Spinal Metastases in Breast Cancer: Single Center Experience

The role of spine stereotactic radiosurgery for patients with breast cancer metastases

PURPOSE

Breast cancer that metastasizes to the spine is associated with low quality of life and poor survival. Radiosurgery has an increasing role in this patient population. This single-institution (2003-2023) study analyzes clinical outcomes and prognostic factors for patients who underwent spinal stereotactic radiosurgery (SSRS) for metastatic breast cancer.

METHODS

Ninety patients (155 unique breast cancer spinal metastases) were treated with SSRS. The median age was 57 years (range: 35-88), and the median KPS was 80 (range: 40-100). Forty-two (27%) lesions were managed surgically prior to radiosurgery. At SSRS, 75 (48%) lesions impinged or compressed the spinal cord per the epidural spinal cord scale (ESCC). Seventy-nine (51%) lesions were categorized as potentially unstable or unstable by the Spinal Instability Neoplastic Score (SINS).

RESULTS

The median follow-up was 15 months (range: 1-183). The median single-session tumor volume was 25.4 cc (range: 2-197), and the median single-fraction prescription dose was 17 Gy (range: 12-25). Seven (5%) lesions locally progressed. The 1-, 2-, and 5-year local control rates were 98%, 97%, and 92%, respectively. The median overall survival (OS) for the cohort was 32 months (range: 2-183). The 1-, 2-, and 5-year OS rates were 72%, 53%, and 30%, respectively. On univariate analysis, KPS ≥ 80 (p = 0.009, HR: 0.51, 95% CI: 0.31-0.84) was associated with improved OS. Patient-reported pain improved (68%), remained stable (29%), or worsened (3%) following radiosurgery. Fifteen (10%) radiation-induced toxicities were reported.

CONCLUSIONS

Spinal radiosurgery is a safe and highly effective long-term treatment modality for metastases to the spine that originate from breast cancer.

Review of the role of MRI and 18 F-sodium fluoride PET/computed tomography in the characterisation of spinal bone metastases in a cohort of patients with breast cancer

PURPOSE

The purpose of the study was to compare the diagnostic accuracy and relative usefulness of MRI and 18 F-NaF (sodium fluoride) PET/computed tomography (CT) for detection of spinal bone metastases in a cohort of patients with high-risk breast cancer (BrCa).

METHODS

A retrospective study was conducted of patient and lesion-based analyses on 66 consecutive patients (median age, 62.5 years; age range, 33-91 years) who underwent Spinal MRI as well as 18 F-NaF PET-CT for restaging of newly diagnosed recurrent BrCa with no previous bone metastases. Both scans were performed within 20 days of each other. Review of prior images, clinical decisions, multi-disciplinary team discussions and decisions as well as follow-up information including scans and definitive tests was performed at least 12 months after the initial scans.

RESULTS

Of the 66 patients reviewed, 26 patients had documented spinal bone metastases on one or both modalities, while 40 patients were considered bone disease free on both modalities and this was confirmed on follow-up. On lesion-based analysis, the findings of 18 F-NaF PET-CT and spinal MRI were concordant in 51 patients (77.3%). In the remaining patients, 18 F-NaF PET/CT detected more lesions in 4 patients (7.6%) and MRI detected more lesions in 10 patients (15.1%). Interestingly, there was a very high, 97 % concordance (64 patients) between spinal MRI and 18 F-NaF PET-CT when staging of spinal bone metastasis was taken into consideration. In one patient MRI identified two spinal bone metastases which were not seen on 18 F-NaF PET/CT; and, in one patient 18 F-NaF PET/CT showed few spinal bone metastases when no lesion was seen on MRI.

CONCLUSIONS

Our study showed a high level of concordance between 18 F NaF PET-CT and spinal MRI within the setting of detection of bone lesions in the spine in a cohort of patients with high-risk BrCa. In our opinion, this high level of concordance negates the need to perform both tests although each test may be indicated for slightly different reasons. Further longitudinal studies across a longer duration and more centres may provide more definitive answers.

