TranArterial RadioEmbolization (TARE) for HCC
Transarterial Radioembolization, often abbreviated as TARE, is a minimally invasive procedure used primarily in the treatment of liver cancer, particularly in cases where surgery or other forms of treatment may not be viable options. This innovative approach combines the power of radiation therapy with targeted embolization to deliver radiation directly to the tumor site while minimizing damage to healthy surrounding tissue.
Understanding TARE:
| Radiation Biology | Cell cycle and Radiation Biology |
| TARE particle selection | Choosing between Glass-sphere and Resin-sphere |
| T/N Ratio | Link |
Patient Selection in TARE:
| Steps | Recommendations |
|---|---|
| Patient Selection | Tumor Burden and Staging, Liver Function and Performance Status are assessed. Scoring system like STATE score and HAP score can be used. |
| Pre-Procedure Imaging | Triple Phase Computed Tomography or Dynamic Contrast Enhanced Magnetic Resonance Imaging is performed prior to treatment allocation |
| Patient Preparation | Discuss Antiemetic treatment, Intravenous hydration, Analgesic management, and Antibiotic Management. |
| Role of Cone Beam CT | Cone Beam CT can be performed for tumor visualization, targeting, and assessment of treatment completion |
| Response Evaluation | Tumor response to TARE can be assessed using objective radiologic response like mRECIST, EASL. |
| Dosage for TARE | 1. Therapeutic dose to Tumor = 120 Gy 2. Dose limit to healthy liver: - Single time < 30 Gy, - Cumulative dose < 50 Gy 3. Dose limit to Lung < 30 Gy |
| Some Important Publication and studies | Link |
Patient selection for special cases:
| Special Cases | Approach |
|---|---|
| Patients after Liver Resection | Lobar approach is taken where lobes are left lateral lobe (2/3) and left medial lobe (4a/4b) |
| After RFA/MWA | Treated with standard principles and requires no special precautions as long as tumor vascularity is present |
| After TACE | 1. Vessel to tumor has recanalized 2. TACE was not done up to the extent of obstruction of tumor vasculature, chemical vasculitis or induction of parasitizing flow 3. Performance status and child score have not significantly deteriorated 4. Suboptimal results because of obliterated microvasculature |
| Y90 for Metastatic disease | 1. Phase II trails support the use of Intra-arterial therapies 2. 99m Tc MAA uptake means Hypervascular lesion (relative uptake compared to liver parenchyma) 3. Hypovascular lesion has affected drug delivery especially with particles > 300 um (Y90 provides favourable outcome in hypo vascular lesion) |
| Chemotherapy + Y90 Therapy (Phase I, II and III studies done) | 1. Chemotherapy to be discontinued for 2-4 weeks before and after Y90 administration (TheraSpheres) EXCEPTION is Neuro Endocrine Tumor (NET) patient should continue Octeroide and 100-200 ug of Octeroide Bolus on the day of Y90 delivery 2. Patient receiving chemotherapy are at higher risk of Arterial spasm, dissection, rupture 3. 5-Fluorouracil, Irinotecan, Oxaliplatin, Capecitabine esp. Radiosensitizing agents 4. Growth Factor Inhibitor like Bevacizumab/Cetuximab cause Altered vascularity and flow dynamics resulting in less effective Intra-arterial Therapies. |
| RFA+Y90 | Two theories: 1. Y90 (down-staging) then RFA/Ressection 2. RFA (zone of hyperaemia leads to enhanced Y90 uptake) then Y90 |
| Treating patient on the same day as planning mesenteric angiography. | Technically feasible but: 1. All the calculations of dosimetry and LSF need to be completed just in time 2. Continuous nursing care is needed as the whole process will take at least 3-5 hours to complete 3. TheraSphere may not be available in prescribed dose 4. LSF > 20 % may lead to exclusion of patient from Y90 therapy leading to used Y90 dose 5. 99mTc-MAA may cause embolic effect and need 2-3 hours to allow normal physiological breakdown 6. Vessel that are coil embolized for vascular redistribution need hours to days for complete embolisation |
| Radiation Segmentectomy | 1. Target tissue is small 2. Feeding vessel to the tumor only 3. TheraSphere is not low enough to deliver 80-150 Gy to tissue after decay (as lowest activity available is 0.75Gbq and for a target dose of 100Gy corresponding target tissue 0.375kg) 4. SIR-Spheres preferred because of no lower limit available. |
DELIVERY OF CHOICE FOR HCC/METASTASIS:
| Multilobar HCC | Metastasis - Focal or unilocular (Feeding vessel visible) |
|
|---|---|---|
| Normal Bilirubin | Lobar Infusions | Lobar or segmental infusion |
| Elevated Bilirubin 1. HCC - raised levels are generally due to liver failure 2. Mets - Raised Bilirubin levels are generally due to obstructive process | Uncertain | Segmental infusion only |
Post-Procedure Care:
- Prophylactic use of anti ulcer medication in all the patients at the time of discharge to minimise GI irritation.
- Tapering 5 day steroid dose pack to counter fatigue.
- Sudden onset chills, shakes and fever (Para-neoplastic fever syndrome – likely due to release of pyretic agents like CRP and TNF). Seen more commonly in patients with AP shunting and PVT. Managed with – Meperidine, diphenhydramine and paracetamol
- Follow up – after 14 days ( four half lives – 12 days) and clinically accessed especially for ECOG status.
- Second procedure can be taken 30 days after the first treatment.
Complications:
- Post-Embolization Syndrome
- Radiation Gastritis, GI ulcer and Pancreatitis
- Radiation Pneumonitis
- Radiation Hepatitis – Anicteric Ascites, increased ALP, thrombocytopenia and veno-occlusive disease
Systemic Steroid therapy may control the progression - Lymphopenia – more commonly seen with glass microspheres
- Biliary Injury
- Hepatic Fibrosis and PHTN
- Radiation Cholecystitis