TITLE: Immediate vs Delayed Neuromodulation with Stereotactic Radiosurgery to the Pituitary for Refractory Oncologic Pain (INSPiRe)
INVESTIGATORS:
Scott Soltys (1)
Elham Rahimy (1)
Scott Jackson (1)
- Department of Radiation Oncology
DATE: Wednesday, 29 April 2026
TIME: 3:00–4:30 PM
LOCATION: Room R358, Edwards Building, 300 Pasteur Drive, Stanford, CA
WEBPAGE: https://dbds.stanford.edu/data-studio/
ABSTRACT
The Data Studio Workshop brings together a biomedical investigator with a group of experts for an in-depth session to solicit advice about statistical and study design issues that arise while planning or conducting a research project. This week, the investigator(s) will discuss the following project with the group.
INTRODUCTION
Control of medically refractory cancer pain is an unmet need affecting almost two-thirds of advanced stage cancer patients. Many patients require opiates, to which they can develop tolerance and require higher doses, with problematic side effects including nausea, constipation, and sedation. Ablation/modulation of the pituitary via different techniques (surgical, chemical, and more recently with radiotherapy) has demonstrated significant and fast pain relief in non-randomized studies dating back to the 1950s. There is a need for a randomized trial to evaluate the efficacy and safety of pituitary SRS for refractory cancer pain. A sham-arm is needed for comparison given the known enhanced placebo-effect of procedural treatments, including radiotherapy.
HISTORICAL DATA
As summarized in Table 1, rapid, clinically significant pain relief is expected in these patients with cancer pain otherwise refractory to current management. With reduction in opioid dose and side effects, quality of life would be expected to improve.

STUDY POPULATION
Patients with incurable cancer with refractory moderate/severe cancer pain, defined as pain score of 6–10 on the Brief Pain Inventory for ‘average pain in the last 24 hours’ or 4–10 with a morphine equivalent dose (MED) > 100mg per day
STUDY DESIGN
Randomized Phase II, single-blind, sham-controlled, uni-directional cross-over trial.
Study Intervention: Stereotactic RadioSurgery (SRS) to the pituitary, immediate 160 Gy Dmax versus sham of 0 Gy, with cross-over to treatment for sham non-responders.
Patients will be randomized to SRS or a sham treatment in which no radiation is delivered.
Patients without a pain-response at 14 days post-treatment in the sham group may cross-over to the SRS arm and receive treatment on day 15 (up to day 21).
Sample Size: 24 total patients (12 patients per arm)
Number of Sites: Single institution
Study Duration: 36 months with estimated accrual of 8 patients per year.
Participant Duration: 24 months or until time of death.
HYPOTHESIS & OBJECTIVES
We hypothesize that pituitary SRS is associated with meaningful pain improvement at 2 weeks compared to sham-treatment. The Primary objective is to determine whether pituitary SRS is associated with improved pain response at 14 +/- 2 days post-SRS compared to sham treatment, using International Consensus on Palliative Radiotherapy Endpoints (ICPRE) definition of pain response. There are five secondary objectives. First is to determine whether pituitary SRS is associated with improved pain response at 14 +/- 2 days post-SRS compared to baseline, using other definitions of pain response: (percentage >30% pain score reduction, or substantial pain response >4-point pain score reduction or percentage >50% pain score reduction). Second is to determine whether pituitary SRS is associated with improved Patient Global Impression of Change (PGIC) on day 14+/-2 days. Third is to determine whether pituitary SRS is associated with improved quality of life through the European Organization for Research and Treatment of Cancer (EORTC) quality of life questionnaire core-30 (QLQ-C30) and brain cancer specific module (QLQ-BN20), quality-adjusted life year (QALY) through the EuroQol (EQ)-5D questionnaire, and caregiver quality of life through the Caregiver Quality of Life Index-Cancer (CQOLC) scale. Fourth is to determine the median overall survival following pituitary SRS. Fifth is to determine if pain response is associated with improved overall survival compared to patients without a pain response.
