Percutaneous Thermal Segmentectomy: A Conversation With Pierleone Lucatelli, MD, PhD

IO Learning spoke with Dr Pierleone Lucatelli, an interventional radiologist at the Policlinico Umberto I in Rome, Italy, regarding his recently published proof of concept study on percutaneous thermal segmentectomy. This multicenter, retrospective experience examined the combination of balloon-occluded microwave ablation followed by balloon-occluded transarterial chemoembolization in patients with liver malignancies >3 cm.

Ami Peltier:  Welcome to IOL Radio. I’m Ami Peltier, Managing Editor of IO Learning, a digital publication geared toward interventional oncologists and the news source for the symposium on Clinical Interventional Oncology. Today, we’re pleased to welcome Dr Pierleone Lucatelli. Dr. Lucatelli and his colleagues at the Policlinico Umberto I  in Rome, Italy recently reported their multicenter retrospective experience on the combination of balloon-occluded microwave ablation followed by balloon-occluded transarterial chemoembolization in patients with liver malignancies >3 cm. He is here to tell us about the results of this proof of concept study, which recently published in the journal of Cardiovascular and Interventional Radiology. The study focused on the appearance and volume of necrotic area, as well as safety profile and oncological results. Welcome, Dr. Lucatelli, please begin by telling us about your study objective. 

Dr Lucatelli: The aim of this article was to report the retrospective analysis of the first 23 patients with different etiology of liver malignancy, either primary or secondary cancer patients with a lesion >3 centimeters. The major limitation of ablative treatments is the tumor dimension that according to international guidelines, and being European, our approved guideline is the CIRSE guideline, that suggests to perform treatment in an ablative fashion when lesions are below 3 centimeters. Why? Because if you consider the different vendors' ablation instructions that are included with your machine, you will recognize that you will not be able to have an appropriate safety ablative margin if your target lesion range is between 3 to 5 centimeters or even more, because ideally you are asked to create an ablative margin of more than 5 millimeters in each direction to perform a safe treatment.

The first experience was proposed by Roberto Iezzi at the Cattolica University in Rome and investigated the safety profile and the tolerability of such a treatment. Dr Iezzi  was then joined by myself (from the Sapienza University of Rome in Rome, Italy), Renato Argirò (from the University Hospital of Rome Tor Vergata in Rome, Italy), and Laura Crocetti (from the University of Pisa in Pisa, Italy) to merge our experience with the combination of ablation under temporary vascular occlusion of the segmental artery feeding the tumor, eventually followed by balloon-occluded transarterial chemoembolization (b-TACE).

In the last 4 years, my research group has focused our attention on the balloon-occluded TACE procedure, investigating the advantages of performing a transarterial embolization procedure under temporary occlusion. The major featured benefit is the distribution of flow toward the targeted tumor, which has been demonstrated in both Asian and European literature to promote novel typology of embolization—that is, pressure-gradient driven embolization. This has been demonstrated to ameliorate the response rate of TACE treatment, but this is still not enough; a 60% complete response rate in a patient with a tumor between 3-5 centimeters is clearly an unmet need for a patient who are seeking a curative treatment.

In our study, by achieving temporary occlusion of the feeding vessel while concomitantly adding microwave ablation, we were able to increase the volume of the necrotic area by 100% with a single antenna positioning and significantly reduce the amount of drug and embolic needed to finish the procedure. After retrospectively analyzing the morphology and the dimensions of the obtained necrotic area, we were struck by how the morphology of the necrotic area was not only 100% greater than suggested by the manufacturer-provided information, but also different in shape. Rather than being rounded in shape (as suggested by the machine’s specifications), the necrotic area was irregularly and triangularly shaped. We analyzed the necrotic area in detail, including the segmental vascular anatomy that we occluded temporarily, and advanced imaging showed a clear coherence and tracing of the occluded vascular segment and obtained the morphology shape of the necrotic area.
    
This may act as a game changer in the field of liver oncology because this technique has no fancy devices and has no major learning curve, because the positioning of a single microwave antenna and positioning of a balloon temporary occlusion microcatheter is part of our everyday clinical practice. The technique is not really complex and uses no guiding software or fancy equipment. Nonetheless, we were able to ameliorate the complete tumor response, which is known to be the strongest predictive factors for overall survival, up to 90% in a sustained fashion, despite facing lesions of up to 5 centimeters in median diameter. 

