The Cost-Effectiveness of Surgical Intervention for Spinal Metastases: A Model-Based Evaluation

Determining patients with spinal metastases suitable for surgical intervention: A cost-effective analysis

BACKGROUND

Both nonoperative and operative treatments for spinal metastasis are expensive interventions. Patients' expected 3-month survival is believed to be a key factor to determine the most suitable treatment. However, to the best of our knowledge, no previous study lends support to the hypothesis. We sought to determine the cost-effectiveness of operative and nonoperative interventions, stratified by patients' predicted probability of 3-month survival.

METHODS

A Markov model with four defined health states was used to estimate the quality-adjusted life years (QALYs) and costs for operative intervention with postoperative radiotherapy and radiotherapy alone (palliative low-dose external beam radiotherapy) of spine metastases. Transition probabilities for the model, including the risks of mortality and functional deterioration, were obtained from secondary and our institutional data. Willingness to pay thresholds were prespecified at $100,000 and $150,000. The analyses were censored after 5-year simulation from a health system perspective and discounted outcomes at 3% per year. Sensitivity analyses were conducted to test the robustness of the study design.

RESULTS

The incremental cost-effectiveness ratios were $140,907 per QALY for patients with a 3-month survival probability >50%, $3,178,510 per QALY for patients with a 3-month survival probability <50%, and $168,385 per QALY for patients with independent ambulatory and 3-month survival probability >50%.

CONCLUSIONS

This study emphasizes the need to choose patients carefully and estimate preoperative survival for those with spinal metastases. In addition to reaffirming previous research regarding the influence of ambulatory status on cost-effectiveness, our study goes a step further by highlighting that operative intervention with postoperative radiotherapy could be more cost-effective than radiotherapy alone for patients with a better survival outlook. Accurate survival prediction tools and larger future studies could offer more detailed insights for clinical decisions.

Prognosis after Palliative Surgery for Patients with Spinal Metastasis: Comparison of Predicted and Actual Survival

Simple Summary

Increased options for cancer treatment have made the prediction of prognosis an important factor in therapeutic decision making. The aim of this study was to assess the clinical significance of prognosis–scoring systems and to identify predictors for 6–month mortality after palliative surgery. The median actual survival period was longer than the predicted life expectancy based on the revised Tokuhashi score and new Katagiri score. However, 21.3% of patients died of cancers within 6 months after palliative surgery. A statistical analysis showed that a higher CRP/albumin ratio (odds ratio: 0.39; cut–off 0.409) and absence of postoperative adjuvant therapy (odds ratio: 7.15) were independent risk factors for poor survival. Our findings suggest the need for careful consideration to determine if palliative surgery is the best option for a patient with these negative prognostic factors, regardless of life expectancy predicted based on a prognosis score.

Abstract

Prediction of prognosis is a key factor in therapeutic decision making due to recent the development of therapeutic options for spinal metastases. The aim of the study was to examine predictive scoring systems and identify prognostic factors for 6–month mortality after palliative surgery. The participants were 75 patients with spinal metastases who underwent palliative surgery and had a minimum follow–up period of 1 year. Associations of actual survival with categories based on the revised Tokuhashi score and new Katagiri score were evaluated. Univariate and multivariate analyses were performed to identify prognostic factors for 6–month mortality after palliative surgery. The median actual survival period was longer than those predicted using the scoring systems. However, 21.3% of patients died of cancers within 6 months after surgery. A higher CRP/albumin ratio (odds ratio: 0.39; cut–off 0.409) and absence of postoperative adjuvant therapy (odds ratio: 7.15) were independent risk factors for 6–month mortality. There was no association of mortality with primary site, severity of sarcopenia, or other biomarkers. These results suggest that careful consideration is needed to determine whether palliative surgery is the best option for patients with a high preoperative CRP/albumin ratio and/or absence of postoperative adjuvant therapy, regardless of predictions made from scoring systems.

Cost-Utility Analysis Compared Between Radiotherapy Alone and Combined Surgery and Radiotherapy for Symptomatic Spinal Metastases in Thailand

Objective

To investigate the patient quality of life and cost-utility compared between radiotherapy alone and combined surgery and radiotherapy for spinal metastasis (SM) in Thailand.

Methods

Patients with SM with an indication for surgery during 2018–2020 were prospectively recruited. Patients were assigned to either the combination surgery and radiotherapy group or the radiotherapy alone group. Quality of life was assessed by EuroQol-5D-5L (EQ-5D-5L) questionnaire, and relevant healthcare costs were collected pretreatment, and at 3-month and 6-month posttreatment. Total lifetime cost and quality-adjusted life-years (QALYs) were estimated for each group.

Results

Twenty-four SM patients (18 females, 6 males) were included. Of those, 12 patients underwent combination treatment, and 12 underwent radiotherapy alone. At 6-month posttreatment, 10 patients in the surgery group, and 11 patients in the nonsurgery group remained alive for a survival rate of 83.3% and 91.7%, retrospectively. At 6-month posttreatment, the mean utility in the combination treatment group was significantly better than in the radiotherapy alone group (0.804 ± 0.264 vs. 0.518 ± 0.282, respectively; p = 0.011). Total lifetime costs were 59,863.14 United States dollar (USD) in the combination treatment group and 24,526.97 USD in the radiation-only group. The incremental cost-effectiveness ratio using 6-month follow-up data was 57,074.01 USD per QALY gained.

Conclusion

Surgical treatment combined with radiotherapy to treat SM significantly improved patient quality of life compared to radiotherapy alone during the 6-month posttreatment period. However, combination treatment was found not to be cost-effective compared to radiotherapy alone for SM at the Thailand willingness-to-pay threshold of 5,113 USD/QALY.

A Natural History of Patients Treated Operatively and Nonoperatively for Spinal Metastases Over 2 Years Following Treatment: Survival and Functional Outcomes

STUDY DESIGN

Prospective observational study.

OBJECTIVE

We present the natural history, including survival and function, among participants in the prospective observational study of spinal metastases treatment investigation.

SUMMARY OF BACKGROUND DATA

Surgical treatment has been touted as a means to preserve functional independence, quality of life, and survival. Nearly all prior investigations have been limited by retrospective design and relatively short-periods of post-treatment surveillance.

METHODS

This natural history study was conducted using the records of patients who were enrolled in the prospective observational study of spinal metastases treatment study (2017-2019). Eligible participants were 18 or older and presenting for treatment of spinal metastatic disease. Patients were followed at predetermined intervals (1, 3, 6, 12, and 24-mo) following treatment. We conducted cox proportional hazard regression analysis adjusting for confounders including age, biologic sex, number of comorbidities, type of metastatic lesion, neurologic symptoms at presentation, number of metastases involving the vertebral body, vertebral body collapse, New England Spinal Metastasis Score (NESMS) at presentation, and treatment strategy.

RESULTS

We included 202 patients. Twenty-three percent of the population had died by 3 months following treatment initiation, 51% by 1 year, and 70% at 2 years. There was no significant difference in survival between patients treated operatively and nonoperatively (P = 0.16). No significant difference in HRQL between groups was appreciated beyond 3 months following treatment initiation. NESMS at presentation (scores of 0 [HR 5.61; 95% CI 2.83, 11.13] and 1 [HR 3.00; 95% CI 1.60, 5.63]) was significantly associated with mortality.

CONCLUSION

We found that patients treated operatively and nonoperatively for spinal metastases benefitted from treatment in terms of HRQL. Two-year mortality for the cohort as a whole was 70%. When prognosticating survival, the NESMS appears to be an effective utility, particularly among patients with scores of 0 or 1.Level of Evidence: 2.