Radiation lobectomy

RL is performed in people with liver cancer, both primary such as hepatocellular carcinoma and metastatic such as from colon adenocarcinoma. Surgical resection is considered the only curative treatment for liver cancer (other than liver transplantation for hepatocellular carcinoma) but it can only be performed in patients with sufficient remnant liver after resection (amongst other criteria). Both PVE and RL are performed in patients who are not surgical candidates due to insufficient future liver remnant (FLR), which is advised to be between 20-30% and 30-40% of the native liver volume in healthy and cirrhotic livers, respectively.[1]

Common side effects include fatigue, abdominal pain, nausea and anorexia, usually self-limiting. Post-radioembolization syndrome occurs in 20-70% of patients that undergo traditional radioembolization, presenting with shakes, chills, fatigue, nausea/vomiting, abdominal pain/discomfort, and/or cachexia and possibly hemodynamic changes, rarely requiring admission. Unfortunately, most data, if not all, is derived from traditional radioembolization outcomes studies and more will be needed to assess the actual incidence and risk of post-radioembolization syndrome in RL.[10][11]

Complications are abscess formation, biliary complications (biloma, radiation induced cholecystitis and cholangitis, biliary necrosis), gastrointestinal complications (diarrhea, radiation induced gastritis and gastrointestinal ulceration), radiation induced pancreatitis, dermatitis, pneumonitis and lymphopenia.[10][11][2]

RL is performed by an interventional radiologist in the angiography suite, in a fashion similar to radioembolization. The procedure is composed of two different portions, a planning phase and the actual radiation lobectomy, usually performed in two different sessions:[10]

1. Planning phase: the patient undergoes planning angiography of the abdominal aorta and its major vessels. The interventional radiologist accesses the femoral artery via Seldinger technique and advances a wire and catheter to the level of the superior mesenteric artery and the celiac axis, injecting contrast in order to delineate the patient's anatomy. Utilizing smaller catheters and wires, he does the same thing evaluating the common hepatic artery, gastroduodenal, proper hepatic, left hepatic, right hepatic and phrenic arteries. The purpose of this planning angiogram is to evaluate for anatomical variants and collaterals that need to be coil embolized, in order to minimize the risk of non-target radioembolization. At this point, once the vascular anatomy has been delineated and necessary vessels have been embolized, the physician will inject 4-5 mCi of tc-99m macroaggregated albumin (MAA) in order to evaluate hepatopulmonary shunting, which serves as a proxy in assessing the risk of developing radiation pneumonitis. The dose of yttrium-90 to be infused is calculated with the manufacturer's formula based on lung shunting, body surface area, liver and tumor volume.
2. Radiation lobectomy: after gaining femoral artery access and advancing a catheter in the right hepatic artery (most often), ⁹⁰Y microspheres are infused in a lobar fashion, optimizing tumor and parenchymal coverage. Once the procedure has been completed, the patient is usually sent to the nuclear medicine department where a Bremsstrahlung scan will demonstrate the distribution of the radioactive material and assess for non-target embolization. Often, patients are started on proton pump inhibitors (with the addition of ursodeoxycholic acid - based on each center's protocol) for gastro-hepatic protection with or without a low-dose corticosteroid for prevention of post radioembolization syndrome and a fluoroquinolone antibiotic when the gallbladder is present (both per center protocol).