Proton hypofractionation produced 10% one-year local failure despite extensive prior irradiation, with grade 3 toxicity confined to multiply reirradiated patients.
Seventy-three percent of failures after nonadherent sacral contouring involved sectors that guidelines recommended including in the clinical target volume.
Proton plans preserved 20-Gy target coverage while reducing spinal cord, oesophageal, lung, and bowel dose compared with photon VMAT.
Spine proton ablative radiotherapy achieved 74% local control at one and two years, with no radiation myelopathy in a reirradiation-enriched cohort.
Higher postoperative CTV minimum BED10 was associated with lower local failure after separation surgery and spine SBRT.
Carbon fiber-reinforced polyetheretherketone implants consistently reduced imaging artifacts and dosimetric uncertainty versus titanium, but clinical outcome evidence remains limited.