growing life expectancy of cancer patients due to improvements in systemic therapies may further increase BM's eventuality and clinical burden in cancer patients.

Evidence Acquisition

Four physicians from five different specialties were interviewed and resumed the most relevant literature of the last 20 years focusing on pain treatment in BM patients.

Results

Treatment for BM ideally involves various types of specialists and assessments. The disease status and patient background should be considered, requiring holistic care and expertise from various medical specialties.

Conclusions

Interventional, nuclear medicine, radiotherapy, and mini-invasive techniques can be safe and effective for relieving pain and modifying health-related QoL in BM patients.

Intramedullary Spinal Cord Metastases from Differentiated Thyroid Cancer, a Case Report

Intramedullary spinal cord metastases (ISCM) are uncommon metastases of the spinal cord. Magnetic resonance (MR) plays an important role in surgical planning when ISCM is suspected in the differential diagnosis. The incidence of ISCM is expected to increase due to the longer survival of cancer patients as well as the widespread use of MR in the diagnosis of neurological syndromes. The management of these patients is controversial because of the multiple clinical presentations and lack of controlled studies on the efficacy of different therapeutic approaches. Increased awareness of this rare entity may lead to an earlier diagnosis with novel imaging approaches at a stage when neurological deficits are reversible. A case of ISCM in a 49-year-old patient with differentiated thyroid cancer is reported.

Hybrid Therapy Versus Total En Bloc Spondyectomy in the Treatment of Solitary Radioresistant Spinal Metastases: A Single-center, Retrospective Study

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

To compare the treatment efficacy of hybrid therapy (HT) with that of total en bloc spondylectomy (TES) in patients with solitary radioresistant high-grade epidural spinal cord compression (ESCC) spinal metastases.

SUMMARY OF BACKGROUND DATA

Both HT and TES can yield good results for solitary radioresistant metastatic spinal tumors with high-grade ESCC. However, there is still a lack of comparative studies on the treatment efficacy of these 2 methods.

MATERIALS AND METHODS

We retrospectively reviewed patients with the above-mentioned tumors between January 2012 and May 2019. A total of 157 patients underwent surgery, 64 of whom received HT and 93 were treated with TES. Propensity score matching (1:1 ratio) allowed the generation of best-matched pairs for the 2 categories. Local control rates and survival rates were estimated using the Kaplan-Meier method.

RESULTS

All patients had a minimum 2-year follow-up. The longest follow-up period was 88 months. The survival rates and local progression-free survival rates after HT were comparable with those after TES at 1 year (84.6% vs. 83.1% and 90.2% vs. 90%, respectively), 2 years (60.8% vs. 64.3% and 64.1% vs. 62.1%, respectively), and 5 years (18.8% vs. 24.1% and 24.4% vs. 28.4%, respectively). There were no significant differences in pain control, improvement in neurological status, spine stabilization restoration, incidence of perioperative complications, and improvement in quality of life between the groups. However, HT showed more advantages than TES in that it had a shorter operative time and lower intraoperative blood loss.

CONCLUSIONS

HT can obtain satisfactory results comparable to TES for solitary radioresistant metastatic spinal tumors with high-grade ESCC. In addition, HT has a shorter operative time and fewer perioperative complications than TES. HT may be a promising treatment for solitary radioresistant metastatic spinal tumors with high-grade ESCC.

Feasibility of postoperative spine stereotactic body radiation therapy in proximity of carbon and titanium hybrid implants using a robotic radiotherapy device

Background and purpose

To assess the feasibility of postoperative stereotactic body radiation therapy (SBRT) for patients with hybrid implants consisting of carbon fiber reinforced polyetheretherketone and titanium (CFP-T) using CyberKnife.

Materials and methods

All essential steps within a radiation therapy (RT) workflow were evaluated. First, the contouring process of target volumes and organs at risk (OAR) was done for patients with CFP-T implants. Second, after RT-planning, the accuracy of the calculated dose distributions was tested in a slab phantom and an anthropomorphic phantom using film dosimetry. As a third step, the accuracy of the mandatory image guided radiation therapy (IGRT) including automatic matching was assessed using the anthropomorphic phantom. For this goal, a standard quality assurance (QA) test was modified to carry out its IGRT part in presence of CFP-T implants.

Results

Using CFP-T implants, target volumes could precisely delineated. There was no need for compromising the contours to overcome artifact obstacles. Differences between measured and calculated dose values were below 11% for the slab phantom, and at least 95% of the voxels were within 5% dose difference. The comparisons for the anthropomorphic phantom showed a gamma-passing rate (5%, 1 mm) of at least 97%. Additionally the test results with and without CFP-T implants were comparable. No issues concerning the IGRT were detected. The modified machine QA test resulted in a targeting error of 0.71 mm, which corresponds to the results of the unmodified standard tests.

Conclusion

Dose calculation and delivery of postoperative spine SBRT is feasible in proximity of CFP-T implants using a CyberKnife system.

Radiosurgery for benign vertebral body hemangiomas of the spine: a systematic review and meta-analysis

INTRODUCTION

Spinal vertebral hemangiomas (SVH) are the most common benign tumors of the spine. Here, we performed a systematic review and meta-analysis of radiosurgery (RS) for SVH.

METHODS

We reviewed manuscripts published between January 1990 and December 2020 on PubMed. Tumor control, pain relief and damage to surrounding tissues were evaluated with separate meta-analyses. This study was performed in accordance with the published Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Twenty-three patients with 24 SVH were reported in 3 studies.

