Prognostic factors in patients with spinal metastasis: a systematic review and meta-analysis

Preoperative Performance Status Threshold for Favorable Surgical Outcome in Metastatic Spine Disease

BACKGROUND AND OBJECTIVES

Surgical treatment is an integral component of multimodality management of metastatic spine disease but must be balanced against the risk of surgery-related morbidity and mortality, making tailored surgical counseling a clinical challenge. The aim of this study was to investigate the potential predictive value of the preoperative performance status for surgical outcome in patients with spinal metastases.

METHODS

Performance status was determined using the Karnofsky Performance Scale (KPS), and surgical outcome was classified as "favorable" or "unfavorable" based on postoperative changes in neurological function and perioperative complications. The correlation between preoperative performance status and surgical outcome was assessed to determine a KPS-related performance threshold.

RESULTS

A total of 463 patients were included. The mean age was 63 years (range: 22-87), and the mean preoperative KPS was 70 (range: 30-100). Analysis of clinical outcome in relation to the preoperative performance status revealed a KPS threshold between 40% and 50% with a relative risk of an unfavorable outcome of 65.7% in KPS ≤40% compared with the relative chance for a favorable outcome of 77.1% in KPS ≥50%. Accordingly, we found significantly higher rates of preserved or restored ambulatory function in KPS ≥50% (85.7%) than in KPS ≤40% (48.6%; P < .001) as opposed to a significantly higher risk of perioperative mortality in KPS ≤40% (11.4%) than in KPS ≥50% (2.1%, P = .012).

CONCLUSION

Our results underline the predictive value of the KPS in metastatic spine patients for counseling and decision-making. The study suggests an overall clinical benefit of surgical treatment of spinal metastases in patients with a preoperative KPS score ≥50%, while a high risk of unfavorable outcome outweighing the potential clinical benefit from surgery is encountered in patients with a KPS score ≤40%.

Developmental and Validation of Machine Learning Model for Prediction Complication after Cervical Spine Metastases Surgery

STUDY DESIGN

This is a retrospective cohort study utilizing machine learning to predict postoperative complications in cervical spine metastases surgery.

OBJECTIVES

The main objective is to develop a machine learning model that accurately predicts complications following cervical spine metastases surgery.

SUMMARY OF BACKGROUND DATA

Cervical spine metastases surgery can enhance quality of life but carries a risk of complications influenced by various factors. Existing scoring systems may not include all predictive factors. Machine learning offers the potential for a more accurate predictive model by analyzing a broader range of variables.

METHODS

Data from January 2012 to December 2020 were retrospectively collected from medical databases. Predictive models were developed using Gradient Boosting, Logistic Regression, and Decision Tree Classifier algorithms. Variables included patient demographics, disease characteristics, and laboratory investigations. SMOTE was used to balance the dataset, and the models were assessed using AUC, F1-score, precision, recall, and SHAP values.

RESULTS

The study included 72 patients, with a 29.17% postoperative complication rate. The Gradient Boosting model had the best performance with an AUC of 0.94, indicating excellent predictive capability. Albumin level, platelet count, and tumor histology were identified as top predictors of complications.

CONCLUSIONS

The Gradient Boosting machine learning model showed superior performance in predicting postoperative complications in cervical spine metastases surgery. With continuous data updating and model training, machine learning can become a vital tool in clinical decision-making, potentially improving patient outcomes.

LEVEL OF EVIDENCE

Level III.

Hematologic Malignancies Influence the Accuracy of Prediction of Survival in Patients With Solid Tumor Spinal Metastases Undergoing Surgery

PURPOSE

There is no consensus on how to identify patients with multiple-level spinal metastases who would benefit from surgery. Previous studies have revealed that patients with hematologic malignancies have a significantly longer median survival time than those with solid tumor spinal metastases. We aimed to compare predictors and survival data between patients with spinal metastases, including hematologic malignancies (all-malignancies group), with only those with nonhematologic malignancies (nonhematologic malignancies group).

MATERIALS AND METHODS

This single-center retrospective study included all patients age >18 years who underwent surgery to treat spinal metastases in our department from 2008 to 2018. The patients' baseline characteristics, treatment modalities, and laboratory results were analyzed. Survival was calculated from the date of surgery to the date of confirmed death. Cox regression analysis was used to identify independent predictors of survival.

RESULTS

The study cohort comprised 186 patients with a mean age of 57.1 ± 13.4 years, 101 of whom were male and 18 of whom had hematologic malignancies. The median survival time was 201 days in the all-malignancies group and 168 days in the nonhematologic malignancies group. Independent predictors of survival differed between the two groups. Eastern Cooperative Oncology Group status and response to preoperative chemotherapy were identified as independent factors in both groups. However, radiosensitivity and CNS metastases were identified only in the all-malignancies group, and tumor growth potential, albumin status, and number of vertebrae were identified only in the nonhematologic malignancies group. The receiver operating characteristics were comparable in the two groups: 0.75 in the all-malignancies group and 0.77 in the nonhematologic malignancies group.

CONCLUSION

Longer survival in patients with hematologic malignancies influences the overall prediction of survival. Tumor-specific prognostic factors may improve the prediction of survival in patients with spinal metastases.

Can Survival Scoring Systems for Spinal Metastases be Used to Predict Postoperative Neurologic Recovery? A Retrospective Study on 204 Patients With Thoracolumbar Metastases Treated at a Tertiary Center

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVE

Scoring systems for metastatic disease of the spine are used to select patients for surgical treatment based on survival estimation, but it is unknown whether they can be used to predict the outcome of surgery. This study aims to investigate the association between two widely used prognostic scores and the neurologic function after surgery.

METHODS

Retrospective analysis of 204 patients with thoracolumbar metastases treated with decompressive surgery at Karolinska University Hospital (2001-2020). Modified Bauer and Tokuhashi scores were categorized based on surgical indication, and post-operative neurological function was assessed using the Frankel scale at two different post-surgery intervals.

RESULTS

Modified Bauer scores ≥2 yielded higher late follow-up Frankel scores (3.9 ± 1.1) than scores <2 (3.5 ± 1.1), P = .03. Modified Tokuhashi scores ≥9 correlated with higher Frankel scores (4.5 ± .9) than scores <9 (3.5 ± 1.1), P < .0001. Both scoring systems positively predicted neurological outcomes at late follow-up, with odds ratios of 1.6 (P = .03) for Bauer and 9.2 (P < .0001) for Tokuhashi. However, only Tokuhashi predicted ambulatory function at late follow-up (P < .0001), demonstrating its utility in prognosticating post-surgical mobility.

CONCLUSION

Higher modified Bauer and Tokuhashi scores were associated with better neurologic function at last follow-up, as well as greater likelihood of being able to walk again. The Tokuhashi score was found to be more accurate than the modified Bauer score in predicting the neurological outcome after surgery.

Development and internal validation of machine-learning models for predicting survival in patients who underwent surgery for spinal metastases

STUDY DESIGN

A retrospective study.

PURPOSE

This study aimed to develop machine-learning algorithms for predicting survival in patients who underwent surgery for spinal metastasis.

OVERVIEW OF LITERATURE

This study develops machine-learning models to predict postoperative survival in spinal metastasis patients, filling the gaps of traditional prognostic systems. Utilizing data from 389 patients, the study highlights XGBoost and CatBoost algorithms̓ effectiveness for 90, 180, and 365-day survival predictions, with preoperative serum albumin as a key predictor. These models offer a promising approach for enhancing clinical decision-making and personalized patient care.

METHODS

A registry of patients who underwent surgery (instrumentation, decompression, or fusion) for spinal metastases between 2004 and 2018 was used. The outcome measure was survival at postoperative days 90, 180, and 365. Preoperative variables were used to develop machine-learning algorithms to predict survival chance in each period. The performance of the algorithms was measured using the area under the receiver operating characteristic curve (AUC).

RESULTS

A total of 389 patients were identified, with 90-, 180-, and 365-day mortality rates of 18%, 41%, and 45% postoperatively, respectively. The XGBoost algorithm showed the best performance for predicting 180-day and 365-day survival (AUCs of 0.744 and 0.693, respectively). The CatBoost algorithm demonstrated the best performance for predicting 90-day survival (AUC of 0.758). Serum albumin had the highest positive correlation with survival after surgery.

CONCLUSIONS

These machine-learning algorithms showed promising results in predicting survival in patients who underwent spinal palliative surgery for spinal metastasis, which may assist surgeons in choosing appropriate treatment and increasing awareness of mortality-related factors before surgery.

Implant and construct decision-making in metastatic spine tumour surgery: a review of current concepts with a decision-making algorithm

STUDY DESIGN

Narrative Review.

OBJECTIVE

Metastatic spine tumour surgery (MSTS) is an important treatment modality of metastatic spinal disease (MSD). Increase in MSTS has been due to improvements in our oncological treatment, as patients have increased longevity and even those with poorer comorbidities are now being considered for surgery. However, there is currently no guideline on how MSTS surgeons should select the appropriate levels to instrument, and which type of implants should be utilised.

METHODS

The current literature on MSTS was reviewed to study implant and construct decision making factors, with a view to write this narrative review. All studies that were related to instrumentation in MSTS were included.

