Repeated SBRT for in- and out-of-field recurrences in the liver

PurposeTo evaluate the feasibility and toxicity profile of repeated stereotactic body radiotherapy (SBRT) for recurrent primary or secondary liver tumors.MethodsConsecutive patients with primary (hepatocellular carcinoma [HCC] or cholangiocarcinoma [CCC]) or secondary liver cancer (LM), with intrahepatic recurrence or progression after SBRT, underwent re-SBRT in 3 to 12fractions with amedian time of 15 (range 2-66) months between treatments.ResultsIn all, 24patients which were previously treated with SBRT (30lesions) were retreated with SBRT for in- and out-of-field recurrences (2nd SBRT: n=28, 3rd SBRT: n=2). The median follow-up after re-irradiation was 14months. The median prescribed dose for the first SBRT was 46.5 (range 33-66Gy, EQD2(10)=70.5) Gy and 48 (range 27-66Gy, EQD2(10)=71) Gy for the re-SBRT. The median mean liver dose (D-mean,D- liver) was 6Gy (range 1-25, EQD2(2)=7Gy) for the first SBRT and 10Gy (range 1-63Gy, EQD2(2)=9Gy) for the re-SBRT. Of the 30 re-irradiated lesions 6 were re-irradiated in-field resulting in amedian EQD2(2, maximum) of 359 (range 120-500) Gy for both treatments, with an /=2 to account for liver parenchyma. Treatment was well tolerated. Two patients with stent placement before SBRT developed cholangitis 4 and 14months after re-SBRT. There were no elevations of the serum liver parameters after re-SBRT. One patient developed a grade3 gastrointestinal bleeding. There was no radiation induced liver disease (RILD) observed.ConclusionsRepeated liver SBRT is feasible, without excessive liver toxicity, when there is no considerable overlapping with pre-irradiated portions of the stomach or bowel and enough time for the liver to regenerate.