RESULTS

The follow-up ranged from 7.3 months to 84 months. A vast majority of lesions were located at dorsal level (n= 18, 75%). Twenty (83.3%) clinically presented with pain at initial discovery. Complete, partial and stable response after radiations were described in 45.7% (p< 0.001), 23.6% (p= 0.02) and 37.2% (p= 0.7) of the cases. Overall response was described in 94.1% (p= 0.7). No progressive disease was reported. Pain relief was achieved in 87.5% of patients (p= 0.2). Damage to surrounding tissue caused by irradiation was described in 22.3% (p= 0.02) of cases in only one study, in which there were delivered higher doses of radiation.

CONCLUSIONS

Radiosurgery is safe and effective for SVH. Pain relief in symptomatic patients is extremely high, while local control showed no progressive disease. Damage to surrounding tissues was reported in only one series and included osteitis, osteonecrosis or soft tissue injury after higher radiation doses.

Evolution of surgical treatment of metastatic spine tumors

PURPOSE

The treatment of cancer has transformed over the past 40 years, with medical oncologists, radiation oncologists and surgeons working together to prolong survival times and minimize treatment related morbidity. With each advancement, the risk-benefit scale has been calibrated to provide an accurate assessment of surgical hazard. The goal of this review is to look back at how the role of surgery has evolved with each new medical advance, and to explore the role of surgeons in the future of cancer care.

METHODS

A literature review was conducted, highlighting the key papers guiding surgical management of spinal metastatic lesions.

CONCLUSION

The roles of surgery, medical therapy, and radiation have evolved over the past 40 years, with new advances requiring complex multidisciplinary care.

Fully automated rigid image registration versus human registration in postoperative spine stereotactic body radiation therapy: a multicenter non-inferiority study

To confirm the fully automated rigid image registration (A-RIR) accuracy in postoperative spine stereotactic body radiation therapy (SBRT), we conducted a multicenter non-inferiority study compared to the human rigid image registration (H-RIR). Twenty-eight metastatic cancer patients who underwent postoperative spine SBRT are enrolled-image registration (IR) of planning computed tomography (CT) and CT-myelogram for delineating the spinal cord. The adopted A-RIR workflow is a contour-focused algorithm performing a rigid registration by maximizing normalized mutual information (NMI) restricted to the data contained within the automatically extracted contour. Three radiation oncologists (ROs) from multicenters were prompted to review two blinded registrations and choose one for clinical use. Indistinguishable cases were allowed to vote equivalent, counted A-RIR side. A-RIR is considered non-inferior to H-RIR if the lower limit of the 95% confidence interval (CI) of A-RIR preferable/equivalent is greater than 0.45. We also evaluated the NMI improvement from the baseline and the translational/rotational errors between A-RIR and H-RIR. The A-RIR preferable/equivalent was selected in 21 patients (0.75, 95% CI: 0.55-0.89), demonstrating non-inferiority to H-RIR. The A-RIR's NMI improvement was greater than H-RIR in 24 patients: the mean value ± SD was 0.225 ± 0.115 in A-RIR and 0.196 ± 0.114 in H-RIR (P < 0.001). The absolute translational error was 0.38 ± 0.31 mm. The rotational error was -0.03 ± 0.20, 0.05 ± 0.19, -0.04 ± 0.20 degrees in axial, coronal, and sagittal planes (range: -0.66-0.52). In conclusion, A-RIR shows non-inferior to H-RIR in CT and CT-myelogram registration for postoperative spine SBRT planning.

Predictive factors, preventive implications, and personalized surgical strategies for bone metastasis from lung cancer: population-based approach with a comprehensive cancer center-based study

Background

Bone metastasis (BM) and skeletal-related events (SREs) happen to advanced lung cancer (LC) patients without warning. LC-BM patients are often passive to BM diagnosis and surgical treatment. It is necessary to guide the diagnosis and treatment paradigm for LC-BM patients from reactive medicine toward predictive, preventive, and personalized medicine (PPPM) step by step.

Methods

Two independent study cohorts including LC-BM patients were analyzed, including the Surveillance, Epidemiology, and End Results (SEER) cohort (n = 203942) and the prospective Fudan University Shanghai Cancer Center (FUSCC) cohort (n = 59). The epidemiological trends of BM in LC patients were depicted. Risk factors for BM were identified using a multivariable logistic regression model. An individualized nomogram was developed for BM risk stratification. Personalized surgical strategies and perioperative care were described for FUSCC cohort.

Results

The BM incidence rate in LC patients grew (from 17.53% in 2010 to 19.05% in 2016). Liver metastasis was a significant risk factor for BM (OR = 4.53, 95% CI = 4.38-4.69) and poor prognosis (HR = 1.29, 95% CI = 1.25-1.32). The individualized nomogram exhibited good predictive performance for BM risk stratification (AUC = 0.784, 95%CI = 0.781-0.786). Younger patients, males, patients with high invasive LC, and patients with other distant site metastases should be prioritized for BM prevention. Spine is the most common site of BM, causing back pain (91.5%), pathological vertebral fracture (27.1%), and difficult walking (25.4%). Spinal surgery with personalized spinal reconstruction significantly relieved pain and improved daily activities. Perioperative inflammation, immune, and nutrition abnormities warrant personalized managements. Radiotherapy needs to be recommended for specific postoperative individuals.