RESULTS

A total of 58 studies were included in this review. We discuss novel decision-making models that should be taken into account when planning for surgery in patients undergoing MSTS. These factors include the quality of bone for instrumentation, the extent of the construct required for MSTS patients, the use of cement augmentation and the choice of implant. Various studies have advocated for the use of these modalities and demonstrated better outcomes in MSTS patients when used appropriately.

CONCLUSION

We have established a new instrumentation algorithm that should be taken into consideration for patients undergoing MSTS. It serves as an important guide for surgeons treating MSTS, with the continuous evolvement of our treatment capacity in MSD.

LEVEL OF EVIDENCE IV

Predictors for quality of life, pain and functional outcomes after surgical treatment of metastatic disease in the spine

BACKGROUND

While predictors for postoperative survival in spine tumour patients have been identified, there is limited evidence for predictors of postoperative Quality of Life (QoL), pain and functional outcome.

METHODS

One hundred and fifty-three consecutive patients, who had undergone surgery for symptomatic spinal metastases between June 2016 and April 2019, were interviewed preoperatively and during follow-ups at three, six and 12 months using the EQ-5D-3L, COMI, and ODI questionnaires. Differences in means exceeding the specific Minimal Clinically Important Difference (MCID) values were considered clinically significant.

RESULTS

Thirty-three percent of the patients were reported dead after 12 months. Only one metastasis compared to multiple metastases has 7.9 the Odds for an improved EQ-5D-3L score at three months. No neoadjuvant metastatic irradiation has 6.8 the Odds for the improvement at that time against performed radiation. A preoperative ODI score between 50.1 and 100 has 22.0 times the odds compared to the range from 0 to 50 for an improved EQ-5D-3L after three months, and 12.5 times the odds in favour of improved COMI after three months, and 13.6 times the odds for improvement of ODI at the three-month follow-up. A preoperative COMI score ranging from 5.0 to 10 has 21 times the odds of a COMI between 0 and 5 for an improved EQ-5D-3L score and 11 times the odds for an improved ODI after 12 months. Other predictors showed no statistically significant improvement.

CONCLUSION

An improvement in QoL, pain and spinal function after 12 months can be predicted by a subjective preoperative poor health condition. Impaired spinal function before surgery, a singular metastasis and no previous irradiation is predictive of improved spinal function and quality of life three months after surgery.

Development of Machine-Learning Models to Predict Ambulation Outcomes Following Spinal Metastasis Surgery

STUDY DESIGN

Retrospective cohort study.

PURPOSE

This study aimed to develop machine-learning algorithms to predict ambulation outcomes following surgery for spinal metastasis.

OVERVIEW OF LITERATURE

Postoperative ambulation status following spinal metastasis surgery is currently difficult to predict. The improved ability to predict this important postoperative outcome would facilitate management decision-making and help in determining realistic treatment goals.

METHODS

This retrospective study included patients who underwent spinal metastasis at a university-based medical center in Thailand between January 2009 and November 2021. Collected data included preoperative parameters and ambulatory status 90 and 180 days following surgery. Thirteen machine-learning algorithms, namely, artificial neural network, logistic regression, CatBoost classifier, linear discriminant analysis, extreme gradient boosting, extra trees classifier, random forest classifier, gradient boosting classifier, light gradient boosting machine, naïve Bayes, K-neighbor classifier, Ada boost classifier, and decision tree classifier were developed to predict ambulatory status 90 and 180 days following surgery. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC) and F1-score.

RESULTS

In total, 167 patients were enrolled. The number of patients classified as ambulatory 90 and 180 days following surgery was 140 (81.9%) and 137 (82.0%), respectively. The extreme gradient boosting algorithm was found to most accurately predict 180-day ambulatory outcome (AUC, 0.85; F1-score, 0.90), and the decision tree algorithm most accurately predicted 90-day ambulatory outcome (AUC, 0.94; F1-score, 0.88).

CONCLUSIONS

Machine-learning algorithms were effective in predicting ambulatory status following surgery for spinal metastasis. Based on our data, the extreme gradient boosting and decision tree best predicted postoperative ambulatory status 180 and 90 days after spinal metastasis surgery, respectively.

Outcomes and Complications of Surgery for Symptomatic Spinal Metastases; a Comparison Between Patients Aged ≥ 70 and <70

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Physicians may be deterred from operating on elderly patients due to fears of poorer outcomes and complications. We aimed to compare the outcomes of surgical treatment of spinal metastases patients aged ≥70-yrs and <70-yrs.

MATERIALS AND METHODS

This is a retrospective study of patients surgically treated for metastatic epidural spinal cord compression and spinal instability between January-2005 to December-2021. Follow-up was till death or minimum 1-year post-surgery. Outcomes included post-operative neurological status, ambulatory status, medical and surgical complications. Two Sample t-test/Mann Whitney U test were used for numerical variables and Pearson Chi-Squared or Fishers Exact test for categorical variables. Survival was presented with a Kaplan-Meier curve. P < .05 was significant.

RESULTS

We identified 412 patients of which 29 (7.1%) patients were excluded due to loss to follow-up and previous surgical treatment. 79 (20.6%) were ≥70-yrs. Age ≥70-yrs patients had poorer ECOG scores (P = .0017) and Charlson Comorbidity Index (P < .001). No significant difference in modified Tokuhashi score (P = .393) was observed with significantly more ≥ prostate (P < .001) and liver (P = .029) cancer in ≥70-yrs. Improved or maintained normal neurological function (P = .934), independent ambulatory status (P = .171), and survival at 6 months (P = .119) and 12 months (P = .659) was not significantly different between both groups. Medical (P = .528) or surgical (P = .466) complication rates and readmission rates (P = .800) were similar.

CONCLUSION

≥70-yrs patients have comparable outcomes to <70-yr old patients with no significant increase in complication rates. Age should not be a determining factor in deciding surgical management of spinal metastases.

MRI feature-based radiomics models to predict treatment outcome after stereotactic body radiotherapy for spinal metastases

OBJECTIVE

This study aimed to extract radiomics features from MRI using machine learning (ML) algorithms and integrate them with clinical features to build response prediction models for patients with spinal metastases undergoing stereotactic body radiotherapy (SBRT).

METHODS

Patients with spinal metastases who were treated using SBRT at our hospital between July 2018 and April 2023 were recruited. We assessed their response to treatment using the revised Response Evaluation Criteria in Solid Tumors (version 1.1). The lesions were categorized into progressive disease (PD) and non-PD groups. Radiomics features were extracted from T1-weighted image (T1WI), T2-weighted image (T2WI), and fat-suppression T2WI sequences. Feature selection involved intraclass correlation coefficients, minimal-redundancy-maximal-relevance, and least absolute shrinkage and selection operator methods. Thirteen ML algorithms were employed to construct the radiomics prediction models. Clinical, conventional imaging, and radiomics features were integrated to develop combined models. Model performance was evaluated using receiver operating characteristic (ROC) curve analysis, and the clinical value was assessed using decision curve analysis.

RESULTS

We included 194 patients with 142 (73.2%) lesions in the non-PD group and 52 (26.8%) in the PD group. Each region of interest generated 2264 features. The clinical model exhibited a moderate predictive value (area under the ROC curve, AUC = 0.733), while the radiomics models demonstrated better performance (AUC = 0.745-0.825). The combined model achieved the best performance (AUC = 0.828).

CONCLUSION

The MRI-based radiomics models exhibited valuable predictive capability for treatment outcomes in patients with spinal metastases undergoing SBRT.

CRITICAL RELEVANCE STATEMENT

Radiomics prediction models have the potential to contribute to clinical decision-making and improve the prognosis of patients with spinal metastases undergoing SBRT.

KEY POINTS

• Stereotactic body radiotherapy effectively delivers high doses of radiation to treat spinal metastases. • Accurate prediction of treatment outcomes has crucial clinical significance. • MRI-based radiomics models demonstrated good performance to predict treatment outcomes.

Life-threatening perioperative complications among older adults with spinal metastases: An analysis based on a nationwide inpatient sample of the US

INTRODUCTION

We aimed to investigate the prognostic determinants of life-threatening and fatal complications in patients <80 and ≥ 20 years of age and those ≥80 years who were undergoing surgery for spinal metastases.

MATERIALS AND METHODS

Based on data between 2005 and 2018 extracted from National Inpatient Sample as the largest longitudinal hospital inpatient databases in the United States, statistical analyses were performed to identify prognostic factors (age, sex, household income, insurance status, major comorbidities, primary site of malignancy, types of surgery, surgical approaches, types of hospital admission, and hospital-related characteristics) for major and fatal perioperative complications among older adult patients.