Spinal Metastases and the Evolving Role of Molecular Targeted Therapy, Chemotherapy, and Immunotherapy

Metastatic involvement of the spine is a common complication of systemic cancer progression. Surgery and external beam radiotherapy are palliative treatment modalities aiming to preserve neurological function, control pain and maintain functional status. More recently, with development of image guidance and stereotactic delivery of high doses of conformal radiation, local tumor control has improved; however recurrent or radiation refractory disease remains a significant clinical problem with limited treatment options. This manuscript represents a narrative overview of novel targeted molecular therapies, chemotherapies, and immunotherapy treatments for patients with breast, lung, melanoma, renal cell, prostate, and thyroid cancers, which resulted in improved responses compared to standard chemotherapy. We present clinical examples of excellent responses in spinal metastatic disease which have not been specifically documented in the literature, as most clinical trials evaluate treatment response based on visceral disease. This review is useful for the spine surgeons treating patients with metastatic disease as knowledge of these responses could help with timing and planning of surgical interventions, as well as promote multidisciplinary discussions, allowing development of an individualized treatment strategy to patients presenting with widespread multifocal progressive disease, where surgery could lead to suboptimal results.

Assessing long-term locoregional control of spinal osseous metastases after microwave ablation

Osseous metastases to the spine result in significant pain and decreased quality of life. The purpose of this study was to evaluate the long-term efficacy of microwave ablation (MWA) for the treatment of spinal metastases regarding pain reduction and local control of disease progression. In this single center retrospective study, patients with osseous metastases to the spine undergoing MWA with vertebroplasty from 2013 to 2020 were included. Locoregional control of metabolic activity at the treated level was assessed using PET/CT scan both pre- and post-procedure. Pain reduction was measured using change in visual analog scale (VAS) pain score. Forty-eight spinal levels were treated with MWA in 28 patients (57 % male, mean age 68 ± 9 years). Median ablation time, energy, and temperature were 4 min and 13 s, 3.6 kJ, and 80 °C, respectively. Median pre-procedure maximum standard uptake value (SUVmax) was significantly reduced following ablation, from 4.55 (IQR 3.65-6.1) to 0 (IQR 0-1.8; p < 0.001), over an average of 29 ± 14.1 month follow up period. Pre-procedure VAS pain score was reduced from median (IQR) of 8 (6.5-9) to 1(1-2), 2(1-3) and 1(0.5-3) at 24 h, four weeks, and six months post-procedure, respectively (all p < 0.001 with respect to pre-procedure scores). In conclusion, this study supports microwave ablation as an effective technique for pain palliation and long-term locoregional tumor control of oligometastatic spinal disease as assessed by metabolic response.

Survival of Spinal Metastasis Disease based on Immunohistochemistry Subtype of Breast Cancer: A Systematic Review and Meta-analysis

BACKGROUND: Breast cancer is categorized as a slow-growth tumor in the spinal metastases disease (SMD) scoring system. Based on immunohistochemistry, breast cancer has four subtypes: Luminal A (LumA), luminal B (LumB), human epidermal growth factor 2 (Her-2) type, and triple-negative breast cancer (TNBC). TNBC has the poorest prognosis. AIM: This study aimed to describe the survival time of breast cancer with SMD based on immunohistochemistry subtypes through systematic review and meta-analysis. METHODS: This is a systematic review and meta-analysis study. This study used electronic articles published in PubMed and CENTRAL online database. We used keywords ([breast] AND [cancer] AND [spine] AND [metastasis]) to find eligible studies. Articles included were full-text studies in English. Survival time as the outcome was pooled according to the immunohistochemistry subtype of breast cancer. Statistical analysis was performed using software Stata. RESULTS: Five articles met our inclusion and exclusion criteria. LumA, LumB, Her-2 type, and TNBC have a survival time of 32.84 months, 35.20 months, 60.8 months, and 14.27 months, respectively. CONCLUSION: TNBC has the lowest survival time in the pooled analysis. We proposed TNBC be categorized as a moderate growth primary tumor.

