Malignant Cord Compression and Timing of Post-Operative Radiotherapy

Abstract

<h3>Purpose/Objective(s)</h3> Malignant spinal cord compression (MSCC) warrants prompt intervention that often involves neurosurgical decompression followed by radiation therapy (RT). However, post-surgical management including rehabilitation and time for wound healing can delay initiation of post-operative RT. This study aims to retrospectively review the time to initiation (TTI) of RT after surgical intervention for MSCC and its association with ambulatory status at 3 months post-treatment. We also compare TTI in patients discharged to home versus inpatient rehabilitation or skilled nursing facility. <h3>Materials/Methods</h3> We queried our institutional database for patients with solid malignancies and spinal metastases with Bilsky 2 or 3 MSCC who underwent surgical intervention and post-operative RT between 2015-2021. In patients who were ambulatory peri-operatively, we computed the relative risk of decreased ambulation at 3-month follow up using different TTI cutoff values of 30, 42, and 56 days. P values were generated using a 2-sided Fisher's Exact Test. TTI was also evaluated in all patients who underwent post-operative RT based on their discharge to home, skilled nursing facility, or inpatient rehabilitation. <h3>Results</h3> We found 128 patients with MSCC who underwent surgery. Within this group, 68 were ambulatory peri-operatively, received post-operative RT, and had at least 3 months of follow up. Three-month ambulatory rates for TTI of ≤ 30 vs >30 days, ≤ 42 vs > 42 days, and ≤ 56 vs > 56 days were 86% vs 70% (p=0.218), 85% vs 59% (p=0.032), and 83% vs 50% (p=0.028), respectively. Relative risks for inability to ambulate are shown in Table 1. For all patients who received post-operative RT without wound complications causing delays in RT, TTI based on discharge to home (n=42), skilled nursing facility (n=3), or inpatient rehab (n=26) was 28 days (IQR 19-36.75), 21 days (IQR 15-21), and 37 days (IQR 25.25-52.5), respectively. Nine patients were found to have locally recurrent disease-causing cord compression; two recurred after post-operative RT while seven recurred prior to post-operative RT. <h3>Conclusion</h3> The relative risk of inability to ambulate after surgical resection for MSCC was significantly higher if RT was initiated at >42 days after surgery, and even lower at >56 days after surgery. Patients discharged to inpatient rehab had the longest interval between surgery and RT. Further studies evaluating the optimal timing of post-operative RT and causes for delay are needed.