The Role of Radiation Lobectomy in the Management of Primary and Metastatic Hepatic Disease
Radiation lobectomy is an evolving technique that offers an alternative to portal vein embolization for patients who are not surgical candidates as a result of insufficient future liver remnant. In this interview, Robert Lewandowski, MD, an interventional radiologist and Director of Interventional Oncology at Northwestern University Feinberg School of Medicine in Chicago, describes the rationale for radiation lobectomy, as well as recent advances and practical tips.
Which types of patients may benefit from radiation lobectomy?
Radioembolization has been historically performed in a lobar (as opposed to segmental) fashion for patients with unresectable liver malignancies. This approach has been successful at providing local tumor control. Longitudinal experience has revealed that in patients with unilobar disease, there is an atrophy/hypertrophy complex after lobar radioembolization: there is atrophy of the treated hepatic lobe with compensatory hypertrophy of the contralateral hepatic lobe.
The term radiation lobectomy came about to describe the concept of taking advantage of this atrophy/hypertrophy complex to facilitate surgical resection in patients presenting with unilobar liver cancer and insufficient future liver remnant to have surgery. Radiation lobectomy offers the potential of tumor control with concurrent future liver remnant hypertrophy.
Do any other procedures currently accomplish the goal of stimulating hypertrophy in patients with future liver remnants that would otherwise be too small?
Yes, alternative therapies to radiation lobectomy include portal vein embolization and associating liver partition and portal vein ligation for staged hepatectomy (ALPPS). Portal vein embolization is a percutaneous procedure that involves embolizing the portal vein ipsilateral to the liver tumor, shunting blood to the future liver remnant, resulting in future liver remnant hypertrophy.
What are some considerations in the decision to treat with PVE vs radiation lobectomy?
Radiation lobectomy versus portal vein embolization is an area of debate and dialogue. Portal vein embolization has been the gold-standard approach to promoting surgery by increasing the future liver remnant. The rate and degree of future liver remnant hypertrophy from portal vein embolization often facilitates surgical resection in 3 to 4 weeks post procedure. However, one drawback to portal vein embolization is that we are not concurrently treating the cancer while promoting growth of the future liver remnant. In fact, portal vein embolization can increase tumor growth rate kinetics. Because of this, literature review reveals that up to 1/3rd of patients undergoing portal vein embolization do not have surgical resection, many of these due to tumor progression.
In contrast to portal vein embolization, radiation lobectomy offers the capacity to treat the tumor while promoting hypertrophy of the liver remnant. When patients eventually undergo liver resection, there is a theoretical oncologic benefit to having a non-viable tumor that is mobilized and manipulated during surgery. Another potential advantage with radiation lobectomy is in patients with hepatocellular carcinoma. These patients typically develop cancer in the setting of underlying cirrhosis, and they may have some degree of portal hypertension. Embolizing the portal vein may not be ideal in these patients, especially if they do not hypertrophy or have surgery. Tumor treatment options may be limited in these patients due to the thrombosed portal vein, and there is risk of portal vein thrombus propagation.
Do you see potential for expanding the applications of radiation lobectomy?
As an interventional radiologist, my goal is to expand treatment options to allow for the most curative-intent therapy possible for my patients. In those patients who have preserved liver function, good performance status, and proven tumor biology, I want to help get them to surgical resection. Radiation lobectomy is another tool in my toolbox.
We do need to better understand how to optimize the technique of radiation lobectomy to facilitate surgical resection. Radiation lobectomy is a newer technology and we are still learning how to best perform it.
Any practical tips for operators?
Radiation lobectomy is a very simple procedure; it’s lobar radioembolization. I have more recently modified my technique so that I provide an ablative (boost) radiation dose to the tumor in a selective/segmental fashion while also providing a lobar parenchymal radiation dose to promote hypertrophy of the future liver remnant. I employ this approach to garner the full benefits of aggressive tumor treatment during the interval of future liver remnant hypertrophy. Oncologically, it is beneficial to kill the tumor such that there is no viable disease during mobilization and manipulation of the liver during surgical resection.
Has this approach spread to other centers?
More centers are starting to use the approach I described. These include but are not limited to Mount Sinai in New York City, University of Washington in Seattle, and the Jacksonville Mayo Clinic. These techniques are areas of interest and discussion at national conferences, and more Interventional Radiologists are becoming well versed in segmental or ablative dosing radioembolization, as well as radiation lobectomy to facilitate surgery. It is becoming more mainstream.
What has been your experience with discussing this procedure at tumor boards?
A multidisciplinary approach to cancer care is paramount. In most settings, the goal is to provide patients the opportunity for the most aggressive/curative-intent therapy that we can. In my experience, liver surgeons are very keen to employ techniques such as radiation lobectomy and/or portal vein embolization to convert more patients to liver resection.
Any upcoming studies to look forward to?
Future studies will focus on optimizing the techniques of radioembolization. Prospective studies will be important to move this technology forward.
Have there been any studies in the past year that have advanced the field in this area?
A paper by Palard and colleagues examined the optimal liver parenchyma radiation dose to facilitate maximum hypertrophy of the contralateral lobe. I think we are starting to understand the mechanics of the procedure and how to maximize positive effects.
Lewandowski RJ, Donahue L, Chokechanachaisakul A, et al. (90) Y radiation lobectomy: Outcomes following surgical resection in patients with hepatic tumors and small future liver remnant volumes. J Surg Oncol. 2016 Jul;114(1):99-105.
Palard X, Edeline J, Rolland Y, et al. Dosimetric parameters predicting contralateral liver hypertrophy after unilobar radioembolization of hepatocellular carcinoma. Eur J Nucl Med Mol Imaging. 2018;45(3):392-401.