Last reviewed by Dr. Dharmender Malik on 8 May 2026 · this article reflects the published evidence and current clinical practice at FMRI Gurugram.
Introduction
The patient is a 62-year-old man with hepatocellular carcinoma in the setting of chronic hepatitis B. The CT shows a 4 cm tumour in segment 7 of the liver and a smaller lesion in segment 5. Liver function is preserved — Child-Pugh A. He is on the transplant list. The wait at his centre is approximately nine months. The question on the team's mind, in our weekly multidisciplinary review, is the same one that comes up almost every Tuesday: what do we do to keep this disease in check until an organ becomes available?
This is the clinical territory where TARE — transarterial radioembolization with Yttrium-90 microspheres — does some of its most useful work. This article is for patients and families who have heard the procedure mentioned in a multidisciplinary opinion, and for referring hepatologists and surgeons who want a quick reference on how TARE fits in the transplant-candidate pathway.
What TARE actually is
TARE is an interventional radiology procedure performed by an interventional radiology team in collaboration with the nuclear medicine team. A catheter is placed via the femoral or radial artery and advanced into the branch of the hepatic artery feeding the tumour. Through that catheter, microscopic spheres loaded with the radioisotope Yttrium-90 are infused.
The biology that makes the procedure work is liver-specific: hepatocellular carcinoma derives almost all of its blood supply from the hepatic artery, while normal liver tissue derives most of its blood supply from the portal vein. Microspheres delivered into the hepatic artery preferentially reach the tumour and lodge in its capillary bed. They emit beta radiation locally over about two weeks (Y-90 half-life is 64 hours, with most of the radiation delivered in the first ten days). The tumour receives a very high local dose — often above 100 Gray — while the surrounding normal liver receives a much lower dose.
"The microspheres are physical embolic agents that also happen to be radioactive. The selectivity is partly geographic — they go where the artery delivers them — and partly biological — the tumour wants the artery, the normal liver does not."
Two commercial products are commonly used: TheraSphere (Boston Scientific; glass microspheres) and SIR-Spheres (Sirtex; resin microspheres). They differ in microsphere size, embolic load, and dose calibration, but the clinical principle is the same.
Bridging versus downstaging
This is the conceptual distinction that determines almost everything else about the treatment plan.
Bridging
Bridging therapy is given to a patient who is already within standard transplant criteria (most commonly the Milan criteria, see below) and is on the transplant waiting list. The goal is to prevent the disease from progressing beyond criteria during the wait — which would mean removal from the list. Bridging is, in essence, holding the disease in place until an organ becomes available. The wait can be months to over a year depending on geography and listing rules.
Downstaging
Downstaging is given to a patient whose disease exceeds standard transplant criteria at presentation. The goal is to reduce the tumour burden to bring the patient back within criteria — at which point the patient becomes transplant-eligible. Downstaging protocols exist with defined criteria, and patients who successfully downstage and remain stable for a defined observation period (typically 3 to 6 months) are then listed for transplant.
The decision is not always one or the other. Some patients sit on the borderline of criteria, and the team treats with TARE while watching closely how the disease responds. The goal in either case is the same: get the patient to a curative transplant in good condition.
The criteria backbone
Three criteria sets dominate transplant decision-making for HCC. They are worth understanding because the entire bridging-vs-downstaging conversation hangs on them.
Transplant criteria for HCC
- Milan criteria — single tumour ≤ 5 cm, OR up to 3 tumours each ≤ 3 cm, with no vascular invasion or extrahepatic spread. The classical eligibility ceiling, established in 1996.
- UCSF criteria — single tumour ≤ 6.5 cm, OR up to 3 tumours with the largest ≤ 4.5 cm and total tumour diameter ≤ 8 cm. A modest expansion that increases the eligible patient pool with comparable post-transplant survival.