RESULTS

A total of 31,925 patients aged ≥ 20y who were undergoing surgery for spinal metastasis were identified (< 80 y: n = 28,448; ≥ 80 y: n = 35,37). After adjustment, age ≥80 y was significantly associated with greater risk of perioperative cardiac arrest (adjusted odds ratio [aOR]: 1.34, 95% confidence interval [CI]: 1.03-1.73) and acute kidney injury (AKI) (aOR: 1.23, 95% CI: 1.07-1.41) but lower risk of venous thromboembolic event (VTE) (aOR: 0.80, 95% CI: 0.66-0.96) than <80y. Factors predicting life-threatening complications among patients ≥ 80y were: male sex (<80 y: aOR = 1.14; ≥ 80 y: aOR = 1.35), higher score on Charlson Comorbidity Index (CCI) (80 y, aOR = 1.21-2.67; ≥ 80 y: aOR = 1.25-2.55), open surgery (<80 y: aOR = 1.24; ≥ 80 y: aOR = 1.35), and greater Metastatic Spinal Tumor Frailty Index (MSTFI) (<80 y: aOR = 2.48-10.03; ≥ 80 y: aOR = 2.69-11.21). Among patients <80y, factors predicting life-threatening complications were: male sex, Black race, greater CCI score, primary tumor at kidney, hematologic cancer, other/unspecified primary site, certain surgical procedures, open surgery, greater MSTFI, emergent admission, and low hospital volume.

DISCUSSION

This study identifies a list of independent risk factors for the presence of life-threatening complications among patients <80 and ≥ 80y who were undergoing surgery for spinal metastasis. The findings contribute to the development of clinical strategies for the surgical management of spinal metastasis, especially for octogenarians, and lower the risk of unfavorable inpatient outcomes.

Spinal lesions in multiple myeloma: Primary bone tumors with distinct prognostic factors

PURPOSE

Although prognostic factors of spinal multiple myeloma (MM) seem to differ from those of other spine metastases (SpM), the data in the literature remains scarce.

METHODS

A prospective population of 361 patients treated for spine MM lesions between January 2014 and 2017.

RESULTS

OS for our series was 59.6 months (SD 6.0 months; CI 95%: 47.7-71.3). Cox multivariate proportional-hazards analysis showed that bone marrow transplant [HR: 0.390, 95% CI 0.264-0.577; p < 0.0001] and light-chain isotype [HR: 0.748, 95% CI 0.318-1.759; p = 0.005] were independent predictors of longer survival. In contrast, age >80 years [HR: 2.7, 95% CI 1.6-4.3; p < 0.0001], ISS III [HR: 2.510, 95% CI 2.01-3.124; p = 0.001], IgA isotype [HR: 1.475, 95% CI 1.031-2.11; p = 0.034] and IgD/M isotype [HR: 2.753, 95% CI 1.230-6.130; p = 0.013] were independent poor prognostic factors. However, ECOG (p = 0.486), spine surgery (p = 0.391), spine radiotherapy (p = 0.260), epidural involvement (p = 0.259), the number of vertebra lesions (p = 0.222), and synchronous/metachronous timeline (p = 0.412) were not significantly associated with improved OS.

CONCLUSIONS

Spinal involvement in the context of MM does not influence OS. The main prognostic factors to consider before spinal surgery are the characteristics of the primary MM disease (ISS score, IgG isotype and systemic treatment).

Simple and Reliable Magnetic Resonance Imaging Parameter to Predict Postoperative Ambulatory Function in Patients With Metastatic Epidural Spinal Cord Compression

STUDY DESIGN

Retrospective case-control study.

OBJECTIVES

The aim of this study was to develop a simple and reliable imaging parameter to predict postoperative ambulatory status in patients with metastatic epidural spinal cord compression (MESCC).

METHODS

Sixty-three patients with MESCC underwent spine surgery because of neurologic deficits were included. On preoperative axial MRI, the cord compression ratio was analyzed for postoperative ambulatory status. The relationship between other imaging features, such as fracture of the affected vertebra and increased T2 signal intensity of the spinal cord at the compression level, and the postoperative ambulatory status were also analyzed.

RESULTS

Cord compression ratio and increased T2 signal change of the spinal cord were significantly different between the postoperative ambulatory group and the non-ambulatory group. Receiver operating characteristic analysis showed that the optimal cut-off value was 0.84. In the multivariate regression analysis, only a cord compression ratio of more than 0.84 was significantly associated with postoperative ambulatory status (odds ratio = 10.80; 95% confidence interval = 2.79-41.86; P = .001). Interobserver/intraobserver agreements were strong for the cord compression ratio, however those agreements were weak for increased T2 signal intensity.

CONCLUSIONS

On preoperative MRI, the cord compression ratio may predict postoperative ambulatory status in patients with MESCC. The measurement of this imaging parameter was simple and reliable. This imaging predictor may be helpful for both clinicians and patients.

Predictive model based on DCE-MRI and clinical features for the evaluation of pain response after stereotactic body radiotherapy in patients with spinal metastases

OBJECTIVE

To investigate the correlation of conventional MRI, DCE-MRI and clinical features with pain response after stereotactic body radiotherapy (SBRT) in patients with spinal metastases and establish a pain response prediction model.

METHODS

Patients with spinal metastases who received SBRT in our hospital from July 2018 to April 2022 consecutively were enrolled. All patients underwent conventional MRI and DCE-MRI before treatment. Pain was assessed before treatment and in the third month after treatment, and the patients were divided into pain-response and no-pain-response groups. A multivariate logistic regression model was constructed to obtain the odds ratio and 95% confidence interval (CI) for each variable. C-index was used to evaluate the model's discrimination performance.

RESULTS

Overall, 112 independent spinal lesions in 89 patients were included. There were 73 (65.2%) and 39 (34.8%) lesions in the pain-response and no-pain-response groups, respectively. Multivariate analysis showed that the number of treated lesions, pretreatment pain score, Karnofsky performance status score, Bilsky grade, and the DCE-MRI quantitative parameter K^trans were independent predictors of post-SBRT pain response in patients with spinal metastases. The discrimination performance of the prediction model was good; the C index was 0.806 (95% CI: 0.721-0.891), and the corrected C-index was 0.754.

CONCLUSION

Some imaging and clinical features correlated with post-SBRT pain response in patients with spinal metastases. The model based on these characteristics has a good predictive value and can provide valuable information for clinical decision-making.

KEY POINTS

• SBRT can accurately irradiate spinal metastases with ablative doses. • Predicting the post-SBRT pain response has important clinical implications. • The prediction models established based on clinical and MRI features have good performance.

Validation of Traditional Prognosis Scoring Systems and Skeletal Oncology Research Group Nomogram for Predicting Survival of Spinal Metastasis Patients Undergoing Surgery

BACKGROUND

Many scoring systems that predict overall patient survival are based on clinical parameters and primary tumor type. To date, no consensus exists regarding which scoring system has the greatest predictive survival accuracy, especially when applied to specific primary tumors. Additionally, such scores usually fail to include modern treatment modalities, which influence patient survival. This study aimed to evaluate both the overall predictive accuracy of such scoring systems and the predictive accuracy based on the primary tumor.

METHODS

A retrospective review on spinal metastasis patients who were aged more than 18 years and underwent surgical treatment was conducted between October 2008 and August 2018. Patients were scored based on data before the time of surgery. A survival probability was calculated for each patient using the given scoring systems. The predictive ability of each scoring system was assessed using receiver operating characteristic analysis at postoperative time points; area under the curve was then calculated to quantify predictive accuracy.

RESULTS

A total of 186 patients were included in this analysis: 101 (54.3%) were men and the mean age was 57.1 years. Primary tumors were lung in 37 (20%), breast in 26 (14%), prostate in 20 (10.8%), hematologic malignancy in 18 (9.7%), thyroid in 10 (5.4%), gastrointestinal tumor in 25 (13.4%), and others in 40 (21.5%). The primary tumor was unidentified in 10 patients (5.3%). The overall survival was 201 days. For survival prediction, the Skeletal Oncology Research Group (SORG) nomogram showed the highest performance when compared to other prognosis scores in all tumor metastasis but a lower performance to predict survival with lung cancer. The revised Katagiri score demonstrated acceptable performance to predict death for breast cancer metastasis. The Tomita and revised Tokuhashi scores revealed acceptable performance in lung cancer metastasis. The New England Spinal Metastasis Score showed acceptable performance for predicting death in prostate cancer metastasis. SORG nomogram demonstrated acceptable performance for predicting death in hematologic malignancy metastasis at all time points.

CONCLUSIONS

The results of this study demonstrated inconsistent predictive performance among the prediction models for the specific primary tumor types. The SORG nomogram revealed the highest predictive performance when compared to previous survival prediction models.

The role of surgery in the treatment of metastatic bone tumor

Surgery for bone metastasis has two primary goals-palliative care to relieve pain, instability and paralysis, and tumor resection for curing the disease. Oncologically en bloc resection, followed by a reconstruction of the bone defect is the treatment of choice in single bone metastasis from renal cell carcinoma or thyroid cancer. Bone metastases may occur in the extremities, pelvis, or spine, and different resection and reconstruction methods depend on the regional anatomy. For instance, multiple options are available for reconstruction of the pelvis, especially for the acetabulum, including anatomical reconstruction using custom-made implants or recycled autologous bone grafting when a long-term prognosis is expected. Recently, for the spine, total en bloc spondylectomy is extensively performed despite the initial limitations of surgical invasiveness, such as blood loss. Principally, palliative surgery aims to maintain lasting bony stability with minimal surgical invasiveness. Intramedullary nails and plate fixation are frequently used in the extremities but the postoperative failure rate is relatively high. Therefore, surgeons should consider the use of long intramedullary nails and long-type stems for endoprosthesis reconstruction along with cement fixation to reduce the failure rate. Although short-term complications, such as dislocation, have been observed with endoprosthesis reconstruction, it is stable in the long-term follow-up. Percutaneous bone cement injection into the spine and pelvis is also effective and less invasive.

