189P - Stereotactic body radiotherapy in primary hepatocellular carcinoma and oligometastatis to liver: A single Institution experience

Abstract

BackgroundThis study evaluates the local control rates of patients treated with Stereotactic Body Radiotherapy (SBRT) for unresectable primary Hepatocellular carcinoma and oligometastatic liver lesions. Methods21 patients with 26 lesions treated with SBRT between February 2015 and March 2018. 3/21(14.2%) patients were primary hepatocellular carcinoma, 2/21(9.4%) were primary cholangiocarcinoma and 16/21(76.1%) patients were metastatic lesions. 16/21 patients had single, 3/21patients had two and 1/21 patient had three lesions. Patients were immobilized with thermoplastic mask with an indigenous abdominal compression device for motion management. Radiation planning triple phase CT scan with slice thickness of 1mm were fused with PET/CT scan and MRI scan. GTV is delineated and ITV is generated based on CT image data set in multiple phases of respiration. Adequate PTV margin was given.2/21(9.4%) patients were treated with IMRT technique, 17/21(79%) were planned with volumetric arc technique and 2/21(9.4%) were treated with helical Tomotherapy. The mean volume of the lesions treated was 31.1cc (Range,1.5cc to 314.9cc). Dose ranged from 18Gy-24Gy in single fraction, 24Gy-54Gy in three fractions and 30Gy-50Gy in 5 fractions. Mean volume of normal liver is 1195cc. Mean dose to 700cc of normal liver was 365.8cGy (Range, 11.7cGy-1428.6cGy). All the patients received different types of systemic therapy also. ResultsThe median follow up was 24 months.All 21 patients were evaluable for response based on triple phase computed tomography scan obtained in every 3 months after completion of SBRT. All 5/5(100%) patients of primary HCC and cholangiocarcinoma and 15/16 (93.7%) patients with metastatic lesionswere in radiological complete response at local site at the end of 12 months. Two year local control rate for metastatic lesions was 90%. there was no grade 3 or higher toxicity. ConclusionsIn our series of 21 patients of primary hepatocellular carcinoma and oligometastatic liver lesions excellent local control has been achieved by SBRT with acceptable toxicity. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.