Conclusions

The presence of liver metastasis is a strong predictor of LC-BM. It is recommended to take proactive measures to prevent BM and its SREs, particularly in young patients, males, high invasive LC, and LC with liver metastasis. BM surgery and perioperative management are personalized and required. In addition, adjuvant radiation following separation surgery must also be included in PPPM-guided management.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-022-00270-9.

Focused versus conventional radiotherapy in spinal oncology: is there any difference in fusion rates and pseudoarthrosis?

INTRODUCTION

Radiotherapy is considered standard of care for adjuvant peri-operative treatment of many spinal tumors, including those with instrumented fusion. Unfortunately, radiation treatment has been linked to increased risk of pseudoarthrosis. Newer focused radiotherapy strategies with enhanced conformality could offer improved fusion rates for these patients, but this has not been confirmed.

METHODS

We performed a retrospective analysis of patients at three tertiary care academic institutions with primary and secondary spinal malignancies that underwent resection, instrumented fusion, and peri-operative radiotherapy. Two board certified neuro-radiologists used the Lenke fusion score to grade fusion status at 6 and 12-months after surgery. Secondary outcomes included clinical pseudoarthrosis, wound complications, the effect of radiation timing and radiobiological dose delivered, the use of photons versus protons, tumor type, tumor location, and use of autograft on fusion outcomes.

RESULTS

After review of 1252 spinal tumor patients, there were 60 patients with at least 6 months follow-up that were included in our analyses. Twenty-five of these patients received focused radiotherapy, 20 patients received conventional radiotherapy, and 15 patients were treated with protons. There was no significant difference between the groups for covariates such as smoking status, obesity, diabetes, intraoperative use of autograft, and use of peri-operative chemotherapy. There was a significantly higher rate of fusion for patients treated with focused radiotherapy compared to those treated with conventional radiotherapy at 6-months (64.0% versus 30.0%, Odds ratio: 4.15, p = 0.036) and 12-months (80.0% versus 42.1%, OR: 5.50, p = 0.022). There was a significantly higher rate of clinical pseudoarthrosis in the conventional radiotherapy cohort compared to patients in the focused radiotherapy cohort (19.1% versus 0%, p = 0.037). There was no difference in fusion outcomes for any of the secondary outcomes except for use of autograft. The use of intra-operative autograft was associated with an improved fusion at 12-months (66.7% versus 37.5%, OR: 3.33, p = 0.043).

CONCLUSION

Focused radiotherapy may be associated with an improved rate of fusion and clinical pseudoarthrosis when compared to conventional radiation delivery strategies in patients with spinal tumors. Use of autograft at the time of surgery may be associated with improved 12-month fusion rates. Further large-scale prospective and randomized controlled studies are needed to better stratify the effects of radiation delivery modality in these patients.

Radiotherapy of bone metastases

We present the update of the recommendations of the French society of oncological radiotherapy on bone metastases. This is a common treatment in the management of patients with cancer. It is a relatively simple treatment with proven efficacy in reducing pain or managing spinal cord compression. More complex treatments by stereotaxis can be proposed for oligometastatic patients or in case of reirradiation. In this context, increased vigilance should be given to the risks to the spinal cord.

Hybrid Therapy for Metastatic Disease

Metastatic spine disease represents a complex clinical entity, requiring a multidisciplinary treatment team to formulate treatment plans that treat disease, palliate symptoms, and give patients the greatest quality-of-life. With the improvement in focused radiation technologies, the role of surgery has changed from a standalone treatment to an adjuvant supporting other treatment modalities. As patients within this population are often exceptionally frail, there has been increased emphasis on the smallest possible surgery to achieve the team's treatment goals. Surgeons have increasingly turned to more minimally invasive techniques for treating spinal metastases. The use of these procedures, called separation surgery, centers around the goal of decompressing the neural elements, creating or maintaining mechanical stability, and allowing enough room for high-dose radiation to minimize cord dose.

[Stereotactic body radiation therapy for spine bone oligometastatic disease]

Stereotactic radiotherapy is an ever more common technique, regardless of the location treated. However, spinal stereotactic radiotherapy requires a particular technicality in order to ensure its proper realization. There is now a large literature defining the type of imaging to be used, the dose to be delivered and the delineation of target volumes. This technique can achieve a significant local control and an interesting analgesic efficiency. However, its place in relation to conventional radiotherapy remains limited because it requires MRI imaging and a significantly longer patient management during the treatment fraction. In this context, it is currently mainly restricted to oligometastatic patients or for re-irradiations.

Recent advances and new discoveries in the pipeline of the treatment of primary spinal tumors and spinal metastases: A scoping review

The field of spinal oncology has substantially evolved over the past decades. This review synthesizes and appraises what was learned and what will potentially be discovered from the recently completed and ongoing clinical studies related to the treatment of primary and secondary spinal neoplasms. This scoping review included all clinical studies on the treatment of spinal neoplasms registered in the ClinicalTrials.gov website from February/2000 to December/2020. The terms "spinal cord tumor", "spinal metastasis", and "metastatic spinal cord compression" were used. Of the 174 registered clinical studies on primary spinal tumors and spinal metastasis, most of the clinical studies registered in this American registry were interventional studies led by single institutions in North America (n=101), Europe (n=43), Asia (n=24) or other continents (n=6). The registered clinical studies mainly focused on treatment strategies for spinal neoplasms (90.2%) that included investigating stereotactic radiosurgery (n=33), radiotherapy (n=21), chemotherapy (n=20), and surgical technique (n=11). Of the 69 completed studies, the results from 44 studies were published in the literature. In conclusion, this review highlights the key features of the 174 clinical studies on spinal neoplasms that were registered from 2000 to 2020. Clinical trials were heavily skewed towards the metastatic population as opposed to the primary tumours which likely reflects the rarity of the latter condition and associated challenges in undertaking prospective clinical studies in this population. This review serves to emphasize the need for a focused approach to enhancing translational research in spinal neoplasms with a particular emphasis on primary tumors.