Characteristics of Patients Undergoing Surgical Treatment for Spinal Metastases From Colorectal Cancer: A Comparison With Non-Small Cell Lung Cancer

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

This study aimed to investigate the prognosis and characteristics of patients undergoing surgical treatment for colorectal cancer (CRC) spinal metastasis. To better understand the characteristics of such patients, their results were compared with those with spinal metastasis from non-small cell lung cancer (NSCLC), as the prognosis of these patients is well-studied.

SUMMARY OF BACKGROUND DATA

CRC commonly metastasizes to the liver or lung, while spinal metastases occur infrequently. The literature contains very few studies evaluating the prognosis of patients with spinal metastases from CRC.

MATERIALS AND METHODS

A consecutive 155 patients who underwent surgical treatment for spinal metastases from CRC (n=35) or NSCLC (n=120) between 2010 and 2018 were included in this study. Data were collected throughout the disease course, including those concerning all cancer-related treatments for both the primary cancer and spinal metastasis. Categorical variables were divided into patient, tumor, and treatment factors, and postoperative survival times were compared between the CRC and NSCLC groups.

RESULTS

The mean interval from cancer diagnosis to spinal metastasis was significantly greater in CRC group (32.5 mo) than in NSCLC group (12.9 mo). Concurrent spinal metastasis was more common in NSCLC group than CRC group (45.0% vs. 17.2%; P=0.003). Visceral metastasis was found more frequently in CRC group than NSCLC group (77.1% vs. 42.5%; P<0.001). The proportion of patients undergoing postoperative systemic treatment was significantly higher in NSCLC group than CRC group (59.2% vs. 20.0%; P<0.001). Median survival time after spine surgery was 4.2 months in CRC group and 5.8 months in NSCLC group (P=0.015).

CONCLUSIONS

The prognosis after surgical treatment for CRC spinal metastasis was poor, and worse than that of NSCLC group. These results can be explained by the later development of spinal metastases and the limited chance of postoperative medical treatment in CRC spinal metastasis.

Analysis of Short-Term versus Long-Term Readmission-Free Survival After Metastatic Spine Tumor Surgery

BACKGROUND

Readmission-free survival (ReAFS) is a novel clinical and quality metric after metastatic spine tumor surgery (MSTS). We believe that factors influencing ReAFS after index MSTS vary based on time. We considered 2 time frames and defined short-term ReAFS as survival without an unplanned hospital readmission up to 90 days and long-term ReAFS as survival without unplanned hospital readmission up to 1 year after MSTS.

METHODS

We retrospectively analyzed 266 patients who underwent MSTS between 2005 and 2016. All relevant oncologic, surgical and follow-up data were collected. Multivariate logistic regression analysis was used to analyze prognostic factors associated with higher probability of short-term ReAFS and long-term ReAFS.

RESULTS

Multivariate analysis showed that Eastern Cooperative Oncology Group score ≤2 (P = 0.011), preoperative hemoglobin (Hb) level >12 g/dL (P = 0.008), ≤3 comorbidities (P = 0.052), shorter index length of stay ≤10 days (P = 0.007), and absence of neurologic/hematologic complications during index stay (P = 0.015) significantly increased the probability of short-term ReAFS, whereas preoperative Hb level >12 g/dL (P = 0.003) or tumor primaries with advanced treatment modalities such as breast (P = 0.012), hematologic (P = 0.006), prostate (P = 0.004), and renal/thyroid (P = 0.038) as opposed to aggressive lung tumor primaries were associated with significantly higher probability of long-term ReAFS.

CONCLUSIONS

Patient and treatment factors predominantly influence ReAFS up to 90 days, whereas primary tumor-related factors alongside general health influence ReAFS beyond 90 days after index MSTS. Awareness of these factors may help oncologists and surgeons optimize treatment planning. The clinical significance of this study will continue to evolve, because we have been witnessing over the past decade that patients are becoming more involved in both their general health and understanding the natural history of the diseases that affect them.

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.

Prognostic scores for survival as decisional support for surgery in spinal metastases: a performance assessment systematic review

PURPOSE

To review the evidence on the relative prognostic performance of the available prognostic scores for survival in spinal metastatic surgery in order to provide a recommendation for use in clinical practice.

METHODS

A systematic review of comparative external validation studies assessing the performance of prognostic scores for survival in independent cohorts was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Eligible studies were identified through Medline and Embase until May 2021. Studies were included when they compared at least four survival scoring systems in surgical or mixed cohorts across all primary tumor types. Predictive performance was assessed based on discrimination and calibration for 3-month, 1-year and overall survival, and generalizability was assessed based on the characteristics of the development cohort and external validation cohorts. Risk of bias and concern regarding applicability were assessed based on the 'Prediction model study Risk Of Bias Assessment Tool' (PROBAST).

RESULTS

Twelve studies fulfilled the inclusion criteria and covered 17 scoring systems across 5.130 patients. Several scores suffer from suboptimal development and validation. The SORG Nomogram, developed in a large surgical cohort, showed good discrimination on 3-month and 1-year survival, good calibration and was superior in direct comparison with low risk of bias and low concern regarding applicability. Machine learning algorithms are promising as they perform equally well in direct comparison. Tokuhashi, Tomita and other traditional risk scores showed suboptimal performance.

CONCLUSION

The SORG Nomogram and machine learning algorithms outline superior performance in survival prediction for surgery in spinal metastases. Further improvement by comparative validation in large multicenter, prospective cohorts can still be obtained. Given the heterogeneity of spinal metastases, superior methodology of development and validation is key in improving future machine learning systems.

Surgical Metastasectomy in the Spine: A Review Article

BACKGROUND

The use of surgical metastasectomy (SM) has increased across cancer types in recent decades despite the increasing efficacy of modern systemic treatment modalities. Symptomatic spinal metastases severely compromise patients' performance status. However, as spinal SM is a complex surgery with potentially significant complications, it is not considered the treatment of choice.

METHODS

We reviewed the articles on SM in several primary cancers with different types of metastatic lesions and extracted the data from relevant articles to provide a comprehensive review including the surgical techniques, indications, reported outcomes, and future prospects of SM in spinal metastases.

RESULTS

Total en bloc spondylectomy (TES) is a method of spinal SM associated with a lower risk of tumor recurrence and complications. Intralesional transpedicular osteotomy using a fine threadwire saw allows prevention of spinal cord and nerve root injuries. Spinal SM is considered suitable for patients with controlled primary disease having no evidence of disseminated extraspinal metastases, a completely resectable solitary lesion in the spine, and adequate cardiopulmonary reserve to tolerate the surgery. Metastatic lesions from kidney and thyroid cancers have been reported as the best candidates for spinal SM. Although data about spinal SM are limited, the reported outcomes are favorable with acceptable local recurrence rates in long-term follow-up.

CONCLUSION

In patients with isolated resectable spinal metastases, complete SM including TES is a useful option as it can improve function and survival. However, appropriate patient selection and surgical feasibility remain the most important aspects of management.

IMPLICATIONS FOR PRACTICE

Surgical metastasectomy for spinal metastases may be a potentially curative treatment option with a low risk of local recurrence and lead to prolonged long-term survival if appropriate patients are selected and if the surgery is carried out by experienced surgeons in high-volume centers.

Radiotherapy and Surgical Advances in the Treatment of Metastatic Spine Tumors: A Narrative Review

Spine tumors encompass a wide range of diseases with a commensurately broad spectrum of available treatments, ranging from radiation for spinal metastases to highly invasive en bloc resection for primary vertebral column malignancies. This high variability in treatment approaches stems both from variability in the goals of surgery (e.g., oncologic cure vs. symptom palliation) and from the significant advancements in surgical technologies that have been made over the past 2 decades. Among these advancements are improvements in surgical technique, namely minimally invasive approaches, increased availability of focused radiation modalities (e.g., proton therapy and linear accelerator devices), and new surgical technologies, such as carbon fiber-reinforced polyether ether ketone rods. In addition, several groups have described nonsurgical interventions, such as vertebroplasty and kyphoplasty for spinal instability secondary to pathologic fracture, and lesion ablation with spinal laser interstitial thermoablation, radiofrequency ablation, or cryoablation. We provide an overview of the latest technological advancements in spinal oncology and their potential usefulness for modern spinal oncologists.

Surgical management of spinal metastases involving the cervicothoracic junction: results of a multicenter, European observational study

OBJECTIVE

Surgical management of spinal metastases at the cervicothoracic junction (CTJ) is highly complex and relies on case-based decision-making. The aim of this multicentric study was to describe surgical procedures for metastases at the CTJ and provide guidance for clinical and surgical management.

