Re-irradiation spine stereotactic body radiotherapy following high-dose conventional radiotherapy for metastatic epidural spinal cord compression: a retrospective study

Jpn J Radiol. 2024 Jun;42(6):662-672. doi: 10.1007/s11604-024-01539-x. Epub 2024 Feb 28.

Abstract

Purpose: We aimed to evaluate the efficacy and safety of re-irradiation stereotactic body radiation therapy (SBRT) in patients with metastatic epidural spinal cord compression (MESCC) following high-dose conventional radiotherapy.

Materials and methods: Twenty-one patients met the following eligibility criteria: with an irradiation history of 50 Gy2 equivalent dose in 2-Gy fractions (EQD2) or more, diagnosed MESCC in the cervical or thoracic spines, and treated with re-irradiation SBRT of 24 Gy in 2 fractions between April 2018 and March 2023. Prior treatment was radiotherapy alone, not including surgery. The primary endpoint was a 1-year local failure rate. Overall survival (OS) and treatment-related adverse events were assessed as the secondary endpoints. Since our cohort includes one treatment-related death (TRD) of esophageal perforation, the cumulative esophageal dose was evaluated to find the dose constraints related to severe toxicities.

Results: The median age was 68, and 14 males were included. The primary tumor sites (esophagus/lung/head and neck/others) were 6/6/7/2, and the median initial radiotherapy dose was 60 Gy2 EQD2 (range: 50-105 Gy2, 60-70/ > 70 Gy2 were 11/4). Ten patients underwent surgery followed by SBRT and 11 SBRT alone. At the median follow-up time of 10.4 months, 17 patients died of systemic disease progression including one TRD. No radiation-induced myelopathy or nerve root injuries occurred. Local failure occurred in six patients, with a 1-year local failure rate of 29.3% and a 1-year OS of 55.0%. Other toxicities included five cases of vertebral compression fractures (23.8%) and one radiation pneumonitis. The cumulative esophageal dose was recommended as follows: Dmax < 203, D0.035 cc < 187, and D1cc < 167 (Gy3 in biological effective dose).

Conclusion: Re-irradiation spine SBRT may be effective for selected patients with cervical or thoracic MESCC, even with high-dose irradiation histories. The cumulative dose assessment across the original and re-irradiated esophagus was recommended to decrease the risk of severe esophageal toxicities.

Keywords: Re-irradiation; Spinal cord compression; Spinal metastases; Stereotactic radiotherapy.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Female
  • Humans
  • Male
  • Middle Aged
  • Radiosurgery* / adverse effects
  • Radiosurgery* / methods
  • Radiotherapy Dosage
  • Re-Irradiation* / methods
  • Retrospective Studies
  • Spinal Cord Compression* / etiology
  • Spinal Cord Compression* / radiotherapy
  • Spinal Cord Compression* / surgery
  • Spinal Neoplasms* / radiotherapy
  • Spinal Neoplasms* / secondary
  • Treatment Outcome