Gamma Knife Pituitary Radiosurgery for Refractory Metastatic Bone Pain: A Single-Centre Retrospective Palliative Case...

Intractable cancer-related pain, particularly from metastatic bone disease, can be severe and refractory to conventional treatments. Gamma Knife pituitary radiosurgery (GKPR), which delivers a high dose of focused radiation to the neurohypophysis, has emerged as a potential minimally invasive palliative option for refractory cancer pain. We report short-term clinical observations from a single-centre retrospective case series of GKPR in patients with treatment-resistant metastatic bone pain.

We retrospectively reviewed four adult patients with intractable cancer-related bone pain who underwent GKPR between years 2023 and 2024. All patients had partial but inadequate response to opioids and other conventional pain treatments prior to GKPR, Karnofsky Performance Status (KPS) >40%, and no prior history of cranial irradiation. GKPR was performed targeting the neurohypophysis using a maximal dose of 140 Gy. Pain relief was assessed using a Visual Analogue Scale (VAS) at pre- and post-radiosurgery, as well as during regular follow-ups. A >50% reduction from baseline pain score was defined as clinically meaningful pain relief. Analgesic requirements and short-term procedural-related adverse events were recorded. Formal endocrinological assessment was not routinely performed in asymptomatic patients due to palliative intention.

A total of four patients with refractory metastatic bone pain secondary to various primary malignancies were included. Baseline VAS score ranged from 8 to 10 (median 9), and KPS ranged from 60% to 90% (median 60%). Three out of four patients (75%) achieved clinically meaningful pain relief following GKPR. The onset of pain reduction >50% occurred between 1 and 14 days post-treatment (median 2 days). A modest reduction in opioid consumption was observed, with a median 14% reduction of daily morphine-equivalent dose, and none required escalation of analgesic medications. Pain improvement was sustained throughout the available follow-up period, with a median duration of 2.5 months (range 0.5-10 months). No immediate procedure-related complications were observed during the follow-up period.

In this small retrospective palliative case series, GKPR was associated with rapid short-term pain reduction in selected patients with refractory cancer-related bone pain without immediate procedure-related complications. Given the limited sample size, short follow-up duration inherent to the palliative setting, and absence of systematic endocrine evaluation, conclusions regarding long-term durability or safety cannot be drawn. Nonetheless, these observations suggest that GKPR may represent a feasible, minimally invasive, palliative option for carefully selected patients, warranting further prospective investigations.