METHODS

Patients eligible for this study were those with metastases at the CTJ (C7-T2) who had been consecutively treated in 2005-2019 at 7 academic institutions across Europe. The Spine Instability Neoplastic Score, neurological function, clinical status, medical history, and surgical data for each patient were retrospectively assessed. Patients were divided into four surgical groups: 1) posterior decompression only, 2) posterior decompression and fusion, 3) anterior corpectomy and fusion, and 4) anterior corpectomy and 360° fusion. Endpoints were complications, surgical revision rate, and survival.

RESULTS

Among the 238 patients eligible for inclusion this study, 37 were included in group 1 (15%), 127 in group 2 (53%), 18 in group 3 (8%), and 56 in group 4 (24%). Mechanical pain was the predominant symptom (79%, 189 patients). Surgical complications occurred in 16% (group 1), 20% (group 2), 11% (group 3), and 18% (group 4). Of these, hardware failure (HwF) occurred in 18% and led to surgical revision in 7 of 8 cases. The overall complication rate was 34%. In-hospital mortality was 5%.

CONCLUSIONS

Posterior fusion and decompression was the most frequently used technique. Care should be taken to choose instrumentation techniques that offer the highest possible biomechanical load-bearing capacity to avoid HwF. Since the overall complication rate is high, the prevention of in-hospital complications seems crucial to reduce in-hospital mortality.

The Effect of Adding Biological Factors to the Decision-Making Process for Spinal Metastasis of Non-Small Cell Lung Cancer

Molecular target therapies have markedly improved the survival of non-small cell lung cancer (NSCLC) patients, especially those with epidermal growth factor receptor (EGFR) mutations. A positive EGFR mutation is even more critical when the chronicity of spinal metastasis is considered. However, most prognostic models that estimate the life expectancy of spinal metastasis patients do not include these biological factors. We retrospectively reviewed 85 consecutive NSCLC patients who underwent palliative surgical treatment for spinal metastases to evaluate the following: (1) the prognostic value of positive EGFR mutation and the chronicity of spinal metastasis, and (2) the clinical significance of adding these two factors to an existing prognostic model, namely the New England Spinal Metastasis Score (NESMS). Among 85 patients, 38 (44.7%) were EGFR mutation-positive. Spinal metastasis presented as the initial manifestation of malignancy in 58 (68.2%) patients. The multivariate Cox proportional hazard model showed that the chronicity of spinal metastasis (hazard ratio (HR) = 1.88, p = 0.015) and EGFR mutation positivity (HR = 2.10, p = 0.002) were significantly associated with postoperative survival. The Uno’s C-index and time-dependent AUC 6 months following surgery significantly increased when these factors were added to NESMS (p = 0.004 and p = 0.022, respectively). In conclusion, biological factors provide an additional prognostic value for NSCLC patients with spinal metastasis.

Analysis of unplanned hospital readmissions up to 2-years after metastatic spine tumour surgery

PURPOSE

The aim of this study was to investigate rates, causes, and risk factors of unplanned hospital readmissions (UHR) within 30 days, 90 days, 1 year and 2 years after metastatic spine tumour surgery (MSTS) to augment multi-disciplinary treatment planning and improve patient education.

METHODS

We retrospectively reviewed 272-patients who underwent MSTS between 2005 and 2016. Hospital records were utilised to obtain demographics, oncological, procedural details, and postoperative outcomes. All UHR within 2 years were reviewed. Primary outcomes were rates, causes, and risk factors of UHR. Risk factors for UHR were evaluated utilising multivariate logistic regression analysis.

RESULTS

Thirty-day, 90 day, 1 year, and 2 year UHR-rates after MSTS were 17.2%, 31.1%, 46.2%, and 52.7%, respectively. Lung cancer primaries had the highest UHR-events (24.7%) whilst renal/thyroid displayed the least (6.6%). Disease-related causes (16.2%) were the most common reason for readmissions across all timeframes, followed by respiratory (13.7%) and progression of metastatic spine disease (12.7%). Urological conditions accounted for majority of readmissions within 30-days; disease-related causes, symptomatic spinal metastases, and respiratory conditions represented the most common causes at 30-90 days, 90 days-1 year, and 1-2 years, respectively. An ECOG >1 (p = 0.057), CCI >7 (p = 0.01), and primary lung tumour (p = 0.02) significantly increased UHR-risk on multivariate analysis.

CONCLUSION

Seventy-four percent of patients had at least one UHR within 2 years of MSTS and majority were secondary to disease-related causes. Majority of first UHR occurred between 30 and 90 days post-surgery. Local disease progression and overall disease progression account for the highest UHR-events at 90 days-1 year and 1-2 year timeframes, respectively. We define UHR in specific timeframes, thus enabling better surveillance and reducing unnecessary morbidity.

Readmission-Free Survival Analysis in Metastatic Spine Tumour Surgical Patients: A Novel Concept

BACKGROUND

Outcomes commonly used to ascertain success of metastatic spine tumour surgery (MSTS) are 30-day complications/mortality and overall/disease-free survival. We believe a new, effective outcome indicator after MSTS would be the absence of unplanned hospital readmission (UHR) after index discharge. We introduce the concept of readmission-free survival (ReAFS), defined as 'the time duration between hospital discharge after index operation and first UHR or death'. The aim of this study is to identify factors influencing ReAFS in MSTS patients.

PATIENTS AND METHODS

We retrospectively analysed 266 consecutive patients who underwent MSTS between 2005 and 2016. Demographics, oncological characteristics, procedural, preoperative and postoperative details were collected. ReAFS of patients within 2 years or until death was reviewed. Perioperative factors predictive of reduced ReAFS were evaluated using multivariate regression analysis.

RESULTS

Of 266 patients, 230 met criteria for analysis. A total of 201 had UHR, whilst 1 in 8 (29/230) had no UHR. Multivariate analysis revealed that haemoglobin ≥ 12 g/dL, ECOG score of ≤ 2, primary prostate, breast and haematological cancers, comorbidities ≤ 3, absence of preoperative radiotherapy and shorter postoperative length of stay significantly prolonged the time to first UHR.

CONCLUSIONS

Readmission-free survival is a novel concept in MSTS, which relies on patients' general condition, appropriateness of interventional procedures and underlying disease burden. Additionally, it may indicate the successful combination of a multi-disciplinary treatment approach. This information will allow oncologists and surgeons to identify patients who may benefit from increased surveillance following discharge to increase ReAFS. We envisage that ReAFS is a concept that can be extended to other surgical oncological fields.

To operate, or not to operate? Narrative review of the role of survival predictors in patient selection for operative management of patients with metastatic spine disease

Accurate prediction of patient survival is an essential component of the preoperative evaluation of patients with spinal metastases. Over the past quarter of a century, a number of predictors have been developed, although none have been accurate enough to be instituted as a staple of clinical practice. However, recently more comprehensive survival calculators have been published that make use of larger data sets and machine learning to predict postoperative survival among patients with spine metastases. Given the glut of calculators that have been published, the authors sought to perform a narrative review of the current literature, highlighting existing calculators along with the strengths and weaknesses of each. In doing so, they identify two "generations" of scoring systems-a first generation based on a priori factor weighting and a second generation comprising predictive tools that are developed using advanced statistical modeling and are focused on clinical deployment. In spite of recent advances, the authors found that most predictors have only a moderate ability to explain variation in patient survival. Second-generation models have a greater prognostic accuracy relative to first-generation scoring systems, but most still require external validation. Given this, it seems that there are two outstanding goals for these survival predictors, foremost being external validation of current calculators in multicenter prospective cohorts, as the majority have been developed from, and internally validated within, the same single-institution data sets. Lastly, current predictors should be modified to incorporate advances in targeted systemic therapy and radiotherapy, which have been heretofore largely ignored.

Predicting tumor-specific survival in patients with spinal metastatic renal cell carcinoma: which scoring system is most accurate?

OBJECTIVE

Although several prognostic scores for spinal metastatic disease have been developed in the past 2 decades, the applicability and validity of these models to specific cancer types are not yet clear. Most of the data used for model formation are from small population sets and have not been updated or externally validated to assess their performance. Developing predictive models is clinically relevant as prognostic assessment is crucial to optimal decision-making, particularly the decision for or against spine surgery. In this study, the authors investigated the performance of various spinal metastatic disease risk models in predicting prognosis for spine surgery to treat metastatic renal cell carcinoma (RCC).

METHODS

Data of patients who underwent surgery for RCC metastatic to the spine at 2 tertiary centers between 2010 and 2019 were retrospectively retrieved. The authors determined the prognostic value associated with the following scoring systems: the Tomita score, original and revised Tokuhashi scores, original and modified Bauer scores, Katagiri score, the Skeletal Oncology Research Group (SORG) classic algorithm and nomogram, and the New England Spinal Metastasis Score (NESMS). Regression analysis of patient variables in association with 1-year survival after surgery was assessed using Cox proportional hazard models. Calibration and time-dependent discrimination analysis were tested to quantify the accuracy of each scoring system at 3 months, 6 months, and 1 year.

