SOLSTICE preliminary data show cryoablation has “acceptable safety profile” in treatment of selected lung metastases

Cryoablation ice balls

The SOLSTICE clinical study constitutes the largest multicentre, prospective study focused on the clinical use and effectiveness of cryotherapies for patients with primary cancer lesions that have metastasised to the lung. The study was launched in 2014 by Galil Medical, which is now a part of BTG.

Preliminary outcomes from SOLSTICE find that percutaneous CT-guided cryoablation demonstrates an acceptable safety profile for treatment of lung metastases ≤3.5cm. The most common procedure-related event was pneumothorax.

Patrick W Eiken, Department of Radiology, Mayo Clinic, Rochester, USA, presented the preliminary safety outcome at CIRSE 2016, Barcelona, Spain. Matthew Callstrom, Mayo Clinic, Rochester, USA and Thierry de Baere, Institut Gustave Roussy, Villejuif, France are the lead investigators of the study.

SOLSTICE (Study of metastatic lung tumours targeted by interventional cryoablation evaluation) calls for two years of follow-up, with a projected enrolment of approximately 125 patients.

Researchers in Europe and the USA treated patients with up to six pulmonary metastases with CT-guided percutaneous cryoablation. The patients were followed-up at one week and three, six, 12, and 24 month and the investigators used the Common Terminology Criteria for Adverse Events (CTCAE) 4.03 to assess complications.

Eiken told delegates that 126 patients (64 males, 62 females; mean age 64 years) with 219 tumours were treated in 163 cryoablation procedures. Sixty-two percent (n=78) of the patients had one tumour, and 40% had two, or more. The mean tumour size was 1.2cm (0.4– 4.5cm).

The researchers used general anaesthesia in 69% (n=113) of procedures, conscious sedation in 29% (n=47), and local anaesthesia in 2% (n=3). The treatment time ranged from 30 to 225 minutes (mean time was 72.9 minutes).

There were 98 procedure-related events within 30 days of the treatment. Thirty-seven percent were classified CTCAE grade one (n=36), 57% grade two (n=57), 5% grade three (n=5), and 1% grade four (n=1). The most frequent event was pneumothorax, of which 8% (n=4) were grade one, 83% (n=40) grade two, and 8% (n=4) grade three. Six percent (n=6) of all events were grade three or higher: grade three pneumothoraces (n=4), grade three pleural haemorrhage (n=1), and grade four gas embolism (n=1). All events resolved without further sequelae.

The interim analysis of the ECLIPSE trial at one-year, published in the Journal of Thoracic Oncology in October 2015 by de Baere et al, found that cryoablation is a safe and effective treatment for pulmonary metastases with quality of life preserved following intervention. ECLIPSE, a prospective, multicentre, single-arm study, set out to assess the feasibility, safety and local tumour control of cryoablation for the treatment of pulmonary metastases in 40 patients with 60 lung metastases.