ENDPOINTS
The primary endpoint is Pain response (complete and partial responses) at 14 +/- 2 days post-SRS compared to baseline, using ICPRE definitions. There are multiple secondary endpoints:
Pain evaluated daily with BPI-SF (short form) on days 1–7 (treatment is day 0), day 10 +/- 2 days, day 14 +/- 2 days, weekly for 2 months, then monthly
Pain response at day 14+/-2 days with >30% pain score reduction
Pain response at day 14+/-2 days with >50% pain score reduction
Pain response at day 14+/-2 days with >4-point pain score reduction
Patients’ Global Impression of Change (PGIC) Score on day 14+/-2 days
EORTC QLQ-C30 and QLQ-BN20
QALY through the EQ-5D questionnaire
CQOLC scale
Overall survival of three patient subgroups: 1) initially randomized to 0 Gy versus 160 Gy; 2) who ultimately received 160 Gy versus 0 Gy; 3) with pain response versus those without pain response
STATISTICAL PLAN
Sample size was calculated for the primary endpoint (pain response at 14 days between sham versus SRS arms) using an expected response rate of 80% in the SRS arm, 20% in the sham arm, 2-sided alpha of 0.05, and beta of 0.2 (power of 80%). This calculation yielded a requirement of at least 10 patients per arm. Assuming 10% dropout, 12 patients per arm are required. If dropout rate exceeds 10%, additional patients will be accrued upon approval.
STATISTICAL QUESTIONS
- Is this correct/ideal under Study Design: “Permutation with random block sizes will be used for treatment assignments to balance the stratification variables of histology (breast/prostate versus other) and pain type (nociceptive-somatic versus nociceptive-visceral and mixed nociceptive/neuropathic). The randomization list will be developed and uploaded to RedCap.”
- Is this correct/ideal under Study Population: “Only patients that receive initial SRS or sham SRS will be considered evaluable for safety and efficacy endpoints. Unevaluable patients may be replaced by additional participants.”
- Ying’s comment: “The language of replacement of evaluable participants makes sense for patients who are randomized but never receive study treatments. I am not sure about non-evaluable status for early drop-off patients. Once a patient received treatment, they are in the ITT population. Because you evaluate pain daily, you may be able to impute pain status even if they drop out earlier. We will need a missing data strategy to handle missing data in the final analysis.”
- Our question: How do we approach this? What should we write for the missing data strategy?
- Is this correct/ideal under Analysis Plan: “For patients who are not evaluable for pain response at Day 14 (+/- 2 days), their response status will be imputed. The patient requires at least one baseline pain score and at least one pain score from days 5–16 to be evaluable. The response rates will be listed as percentages with 95% confidence intervals for each arm. Relative response rate and odds ratio will be estimated with 95% confidence intervals. Statistical inference for comparing pain response between pituitary SRS and sham groups will utilize a Fisher’s exact test. Sensitivity analysis can be done to analyze cross-over data to see if the results are consistent in the direction for a McNemar test. Of note, the study is not powered by cross-over.”
ZOOM MEETING INFORMATION
Join from PC, Mac, Linux, iOS or Android: https://stanford.zoom.us/j/92414292941?pwd=9sQzfFbJpC71PyS5kRofKsT86nEWD9.1
Password: 124320
Or iPhone one-tap (US Toll): +18333021536,,92414292941# or +16507249799,,92414292941#
Or Telephone:
Dial: +1 650 724 9799 (US, Canada, Caribbean Toll) or +1 833 302 1536 (US, Canada, Caribbean Toll Free)
Meeting ID: 924 1429 2941
Password: 124320
International numbers available: https://stanford.zoom.us/u/aMbftTO9
Meeting ID: 924 1429 2941
Password: 124320
SIP: 92414292941@zoomcrc.com
Password: 124320