- MELD-Na score — a separate measure of liver function severity used for organ allocation prioritisation, distinct from tumour-based eligibility. Patients with HCC often receive MELD exception points reflecting the natural history of their tumour.
Different transplant programmes operate under different rules. Understanding which framework your transplant programme uses is the first conversation to have.
The workup
Before TARE is offered, the team performs a structured workup:
- Multiphase contrast-enhanced MRI or CT — to map every tumour, characterise vascular supply, and confirm that disease is liver-confined.
- Blood work — liver function (Child-Pugh classification), kidney function, coagulation, complete blood count, alpha-fetoprotein.
- Hepatology and transplant surgery review — confirms transplant candidacy and the bridging-vs-downstaging goal.
- Mapping angiogram with technetium-99m MAA — performed about two weeks before the planned Y-90 infusion. The MAA simulates how Y-90 will distribute. The scan also identifies lung shunting (the small fraction of microspheres that bypass the liver and lodge in the lungs); patients with lung shunting above defined thresholds are not safe candidates.
- Dosimetry calculation — by the nuclear medicine team, using the mapping data to determine the personalised Y-90 dose.
Treatment day
The TARE infusion itself takes about an hour. The patient is awake, with light sedation, in the interventional radiology suite. After the infusion, the catheter is removed, the access site is closed, and the patient is monitored for a few hours. Most patients are discharged the same evening or the next morning.
For the next 7 to 14 days, the patient may experience post-radioembolization syndrome — fatigue, low-grade fever, mild right-upper-quadrant discomfort, and nausea. These are managed symptomatically. The team checks in by phone over the first two weeks. Imaging response assessment is performed at 1 to 3 months with contrast-enhanced MRI or CT.
Figure 1. The TARE pathway from transplant listing through Y-90 delivery and follow-up. The mapping angiogram (step 3) is the safety gate that confirms the patient is anatomically suitable for the planned dose.
The multidisciplinary OMT workflow
TARE for transplant candidates is never a unilateral decision. The Optimal Medical Therapy (OMT) framework requires a multidisciplinary team review at each major decision point. At FMRI, this means a weekly hepatobiliary tumour board attended by:
- Hepatologist (liver function, viral hepatitis management, transplant candidacy)
- Transplant surgeon (transplant criteria, listing decisions)
- Interventional radiologist (procedural feasibility, vascular anatomy)
- Nuclear medicine physician (dosimetry, Y-90 planning)
- Medical oncologist (systemic therapy options if disease progresses)
- Diagnostic radiologist (imaging interpretation, response assessment)
The goal of the multidisciplinary review is to choose, for each individual patient, the locoregional therapy with the best chance of achieving the bridging or downstaging goal — TARE, transarterial chemoembolization (TACE), radiofrequency or microwave ablation, or stereotactic body radiation therapy. Each has indications and contraindications, and each patient's anatomy and disease burden tilt the choice in different directions. There is no single right answer for HCC; there is a right multidisciplinary process.
What the outcomes data shows
The two most important pieces of evidence specific to TARE in HCC are:
- LEGACY study (Salem et al, Hepatology 2021)[1] — A retrospective multicentre study of 162 patients with solitary unresectable HCC ≤ 8 cm treated with Y-90 radioembolization. Three-year overall survival was 86 percent, and 96 percent of treated lesions met response criteria. The data established TARE as a strong locoregional option for selected solitary HCC.
- DOSISPHERE-01 trial (Garin et al, Lancet Gastroenterology & Hepatology 2021)[2] — A randomised study comparing personalised dosimetry to standard dosimetry. Personalised dosimetry produced higher response rates and improved overall survival, establishing the role of careful dosimetry as part of the TARE planning workflow.
Specific to bridging: published series from major transplant centres show that patients bridged with TARE have transplant outcomes comparable to those of patients listed with smaller tumour burden. Specific to downstaging: published series show that approximately 50 to 70 percent of carefully selected patients can be successfully downstaged into transplant criteria with locoregional therapy (TARE plus or minus other modalities). Once successfully downstaged and observed, post-transplant survival in these patients approaches that of patients listed within criteria from the start.
