STAT RAD: Prospective Dose Escalation Clinical Trial of Single Fraction Scan-Plan-QA-Treat Stereotactic Body Radiation Therapy for Painful Osseous Metastases

Abstract

Purpose: Radiation therapy is a well-established treatment for symptomatic bone metastases. Despite continued advances in both planning techniques and treatment delivery, the standard workflow has remained relatively unchanged, often requiring 1 to 3 weeks and resulting in patient inconvenience and delayed palliation. We developed an expedited method wherein computed tomography simulation, treatment planning, quality assurance, and treatment delivery are performed in 1 day. This prospective pilot clinical trial evaluates the safety, efficacy, and patient satisfaction of this rapid workflow.

Methods and materials: Patients with 1 to 3 painful bone metastases were prospectively enrolled and treated with 1 fraction of stereotactic body radiation therapy, using a same-day Scan-Plan-QA-Treat workflow, termed STAT RAD, in a phase 1/2 dose escalation trial from 8 Gy to 15 Gy per fraction. Bone pain, opioid use, patient satisfaction, performance status, and quality of life were evaluated before and at 1, 4, 8, 12, 26, and 52 weeks after treatment. Outcomes and treatment-related toxicity were analyzed.

Results: A total of 49 patients were enrolled, and 46 patients with 60 bone metastases were treated per the protocol. Partial or greater pain response occurred in 50% of patients at 1 week, 75% of patients at 8 weeks, 68.7% of patients at 6 months, and 33.3% of patients at 12 months. There were 2 grade-3 toxicities, including 1 spinal fracture associated with disease progression and hyperbilirubinemia. Reirradiation was required in 16.7% of treated lesions at a median time to retreatment of 4.9 months. Most patient responses (78.6%) indicated that patients would choose this workflow again.

Conclusions: The results demonstrate that treating bone metastases with palliative stereotactic body radiation therapy via a single-fraction, patient-centric workflow is feasible and safe with doses up to 15 Gy. However, pain response decreased at 12 months and was associated with a 16.7% retreatment rate, which suggests that further dose escalation is warranted.