Effectiveness of Leksell gamma knife hypophysectomy on cancer-related intractable pain - a single-center experience.

Objectives: Hypophysectomy is a method used in analgesia in patients with painful bone metastases. The pain relief after this procedure is not pathophysiologically fully understood. In only a few studies Leksell gamma knife (LGK) was used for radiosurgical hypophysectomy. In our study, we performed the LGK hypophysectomy in patients with intractable cancer-related pain due to bone metastases and evaluated the impact of this method on pain relief.

Methods: From 1994 to 2020 we enrolled 20 patients with the diagnosis of disseminated carcinoma. All patients underwent radiosurgical hypophysectomy on LGK. The maximum dose was 150-200Gy. The dose to the optic pathway was 9,8Gy on average.

Results: Six patients died before the first follow-up and we did not receive any posttreatment information from 4 patients. In all the rest 10 evaluated patients pain relief was achieved (0-50% of pre-procedural pain). The hypophysectomy effect lasted for the rest of their lives (the mean follow-up period was 12,6 months). In three patients we observed hormonal disbalance - hypocortisolism and diabetes insipidus with good response to substitutional therapy, one patient developed a temporary abducens nerve palsy. No other adverse events were observed.

Conclusion: Our results suggest that the LGK hypophysectomy is an effective and safe procedure to reduce cancer-related intractable pain, especially in bone metastases of hormonally dependent tumors.