Multidisciplinary care of breast cancer patients: a scoping review of multidisciplinary styles, processes, and outcomes

Background

Clinical practice guidelines recommend a multidisciplinary approach to cancer care that brings together all relevant disciplines to discuss optimal disease management. However, the literature is characterized by heterogeneous definitions and few reviews about the processes and outcomes of multidisciplinary care. The objective of this scoping review was to identify and classify the definitions and characteristics of multidisciplinary care, as well as outcomes and interventions for patients with breast cancer.

Methods

A systematic search for quantitative and qualitative studies about multidisciplinary care for patients with breast cancer was conducted for January 2001 to December 2017 in the following electronic databases: medline, embase, PsycInfo, and cinahl. Two reviewers independently applied our eligibility criteria at level 1 (title/abstract) and level 2 (full-text) screening. Data were extracted and synthesized descriptively.

Results

The search yielded 9537 unique results, of which 191 were included in the final analysis. Two main types of multidisciplinary care were identified: conferences and clinics. Most studies focused on outcomes of multidisciplinary care that could be variously grouped at the patient, provider, and system levels. Research into processes tended to focus on processes that facilitate implementation: team-working, meeting logistics, infrastructure, quality audit, and barriers and facilitators.

Summary

Approaches to multidisciplinary care using conferences and clinics are well described. However, studies vary by design, clinical context, patient population, and study outcome. The heterogeneity of the literature, including the patient populations studied, warrants further specification of multidisciplinary care practice and systematic reviews of the processes or contexts that make the implementation and operation of multidisciplinary care effective.

Outcomes and prognostic factors for surgically treated patients with breast cancer spine metastases

Purpose

The aim of this study is to provide some useful insights into the treatments, outcomes, and prognostic factors of patients with breast cancer spine metastases (BCSM).

Methods

We report a retrospective case series analyzing 87 patients with BCSM who underwent surgical interventions. Independent prognostic factors for SMFS and OS were extracted using univariate and multivariate analyses, the Kaplan-Meier method and the Cox proportional hazards model.

Results

The mean time between primary diagnoses and spinal metastases was 46.8 (median 41, range 0-147 months) months. The analysis showed that lymph node metastasis (p = 0.043, HR 10.498, 95%CI 1.074-102.588) and estrogen receptor (ER) status (p = 0.004, HR 0.368, 95%CI 0.189-0.721) can significantly affect SMFS. Furthermore, visceral metastasis (p = 0.042, HR 2.383, 95%CI 1.032-5.501), multiple metastases (p = 0.035, HR 2.538, 95%CI 1.066-6.048) and post-op chemotherapy (p = 0.003, HR 0.312, 95%CI 0.144-0.675) have significant effects on OS. Lastly, patients identified as Luminal A subtype have longer OS.

Conclusions

Lymph node metastases and ER status are independent risk factors in predicting BCSM. Moreover, visceral metastasis, multiple metastases of the spine and post-op chemotherapy are independent prognostic factors. Luminal subtypes have higher rate, but late onset of spine metastases and prolonged survival.

Effect of MRI on breast tissue expanders and recommendations for safe use

INTRODUCTION

Ferromagnetic port-containing breast tissue expanders are currently labeled MRI-unsafe because of the presumption that magnets should not enter the machine. However, designating these devices as MRI-unsafe can lead to unnecessary procedures or suboptimal imaging choices. This study provides an ex vivo analysis of how breast tissue expanders behave when subjected to strong magnetic fields to determine which variables might affect clinical risk.

METHODS

Three different brands of tissue expanders were evaluated in three MRI environments. Translational force was determined using the deflection angle method. Torque on empty, saline-filled, and air-filled expanders was evaluated on a 0-4 scale. Magnetic field was measured using a gaussmeter. The weight required to prevent displacement of the expanders was determined for both air- and saline-filled expanders. Temperature over time was measured using an alcohol thermometer.