International Multi-institutional Patterns of Contouring Practice and Clinical Target Volume Recommendations for Stereotactic Body Radiation Therapy for Non-Spine Bone Metastases

PURPOSE

Despite the increasing use of stereotactic body radiation therapy for non-spine bone metastases (NSBM), there is no established standard for target delineation. The objective of this study was to provide consensus recommendations on clinical target volume (CTV) delineation based on international expert contours.

METHODS AND MATERIALS

Eleven cases of NSBM were contoured by 9 international radiation oncologists. For each case, the gross tumor volume was provided on the simulation computed tomography scans with accompanying magnetic resonance imaging. Participants contoured the CTV and completed a clinical survey. Agreement between CTV contours were analyzed with simultaneous truth and performance level estimation using the kappa coefficient and the Dice similarity coefficient (DSC) and summarized to establish contouring recommendations. A direction-dependent analysis was applied to the consensus contours to quantify margins.

RESULTS

All CTV contours were completed. Six participants used a single-dose level, whereas 3 used a 2-dose level simultaneous integrated boost (SIB) technique. For the SIB cases, the largest volume receiving a stereotactic body radiation therapy (SBRT) dose was used for contour analysis. There was substantial agreement between contours across cases with a mean kappa of 0.72 (mean sensitivity 0.85, mean specificity 0.97). The mean DSC value was 0.77 (range, 0.67-0.87). Consensus CTV contouring recommendations were (1) an intraosseous CTV margin of 5 to 10 mm should be strongly considered within contiguous bone; (2) an extraosseous margin of 5 to 10 mm should be strongly considered where there is soft tissue disease or cortical bone disruption; (3) CTVs should be manually cropped to respect anatomic barriers to spread (eg, peritoneal cavity, pleura, uninvolved joint space and cortical bone).

CONCLUSIONS

CTV contouring recommendations for NSBM-SBRT were established based on analysis of international expert consensus contours with a high level of agreement. These principles may provide guidance to treating physicians and inform future study until prospective clinical data can provide further refinement.

Spinal metastases 2021: a review of the current state of the art and future directions

Spinal metastases are an increasing societal health burden secondary to improvements in systemic therapy. Estimates indicate that 100,000 or more people have symptomatic spine metastases requiring management. While open surgery and external beam radiotherapy have been the pillars of treatment, there is growing interest in more minimally invasive technologies (eg separation surgery) and non-operative interventions (eg percutaneous cementoplasty, stereotactic radiosurgery). The great expansion of these alternatives to open surgery and the prevalence of adjuvant therapeutic options means that treatment decision making is now complex and reliant upon multidisciplinary collaboration. To help facilitate construction of care plans that meet patient goals and expectations, clinical decision aids and prognostic scores have been developed. These have been shown to have superior predictive value relative to more classic prediction models and may become an increasingly important aspect of the clinical practice of spinal oncology. Here we overview current therapeutic advances in the management of spine metastases and highlight emerging areas for research. Given the rapid advancements in surgical technologies and adjuvants, the field is likely to undergo further transformative changes in the coming decade.

Evaluation of inter- and intra-fraction 6D motion for stereotactic body radiation therapy of spinal metastases: influence of treatment time

Background

The objective of this study was to analyze the amplitude of translational and rotational movements occurring during stereotactic body radiotherapy (SBRT) of spinal metastases in two different positioning devices. The relevance of intra-fractional imaging and the influence of treatment time were evaluated.

Methods

Twenty patients were treated in the supine position either (1) on a body vacuum cushion with arms raised and resting on a clegecel or (2) on an integrated SBRT solution consisting of a SBRT table top, an Orfit™ AIO system, and a vacuum cushion. Alignments between the cone beam computed tomography (CBCT) and the planning computed tomography allowed corrections of inter- and intra-fraction positional shifts using a 6D table. The absolute values of the translational and rotational setup errors obtained for 329 CBCT were recorded. The translational 3D vector, the maximum angle, and the characteristic times of the treatment fractions were calculated.

Results

An improvement in the mean (SD) inter-fraction 3D vector (mm) from 7.8 (5.9) to 5.9 (3.8) was obtained by changing the fixation devices from (1) to (2) (p < 0.038). The maximum angles were less than 2° for a total of 87% for (1) and 96% for (2). The mean (SD) of the intra-fraction 3D vectors (mm) was lower for the new 1.1 (0.8) positioning fixation (2) compared to the old one (1) 1.7 (1.7) (p = 0.004). The angular corrections applied in the intra-fraction were on average very low (0.4°) and similar between the two systems. A strong correlation was found between the 3D displacement vector and the fraction time for (1) and (2) with regression coefficients of 0.408 (0.262–0.555, 95% CI) and 0.069 (0.010–0.128, 95% CI), respectively. An accuracy of 1 mm would require intra-fraction imaging every 5 min for both systems. If the expected accuracy was 2 mm, then only system (2) could avoid intra-fractional imaging.

Conclusions

This study allowed us to evaluate setup errors of two immobilization devices for spine SBRT. The association of inter- and intra-fraction imaging with 6D repositioning of a patient is inevitable. The correlation between treatment time and corrections to be applied encourages us to move toward imaging modalities which allow a reduction in fraction time.