RESULTS

A total of 86 metastatic RCC patients were included (median age 64 years [range 29-84 years]; 63 males [73.26%]). The 1-year survival rate was 72%. The 1-year survival group had a good performance status (Karnofsky Performance Scale [KPS] score 80%-100%) and an albumin level > 3.5 g/dL (p < 0.05). Multivariable-adjusted Cox regression analysis showed that poor performance status (KPS score < 70%), neurological deficit (Frankel grade A-D), and hypoalbuminemia (< 3.5 g/dL) were associated with a higher risk of death before 1 year (p < 0.05). The SORG nomogram, SORG classic, original Tokuhashi, and original Bauer demonstrated fair performance (0.7 < area under the curve < 0.8). The NESMS differentiates survival among the prognostic categories with the highest accuracy (area under the curve > 0.8).

CONCLUSIONS

The present study shows that the most cited and commonly used scoring systems have a fair performance predicting survival for patients undergoing spine surgery for metastatic RCC. The NESMS had the best performance at predicting 1-year survival after surgery.

A Personalized Medicine Approach for the Management of Spinal Metastases with Cord Compression: Development of a Novel Clinical Prediction Model for Postoperative Survival and Quality of Life

Surgery should be considered for patients with metastatic epidural spinal cord compression (MESCC) with a life expectancy of ≥3 months. Given the heterogeneity of the clinical presentation and outcomes, clinical prognostic models (CPMs) can assist in tailoring a personalized medicine approach to optimize surgical decision-making. We aimed to develop and internally validate the first CPM of health-related quality of life (HRQoL) and a novel CPM to predict the survival of patients with MESCC treated surgically. Using data from 258 patients (AOSpine North America MESCC study and Nottingham MESCC registry), we created 1-year survival and HRQoL CPMs using a Cox model and logistic regression analysis with manual backward elimination. The outcome measure for HRQoL was the minimal clinical important difference in EuroQol 5-dimension questionnaire scores. Internal validation involved 200 bootstrap iterations, and calibration and discrimination were evaluated. Longer survival was associated with a higher SF-36 physical component score (hazard ratio [HR], 0.96). In contrast, primary tumor other than breast, thyroid, or prostate (unfavorable: HR, 2.57; other: HR, 1.20), organ metastasis (HR, 1.51), male sex (HR, 1.58), and preoperative radiotherapy (HR, 1.53) were not (c-statistic, 0.69; 95% confidence interval, 0.64-0.73). Karnofsky performance status <70% (odds ratio [OR], 2.50), living in North America (OR, 4.06), SF-36 physical component score (OR, 0.95) and SF-36 mental component score (OR, 0.96) were associated with the likelihood of achieving a minimal clinical important difference improvement in the EuroQol 5-Dimension Questionnaire score at 3 months (c-statistic, 0.74; 95% confidence interval, 0.68-0.79). The calibration for both CPMs was very good. We developed and internally validated the first CPMs of survival and HRQoL at 3 months postoperatively in patients with MESCC using the TRIPOD (transparent reporting of a multivariable prediction model for individual prognosis or diagnosis) guidelines. A web-based calculator is available (available at: http://spine-met.com) to assist with clinical decision-making.

Treatment Strategy for Metastatic Spinal Tumors: A Narrative Review

Metastatic spinal tumors are common, and their rising incidence can be attributed to the expanding aging population and increased survival rates among cancer patients. The decision-making process in the treatment of spinal metastasis requires a multidisciplinary approach that includes medical and radiation oncology, surgery, and rehabilitation. Various decision-making systems have been proposed in the literature in order to estimate survival and suggest appropriate treatment options for patients experiencing spinal metastasis. However, recent advances in treatment modalities for spinal metastasis, such as stereotactic radiosurgery and minimally invasive surgical techniques, have reshaped clinical practices concerning patients with spinal metastasis, making a demand for further improvements on current decision-making systems. In this review, recent improvements in treatment modalities and the evolution of decision-making systems for metastatic spinal tumors are discussed.

Spine and Non-spine Bone Metastases - Current Controversies and Future Direction

Bone is a common site of metastases in advanced cancers. The main symptom is pain, which increases morbidity and reduces quality of life. The treatment of bone metastases needs a multidisciplinary approach, with the main aim of relieving pain and improving quality of life. Apart from systemic anticancer therapy (hormonal therapy, chemotherapy or immunotherapy), there are several therapeutic options available to achieve palliation, including analgesics, surgery, local radiotherapy, bone-seeking radioisotopes and bone-modifying agents. Long-term use of non-steroidal analgesics and opiates is associated with significant side-effects, and tachyphylaxis. Radiotherapy is effective mainly in localised disease sites. Bone-targeting radionuclides are useful in patients with multiple metastatic lesions. Bone-modifying agents are beneficial in reducing skeletal-related events. This overview focuses on the role of surgery, including minimally invasive treatments, conventional radiotherapy in spinal and non-spinal bone metastases, bone-targeting radionuclides and bone-modifying agents in achieving palliation. We present the clinical data and their associated toxicity. Recent advances are also discussed.

Surgical treatment of metastatic spine disease: an update on national trends and clinical outcomes from 2010 to 2014

BACKGROUND CONTEXT

Metastatic spine disease (MSD) is becoming more prevalent as medical treatment for cancers advance and extend survival. More MSD patients are treated surgically to maintain neurological function, ambulation, and quality of life.

PURPOSE

The purpose of this study was to use a large, nationally representative database to examine the trends, patient outcomes, and health-care resource utilization associated with surgical treatment of MSD.

DESIGN

This was an epidemiologic study using national administrative data from the Nationwide Readmissions Database (NRD).

PATIENT SAMPLE

All patients in the NRD from 2010 to 2014 who underwent spinal surgery were included in the study.

OUTCOME MEASURES

Mortality, blood transfusion, complications, length of stay, cost, and discharge location during index hospitalization as well as hospital readmission and revision surgery within 90-days of surgery were analyzed.

METHODS

International Classification of Diseases, Ninth Revision, (ICD-9) codes was used to identify patients of interest within the NRD from 2010 to 2014. Patients were separated into two cohorts - those with MSD and those without. Trends for surgical treatment of MSD were assessed and outcomes measures for both cohorts were analyzed and compared.

RESULTS

The number of surgical treatments for MSD increased from 6,007 in 2010 to 7,032 in 2014 (p-trend<.0001) which represented a 17.1% increase. During index hospitalization, MSD patients had an increased risk of mortality (odds ratio [OR]=3.22, 95% confidence interval [CI]: 2.85-3.63, p<.0001), blood transfusion (OR=2.93, 95% CI: 2.66-3.23, p<.0001), any complication (OR=1.24, 95% CI: 1.18-1.31, p<.0001), and discharge to skilled nursing facility (OR=1.51, 95% CI:1.41-1.61, p<.0001). MSD patients had longer average length of stay (13.05 vs. 4.56 days, p<.0001) and cost ($49,421.75 vs. $26,190.37, p<.0001) during index hospitalization. Furthermore, MSD patients had an increased risk of hospital readmission (OR=2.82, 95% CI: 2.68-2.96, p<.0001), readmission for surgical site infection (OR=2.38, 95% CI: 2.20-2.58, p<.0001), and readmission with neurologic deficits (OR=1.62, 95% CI: 1.27-2.06, p<.0001) despite a decreased risk of revision fusion (OR=0.71, 95% CI: 0.53-0.96, p=.026).

CONCLUSIONS

The number of MSD patients who undergo surgical treatments is increasing. Not only do these patients have worse outcomes during index hospitalization, but they are also at an increased risk of hospital readmission for surgical site infection and neurologic complications. These findings stress the need for multidisciplinary perioperative treatment plans that mitigate risks and facilitate quick, effective recovery in these unique, at-risk patients.

Development of Machine Learning Algorithms for Prediction of 30-Day Mortality After Surgery for Spinal Metastasis

BACKGROUND

Preoperative prognostication of short-term postoperative mortality in patients with spinal metastatic disease can improve shared decision making around end-of-life care.

OBJECTIVE

To (1) develop machine learning algorithms for prediction of short-term mortality and (2) deploy these models in an open access web application.

METHODS

The American College of Surgeons, National Surgical Quality Improvement Program was used to identify patients that underwent operative intervention for metastatic disease. Four machine learning algorithms were developed, and the algorithm with the best performance across discrimination, calibration, and overall performance was integrated into an open access web application.

RESULTS

The 30-d mortality for the 1790 patients undergoing surgery for spinal metastatic disease was 8.49%. Preoperative factors used for prognostication were albumin, functional status, white blood cell count, hematocrit, alkaline phosphatase, spinal location (cervical, thoracic, lumbosacral), and severity of comorbid systemic disease (American Society of Anesthesiologist Class). In this population, machine learning algorithms developed to predict 30-d mortality performed well on discrimination (c-statistic), calibration (assessed by calibration slope and intercept), Brier score, and decision analysis. An open access web application was developed for the best performing model and this web application can be found here: https://sorg-apps.shinyapps.io/spinemets/.

CONCLUSION

Machine learning algorithms are promising for prediction of postoperative outcomes in spinal oncology and these algorithms can be integrated into clinically useful decision tools. As the volume of data in oncology continues to grow, creation of learning systems and deployment of these systems as accessible tools may significantly enhance prognostication and management.

