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

Abstract

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.

Keywords: Combined surgery and radiotherapy; Cost-utility; Patient quality of life; Radiotherapy alone; Spinal metastasis.

Fig. 1.

Decision tree (A) and Markov model (B). A decision tree was constructed to divide patients into the 4 following groups according to the health status outcome of each treatment: ambulatory with less pain, nonambulatory with less pain, ambulatory with pain, and nonambulatory with pain. In the Markov model, patients could remain in the same health state or transition to worse health states. Sx+RT, combined surgery, and radiotherapy; RT, radiotherapy alone.

Fig. 2.

Tornado diagram. This model illustrates the result of 1-way sensitivity analysis that was performed to study the effects of altering uncertainty parameters within the 95% confidence interval ranges, including all clinical effects, costs, utilities, and the discount rate on the ICER calculated from the model. ICER, incremental cost-effectiveness ratio; Sx+RT, combined surgery and radiotherapy; RT, radiotherapy alone; USD, United States dollar; QALY, quality-adjusted life-year.

Fig. 3.

Multivariate probabilistic sensitivity analysis. The result was based on 1,000 Monte Carlo simulations. The results are shown as a cost-effectiveness plane (A), and a cost-effectiveness acceptability curve (B). Sx+RT, combined surgery and radiotherapy; RT, radiotherapy alone; USD, United States dollar; QALY, quality-adjusted life-year.