Long-term survival analysis in combined transarterial embolization and stereotactic body radiation therapy versus stereotactic body radiation monotherapy for unresectable hepatocellular carcinoma >5 cm

Background: The survival following transarterial chemoembolization (TACE) alone is still low in unresectable hepatocellular carcinoma (HCC) with almost patients developing disease progression after treatment. There is need to investigate additional therapeutic options that would intensify the initial response to TACE. The present study was to retrospectively compare the outcome and evaluate the prognostic factors of stereotactic body radiation therapy (SBRT) alone or as an adjunct to transarterial embolization (TAE) or TACE in the treatment of HCC >5 cm. Methods: From January 2011 to April 2015, 77 patients received SBRT followed by TAE or TACE (TAE/TACE + SBRT group) and 50 patients received SBRT alone (SBRT group). The dose of SBRT was 30-50 Gy which was prescribed in 3-5 fractions. Eligibility criteria were: a longest tumor diameter >5.0 cm and Child-Turcotte-Pugh (CTP) Class A or B. Exclusion criteria included tumor thrombus, lymph node involvement and extrahepatic metastasis. Results: The median follow-up period was 20.5 months. Median tumor size was 8.5 cm (range, 5.1-21.0 cm). Median overall survival (OS) in the TAE/TACE + SBRT group was 42.0 months versus 21.0 months in the SBRT group. The 1-, 3- and 5-year OS was 75.5, 50.8, and 46.9 % in the TAE/TACE + SBRT group and was 62.4, 32.9, and 32.9 % in the SBRT group, respectively (P = 0.047). The 1-, 3-and 5-year distant metastasis-free survival (DMFS) was 66.3, 44.3, and 40.6 % in the TAE/TACE + SBRT group and was 56.8, 26.1, and 17.4 % in the SBRT group, respectively (P = 0.049). The progression-free survival (PFS) and local relapse-free survival (LRFS) were not significantly different between the two groups. In the entire patient population, a biologically effective dose (BED10) >= 100 Gy and an equivalent dose in 2 Gy fractions (EQD(2)) >= 74 Gy were significant prognostic factors for OS, PFS, LRFS and DMFS. Conclusions: SBRT combined with TAE/TACE may be an effective complementary treatment approach for HCC >5 cm in diameter. BED10 >= 100 Gy and EQD(2) >= 74 Gy should receive more attention when the SBRT plan is designed.