Ami Peltier: Were you surprised by any of these results?

Dr Lucatelli:  We were really surprised, as were our counterparts in oncology and gastroenterology, because all of the treatments were very well tolerated. There were no differences with the combined novel treatment versus a standard ablative procedure, other than some mild pain in the subcapsular region, which was easily pharmacologically managed. No prolonged in-hospital stay was seen. The mean diameter of necrotic area obtained was about 6 centimeters, ranging from 5-7 centimeters, which has never been achieved with a single antenna without this combined technique. We observed no grade 3 or grade 4 adverse events related to the procedure and the patients had no major complaints after the combination procedure.

The other crucial point that I want to underline is that we have been treating different kinds of tumors, such as hepatocellular carcinoma and colorectal cancer carcinoma, tongue cancer metastases, and cholangiocarcinoma that recurred after surgery. This combination treatment may potentially serve as an alternative to surgery. One must remember that surgeons do not really quantify what they are removing; rather, their goal is to leave a healthy safety margin. We are obtaining an appropriate safety margin with this technique despite the lesion diameter. This is true regardless of the type of tumor and regardless of the ablation machine we have employed, which includes devices manufactured by Terumo, Medtronic, RFA Medical HS, and others. The benefit is not coming from the device, but from the technique itself. We are also seeing these results regardless of the duration of the microwave employment.  We always increase the dimension of the necrotic area by applying the microwave energy only after having gained temporary occlusion of the segmental artery feeding the site of treatment. 

Ami Peltier: Do you have any thoughts on the presumed mechanism of action behind this technique?

Dr Lucatelli: We believe that the advantage of determining ablation under temporary occlusion is mainly due to a potential modification of the water content within the segment occluded, because the spread of the microwave does not stop to the target lesion, but spreads toward the boundaries of the vascular occluded segment. This suggests that this temporary vascular occlusion may lead to a different water content within the occluded segment, facilitating its spread far beyond the tumor limits. Therefore, we strongly believe that this technique is not device related, and that is why I want to suggest that the results were completely independent of the different ablation machines employed, and that it is the technique itself that determines the advantage.

Ami Peltier:  Do you have any future studies planned on this technique?

Dr Lucatelli: The 3 universities are now running a randomized control trial in order to fully understand and to support our theory that this technique achieves a purely thermal segmentectomy. This theory is supported by the higher rate of complete response despite the target lesion diameter >5 centimeters. We plan to compare 3 groups. The first will be our standard combined treatment of TACE with microwave ablation under vessel occlusion, the second group will include TACE with microwave ablation without vessel occlusion, and the third group will be treated with ablation under vessel occlusion alone (without subsequent balloon TACE). We are including this third group because we have already treated several patients and theorize that the embolization used after the ablative procedure is useless. If the results bear this out and are statistically significant (or at least similar in terms of response rate), this trial will support the theory that the combination of microwave ablation under balloon occlusion causes the ablative action to spread up to the underlying vascular tracing segment.

Ami Peltier: Any final thoughts or anything you’d like to add?

Dr Lucatelli: This is an easy technique, but the operator must be familiar with standard balloon-occluded TACE procedures, including appropriate microcatheters and patient selection. In Italy, this combined treatment is offered for a lesion that is ultrasound visible so it can be punctured easily. A critical part of an ablative procedure is correct needle positioning, but it can be challenging to place the needle antenna concentrically within a 3-5 cm lesion. Nonetheless, this technique has been used in several patients with large target lesions, and despite the eccentric position of the needle, we achieved appropriate margin and lesion coverage.

Ami Peltier: That concludes this episode of IOL Radio. Thank you to Dr Pierleone Lucatelli for sharing these promising study results with our listeners. To read a transcript of this interview, please visit the podcast page at iolearning.com, where you’ll also find further information on this study if you’d like to learn more. Thanks for listening! 

Reference

1. Lucatelli P, Argirò R, Crocetti L, et al. Percutaneous thermal segmentectomy: proof of concept. Cardiovasc Intervent Radiol. 2022;45(5):665-676. doi:10.1007/s00270-022-03117-y