RESULTS

Magnetic field strength, deflection angle, and torque were the greatest in 3T MRI environments and varied by device manufacturer (Sientra > Mentor > Allergan). Saline-filled expanders required 240 mL and air-filled required 360 mL volume to make the torque undetectable, and the effect of torque could be mitigated with prone positioning. A weight of 120 g was required to prevent displacement of a saline-filled tissue expander and 870 g for an empty expander. There were no appreciable changes in temperature.

CONCLUSIONS

Previously described risks may be reduced by using a 1.5T MRI, device selection, filling expanders with saline, and prone positioning. MRI can be considered in patients with breast tissue expanders when appropriate peri-procedural choices have been made so that the benefits of undergoing MRI outweigh the risks.

CORRELATION OF TOKUHASHI AND TOMITA SCORES WITH THE PROGNOSIS IN METASTATIC BREAST CANCER

ABSTRACT Objective: The purpose of the present study was to evaluate the concordance between the Tokuhashi and Tomita scores with the prognosis of patients with vertebral metastases due to breast tumor, treated at the outpatient clinic of the Universidade Estadual de Campinas (UNICAMP). Methods: Twenty-nine patients with vertebral metastases from breast tumor were retrospectively evaluated. Twenty patients were surgically treated and received adjuvant therapy and only nine received conservative (chemotherapy/radiotherapy) or palliative/support treatment, depending on Tokuhashi and Tomita scores. Results: In this study, all selected patients were females with vertebral metastasis due to breast tumor; mean age of 57.6 years (SD = 11.8 years). The accuracy of the Tokuhashi scale was 62.1% and that of Tomita 72.4%. In addition, the Tomita scale concentrates the majority of the patients’ classifications for more than 12 months (69%), indicating a good relation with the long-term prognosis (> 12 months). None of the evaluated characteristics - age or surgery - statistically influenced the survival of patients with primary breast tumor (p > 0.05). Conclusion: The Tokuhashi and Tomita scores showed good accuracy in relation to the prognosis of patients with spinal metastasis due to breast tumor.

Hardware failure in patients with metastatic cancer to the spine

BACKGROUND

The spine is the most common site of skeletal metastases, affecting approximately 30% of individuals with cancer. The aim of surgical treatment for metastatic spine disease is generally palliative to address pain and/or neurologic compromise, significantly improving patients' quality of life. Patients with metastatic spine disease, however, represent a vulnerable cohort and may have comorbidities or previous treatments that impair the structural integrity of spinal hardware. As such, identifying factors that may contribute to hardware failure is an essential component in treating individuals with metastatic spine disease.

OBJECTIVE

The aim of this study was to identify pre-operative risk factors associated with hardware failure in patients undergoing surgical treatment for metastatic spine disease.

METHODS

A retrospective cohort study was conducted to include patients surgically treated for metastatic spine tumors between 2003 and 2013, at a single institution. A univariate analysis was initially performed to identify associated factors. Any associated factor with a p-value <0.20 was included in the multivariate analysis.

RESULTS

3 patients (1.9%), of the 159 patients included in the study, had failure of the spine instrumentation. 1 patient had metastatic prostate cancer, and 2 had metastatic breast cancer. Patient demographics, co-morbidities, tumor location, and primary tumor etiology were not found to be statistically significant, with respect to hardware failure. Predictive factors included in the multivariate model were other bone metastasis, visceral metastasis, brain metastasis, Modified Rankin scale, previous systemic chemotherapy, previous radiation to the spine, and mean survival. Previous radiation to the spine was the only factor to be significantly associated (p=0.029), present in all three patients with hardware failure. Of note, there was a trend indicating that patients with longer life expectancies were more likely to experience hardware failure (mean survival of 16.7months in non-failure cohort vs. 33months in failure cohort), though this did not achieve statistical significance due to the limited sample size of patients with hardware failure.

