Stereotactic radiosurgery for spinal cholangiocarcinoma metastases: Clinical outcomes and the role of biologically effective dose thresholds.

The mean lesion volume at the time of treatment was 37.4 cm 3 (SD± 23.8 cm³) and the median prescription dose was 20 Gy (IQR = 20-28 Gy).

Patients with Karnofsky Performance Status > 70 tended to receive higher biologically effective dose 10 values, although this exploratory comparison did not reach statistical significance (p = 0.05).

Most notably, no local progression occurred in lesions treated with biologically effective dose 10 >60 Gy (0/5) versus 25% progression (3/12) with biologically effective dose 10 ≤60 Gy, representing a hypothesis-generating signal that warrants further investigation.

CTCAE grade ≥ 3 adverse events were not evidenced after the treatment.