Stereotactic body radiotherapy delivered with IMRT for oligometastatic regional lymph node metastases in hepatocellular carcinoma: a single-institutional study

The optimal treatment to lymph node metastases in hepatocellular carcinoma (HCC) has not been established, yet. Our aim was to evaluate the local control, the survival benefit and the toxicity of stereotactic body radiotherapy (SBRT) delivered with intensity-modulated radiotherapy (IMRT) to oligometastatic regional lymph node in HCC patients. We retrospectively analyzed 15 patients with HCC treated with SBRT delivered using IMRT to 24 regional lymph node metastases. Dose prescriptions were set to 45 Gy in 6 fractions of 7.5 Gy for solitary lesions and 49.5 Gy in 9 fractions of 5.5 Gy for multiple lesions. For the planning target volume, the plan was optimized aiming for a V_95% > 90%. The study endpoints were freedom from local progression (FFLP), progression-free survival (PFS), overall survival (OS) and toxicity. The median follow-up was 18.1 months. The 1-year and 2-year FFLP rates were 100 and 90 ± 9.5%, respectively. The 1-year PFS rate was 46.7 ± 12.9%, and the 1-year and 2-year OS rates were 73.3 ± 11.4 and 28.6 ± 12.7%, respectively. Only one patient had a duodenal ulcer and three patients had liver enzyme elevation in sub-acute toxicity, however there was no grade ≥ 3 toxicity. In conclusion, SBRT delivered with IMRT to lymph node metastases can offer excellent local control with minimal toxicity, and SBRT may improve HCC patients' survival more than conventional radiotherapy.