CONCLUSION

Hardware failure is a risk for all patients who undergo instrumentation following resection for metastatic spine tumors. This study identified that pre-operative radiation may increase the risk for hardware failure in this population.

Clinical outcome of vertebral compression fracture after single fraction spine radiosurgery for spinal metastases

Vertebral compression fracture (VCF) occurs after stereotactic body radiation therapy (SBRT) for spine metastasis. Recently, single fraction radiosurgery (sfSRS) is used more frequently. The aim of this study is to determine the clinical outcome of VCF after sfSRS. Spinal instability neoplastic score (SINS) criteria were used to retrospectively score 143 consecutive vertebral segments in 79 patients treated with SRS. Follow-up MRI, pain, and neurologic assessments obtained every 3-6 months. Pain also scored at 7, 14, and 30 days after sfSRS. Follow up was 16 ± 18 months ±SD, range 3-78. Long-term radiographic control occurred in 94 % of cases. Pain improvement resulted within 7 days in 100 % of cases with severe pain and sustained long-term in 95 %. VCF occurred in 21 % of segments: 30 % were de novo VCF. The overall 1 year fracture free probability (1yFFP) was 76 %. Pre-existing VCF resulted in higher probability to progress: 1yFFP 90 versus 60 %. Symptoms presented in 6 % of cases with de novo VCF and 39 % with progressive. The former were treated with vertebral augmentation (VA), the latter with open surgery. Surgery/VA prior to SRS did not change risk of progressive VCF. Univariate but not multivariate analysis identified histology (colorectal), pre-existing VCF, and pain (severe) as significant predictors of VCF. In conclusion, sfSRS compares favourably to SBRT for radiographic and pain control with similar VCF risk. Patients with pre-existing VCF have a higher probability to progress, become symptomatic, and require surgery. These results may help discussing risk and benefits with patients undergoing sfSRS for spinal metastasis and developing new treatment algorithms.

Cost-effectiveness analysis of single fraction of stereotactic body radiation therapy compared with single fraction of external beam radiation therapy for palliation of vertebral bone metastases

PURPOSE

Stereotactic body radiation therapy (SBRT) has been proposed for the palliation of painful vertebral bone metastases because higher radiation doses may result in superior and more durable pain control. A phase III clinical trial (Radiation Therapy Oncology Group 0631) comparing single fraction SBRT with single fraction external beam radiation therapy (EBRT) in palliative treatment of painful vertebral bone metastases is now ongoing. We performed a cost-effectiveness analysis to compare these strategies.

METHODS AND MATERIALS

A Markov model, using a 1-month cycle over a lifetime horizon, was developed to compare the cost-effectiveness of SBRT (16 or 18 Gy in 1 fraction) with that of 8 Gy in 1 fraction of EBRT. Transition probabilities, quality of life utilities, and costs associated with SBRT and EBRT were captured in the model. Costs were based on Medicare reimbursement in 2014. Strategies were compared using the incremental cost-effectiveness ratio (ICER), and effectiveness was measured in quality-adjusted life years (QALYs). To account for uncertainty, 1-way, 2-way and probabilistic sensitivity analyses were performed. Strategies were evaluated with a willingness-to-pay (WTP) threshold of $100,000 per QALY gained.

RESULTS

Base case pain relief after the treatment was assumed as 20% higher in SBRT. Base case treatment costs for SBRT and EBRT were $9000 and $1087, respectively. In the base case analysis, SBRT resulted in an ICER of $124,552 per QALY gained. In 1-way sensitivity analyses, results were most sensitive to variation of the utility of unrelieved pain; the utility of relieved pain after initial treatment and median survival were also sensitive to variation. If median survival is ≥11 months, SBRT cost <$100,000 per QALY gained.

CONCLUSION

SBRT for palliation of vertebral bone metastases is not cost-effective compared with EBRT at a $100,000 per QALY gained WTP threshold. However, if median survival is ≥11 months, SBRT costs ≤$100,000 per QALY gained, suggesting that selective SBRT use in patients with longer expected survival may be the most cost-effective approach.