Results from a retrospective study presented at the World Conference of Interventional Oncology (WCIO, 6–9 May, New York, USA) show that while both glass- and resin-based Y-90 microspheres have demonstrated efficacy as treatment options for unresectable primary hepatocellular carcinoma and hepatic metastatic disease, there is a difference in survival between patients treated with the different radioembolics.
Radioembolization with resin-based embolics (SIR-Spheres, Sirtex) conferred a statistically significant survival advantage over glass-based Y-90 (Therasphere, BTG) during the first year after treatment, according to the study.
The investigators, R Morgan and colleagues, pointed out that there is limited research on direct comparison of survival between treatments with the two types of embolics. They set out to compare one-year survival differences between glass and resin yttrium-90 (Y-90) microspheres radioembolization of hepatocellular carcinoma or hepatic metastases.
The researchers conducted a retrospective analysis on 126 patients with unresectable primary hepatocellular carcinoma, colorectal, neuroendocrine, or other metastases who received radioembolizationwith glass- or resin-based Y-90 microspheres between 2008 and 2013 at a tertiary care academic medical institution.
They conducted survival analyses to compare time-to-death outcomes between glass-and resin-based Y-90 treatment types. Time-to-death was defined as days between first Y-90 treatment and death due to any cause within 365 days. They also censored survival time for subjects alive at the end of the follow-up period at 365 days. Subjects lost to follow-up were censored based on the date of last contact. Case-wise deletion was used to address missing data, as subjects with incomplete data were excluded from analyses. Morgan and team used a variety of statistical tests such as Kaplan-Meier curves, log-rank tests, and hazard ratios to compare and describe survival between groups.
Morgan et al found that a total of 217 treatments were performed on 126 patients with 136 (63%) using glass particles and 81 (37%) using resin particles. Forty-six (37%) patients had metastatic colorectal cancer, 51 (40%) had primary hepatocellular carcinoma, while 11 (9%) had neuroendocrine and 18 (14%) had other primary liver metastasis. Two-thirds of all patients were male with a median age of 62 years at first treatment. Of the 126 patients, 77 (61.1%) received glass-based Y-90 treatments, of which 52 (67.5%) died prior to one year, 18 (23.4%) were lost to follow-up, and seven (9.1%) were alive at one year. Of the 49 (38.9%) patients who received resin-based Y-90 treatments, 12 (24.5%) died prior to one year, 24 (49%) were lost to follow-up, and 13 (26.5%) were alive at one year when compared to subjects receiving glass-based (p<0.01). Mean time-to-death for glass-based Y-90 treatments was 257.6 days compared to 301.5 days for resin-based. The volume of liver replaced by tumour and the size of two dominant lesions were not significantly different between the two groups.