Global Embolization Oncology Symposium Technologies (GEST; 19–22 May, New York, USA) provided delegates and faculty alike with the opportunity to hear about worldwide approaches to hepatocellular carcinoma (HCC) treatment. The dedicated session comprised discussion of various curative-intent therapies, how to define this as a concept, and how the scope of it might be expanded beyond that which achieves recurrence-free survival. A key takeaway from the session was that the next generation of interventional radiologists hold radiation segmentectomy in high regard, with its advantages now playing out in the form of clinical data.
The session began with Donna D’Souza’s (University of Minnesota, Minneapolis, USA) presentation titled ‘(Thermal) ablation is the only curative-intent therapy for early-stage HCC’. However, she immediately offered the disclaimer that, in reality, she does not believe that it is the only way to treat with curative intent, especially now that we are in “the era of radiation segmentectomy”. Robert Lewandowski (Northwestern University, Chicago, USA) followed on the subject of the latter.
D’Souza started by explaining that the updated 2022 Barcelona Clinic Liver Cancer (BCLC) guidelines still recommend ablation for unresectable, small HCC, with the new addition of transarterial chemoembolization (TACE) or radioembolization as a second-line therapy if ablation is not feasible.
Regarding the definition of ‘curative-intent’, D’Souza described it based on a comparison with surgical resection, which is widely viewed as “the gold standard” for curative-intent therapy for HCC. She elaborated that the rate of complete pathologic necrosis (CPN) after ablation is also of importance in determining local cure rates.
D’Souza proceeded to detail recent data, including randomised controlled trial data out of Hong Kong, which allocated 109 patients to surgical resection and 109 to radiofrequency ablation (RFA). The paper, published in 2017, comprised data gathered over a median follow-up period of 7.7 years, and showed no difference in local recurrence rate, disease-free survival, and survival to 10 years, between ablation and resection, even for larger lesions. D’Souza highlighted the significance of these findings: “traditionally, surgery outperforms ablation for lesions between three and 5cm”. Moreover, the SURF randomised controlled trial, of which some of the results were published in 2021, demonstrated that there was, again, no difference in recurrence-free survival, nor overall survival, at five years.
In conclusion, D’Souza underlined how “ablation is the most evidence-based curative-intent treatment modality for HCC for interventional radiologists”, and also highlighted the high complete pathologic necrosis rates that have been achieved in
Lewandowski then pivoted to explore the curative-intent capacity of ablative, segmental transarterial radioembolization (TARE), using the case of a 95-year-old female who survived two years after undergoing ablative radiation segmentectomy for HCC. Lewandowski explained that the definition of ‘curative intent’ can and should be expanded beyond its current status: achieving a comparable degree of CPN to surgical resection. The implications of a broader scope of the term could be that it comes to encompass treatments that facilitate bridging or downstaging to transplant, namely TARE.
Lewandowski emphasised the role of dosimetry, citing his awareness of threshold doses: targeting HCC with 190 Gray sees almost three times the rate of CPN when compared to lower doses, and targeting a threshold dose of 400 Gray has yielded 100% CPN explant in a retrospective study.
Finally, given the opportunity to field questions from the audience and each other, the panel touched on cryoablation and its performance relative to that of thermal ablation. “There are some pretty good data out there showing that it is effective [and can] outperform RFA,” D’Souza outlined. She also responded to Lewandowski on the topic of SBRT: “in some centres it is becoming more common,” while the existing literature still favours RFA. Panel moderator Nadine Abi-Jaoudeh (University of California Irvine, Irvine, USA) corroborated D’Souza’s “last-resort” approach to using SBRT, but made the point that “younger radiation oncologists are excited about the therapy’s potential.”