Advances in radiotherapy in bone metastases in the context of new target therapies and ablative alternatives: A critical review

In patients with bone metastases (BM), radiotherapy (RT) is used to alleviate symptoms, reduce the risk of fracture, and improve quality of life (QoL). However, with the emergence of concepts like oligometastases, minimal invasive surgery, ablative therapies such as stereotactic ablative RT (SABR), radiosurgery (SRS), thermal ablation, and new systemic anticancer therapies, there have been a paradigm shift in the multidisciplinary approach to BM with the aim of preserving mobility and function survival. Despite guidelines on using single-dose RT in uncomplicated BM, its use remains relatively low. In uncomplicated BM, single-fraction RT produces similar overall and complete response rates to RT with multiple fractions, although it is associated with a higher retreatment rate of 20% versus 8%. Complicated BM can be characterised as the presence of impending or existing pathologic fracture, a major soft tissue component, existing spinal cord or cauda equina compression and neuropathic pain. The rate of complicated BM is around 35%. Unfortunately, there is a lack of prospective trials on RT in complicated BM and the best dose/fractionation regimen is not yet established. There are contradictory outcomes in studies reporting BM pain control rates and time to pain reduction when comparing SABR with Conventional RT. While some studies showed that SABR produces a faster reduction in pain and higher pain control rates than conventional RT, other studies did not show differences. Moreover, the local control rate for BM treated with SABR is higher than 80% in most studies, and the rate of grade 3 or 4 toxicity is very low. The use of SABR may be preferred in three circumstances: reirradiation, oligometastatic disease, and radioresistant tumours. Local ablative therapies like SABR can delay change or use of systemic therapy, preserve patients' Qol, and improve disease-free survival, progression-free survival and overall survival. Moreover, despite the potential benefit of SABR in oligometastatic disease, there is a need to establish the optial indication, RT dose fractionation, prognostic factors and optimal timing in combination with systemic therapies for SABR. This review evaluates the role of RT in BM considering these recent treatment advances. We consider the definition of complicated BM, use of single and multiple fractions RT for both complicated and uncomplicated BM, reirradiation, new treatment paradigms including local ablative treatments, oligometastatic disease, systemic therapy, physical activity and rehabilitation.

Implications of Radiotherapy Utilization in Korea from 2010 to 2019

BACKGROUND

This study was to assess the rate of radiotherapy (RT) utilization according to the modality in South Korea to identify the implications of contemporary RT patterns.

METHODS

We collected information from claims and reimbursement records of the National Health Insurance Service from 2010 to 2019. We classified the location of each institution as capital (Seoul, Incheon, and Gyeonggi-do) and non-capital areas.

RESULTS

The rate of RT utilization in total cancer patients nationwide was 24.5% in 2010, which consistently has increased to 36.1% in 2019 (annual increase estimate [AIE], 4.5%). There was an abrupt increase in patients receiving intensity-modulated RT (IMRT), with an AIE of 33.5%, and a steady decline in patients receiving three-dimensional conformal RT (3DCRT), with an AIE of -7.1%. The commonest RT modality was IMRT (44.5%), followed by 3DCRT and stereotactic RT (SRT) (37.2% and 13.5%) in 2019. An increasing trend of advanced RT (such as IMRT and SRT) utilization was observed regardless of the region, although the AIE in the capital areas was slightly higher than that in non-capital areas.

CONCLUSION

The utilization of overall RT application and especially of advanced modalities remarkably increased from 2010 to 2019. We also found gaps in their AIEs between capital and non-capital areas. We should ensure that advanced RT is accessible to all cancer patients across South Korea.

Dosimetric feasibility of hypofractionation for metastatic bone/bone marrow lesions from paediatric solid tumours

BACKGROUND AND PURPOSE

The aim of this study was to determine the feasibility of hypofractionated schedules for metastatic bone/bone marrow lesions in children and to investigate dosimetric differences to the healthy surrounding tissues compared to conventional schedules.

METHODS

27 paediatric patients (mean age, 7 years) with 50 metastatic bone/bone marrow lesions (n = 26 cranial, n = 24 extra-cranial) from solid primary tumours (neuroblastoma and sarcoma) were included. The PTV was a 2 mm expansion of the GTV. A prescription dose of 36 and 54 Gy EQD2_α/β=10 was used for neuroblastoma and sarcoma lesions, respectively. VMAT plans were optimized for each single lesion using different fractionation schedules: conventional (30/20 fractions, V_95% ≥ 99%, D_0.1cm³ ≤ 107%) and hypofractionated (15/10/5/3 fractions, V_100% ≥ 95%, D_0.1cm³ ≤ 120%)_. Relative EQD2 differences in OARs D_mean between the different schedules were compared.

RESULTS

PTV coverage was met for all plans independently of the fractionation schedule and for all lesions (V_95% range 95.5-100%, V_100% range 95.1-100%), with exception of the vertebrae (V_100% range 63.5-91.0%). For most OARs, relative mean reduction in the D_mean was seen for the hypofractionated plans compared to the conventional plans, with largest sparing in the 5 fractions (< 43%) followed by the 3 fractions schedule (< 40%). In case of PTV overlap with an OAR, a significant increase in dose for the OAR was observed with hypofractionation.

