Biologic mesh spacer placement facilitates safe delivery of dose-intense radiation therapy: A novel treatment option for unresectable liver tumors

Introduction Patients with unresectable liver tumors who fail initial treatment modalities have a poor prognosis (<1 yr). Although effective, delivery of high dose radiation therapy to these tumors is limited by proximity of radiosensitive bowel. We have previously reported that placement of a biologic mesh spacer (BMS) can effectively displace the bowel allowing for dose-intense radiation to be delivered with low short-term toxicity. The purpose of this study was to assess and report the long-term safety and oncologic outcomes of this cohort. Methods From 2012 to 2014 seven patients with unresectable hepatic malignancy (6 IHCC, 1 CRLM) underwent BMS (acellular human dermis) placement (2 open, 5 MIS) prior to radiation therapy. Prospective registry data were reviewed for tumor and treatment details, progression, metastasis and survival. RTOG guidelines were used to define radiation toxicities. Results Mean patient age was 50.4 years (30–62 years) and 4 patients were male (57.1%). Prior to surgery, all patients had been treated for an average of 12.5 months with surgery, chemotherapy, radiation and/or TACE. After surgery, all patients recovered well and received a mean radiation dose of 76.1 Gy (58.1–100 Gy) over 13–25 fractions. 1 patient received SBRT; 4 fractions, 10 Gy each. Maximum dose delivered was 100 Gy (Biologic Equivalent Dose of 140 Gy, α/β = 10). Mean time to initiation of radiation therapy was 24 days (12–48 days) from surgery. No significant GI toxicity was recorded, and no GI bleeding or ulcers were observed. Mean follow-up after XRT was 18.2 months (5.5–31 months). Three patients had no loco-regional progression of disease. 2 patients had infield progression of liver disease and another had progressive lymphadenopathy. 3 patients developed pulmonary metastasis, at a mean time to distant failure of 3 months. There are 4 survivors over 2-years from surgery. Conclusion For patients with unresectable liver tumors, placement of a BMS enhances the safety and efficacy of high-dose radiotherapy, providing a survival benefit via delay in time to progression compared to traditional treatments with no significant short or long term GI toxicity.