Practical Guidelines for Spinal Stereotactic Body Radiation Therapy Posttreatment Follow-Up: Empirical Consensus From...

Spinal stereotactic body radiation therapy (SBRT) provides durable local control for metastatic spine disease but creates new demands for posttreatment surveillance, particularly in health care systems where magnetic resonance imaging (MRI) access is limited. Existing guidelines recommend calendar-based imaging, which is challenging to implement in resource-constrained environments. We aimed to develop practical, risk-stratified follow-up guidelines for post-SBRT surveillance, grounded in real-world feasibility across province-wide oncology centers.

Seven radiation oncologists from 4 SBRT-providing centers (3 tertiary academic and 1 regional) participated in a structured, modified nominal group technique. Panelists reviewed the literature on imaging surveillance, contributed center-specific considerations, and iteratively refined recommendations. Nineteen candidate statements across 4 items were generated. Consensus thresholds were predefined as ≥80% ("strong"), 60% to 79% ("moderate"), and <60% ("no consensus").

In round 1, 11 of 19 statements achieved strong consensus, 5 were moderate, and 3 failed to meet the threshold. Following structured adjudication, word refinement, and 1 item removal, all 18 remaining statements achieved strong consensus in round 2. Key themes included were as follows: (1) anchoring imaging intensity to actionable clinical intent; (2) prioritizing early post-SBRT MRI only when salvage therapy is feasible; (3) de-escalating surveillance in low-risk or systemically progressing patients; (4) tailoring modality selection to resource availability; and (5) integrating tumor-specific considerations, including prostate cancer-specific pathways. The resulting framework replaced rigid schedules with risk-adapted intervals, emphasized clinical triggers and feasibility, and promoted thoughtful resource use.

The consensus-derived guidelines present a pragmatic surveillance strategy for spine SBRT, calibrated to the realities of MRI access and clinical workflows. By embracing risk-adapted imaging, the framework reduces unnecessary investigations, preserves resources, and focuses surveillance where it is most likely to influence clinical outcomes. While rooted in the local context, the recommendations are broadly applicable to settings facing similar constraints. Prospective validation is warranted to evaluate oncologic and patient-reported outcomes under this de-escalated, resource-conscious model.