CONCLUSIONS

For the majority of the cases, iso-effective plans with hypofractionation were feasible with similar or less dose in the OARs. The most suitable fractionation schedule should be personalised depending on the spatial relationship between the PTV and OARs and the prescription dose.

Metastatic Spine Disease: Should Patients With Short Life Expectancy Be Denied Surgical Care? An International Retrospective Cohort Study

BACKGROUND

Despite our inability to accurately predict survival in many cancer patients, a life expectancy of at least 3 mo is historically necessary to be considered for surgical treatment of spinal metastases.

OBJECTIVE

To compare health-related quality of life (HRQOL) in patients surviving <3 mo after surgical treatment to patients surviving >3 mo to assess the validity of this inclusion criteria.

METHODS

Patients who underwent surgery for spinal metastases between August 2013 and May 2017 were retrospectively identified from an international cohort study. HRQOL was evaluated using generic and disease-specific outcome tools at baseline and at 6 and 12 wk postsurgery. The primary outcome was the HRQOL at 6 wk post-treatment measured by the Spine Oncology Study Group Outcomes Questionnaire (SOSGOQ).

RESULTS

A total of 253 patients were included: 40 patients died within the first 3 mo after surgery and 213 patients survived more than 3 mo. Patients surviving <3 mo after surgery presented with lower baseline performance status. Adjusted analyses for baseline performance status did not reveal a significant difference in HRQOL between both groups at 6 wk post-treatment. No significant difference in patient satisfaction at 6 wk with regard to their treatment could be detected between both groups.

CONCLUSION

When controlled for baseline performance status, quality of life 6 wk after surgery for spinal metastasis is independent of survival. To optimize improvement in HRQOL for this patient population, baseline performance status should take priority over expected survival in the surgical decision-making process.

How Can Imaging Help the Radiation Oncologist in Multiple Myeloma Treatment

Multiple myeloma is an incurable malignant tumor of plasma cells of the bone marrow; most patients present a disseminated disease with important bone involvement. Even though a chemotherapy-based approach is the major treatment, radiotherapy often has a supportive role for symptom relief but also a radical role for patients with indolent disease or localized forms. In both cases imaging is the basis for treatment planning and for correct patient classification. This paper aims to describe and summarize how radiation oncologists could use imaging information to personalize the treatment for each patient.

Disparities in Patterns of Conventional Versus Stereotactic Body Radiotherapy in the Treatment of Spine Metastasis in the United States

INTRODUCTION

The improved survival of patients even with metastatic cancer has led to an increase in the incidence of spine metastases, suggesting the need for a more aggressive palliative treatment than conventional external beam radiation therapy (cEBRT). Consequently, spinal stereotactic body radiation therapy (SBRT) has increased in popularity over the past decade. However, there has been no comparison of patterns of usage of cEBRT versus SBRT in the treatment of spinal metastases in the US.

METHODS

The National Cancer Data Base (NCDB) from 2004-2013 was used for analysis. cEBRT was defined as 30 Gy in 10 fractions, 20 Gy in 5 fractions, or 8 Gy in 1 fraction. SBRT was defined as 25-32 Gy infive5 fractions, 24-32 Gy in 4 fractions, 20-32 Gy in three fractions, 14-32 Gy in 2 fractions, or 14-24 Gy in 1 fraction. Single and multivariable associations between patient demographic and cancer characteristics and type of radiation were performed.

RESULTS

From 2004-2013, 23,181 patients with spinal metastases in the United States received cEBRT, while 1,030 received SBRT as part of their first course of treatment. Most patients (88%) received 10 fractions of radiation. Multivariable analysis suggested that non-Medicare or private insurance (adjusted OR 0.4-0.7), African-American race (adjusted OR = 0.8, 95%CI = 0.7-1.0), age 65+ (adjusted OR = 0.8), living in a region with lower population (adjusted OR 0.7), earlier year of diagnosis (OR = 0.9), and receiving treatment in a non-academic/research facility (adjusted OR 0.6) were associated with cEBRT. After controlling for other variables, regional education level was no longer significantly associated with cEBRT.

CONCLUSIONS

Most patients with spine metastases were treated with cEBRT, usually with 10 fractions. Receipt of SBRT was significantly associated with race, insurance, geography, population, type of treatment facility, and year of diagnosis, even after controlling for other factors. These findings raise questions about disparities in access to and delivery of care that deserve further investigation.

The Dancing Cord: Inherent Spinal Cord Motion and Its Effect on Cord Dose in Spine Stereotactic Body Radiation Therapy

BACKGROUND

Spinal cord dose limits are critically important for the safe practice of spine stereotactic body radiotherapy (SBRT). However, the effect of inherent spinal cord motion on cord dose in SBRT is unknown.

OBJECTIVE

To assess the effects of cord motion on spinal cord dose in SBRT.

METHODS

Dynamic balanced fast field echo (BFFE) magnetic resonance imaging (MRI) was obtained in 21 spine metastasis patients treated with SBRT. Planning computed tomography (CT), conventional static T2-weighted MRI, BFFE MRI, and dose planning data were coregistered. Spinal cord from the dynamic BFFE images (corddyn) was compared with the T2-weighted MRI (cordstat) to analyze motion of corddyn beyond the cordstat (Dice coefficient, Jaccard index), and beyond cordstat with added planning organ at risk volume (PRV) margins. Cord dose was compared between cordstat, and corddyn (Wilcoxon signed-rank test).

