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Internal view of patient's torso demonstrating targeted accuracy of TheraSphere Y-90 Glass Microspheres in liver.

TheraSphere™ Y-90 Glass Microspheres

LEGACY study

LEGACY study overview

The LEGACY study is a robust multicenter study confirming TheraSphere as a neoadjuvant or standalone therapy in treating HCC.1

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Updated BCLC guidelines for HCC now include Transarterial Radioembolization (TARE/Y-90) for very early stage (0) and early stage (A) patients.2 These guidelines influence clinical decision making and are based on the LEGACY Study results.1

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Study objective

To assess local tumor control and duration of response following treatment with Y-90 glass microspheres in patients with unresectable solitary HCC lesions.

Key study results


Patients in the LEGACY study responded to TheraSphere treatment(s)


Overall Survival rate in patients with transplant or resection following TheraSphere at 3 years


Demonstrated rate of best response by TheraSphere

Overall survival

(Treated population)

93% overall survival rate in patients with transplant or resection following TheraSphere at 3 years

Graph showing 93% overall survival rate at 3 years in patients with transplant or resection following TheraSphere.

Tumor response

(Best response in evaluable population, localized mRECIST)

88% demonstrated rate of best response by TheraSphere (i.e. CR, PR) by localized mRECIST.

Graph showing 88% (95% CI: 82.4-92.4 N=162) demonstrated rate of best response by TheraSphere (i.e. CR, PR) by localized mRECIST.

Study design

Multi-center, single-arm, retrospective study conducted at 3 U.S. sites.* Consecutive patients meeting the eligibility criteria were treated with TheraSphere Y-90 Glass Microspheres at each site between January 2014 and December 2017.

First and only

  • Used highly clinically relevant criteria for localized tumor control (mRECIST)
  • Reported a median dose to perfused liver volume of 410 Gy
  • Demonstrated 100% of patients achieved CR or PR (localized mRECIST)

Key eligibility criteria

Unresectable solitary lesions (≤ 8 cm); Selective, lobar, or mixed administration of Y-90 glass microspheres (TheraSphere); Treatment purpose (neoadjuvant to transplantation or resection or stand-alone treatment); Child-Pugh score A; BCLC A or BCLC C (ECOG 1); No prior liver transplantation, resection, locoregional treatment or systemic therapy; No portal vein thrombosis or extrahepatic disease.

Table with key baseline characteristics (N=162), median age: 66 years, with % of patients: >= 75 years, 17.9; BCLC A: 60.5, BCLC C: 39.5; median tumor size: 2.6 cm (0.9-8.1 cm).

Primary study endpoints were met

Determined by Blinded Independent Central Review (BICR)



Objective responsive rate

Objective Response Rate (ORR) defined as CR or PR using localized mRECIST (defined as the response within the Y-90 glass microsphere treatment area) with confirmation of response (>4 weeks).



Duration of response (> 6 months)

Duration of Response (DoR) using localized mRECIST.**

Safety: Majority of adverse events were mild and resolved without medical intervention.


LEGACY is the first multicenter study to report a high median perfused volume absorbed dose of 410 Gy with TheraSphere, which resulted in an 88% best response, excellent and durable tumor control and high overall survival rate in patients with early and advanced HCC.


IOL Radio podcast

Listen in to an IOL Radio podcast discussion about the results of the LEGACY Study, a robust multicenter study confirming Boston Scientific’s TheraSphere™ as a neoadjuvant or standalone therapy in treating hepatocellular carcinoma.


The LEGACY study showcase

This presentation provides background on the use of Y-90 glass microspheres to treat HCC, discusses results of the LEGACY study and recently published studies using Y-90 glass microspheres.

HCC: hepatocellular carcinoma; BCLC: Barcelona Clinic Liver Cancer staging system; Y-90: Yttrium-90; Gy: Gray; IQR: Interquartile Range; CR: Complete Response; PR: Partial Response.

* University of Washington, Seattle, WA; Northwestern University, Chicago, IL; Mount Sinai Health System, New York, NY.

** Median follow-up was 29.9 months [95% CI: 24.7, 34.6]..

  1. Salem R, Johnson GE, Kim E, Riaz A, Bishay V, Boucher E, Fowers K, Lewandowski R, Padia SA. Yttrium-90 Radioembolization for the Treatment of Solitary, Unresectable Hepatocellular Carcinoma: The LEGACY Study. Hepatology. 2021 Mar 19. doi: 10.1002/hep.31819.
  2. Reig M, Forner A, Rimola J, et al. BCLC strategy for prognosis prediction and treatment recommendation: The 2022 update. J Hepatol. 2021;S0168-8278(21)02223-6. doi:10.1016/j.jhep.2021.11.018.