Hepatocellular carcinoma locoregional therapies: Outcomes and future horizons

Table 1 Locoregional therapy techniques, benefits, and risks

Locoregional modality	Techniques	Clinical advantages	Clinical risks
TACE	Drug-eluting beads or conventional delivery	Provides both local embolic and chemotherapeutic effect	PES, biloma, liver abscess, liver failure
TAE	Particulate or other embolic agents	Avoids radio and chemotoxicity; less expensive than other embolotherapies	PES, biloma, liver abscess, liver failure
TARE	Y90 microspheres	May be used in early disease with curative intent; intermediate disease can be used to increase FLV to qualify for curative intent surgery; best QoL scores of all options	PRS, RILD, radiation-induced pneumonitis, biloma, liver abscess, liver failure
Ablation	Radiofrequency current, microwaves, or cryoablation	Efficacious as monotherapy for early-stage disease; less morbidity than transarterial therapies	PAS, iatrogenic injury, bleeding

TACE: Transarterial chemoembolization; PES: Post-embolization syndrome; TAE: Transarterial embolization; TARE: Transarterial radioembolization; FLV: Functional liver volume; QoL: Quality of life; PRS: Post-radioembolization syndrome; RILD: Radiation-induced liver disease; PAS: Post-ablation syndrome.

Table 2 Summary of primary outcomes of locoregional therapies for hepatocellular carcinoma

Locoregional technique	Primary outcomes
TACE	TACE provides a survival benefit compared to supportive care in unresectable disease[34]. Concomitant TACE and sorafenib is superior to standalone therapy for unresectable disease[51-53]. Comparisons of DEB-TACE versus cTACE have yet to reveal significant differences in OS and short and long-term complication rates. Further studies are needed for considerations in more specific circumstances[48,49]. When combined with PVE, TACE provides more robust FLR increase and results in better survival compared to monotherapy strategies to enhance FLR[54].
TAE	TAE provides a survival benefit compared to supportive care in unresectable disease[34]. Early data of chemoembolization has shown little survival benefit over TAE, but superior proximate outcomes such as TTP and tumor response compared to TAE[63,64].
TARE	TARE shows similar complication and survival rates to TACE, while producing higher QoL scores and longer TTP[77,78]. TARE segmentectomy for early-stage disease (tumors < 3 cm) results in a 5-year survival of 75%, which is comparable to curative intent therapies such as transplantation and surgical resection[81]. TARE lobectomy provides a significant increase in FLR and is a safe mechanism to treat tumor while inducing contralateral hypertrophy[82-86].
Ablation	In early-stage patients, standalone percutaneous ablation produces comparable survival outcomes to surgical resection[113-116]. RFA and MWA techniques show similar outcomes in early-stage disease (tumor < 3 cm)[108,119]. Combination therapy using TACE and ablation (particularly MWA) provide the best outcomes for large tumors (tumor 3-5 cm)[120].

TACE: Transarterial chemoembolization; DEB-TACE: Drug-eluting bead chemoembolization; cTACE: Conventional transarterial chemoembolization; OS: Overall survival; PVE: Portal vein embolization; FLR: Future liver remnant; TAE: Transarterial embolization; TTP: Time-to-progression; TARE: Transarterial embolization; QoL: Quality of life; RFA: Radiofrequency ablation; MWA: Microwave ablation.