Perspectives on Spinal Precautions in Patients Who Have Cancer and Spinal Metastasis

Bones are the third most common site for cancer metastases, and the axial skeleton is the most frequent skeletal location. In a postmortem study, bone metastases were reported in 70% of breast and prostate cancer patients. Bone metastases from breast, lung, prostate, thyroid, and kidney cancers account for 80% of all bone metastases. Bone lesions exist in 60% of newly diagnosed multiple myeloma patients. With increasing numbers of people who have survived cancer, many patients with cancer and axial skeletal bony metastases will be seen by physical and occupational therapists. Guidelines are lacking on how to perform physical examinations and provide exercise programs for these patients without compromising the diseased spine. In this article, we discuss the available evidence for similar spinal conditions, the biomechanics of spinal load, and changes associated with posture and weight load. We provide recommendations on how to assess a patient's strength, how to strengthen without compromising the diseased spine, and how to teach patients to use correct body mechanics during mobility and activities of daily living.

Research on the predicting power of the revised Tokuhashi system: how much time can surgery give to patients with short life expectancy?

Object

The primary treatment option for symptomatic metastatic spinal tumors is surgery. Prognostic systems are designed to assist in the establishment of the indication and the choice of surgical methodology. The best-known prognostic system is the revised Tokuhashi system, which has a predictive ability of about 60%. In our study, we are attempting to find the reason for its poor predictive ability, despite its proper separation ability.

Methods

We have designed a one-center-based retrospective clinical trial, by which we would like to test the feasibility and the inaccuracy of the revised Tokuhashi system. In our database, there are 329 patients who underwent surgery. Statistical analysis was performed.

Results

A significant increase in survival time was observed in the ‘conservative’ category. Earlier studies reported OS 0.15 at the 180-day control time, in contrast with our 0.38 OS value. The literature suggested supportive care for this category, but in our population, every patient underwent surgery. Our population passes the 0.15 OS value on day 475. We propose an adjustment of the Tokuhashi category scores. We observed significant success in resolving pain. Motor functions were improved or stabilized compared to changes in vegetative dysfunction.

Conclusion

According to our results, the Tokuhashi scoring system makes very conservative predictions and prefers non-surgical palliative or supportive care. Surgical treatment increases the life expectancy of patients in poor condition. We propose modifying the therapeutic options of the revised Tokuhashi system, taking into consideration modern spine surgery techniques.

Spinal Metastasis Surgery: A Proposal for a Predictive Model of Morbidity and Mortality

Objective  To develop a predictive model of early postoperative morbidity and mortality with the purpose of assisting in the selection of the candidates for spinal metastasis surgery.

Methods  A retrospective analysis of consecutive patients operated for metastatic spinal disease. The possible prognostic preoperative characteristics were gender, age, comorbidities, tumor growth rate, and leukocyte and lymphocyte count in the peripheral blood. The postoperative outcomes were 30-day mortality, 90-day mortality and presence of complications. A predictive model was developed based on factors independently associated with these three outcomes. The final model was then tested for the tendency to predict adverse events, discrimination capacity and calibration.

Results  A total of 205 patients were surgically treated between 2002 and 2015. The rates of the 30-day mortality, 90-day mortality and presence of complications were of 17%, 42% and 31% respectively. The factors independently associated with these three outcomes, which constituted the predictive model, were presence of comorbidities, no slow-growing primary tumor, and lymphocyte count below 1,000 cells/µL. Exposure to none, one, two or three factors was the criterion for the definition of the following categories of the predictive model: low, moderate, high and extreme risk respectively. Comparing the risk categories, there was a progressive increase in the occurrence of outcomes, following a linear trend. The discrimination capacity was of 72%, 73% and 70% for 30-day mortality, 90-day mortality and complications respectively. No lack of calibration occurred.

Conclusion  The predictive model estimates morbidity and mortality after spinal metastasis surgery and hierarchizes risks as low, moderate, high and extreme.

Predictive Analytics in Spine Oncology Research: First Steps, Limitations, and Future Directions

The potential of big data analytics to improve the quality of care for patients with spine tumors is significant. At this moment, the application of big data analytics to oncology and spine surgery is at a nascent stage. As such, efforts are underway to advance data-driven oncologic care, improve patient outcomes, and guide clinical decision making. This is both relevant and critical in the practice of spine oncology as clinical decision making is often made in isolation looking at select variables deemed relevant by the physician. With rapidly evolving therapeutics in surgery, radiation, interventional radiology, and oncology, there is a need to better develop decision-making algorithms utilizing the vast data available for each patient. The challenges and limitations inherent to big data analyses are presented with an eye towards future directions.

Association of neurologic deficits with surgical outcomes and health-related quality of life after treatment for metastatic epidural spinal cord compression

BACKGROUND

A critical knowledge gap exists regarding the impact of neurologic deficits on surgical outcomes and health-related quality of life (HRQOL) for patients surgically treated for metastatic epidural spinal cord compression (MESCC).

METHODS

This prospective, multicenter and international study analyzed the impact of the neurologic status on functional status, HRQOL, and postoperative survival. The collected data included the patient demographics, overall survival, American Spinal Injury Association (ASIA) impairment scale, Spinal Instability Neoplastic Score, treatment details and complications and HRQOL measures, including version 2 of the 36-Item Short Form Health Survey (SF-36v2) and version 2.0 of the Spine Oncology Study Group Outcomes Questionnaire (SOSGOQ2.0).

RESULTS

A total of 239 patients surgically treated for spinal metastases were included. Six weeks after treatment, 99 of the 108 patients with a preoperative ASIA grade of E remained stable, 8 deteriorated to ASIA D, and 1 deteriorated to ASIA A. Of 55 patients with ASIA D, 27 improved to ASIA E, 27 remained stable and 1 deteriorated to ASIA C. Of 11 patients with ASIA A to C, 2 improved to ASIA E, 4 improved to ASIA D, and 5 remained stable. At the 6- and 12-week follow-up, better ASIA scores were associated with better scores on multiple SF-36v2 and SOSGOQ items. Postoperatively, patients with ASIA grades of A to D were more likely to have urinary tract infections and wound complications. Patients with a baseline ASIA grade of E or D survived significantly longer.

CONCLUSIONS

Patients with neurologic deficits due to MESCC have worse HRQOL and decreased overall survival. Nevertheless, surgery can result in stabilization or improvement of neurologic function which may translate into better HRQOL. Postoperative care and follow-up are challenging for patients with neurologic deficits because they experience more complications.

Outcomes of surgical treatments of spinal metastases: a prospective study

BACKGROUND

Owing to recent advances in cancer therapy, updated data are required for clinicians counselling patients on treatment of spinal metastases.

OBJECTIVE

To analyse the outcomes of surgical treatments of spinal metastases.

METHODS

Prospective and multicentric study that included consecutively patients operated on for spinal metastases between January 2016 and January 2017. Overall survival was calculated with the Kaplan-Meier method. Cox proportional hazard model was used to calculate hazard ratio (HR) analysing mortality risk according to preoperative Karnofsky performance status (KPS), mobility level and neurological status.

RESULTS

A total of 252 patients were included (145 males, 107 females) aged a mean 63.3 years. Median survival was 450 days. Primary cancer sites were lung (21%) and breast (19%). Multiple spinal metastases involved 122 patients (48%). Concomitant skeletal and visceral metastases were noted in 90 patients (36%). Main procedure was laminectomy and posterior fixation (57%). Overall, pain and mobility level were improved postoperatively. Most patients had normal preoperative motor function (50%) and remained so postoperatively. Patients "bedbound" on admission were the less likely to recover. In-hospital death rate was 2.4% (three disease progression, one septic shock, one pneumonia, one pulmonary embolism). Complication rate was 33%, deep wound infection was the most frequent aetiology. Higher mortality was observed in patients with poorest preoperative KPS (KPS 0-40%, HR = 3.1, p < 0.001) and mobility level ("bedbound", HR = 2.16, p < 0.001). Survival seemed also to be linked to preoperative neurological function.

CONCLUSION

Surgical treatments helped maintain reasonable condition for patients with spinal metastases. Intervention should be offered before patients' condition worsen to ensure better outcomes.

The homogeneous and heterogeneous risk factors for occurrence and prognosis in lung cancer patients with bone metastasis

Purpose

To analyse the homogeneous and heterogeneous risk factors for occurrence and prognosis in lung cancer patients diagnosed with bone metastasis (BM) by using the Surveillance, Epidemiology, and End Results (SEER) database.

Patients and methods

The medical records of lung cancer patients with or without bone metastasis were identified in the SEER database between 2010 and 2015. A multivariate logistic regression analysis was performed to identify risk factors, and a multivariate Cox regression was used to determine the prognostic effects of every variable on survival.

Results

In total, 34,585 eligible patients from the SEER database were included in the analysis. Male gender and metastasis to the liver were factors that were both positively associated with a risk for the development and prognosis of bone metastasis in patients with lung cancer. Younger age, poor tumour differentiation grade, higher N stage (N3), adenocarcinoma and metastasis to the brain were all positively correlated with a risk of occurrence of BM, but these factors were not correlated with an unfavourable prognosis. Age, race, marital status, tumour size and pathologic type were independent risk factors for the prognosis of bone metastasis.