RESULTS

Dice coefficient (0.70-0.95, median 0.87) and Jaccard index (0.54-0.90, median 0.77) demonstrated motion of corddyn beyond cordstat. In 62% of the patients (13/21), the dose to corddyn exceeded that of cordstat by 0.6% to 13.8% (median 4.3%). The corddyn spatially excursed outside the 1-mm PRV margin of cordstat in 9 patients (43%); among these dose to corddyn exceeded dose to cordstat >+ 1-mm PRV margin in 78% of the patients (7/9). Corddyn did not excurse outside the 1.5-mm or 2-mm PRV cord cordstat margin.

CONCLUSION

Spinal cord motion may contribute to increases in radiation dose to the cord from SBRT for spine metastasis. A PRV margin of at least 1.5 to 2 mm surrounding the cord should be strongly considered to account for inherent spinal cord motion.

Separation surgery for metastatic epidural spinal cord compression: A qualitative review

•

Separation surgery is a new concept for metastatic spinal cord compression treatment.

•

Stereotactic radiosurgery increased local control, overcoming radio-resistance’s idea.

•

The surgery goal shifted towards creating targets for radiations avoiding cord damages.

•

Minimal invasive strategies could allow quick return to systemic therapies.

Introduction

The new concept of separation surgery has changed the surgical paradigms for the treatment of metastatic epidural spinal cord compression (MESCC), shifting from aggressive cytoreductive surgery towards less invasive surgery with the aim to achieve circumferential separation of the spinal cord and create a safe target for high dose Stereotactic Body Radiation Therapy (SBRT), which turned out to be the real game-changer for disease’s local control.

Discussion

In this review a qualitative analysis of the English literature has been performed according to the rating of evidence, with the aim to underline the increasingly role of the concept of separation surgery in MESCC treatment. A review of the main steps in the evolution of both radiotherapy and surgery fields have been described, highlighting the important results deriving from their integration.

Conclusion

Compared with more aggressive surgical approaches, the concept of separation surgery together with the advancements of radiotherapy and the use of SBRT for the treatment of MESCC showed promising results in order to achieve a valuable local control while reducing surgical related morbidities and complications.

Linear accelerator-based single-fraction stereotactic body radiotherapy for symptomatic vertebral body hemangiomas: The Mayo Clinic experience

Symptomatic vertebral hemangiomas (SVHs) are rare benign tumors that when symptomatic require procedural intervention or radiotherapy (RT). Although conventionally-fractionated RT has been an alternative to surgical resection, there is very little data on stereotactic body radiotherapy (SBRT) for SVHs. Six consecutively treated patients with SVHs underwent definitive single-fraction SBRT from 2010 to 2018 at our institution. The RT planning parameters, treatment, outcome, and toxicities are reported for 6 patients with 6 total SVHs treated with single-fraction SBRT. Each patient presented with back pain and received single-fraction SBRT to a thoracic vertebral body hemangioma. One patient had received radiofrequency ablation prior to SBRT. The median SBRT dose was 18 Gy (range, 13-20). Following SBRT, 4 (67%) patients reported improvement in presenting symptoms and 2 patients (33%) were refractory. There were no acute or chronic toxicities associated with SBRT including esophagitis, vertebral compression fractures, or myelopathy. To date, this is the largest series of single-fraction SBRT for SVHs. Single fraction SBRT appears to be a feasible option for SVHs. Further studies are needed to confirm our preliminary findings and optimize dose fractionation.

Technological quality requirements for stereotactic radiotherapy : Expert review group consensus from the DGMP Working Group for Physics and Technology in Stereotactic Radiotherapy

This review details and discusses the technological quality requirements to ensure the desired quality for stereotactic radiotherapy using photon external beam radiotherapy as defined by the DEGRO Working Group Radiosurgery and Stereotactic Radiotherapy and the DGMP Working Group for Physics and Technology in Stereotactic Radiotherapy. The covered aspects of this review are 1) imaging for target volume definition, 2) patient positioning and target volume localization, 3) motion management, 4) collimation of the irradiation and beam directions, 5) dose calculation, 6) treatment unit accuracy, and 7) dedicated quality assurance measures. For each part, an expert review for current state-of-the-art techniques and their particular technological quality requirement to reach the necessary accuracy for stereotactic radiotherapy divided into intracranial stereotactic radiosurgery in one single fraction (SRS), intracranial fractionated stereotactic radiotherapy (FSRT), and extracranial stereotactic body radiotherapy (SBRT) is presented. All recommendations and suggestions for all mentioned aspects of stereotactic radiotherapy are formulated and related uncertainties and potential sources of error discussed. Additionally, further research and development needs in terms of insufficient data and unsolved problems for stereotactic radiotherapy are identified, which will serve as a basis for the future assignments of the DGMP Working Group for Physics and Technology in Stereotactic Radiotherapy. The review was group peer-reviewed, and consensus was obtained through multiple working group meetings.

Local Tumor Control for Metastatic Epidural Spinal Cord Compression Following Separation Surgery with Adjuvant CyberKnife Stereotactic Radiotherapy or Image-Guided Intensity-Modulated Radiotherapy

BACKGROUND

We sought to compare local tumor control after conventionally fractionated image-guided intensity-modulated radiotherapy (IMRT) versus adjuvant CyberKnife stereotactic body radiotherapy (SBRT) in patients who underwent separation surgery for metastatic epidural spinal cord compression (MESCC).

METHODS

We retrospectively reviewed patients with MESCC who were treated at our hospital. The Kaplan-Meier method was used to estimate local progression and overall survival.