The numbers vary by centre, by patient selection, and by which criteria are used. The honest summary: TARE works for the right patient at the right time, and that selection requires a functioning multidisciplinary team.
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For patients & referring clinicians
Frequently asked questions
Q01
What is the TARE procedure?
TARE (transarterial radioembolization) is an interventional procedure delivering Y-90 radioactive microspheres via the hepatic artery directly into a liver tumour. The microspheres lodge in the tumour blood supply and emit beta radiation locally over about two weeks.
Q02
How does Y-90 radioembolization work?
Y-90 microspheres are infused via a catheter into the hepatic artery branch supplying the tumour. They lodge in the tumour capillary bed and emit beta radiation with about 2.5 mm tissue penetration over a 64-hour half-life. The localised dose is high while systemic exposure is low.
Q03
Can TARE bridge me to a liver transplant?
Yes. TARE is one of the established locoregional therapies for bridging patients on the transplant list and for downstaging patients beyond standard criteria so they become transplant-eligible. The decision is made in a multidisciplinary review.
Q04
Bridging versus downstaging — what is the difference?
Bridging is given to patients already within transplant criteria to prevent disease progression during the wait. Downstaging is given to patients whose tumour burden exceeds criteria, with the goal of reducing it to within criteria so they become transplant-eligible.
Q05
Who is eligible for TARE?
Patients with predominantly liver-confined HCC, adequate liver function (typically Child-Pugh A or selected B), adequate performance status, and a hepatic arterial anatomy compatible with safe Y-90 delivery as confirmed on a pre-treatment mapping angiogram.
Q06
What are the side effects of TARE?
The most common is post-radioembolization syndrome — fatigue, mild abdominal pain, nausea, and low-grade fever in the first two weeks. Serious complications including radiation-induced liver disease and biliary injury are uncommon when patient selection and dosimetry are careful.
Q07
How long does TARE take to work?
Tumour response to Y-90 develops over weeks to months. Initial response assessment is performed at 1 to 3 months by contrast-enhanced MRI or CT. Some patients continue to develop response over 6 months.
Citations & references
Salem R, Johnson GE, Kim E, et al. Yttrium-90 Radioembolization for the Treatment of Solitary, Unresectable HCC: The LEGACY Study. Hepatology. 2021;74(5):2342-2352.
Garin E, Tselikas L, Guiu B, et al. Personalised versus standard dosimetry approach of selective internal radiation therapy in patients with locally advanced hepatocellular carcinoma (DOSISPHERE-01): a randomised, multicentre, open-label phase 2 trial. Lancet Gastroenterol Hepatol. 2021;6(1):17-29.
European Association for the Study of the Liver. EASL Clinical Practice Guidelines: Management of hepatocellular carcinoma.
J Hepatol. 2018;69(1):182-236.
EASL guidelinesMazzaferro V, Regalia E, Doci R, et al. Liver transplantation for the treatment of small hepatocellular carcinomas in patients with cirrhosis. N Engl J Med. 1996;334(11):693-699.
Yao FY, Ferrell L, Bass NM, et al. Liver transplantation for hepatocellular carcinoma: expansion of the tumor size limits does not adversely impact survival. Hepatology. 2001;33(6):1394-1403.
About the Author
Dr. Ishita B. Sen
MBBS · MD (Nuclear Medicine) · DNB · Post-doctoral Fellowship, Memorial Sloan Kettering Cancer Center, New York
Director and Chief of Nuclear Medicine at Fortis Memorial Research Institute. Co-founder of Theranostic Physicians Private Limited (TPPL). Sub-specialty interest in Y-90 radioembolization dosimetry, working collaboratively with the FMRI hepatobiliary multidisciplinary team for HCC patients.