Remaining Systemic Treatment Options: A Valuable Predictor of Survival and Functional Outcomes after Surgical Treatment for Spinal Metastasis

Conditional survival after surgery for metastatic tumors of the spine: does prognosis change over time?

PURPOSE

Conditional survival (CS) provides a dynamic prediction of patient survival by incorporating the time an individual has already survived given their disease specific characteristics. The objective of the current study was to estimate CS among patients after surgery for spinal cord compression or spinal instability, as well as stratify CS according to relevant patient- and disease-related characteristics.

METHODS

The clinical outcomes of 361 patients undergoing surgical management of metastatic spinal tumors were retrospectively analyzed. Stratification of this cohort according to disease and surgery-specific characteristics allowed for univariate and multivariate statistical analyses of our study population. Observed overall and conditional survival estimates were calculated by the Kaplan-Meier method.

RESULTS

12-month conditional survival in patients undergoing surgical management of metastatic spine tumors increased from 57% at baseline to 70% at 24 months following spine surgery. Overall survival (OS) was influenced by CCI grade, Katagiri tumor type, presence of lung metastasis, type of spine surgery, presence of postoperative systemic therapy and ambulatory status at follow-up. Analyses of OS and CS by prognostic strata were similar with exception of stratification by surgery type. Differences in survival between strata tend to converge over time. Unfavorable factors for OS appear to be less relevant after a period of 24 months following spine surgery.

CONCLUSION

Patients after surgery for metastatic tumors of the spine can expect a positive trend in conditional survival as survivorship increases. Even patients with a more severe disease can be encouraged with gains in conditional survival over time.

LEVEL OF EVIDENCE

Level IV (retrospective cohort study).

Identifying new predictive factors for survival after surgery for spinal metastases: an exploratory in-depth retrospective analysis

OBJECTIVES

In selected patients with symptomatic spinal metastasis from solid tumors, surgery improves quality of life. Since selection is key, inaccurate survival prognostication may result in poor decisions and outcomes. However, most prognostic scores suffer from suboptimal external validation and subsequent mediocre performance. This warrants the ongoing search for factors that better capture the oncological status. This exploratory study aims to identify new preoperative variables that predict survival.

METHODS

A retrospective analysis was conducted on 62 patients from a tertiary care referral center who underwent debulking and/or reconstruction surgery for spinal metastases between 2006 and 2018, and in whom detailed clinical, oncological, surgical and biochemical variables were collected. Univariate and multivariate analyses were performed for overall survival.

RESULTS

Median survival was 13.2 months. Multivariate analysis for overall survival identified that a higher number of organs with metastases, a shorter time to progression on the last line of systemic therapy before surgery (TTPbs), low serum albumin, high alkaline phosphatase, high C-reactive peptide (CRP), presence of brain metastasis and the index spinal level located in the cervical region were independently associated with shorter survival.

CONCLUSION

We confirmed previously known predictors and identified CRP and TTPbs as new variables that were strongly associated with survival. The latter variable may replace primary tumor type, as improved cancer treatments make the primary tumor type less relevant as a predictor. This study is exploratory and its findings need to be validated, preferably in large prospective multicenter studies that are aiming at improving existing models.

Evaluating ambulatory function as an outcome following treatment for spinal metastases: a systematic review

BACKGROUND CONTEXT

Studies regarding treatment of spinal metastases are critical to evidence-based decision-making. However, variation exists in how a key outcome, ambulatory function, is assessed.

PURPOSE

To characterize the sources and tools investigators have used to evaluate ambulatory function as an outcome following treatment of spinal metastases. We also sought to understand the ways ambulatory function has been conceptualized in prior studies.

STUDY DESIGN

Systematic review of the literature.

PATIENT SAMPLE

We identified 44 published studies for inclusion. Samples within these investigations ranged from 20 to 2,096 subjects.

OUTCOME MEASURES

We describe the methods investigators have used to evaluate ambulatory function following treatment for spinal metastases.

METHODS

We conducted a systematic review through PubMed, Scopus and Web of Science following PRISMA guidelines. We included studies that consisted of adult patients receiving operative or non-operative treatment for spinal metastases. We also required that study investigators specified post-treatment ambulatory function as an outcome. We recorded year of publication, study design, types of spinal metastases included in the study, treatments employed, and sample size. We also described the source (medical record, study-specific observer and/or provider, patient and/or participant), tool (standardized measure, quantitative, qualitative) and concept (eg, ambulatory vs. non-ambulatory; independent ambulation vs. ambulatory with assistance vs. non-ambulatory) used to assess ambulatory function.

RESULTS

We found the plurality of studies relied on medical record documentation as their source. Amongst prospective studies, only a minority used a quantitative measure (eg, prespecified degree of walking ability) to assess ambulatory function. Most studies conceptualized ambulatory function as a dichotomized outcome, typically ambulatory versus non-ambulatory or a similar equivalent.

CONCLUSIONS

Wide variation exists in how ambulatory function is defined in studies involving patients with spinal metastases. We suggest several improvements that will allow a more robust assessment of the quality and quantity of ambulatory function among patients treated for spinal metastases.

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.

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.