Stereotactic body radiation therapy for spinal metastases from gastrointestinal primary cancers

Abstract

Purpose: Metastases from gastrointestinal (GI) primary cancers are considered relatively radioresistant. This study is one of the largest to evaluate outcomes following stereotactic body radiation therapy (SBRT) for GI cancer spinal metastases and supplements its findings with a review of the literature.

Methods: A prospectively maintained single-institution database of spinal metastases treated with SBRT was analyzed. Seventy-five patients with 106 GI primary cancer spinal metastases were identified. The median single-fraction dose was 16 Gy (interquartile range (IQR): 14-16). Multi-fraction regimens ranged from 18 to 35 Gy over 2-5 fractions.

Results: Median follow-up was 5 months (IQR: 1-13). Cumulative incidence rates of 3-, 6-, and 12-month local failure (LF) were 5%, 9%, and 10%, respectively. Rates of 12-month LF were 6% for gastroesophageal, 10% for hepatobiliary, and 13% for colorectal cancers. Multilevel tumors ≥ 2 vertebrae were associated with LF (p = 0.006, HR: 5.61, 95% CI: 1.61-19.5). Rates of 3-, 6-, and 12-month overall survival (OS) were 68%, 50%, and 41%, respectively. Multivariable analysis showed epidural disease associated with inferior OS (p = 0.037, HR: 1.75, 95% CI: 1.04-2.96). Complete or partial pain responses for 93 tumors (88%) presenting with pain were 60%, 51%, 32%, and 32% after 1, 3, 6, and 12 months, respectively. Ten vertebral compression fractures (9%) developed following treatment. Twelve radiation toxicities (11%) were observed, with no cases of neuropathy or myelopathy.

Conclusions: SBRT offers effective local tumor control and pain palliation with minimal toxicity for GI cancer spinal metastases, whose incidence is expected to rise with advances in screening and systemic therapies.

Keywords: Gastrointestinal; Radiosurgery; Spinal stereotactic body radiation therapy; Spine metastasis; Stereotactic body radiation therapy; Tumor control.