RESULTS

Fifty-six patients with MESCC underwent separation surgery between 2013 and 2018, among whom 6 were lost to follow-up, 24 received conventionally fractionated image-guided IMRT, and 26 were treated with CyberKnife SBRT. The median follow-up was 16.5 months (range, 2.1-47.5 months). Eleven patients experienced local failure including 9 and 2 from the IMRT and SBRT groups, respectively. The local progression-free survival rates were significantly higher in the SBRT group than IMRT group at 6 months (95.5% vs. 82.0%), 1 year (90.9% vs. 71.8%), and 2 years (90.9% vs. 57.6%) (P = 0.035). Multivariate Cox proportional hazards regression analysis identified radiotherapy method (P = 0.034) and receipt of preoperative radiotherapy (P = 0.047) as significant predictors of local control, while visceral metastasis (P = 0.048) and high-malignancy primary tumor type (P = 0.002) were negative predictors of overall survival. Moreover, postoperative SBRT was noninferior to IMRT in terms of pain control, adverse effects, and performance in treating irradiated spinal metastases.

CONCLUSIONS

Hybrid surgery-radiosurgery therapy is a safe and effective treatment option for patients with MESCC. SBRT provided higher local control rates compared with IMRT. Thus postoperative SBRT should be considered for patients expected to have relatively long survival.

Efficacy Analysis of Separation Surgery Combined with SBRT for Spinal Metastases-A Long-Term Follow-Up Study Based on Patients with Spinal Metastatic Tumor in a Single-Center

Objective

Follow‐up data of patients with spinal metastatic tumors were analyzed to investigate the effect of separation surgery combined with SBRT on clinical outcomes.

Methods

The clinical data of 52 patients with spinal metastatic tumors admitted to our hospital from January 2015 to December 2018 were retrospectively analyzed. There were 24 males and 28 females, aged 25–77 years, with an average of 56.7 ± 7.4 years. The separation surgery of all patients was successfully completed and followed up. Frankel neurological function grading, Karnofsky performance scores, VAS scores, Epidural spinal cord compression (ESCC) grading and muscle strength grading were used to assess the patients’ condition. Kaplan‐Meier analysis and the Log⁃rank test were used to calculate the hazard ratio (HR) and the 95% feasible interval for patients with different ages, genders, and treatments. The multivariate Cox regression model was used to calculate the risk value HR and the 95% feasible interval in patients undergoing only separation surgery or separation surgery combined with SBRT.

Results

After separation surgery, 46 patients had pain relief (88.5%), and the average VAS score decreased to 2.17 ± 0.52 points, which was significantly improved compared with preoperative score (P < 0.01). Muscle strength grading decreased in seven cases, showed no change in two cases, and recovered in 19 cases. Postoperative Frankel neurological function grading and Karnofsky performance scores were also significantly improved compared with preoperative scores (P < 0.01). The patients who accepted separation surgery were followed up for 9–47 months (26.3 ± 18.1 months), and 15 patients died due to the deterioration of the primary tumor. Thirteen patients received SBRT after surgery, including 12 cases of pain relief. The average VAS score of these 13 patients decreased to 1.64±0.41 points, which was significantly improved compared with preoperative and postoperative (P < 0.01), and muscle strength recovered in eight cases. Frankel neurological function grading and Karnofsky performance scores of these patients were also significantly improved compared with preoperative and postoperative Frankel neurological function grading and Karnofsky performance scores (P < 0.01). The patients who accepted separation surgery combined with SBRT were followed up for 11–38 months (mean 22.5 ± 10.2 months), and five cases died of primary tumor. Univariate and multivariate analysis showed that separation surgery combined with SBRT was an independent predictor of overall survival rate (OS).

Conclusions

Separation surgery combined with SBRT is an effective way to treat spinal metastatic tumors as it not only has smaller surgical trauma, but can also significantly relieve pain, improve nerve function, and relieve spinal cord compression.

Local Control and Toxicity of Multilevel Spine Stereotactic Body Radiotherapy

BACKGROUND

Spine stereotactic body radiotherapy (sSBRT) is commonly limited to 1 or 2 vertebral levels given a paucity of efficacy and toxicity data when more than 2 levels are treated.

OBJECTIVE

To prove our hypothesis that multilevel sSBRT could provide similar rates of local control (LC) (primary endpoint) and toxicity as single-level treatment using the same clinical target, planning target, and planning organ-at-risk volumes.

METHODS

We analyzed consecutive cases of sSBRT treated from 2013 to 2017. Time-to-event outcomes for single-level and multilevel cases were compared using mixed effect Cox models and differences in toxicity rates were evaluated using linear mixed effect models. All models incorporate a patient-level random intercept to account for any within-patient correlation across cases.

RESULTS

There were 101 single-level and 84 multilevel sSBRT cases (2-7 continuous vertebral levels). One-year LC was 95% vs 85%, respectively. After adjusting for baseline covariates, dose delivered, and accounting for within-patient correlation, there was no significant difference in time to local failure (hazard ratio, HR 1.79 [0.59-5.4]; P = .30). Pain improved in 83.5% of the 139 initially symptomatic tumors. There were no significant differences in grade 2+ acute or late toxicities between single-level and multilevel sSBRT.

CONCLUSION

With rigorous patient immobilization, quality assurance, and image guidance, multilevel sSBRT provides high rates of LC, similar to single-level treatment, without need for larger planning volume margins. Efforts to improve prognostication and case selection for multilevel sSBRT are warranted to ensure that the benefits of improved LC over palliative radiation are justified.