An Open-Label, Analgesic Efficacy and Safety of Pituitary Radiosurgery for Patients With Opioid-Refractory Pain: Study Protocol for a Randomized Controlled Trial.

Abstract

Hypophysectomy performed by craniotomy or percutaneous techniques leads to complete pain relief in more than 70% to 80% of cases for opioid refractory cancer pain. Radiosurgery could be an interesting alternative approach to reduce complications. To assess the analgesic efficacy compared with standard of care is the primary goal. The secondary objectives are to assess ophthalmic and endocrine tolerance, drug consumption, quality of life, and mechanisms of analgesic action. The trial is multicenter, randomized, prospective, and open-label with 2 parallel groups. This concerns patients in palliative care suffering from nociceptive or mixed cancer pain, refractory to standard opioid therapy. Participants will be randomly assigned to the control group receiving standards of care for pain according to recommendations, or to the experimental group receiving a pituitary GammaKnife (Elekta, Stockholm, Sweden) radiosurgery (160 Gy delivered in pituitary gland) associated with standards of care. Evaluation assessments will be taken at baseline, day0, day4, day7, day14, day28, day45, month3, and month6. We could expect pain improvement in 70% to 90% of cases at day4. In addition we will assess the safety of pituitary radiosurgery in a vulnerable population. The secondary endpoints could show decay of opioid consumption, good patient satisfaction, and improvement of the quality of life. The design of this study is potentially the most appropriate to demonstrate the efficacy and safety of radiosurgery for this new indication. New recommendations could be obtained in order to improve pain relief and quality of life.