RCT of the 4mm vs. the 8mm Collimator for GKR of Brain Micrometastases

Optimal Radiation Method for Gamma Knife Radiosurgery of Brain Micrometastases: A Multi-centre Randomised Clinical Trial (RCT) of the 4mm vs. the 8mm Collimator.

Gamma Knife Radiosurgery (GKR) is a well-established treatment modality for brain metastasis (Chiou 2013; Salvetti, Nagaraja et al. 2013). Large multicentre series have been published on patients with single and multiple cerebral metastases, treated with GKR over a period of 30 years (Karlsson, Hanssens et al. 2009). Multiple institutions have reported a consistently high local tumour control rate of 80%-90% following GKR (Chang, Lee et al. 2000; Da Silva, Nagayama et al. 2009; Salvetti, Nagaraja et al. 2013).

There is controversy over the use of GKR and/or Whole Brain Radiotherapy (WBRT) in patients with multiple metastases. WBRT provides a lower rate of distant recurrences, whereas GKR achieves good local control of treated lesions without the deleterious side effects of radiotherapy (Lippitz, Lindquist et al. 2014). This discussion is mainly focused on the risk of distant recurrences, which is lower if WBRT is given. There is evidence showing that Radiosurgery (RS) based on high contrast/resolution stereotactic MRI decreases the incidence and lengthens the time to distant recurrences (Hanssens, Karlsson et al. 2011). As a result, the current tendency is to treat all the lesions visible in high contrast/resolution images the day of Gamma Knife; which is followed by regular MRI follow ups and subsequent GKR for distant recurrences in order to avoid/delay WBRT.

It has been estimated that more than a half of distant recurrences will grow from tumour cells that were already in the brain (as micrometastases) when radiosurgery is delivered, but not much has been studied on the optimal prescription and radiation delivery method for these lesions. There is controversy over which collimator should be used when treating micro-metastases (BmM). These lesions can either be treated with the 4mm collimator at an isodose between the 40% and 90%, or the 8mm collimator at an isodose above 90%. The 8 mm collimator is thought to offer better Local Control Rate (LCR) with the advantage of faster delivered treatments, while the 4 mm collimator is considered to be safer, given its steep dose fall-off. It is the aim of this study to find out which of the 4 mm or 8 mm collimators can achieve the higher LCR with less complications. A large number of lesions will be randomised to either the 4 or the 8 mm collimator and the patients followed up to evaluate clinical efficacy.

Study Overview

• Status: Unknown
• Conditions: Brain Micrometastases
• Intervention / Treatment: Radiation: GKR with a single shot of the 8 mm collimator; Radiation: GKR with a single shot of the 4 mm collimator

• Study Type: Interventional
• Enrollment (Anticipated): 298
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Alvaro Villabona, Dr; Phone Number: +44 020 3448 4076; Email: a.villabona.11@ucl.ac.uk

Study Locations

• United Kingdom
  • London, United Kingdom, SW5 0TU
    • Not yet recruiting
    • Gamma Knife Centre at BUPA Cromwell Hospital
    • Contact: Bodo Lippitz, MD; Phone Number: 020 7460 5938; Email: bodo.lippitz@cromwellhospital.com
    • Principal Investigator: Bodo Lippitz, MD
    • Sub-Investigator: Christer Lindquist, MD, PhD
  • London, United Kingdom, WC1N 3BG
    • Recruiting
    • The Gamma Knife Centre at Queen Square
    • Contact: Alvaro Villabona, Dr; Phone Number: +44 020 3448 4076; Email: a.villabona.11@ucl.ac.uk
    • Sub-Investigator: Ian Paddick, MSc,MIPM
    • Sub-Investigator: Naomi Fersht, PhD, FRCR
    • Sub-Investigator: Rolf Jäger, MD, FRCR
    • Sub-Investigator: Katherine Miszkiel, MRCP, FRCR
    • Sub-Investigator: Alvaro Villabona, MBBS, MSc
    • Principal Investigator: Neil Kitchen, MD, FRCS(SN)
  • Sheffield, United Kingdom, S10 3BR
    • Not yet recruiting
    • BMI Thornbury Hospital
    • Contact: Andras Kemeny, FRCS, MD; Phone Number: 01142674651; Email: aakemeny@gmail.com
    • Principal Investigator: Andras Kemeny, FRCS, MD
    • Sub-Investigator: Matthias Radatz, FRCS
    • Sub-Investigator: Jeremy Rowe, FRCS

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Adult patients with brain metastasis from any primary tumour receiving GKR.
• All intracranial micro-metastases including lesions located in the cerebral hemispheres, thalamus, basal ganglia and cerebellum and excluding lesions located in the brain stem below the level of the superior colliculi.
• Target volume < 0.14 cc3 and maximum diameter < 7 mm.
• The subject consents to participate in the study.

Exclusion Criteria:

• Inability to consent
• Younger than 18 years of age.
• Lesions in the brainstem (below the level of the superior colliculi) are better treated with the 4 mm collimator and they will be excluded from the study.
• Patients with more than 25 brain lesions suitable for randomisation will be excluded from the study.
• Co-morbidity or previous treatment such as surgery, chemotherapy or WBRT is not to be considered as exclusion criteria.
• Pregnancy in the context of brain metastases is not a contraindication for GKR, and therefore it will not be considered as exclusion criteria for this trial.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 8 mm collimator; GKR with a single shot of the 8 mm collimator	Radiation: GKR with a single shot of the 8 mm collimator; Gamma Knife Radiosurgery (GKR) with a single shot of the 8 mm collimator at an isodose above 90%.
Experimental: 4 mm collimator; GKR with a single shot of the 4 mm collimator	Radiation: GKR with a single shot of the 4 mm collimator; Gamma Knife Radiosurgery (GKR) with a single shot of the 4 mm collimator at an isodose between the 40% and 90%.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Local control rate (LCR)	LCR will be evaluated through volumetric assessment of the lesion the day of Gamma Knife and in subsequent follow up MRI scans	up to 24 months after treatment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adverse radiation effects (ARE)	The following radiological and clinical outcomes will be used to assess ARE: Bleeding from randomised lesions, Perilesional radiation induced necrosis, Severe peri-lesional oedema, New onset or worsened neurological deficit attributable to a randomised lesion	up to two years

Collaborators and Investigators

• Sponsor: University College, London
• Collaborators: University College London Hospitals
• Investigators: Study Chair: Neil Kitchen, Mr, The National Hospital for Neurology and Neurosurgery

Publications and helpful links

Helpful Links

• Related Info

Study record dates

Study Major Dates

• Study Start: September 1, 2014
• Primary Completion (Anticipated): April 1, 2020
• Study Completion (Anticipated): April 1, 2021

Study Registration Dates

• First Submitted: August 18, 2014
• First Submitted That Met QC Criteria: August 18, 2014
• First Posted (Estimate): August 19, 2014

Study Record Updates

• Last Update Posted (Estimate): March 20, 2015
• Last Update Submitted That Met QC Criteria: March 19, 2015
• Last Verified: March 1, 2015

More Information

Terms related to this study

• Keywords: Brain; Neoplasm Micrometastasis; Gamma Knife Radiosurgery
• Additional Relevant MeSH Terms: Pathologic Processes; Neoplasms; Neoplastic Processes; Neoplasm Metastasis; Neoplasm Micrometastasis
• Other Study ID Numbers: 14/0050; 14/LO/0791 (Other Identifier: Queen Square Research Ethics Committee); 145268 (Other Identifier: Integrated Research Application System (IRAS))