What is the SIRFLOX study?
SIRFLOX1 is an international research study that evaluated a new treatment option for patients with colorectal cancer that has spread to the liver. The study compared the results of adding Selective Internal Radiation Therapy (SIRT) using SIR-Spheres® Y-90 resin microspheres to a standard treatment with chemotherapy alone.
What did the SIRFLOX study show, and what could this mean for me?
The SIRFLOX study did not meet its primary enpoint of superior progression-free survival, taking into account progression inside and outside the liver but the results indicate that, in patients just diagnosed with unresectable liver metastases from colorectal cancer, the addition of SIR-Spheres Y-90 resin microspheres to standard chemotherapy extends the time before tumours in the liver start to grow again. This is important because the liver is the main organ where colorectal cancer spreads to first and these liver tumours most often cause the patient’s health status to decline.
REsect2 is a retrospective analysis of the SIRFLOX study patient cohort. The extensive radiological database of SIRFLOX was evaluated by a panel of 14 HPB (Hepato-Pancreato-Biliary) surgeons from leading medical centres in Belgium, France, Germany, Italy, The Netherlands, Spain, the UK and the USA to compare potential liver resectability (liver tumour removal) at baseline and follow-up.
REsect demonstrated that the addition of SIR-Spheres Y-90 resin microspheres to standard chemotherapy significantly increased the proportion of patients determined to have resectable liver metastases compared with chemo alone (38.11% in the SIRT + chemotherapy arm vs. 28.95% in the chemotherapy alone arm; p < 0.0001).
What are the FOXFIRE and FOXFIRE Global Studies?
In addition to the SIRFLOX study, two other large studies evaluated the benefit of adding SIRT using SIR-Spheres Y-90 resin microspheres to standard treatment with chemotherapy. These two randomised controlled studies, which had a very similar design as SIRFLOX, are called FOXFIRE, which was conducted in the UK, and an international study called FOXFIRE Global.
In a combined analysis the results of these three studies, including 1,100 patients, provided further information on the survival benefit from the addition of SIR-Spheres Y-90 resin microspheres to standard chemotherapy.
What did the FOXFIRE Combined Analysis show, and what could this mean for me?
The FOXFIRE combined analysis3 did not reach its primary endpoint of an overall survival (OS) benefit between patients treated with SIRT plus first-line chemotherapy compared to patients treated with chemotherapy alone. However, the study has significantly enriched scientific understanding of the role of SIRT in the management of mCRC, particularly in the liver, which is the organ of greatest risk.
Importantly, in subgroup analyses of the FOXFIRE combined analysis, a strong signal was identified indicating that the addition of SIR-Spheres Y-90 resin microspheres to first-line chemotherapy for mCRC may significantly increase OS in patients with right-sided primary colon tumours, whose median overall survival increased by 4.9 months and risk of death was reduced by 36% (HR: 0.64; 95% CI: 0.46–0.89; p=0.007).4
Patients with right-sided primary colon tumours represent more than a third (35–38%) of all metastatic colon cancer patients.5 This group of patients have a very poor prognosis compared to patients with other colorectal cancers, represent a major unmet medical need with fewer treatment options available and are an important focus of cancer research today.
Based on these results, SIRT with SIR-Spheres Y-90 resin microspheres is a treatment option that can be offered to patients with colorectal cancer that has spread only or mainly to the liver.
Only your medical oncologist, in consultation with the multidisciplinary team, can assess if SIRT is right for you. Please contact your treating doctor to learn more about SIRT and the results of the FOXFIRE combined analysis.
1. van Hazel GA et al. J Clin Oncol 2016; 34:1723–31.
2. Garlipp B et al. E-AHPBA 2017; Abs. FP 15.08.Wasan HS et al. Lancet Oncol 2017; 18: 1159-71
3. Wasan HS et al. Lancet Oncol 2017; 18: 1159-71.
4. Van Hazel G et al. Ann Oncol 2017; ESMO 19th WCGIC, Abs. LBA-006.
5. Petrelli F et al. JAMA Oncol 2017; 3: 211–19.