Reply
Authors: Riad Salem, Michael Vouche, Ali Habib, Edward Kim, Kent T. Sato, Ryan Hickey, Robert Lewandowski
Journal: Hepatology (2014)

Potential conflict of interest: Dr. Kim advises Onyx and is on the speakers' bureau for BTG. Dr. Salem advises BTG. Dr. Lewandowski advises BTG. We thank Professor Seror for an in‐depth review of our article.1 We take the opportunity to make a few comments and respond to the queries. Comment First, the accepted terminology is radiation segmentectomy. This term is now routinely used, and several other studies refer to it as such. Second, we highlight that nowhere in our article did we use the term "curative" when referencing this new technique. However, because this was raised, we state our position that the term "potentially curative," when applied to ablation, should either be eliminated (local/distant recurrences frequent) or similarly applied to transarterial therapies in early disease, where complete pathological necrosis (CPN) as well as long recurrence/progression‐free and overall survivals may also be achieved in select cases. Third, though we agree that the risk of tract seeding may be overestimated, many centers contraindicate ablation in transplant patients. For such centers, radiation segmentectomy explicitly addresses this concern with no risk of tract seeding. Response Our cohort was indeed comprised of 50% Child‐Pugh B patients. These patients provide radiology‐pathology data at transplantation, no different to ablation. Their inclusion was appropriately interpreted with statistical censoring. We are uncertain of response difficulties to which the researchers allude, because necrosis and size reduction were observed, similar to other transarterial therapies. We disagree with the perceived differences in time to transplant between series, because confidence intervals overlap and differ only by weeks. Also, strict comparison of pathology data must be tempered, because those lesions were ablatable (and therefore ablated), whereas our patients were unablatable. The issue of "complete necrosis" deserves further comment. Whereas some centers use pathology‐reporting scales at 10% intervals (i.e., 51%‐60% and 61%‐70%), our group concluded long ago that this could not be reproduced, given its predominantly subjective component; pathologists cannot consistently differentiate 51%‐60% from 61%‐70% necrosis. Hence, we adopted a <50% and 51%‐99% scale (even if few viable cells noted) as well as CPN. In reality, all of our segmentectomy patients exhibited >90% necrosis, irrespective of tumor size or location. The query about pathology of the nontumorous segment is of interest; as mentioned in the article, the radiated segment was atrophied and scarred. Radiation segmentectomy applies "ablative" doses to small sectors of liver containing tumor; an atrophied and scarred tumor‐bearing segment is the intent. Normal parenchymal preservation is not. We agree that the definition of "difficult location" should be clarified. However, whereas experts purport to ablate tumors in difficult locations (dome, caudate, and abutting the heart or stomach), Seror et al. reported that the no‐touch technique, an approach meant to increase CPN rates, could only be achieved in 11 of 29 cases (as a result of lesion size or location). Ironically, in that series, two ablated dome tumors resulted in diaphragmatic injury necessitating surgical repair, suggesting the imposition of ablation in this setting, rather than a recognition of its limitations and subsequent selection of another potentially equally effective treatment.2 Furthermore, high‐risk ablation involves general anesthesia, multiple liver punctures and probes, 2 or more days of admission, and potential injury to adjacent structures. In contrast, radiation segmentectomy is an outpatient, same‐day treatment using moderate sedation with a benign adverse event profile.3 Such adverse event differences are important considerations when selecting between high‐risk ablation and radiation segmentectomy. In conclusion, centers now have the option of transarterial ablation for high‐risk lesions, with the potential for CPN.