Gastric injury from ⁹⁰Y to left hepatic lobe tumors adjacent to the stomach: fact or fiction?

Purpose: Radioembolization with ⁹⁰Y microspheres is a locoregional radiation therapy for unresectable hepatic neoplasm. Non-target delivery of ⁹⁰Y microspheres resulting in gastrointestinal (GI) symptoms is a recognized complication; there is minimal knowledge regarding the radiation effect to the gastric wall from left hepatic lobe ⁹⁰Y treatments. Our aim was to study the incidence of GI complications when the target tissue (hepatic parenchyma ± tumor) is in close proximity to the gastric wall. We hypothesized that liver (tumor) to stomach proximity does not correlate with increased toxicity. Methods: Between November 2011 and September 2013, we studied all patients who underwent left lobe radioembolization with ⁹⁰Y glass microspheres. With Institutional Review Board (IRB) approval, we retrospectively reviewed MRI/CT images of these patients, identifying a subset of patients with the left hepatic lobe <1 cm from the gastric wall. Patients were seen in clinic 1 month posttreatment and subsequently at 3-month intervals. Short- and long-term gastric adverse events were tabulated. Results: Ninety-seven patients successfully underwent left hepatic lobe ⁹⁰Y microsphere radioembolization in which the average distance from the liver to the stomach wall was 1.0 ± 2.8 mm. The average dose for patients who received radioembolization to the left hepatic lobe was 109 ± 57 Gy. Fifty patients had tumor within 1 cm of the gastric wall. The average dose for patients who received radioembolization to the left hepatic lobe with tumor within 1 cm of the gastric wall was 121 ± 41 Gy. There were no reportable or recordable medical events. Of the patients, 34 % reported abdominal pain that was grade 1–2; 65 % of the patients reported no abdominal pain. None of the 97 patients developed a clinically evident GI ulcer. Conclusion: Patients with left lobe tumors adjacent to or abutting the stomach do not exhibit acute or chronic radiation effects following radioembolization with glass microspheres.