Conclusion

The morbidity of bone metastasis in lung cancer patients is dismal, with a rate of 25.9%. The findings of this study estimate the homogeneous and heterogeneous risk factors for the occurrence and prognosis of bone metastasis in lung cancer patients, which may provide clinical guidelines for physicians.

Treatment, complications, and outcomes of metastatic disease of the spine: from Patchell to PROMIS

Spinal metastases are common in patients with cancer. As cancer treatments improve and these patients live longer, the number who present with metastatic spine disease will increase. Treatment strategies for these patients continues to evolve. In particular, since the prospective randomized controlled study in 2005 by Patchell et al. showed increased survival with decompressive surgical treatment of spinal metastases, there is a growing body of literature focusing on surgical management and complications of surgery for this disease. Surgery is often one component of a multimodal treatment approach with chemotherapy and radiation, which makes it difficult to parse the benefits of each individual treatment in outcome studies. Additionally, there has been more recent emphasis placed on patient-reported outcomes (PRO) after treatment for metastatic spine disease. In this review, we summarize treatments of metastatic spinal disease, possible perioperative complications, and validated tools used to assess outcomes for these patients.

Prognostic Factors for Patients With Undifferentiated High Grade Pleomorphic Sarcoma of the Spine

STUDY DESIGN

Retrospective survival analysis of 44 undifferentiated high grade pleomorphic sarcoma (UPS) of the spine.

OBJECTIVE

To identify factors related to overall survival (OS) and help decision making in the treatment of undifferentiated high grade pleomorphic sarcoma of the spine.

SUMMARY OF BACKGROUND DATA

UPS is an aggressive malignant tumor rarely originating from the spine. Due to its scarcity, only a few studies had been reported to describe the clinical features, treatments, and outcomes of sporadic cases, devoid of evaluation on prognostic factors.

METHODS

Enrolled in this survival analysis were 44 patients who underwent surgery and adjuvant therapies from January 1999 to December 2015. Kaplan-Meier methods were applied to estimate the overall survival. A multivariate Cox algorithm was applied to recognize factors independently associated with overall survival.

RESULTS

Multivariate analysis suggested that age greater than or equal to 55 years (hazard ratio [HR], 3.923, P < 0.001), Eastern Cooperative Oncology Group (ECOG) score four (HR, 4.656, P < 0.001), and subtotal resection or piecemeal total resection (HR, 4.375, P < 0.001) were independently associated with poor overall survival.

CONCLUSION

We identified independent prognostic factors of UPS of the spine. Subtotal resection or piecemeal total resection, age more than or equal to 55 years and ECOG score four are factors adversely affecting overall survival of patients with UPS of the spine.

LEVEL OF EVIDENCE

4.

Hypoalbuminemia as an Independent Risk Factor for Perioperative Complications Following Surgical Decompression of Spinal Metastases

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Malnutrition has been shown to be a risk factor for poor perioperative outcomes in multiple surgical subspecialties, but few studies have specifically investigated the effect of hypoalbuminemia in patients undergoing operative treatment of metastatic spinal tumors. The aim of this study was to assess the role of hypoalbuminemia as an independent risk factor for 30-day perioperative mortality and morbidity after surgical decompression of metastatic spinal tumors using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2011 to 2014.

METHODS

We identified 1498 adult patients in the ACS-NSQIP database who underwent laminectomy and excision of metastatic extradural spinal tumors. Patients were categorized into normoalbuminemic and hypoalbuminemic (ie, albumin level <3.5 g/dL) groups. Univariate and multivariate regression analyses were performed to examine the association between preoperative hypoalbuminemia and 30-day perioperative mortality and morbidity. Subgroup analysis was performed in the hypoalbuminemic group to assess the dose-dependent effect of albumin depletion.

RESULTS

Hypoalbuminemia was associated with increased risk of perioperative mortality, any complication, sepsis, intra- or postoperative transfusion, prolonged hospitalization, and non-home discharge. However, albumin depletion was also associated with decreased risk of readmission. There was an albumin level-dependent effect of increasing mortality and complication rates with worsening albumin depletion.

CONCLUSIONS

Hypoalbuminemia is an independent risk factor for perioperative mortality and morbidity following surgical decompression of metastatic spinal tumors with a dose-dependent effect on mortality and complication rates. Therefore, it is important to address malnutrition and optimize nutritional status prior to surgery.

Incidence and Predictors of Hardware Failure After Instrumentation for Spine Metastasis: A Single-Institutional Series

OBJECTIVE

We report a retrospective analysis of hardware failure in patients requiring instrumentation for spinal metastasis.

METHODS

In a retrospective study at a single institution, we identified 58 patients who underwent spinal instrumentation for metastasis from 2012 to 2018. Hardware failure was defined as screw pullout/loosening, cage migration, progressive kyphosis, or an otherwise-noticeable instrumentation deficit detectable on imaging. Risk factors for hardware failure with a P < 0.05 in in univariate were included in multivariate logistic regression models controlled for age, sex, and previously identified risk factors for hardware failure.

RESULTS

In total, 58 patients required instrumentation for metastatic spine disease. Median age was 60.2 years (interquartile range 49.0-66.3), 38 patients (65.5%) were male, and median follow-up was 8.1 months (interquartile range 3.1-20.7). Eight patients (13.8%) developed signs of hardware failure during follow-up, of whom 2 patients (3.4%) underwent operative revision. In univariate analysis, Eastern Cooperative Oncology Group performance status >2 (P = 0.049) and multiple myeloma lesions (P = 0.010) were significant predictors of failure. Both factors maintained significance in a multivariate logistic regression model controlled for age, sex, history of spine radiation, and number of fused levels with P = 0.047; odds ratio 12.7 (95% confidence interval 1.03-156.4) for Eastern Cooperative Oncology Group performance status over 2 and P = 0.012; odds ratio 31.5 (95% confidence interval 2.2-460.0) for multiple myeloma lesions.

CONCLUSIONS

The rate of hardware failure in this cohort was 13.8%, although operative revision rate was 3.4%. Spinal instrumentation in patients with poor preoperative functional status or multiple myeloma may be more likely to develop instrumentation failure.

Kidney and Thyroid Cancer-Specific Treatment Algorithm for Spinal Metastases: A Validation Study

BACKGROUND

Spinal metastases (SMs) from kidney and thyroid cancers have several common features suggesting that excisional surgery for isolated and removable SMs can improve survival. We propose a simple treatment algorithm for SMs from these cancers. Our study aimed to evaluate the efficacy of the algorithm.

METHODS

We performed a retrospective analysis of the data of 69 consecutive patients (48 with kidney and 21 with thyroid cancers) who underwent excisional surgery for SMs between 1995 and 2014. The patients were retrospectively classified into an indicated group for excisional SM surgery and a nonindicated group according to our algorithm, and the Tokuhashi and Tomita scoring systems. Patients in the indicated group were expected to survive ≥2 years postoperatively, whereas those in the nonindicated group were not. The positive predictive value and negative predictive value (NPV) were calculated using the predicted versus actual survival times of the patients. Survival was defined as the time from the first excisional surgery for the spinal lesion to death or the last follow-up of ≥2 years.

RESULTS

For patients with kidney cancer, the 2- and 5-year survival rates were 85.4% and 60.4%, respectively. For patients with thyroid cancer, the 2- and 5-year survival rates were 100% and 83.8%, respectively. Our algorithm had a compatible high positive predictive value (95.5%) and NPV (100%), whereas the Tokuhashi and Tomita scoring systems had low NPVs of 15.8% and 13.3%, respectively.

CONCLUSIONS

Our treatment algorithm of SMs from kidney and thyroid cancers is useful for determining an adequate treatment including excisional surgery.

The Role of Prognostic Scoring Systems in Assessing Surgical Candidacy for Patients With Vertebral Metastasis: A Narrative Review

STUDY DESIGN

Narrative review.

OBJECTIVES

To review the relevant literature regarding scoring systems for vertebral metastases and quantify their role in contemporary orthopedic practice.

METHODS

A literature search of PubMed, Google Scholar, and Embase was performed on February 7, 2017. Eight scoring systems were selected for detailed review-7 of which were scores focused solely on patient prognosis (Tokuhashi, Tomita, Bauer, Oswestry Spinal Risk Index, Van der Linden, Rades, and Katagiri). The eighth system reviewed was the Spinal Instability Neoplastic Score, which examines for impending spinal instability in patients with vertebral metastases and represents a novel approach compared with hitherto scoring systems.

RESULTS

The Bauer and Oswestry Spinal Risk Index have the most accurate prognostic predictive ability, with the newer Oswestry Spinal Risk Index being favored by the contemporary literature as it demands less investigation and is therefore more readily accessible. There was a growing trend in studies designed to customize scoring systems for individual cancer pathological subtypes. The Spinal Instability Neoplastic Score shows good reliability for predicting instability among surgeons and oncologists.

CONCLUSIONS

The increased understanding of cancer pathology and subsequent development of customized treatments has led to prolonged survival. For patients with vertebral metastases, this affects surgical candidacy not only on the basis of prognosis but also provides prolonged opportunity for the development of spinal instability. Scoring systems have a useful guidance role in these deciding for/against surgical intervention, but in order to remain contemporary ongoing review, development, and revalidation is mandatory.