Stereotactic radiosurgery for lung cancer spinal metastases.

Purpose: Lung cancer spinal metastases may present with intractable pain and neurological deficits. This study is one of the largest to examine outcomes following stereotactic radiosurgery (SRS) in this patient population.

Methods: A single institution retrospectively collected database of patients with lung cancer spinal metastases treated with SRS between 2003-2023 was analyzed. The primary outcome was local control (LC). Secondary outcomes included pain response, overall survival (OS), and radiation-induced toxicity. The median single-fraction dose was 16 Gy (range: 12-20). Multi-fractionated treatments utilized doses of 18-30 Gy in 2-5 fractions.

Results: One hundred twenty-two patients with 167 lesions met inclusion criteria. Prior to radiosurgery, 21 lesions (13%) underwent open resection and 131 lesions (78%) received external beam radiation therapy. Median follow-up was 4 months (range: 1-133). Fifteen lesions (9%) locally recurred 5 months (range: 1-10) after treatment. Six-month and 1-year LC rates were 88% and 75%, respectively. Patient-reported pain predominantly improved or remained stable (67%) after treatment; worsened pain was associated with inferior LC (p < 0.01, HR: 22.7, 95% CI: 2.5-207.1) and development of radiation-induced vertebral compression fractures (VCFs) (p < 0.01, OR: 34.2, 95% CI: 3.0-392.4). Six-month and 1-year OS rates were 45% and 23%, respectively. Low functional status (Karnofsky Performance Score ≤ 70) was associated with inferior LC (p = 0.03, HR: 3.7, 95% CI: 1.1-12.1) and OS (p = 0.03, HR: 1.8, 95% CI: 1.1-2.9). Thirty-one radiation-induced toxicities (19%), including 13 VCFs (8%), were observed.

Conclusions: Radiosurgery provides LC and pain palliation with minimal rates of toxicity in a challenging patient population with lung cancer spinal metastases.