Feasibility Study of FLASH Radiotherapy for the Treatment of Symptomatic Bone Metastases

Not Applicable

Completed

Conditions: Bone Metastasis

Interventions: Radiation: FLASH Radiotherapy

Registration Number: NCT04592887

Lead Sponsor: Varian, a Siemens Healthineers Company

Brief Summary: This purpose of this study is to assess the feasibility of FLASH radiotherapy for the palliative treatment of painful bone metastases. FLASH radiotherapy is radiation treatment delivered at ultra-high dose rates compared to conventional radiation treatment.

Detailed Description: This clinical investigation is designed to assess the workflow feasibility of FLASH radiotherapy treatment in a clinical setting, as well as the toxicities, and pain relief when used to treat bone metastasis(-es) in the extremities (excluding feet, hands, wrists). FLASH radiotherapy has been shown in preclinical studies to cause less injury to surrounding normal tissues during radiation treatment, while still having similar tumor cell killing. Patients at least 18 years of age with painful bone metastases located in the limbs will be considered for the study. These patients represent an ideal population for a feasibility study of FLASH radiotherapy as they are known to benefit from the palliative effects of radiotherapy using single dose radiation regimens of 8Gy which is what is being used in this investigation. After treatment, patients will be assessed for pain response as well as any adverse side-effects of radiation. The workflow feasibility of the treatment will also be evaluated.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 10

Inclusion Criteria

Patient age at least 18 years
Up to 3 painful bone metastasis(-es) in the extremities
Bone metastases that can be treated using pre-defined treatment field sizes (7.5 cm x 7.5 cm; 7.5 cm x 10 cm; 7.5 cm x 12 cm; 7.5 cm x 14 cm; 7.5 cm x 16 cm; 7.5 cm x 18 cm; 7.5 cm x 20 cm), without overlap of radiation fields
Life expectancy of >2 months (in the judgement of the investigator)
Patients who are able to comply with the protocol
Provision of signed and dated informed consent form

Exclusion Criteria

Prior radiotherapy to the treatment site(s)
Lesions of the feet, hands, wrists are not eligible treatment sites for FLASH
More than 3 painful bone metastases of the limbs requiring palliative radiotherapy
Tumor lysis of >50% of the circumferential bone cortex, or other factors considered to place the subject at significant risk of pathologic fracture
Patients with bone fractures and/or metal implants in the treatment field
Patients who will receive cytotoxic chemotherapy within 1 week prior to or 1 week following their planned radiation treatment
Prior local therapy modality to the treatment site(s) within 2 weeks of study enrollment
Patients with pacemakers or other implanted devices at risk of malfunction during radiotherapy
Patients with any other medical condition or laboratory value that would, at the discretion of the investigator, preclude the patient from participation in this clinical investigation
Patients at known risk of enhanced normal tissue sensitivity to radiotherapy due to inherited predisposition or documented comorbidity that might lead to hypersensitivity to ionizing radiation
Patients enrolled in any other clinical studies the investigator believes to be in conflict with this clinical investigation.
Patients who are pregnant or nursing

Study & Design

Study Type: INTERVENTIONAL

Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
FLASH radiotherapy for painful bone metastasis(-es)	FLASH Radiotherapy	-

Primary Outcome Measures

Name	Time	Method
Workflow Feasibility	Will be assessed within 4 weeks of subject enrollment.	Number of participants whose treatment was delayed by more than 7 business days from simulation to treatment when related to the investigational device (excluding delays due to patient or facility factors not related to study treatment). The investigational site staff will measure the number of days delay in time to treatment due to problems involving the investigational device. The workflow feasibility outcome measure is met for an individual subject if the delay is measured as less than 7 days. The outcome measure data table provides the mean and full range days of treatment delay for the 10 participants.
Assessment of Radiation-related Toxicities That Are Possibly, Probably, or Definitely Related to FLASH Radiotherapy.	Assessed from start of treatment until subject death or lost to follow-up, up to 17.8 months	Toxicities that are possibly, probably, or definitely related to FLASH radiotherapy. Toxicities will be classified per CTCAE version 5.0. The outcome measure data table summarizes the total number of adverse events possibly, probably, definitely related to treatment that were reported in the 10 participant cohort. Eleven adverse events were grade 1 and one adverse event was grade 2, as classified by CTCAE version 5.0.

Secondary Outcome Measures

Name	Time	Method
Number of Participants Who Experienced a Pain Flare.	First 10 days post FLASH treatment	Pain was assessed by patient reported validated 10 point pain flare questionnaire. Pain flare is defined as either of the following: A) a minimum of a two-point increase in the worst pain score for the treated site without a reduction in analgesic intake; or B) a 25% or greater increase in analgesic intake based on daily oral morphine equivalence without a reduction in the worst pain score.
Number of Participants With Increased Use of Pain Medication in First 10 Days Post FLASH Treatment	Within 10 days after treatment.	Use of pain medication by study participant during days 1-10 following FLASH treatment was collected as it constituted one of the defining criteria (criteria B) for the pain flare outcome measure. Pain flare is defined as either of the following: A) a minimum of a two-point increase in the worst pain score for the treated site without a reduction in analgesic intake; or B) a 25% or greater increase in analgesic intake based on daily oral morphine equivalence without a reduction in the worst pain score.
Pain Relief	At 3 month follow up	Percentage of treated sites achieving pain relief as measured using patient reported outcome questionnaires (Brief Pain Inventory Questionnaire, Treated Sites Pain Questionnaire). Categories of pain relief included complete, partial, stable or progressive response. Complete response (CR) = no pain at 3 months Partial response (PR) = an average pain score that is ≥2 points lower than initial Stable disease (SD) = an average pain score that is ±1 point change from initial Progressive disease (PD) = an average pain score that is ≥2 points higher than initial