3014 - Outcomes and Predictive Factors in Large Hepatocellular Carcinoma Managed with Image-Guided Hypo-Fractionated Radiotherapy

R. Kumar¹, S. S. Neibart², J. Kim¹, S. Mamidanna¹, T. Cui¹, M. P. Deek¹, and S. K. Jabbour¹; ¹Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, ²Harvard Radiation Oncology Program, Boston, MA

Purpose/Objective(s): In liver confined hepatocellular carcinoma (HCC) patients who are ineligible for curative treatments, radiation treatment (RT) serves as a crucial local therapy. With evolving EBRT dose, technique, and prognostic factors, we suggest that viral causes and cirrhosis severity influence survival in larger HCC managed with hypo-fractionated radiation (HFRT). Materials/

Methods: We retrospectively reviewed 60 patients of HCC treated with HFRT at our institution. The HFRT regimen was selected to ensure that the RT dose to the healthy liver and organs at risk (OAR) met the established dosimetric guidelines. Image guided techniques were used for motion management, target delineation and treatment. Large lesions were defined as lesions greater than 5 cm in size or 100 cc in volume. The RT dose ranged from 40 Gy to 67.5 Gy in 5 – 15 fractions. The biologically equivalent dose (BED) for tumor ranged from 58.5 Gy₁₀ to 100 Gy₁₀. Local control (LC) and Overall survival (OS) was evaluated by Kaplan-Meier analysis, with log-rank test for subgroup analysis. Multivariate Cox regression analysis was performed to identify additional prognostic factors.
Results: The mean duration of follow-up was 24 months. The median age was 70 years (range 50 – 90) and 78.3% were males. 34 patients had viral (HBC or HCV) as etiological factors. 44 patients had CP-A class cirrhosis while 14 had CP-B and 2 had CP-C class. BCLC stage A, B, C and D was seen in 2, 14, 33 and 2 patients, respectively. Vascular involvement was present in 14 patients and prior trans arterial chemo embolization (TACE) was done in 31 patients. The median size of lesion was 8 cm (range 2 -14 cm) and median volume of lesion was 238 cc (range 10 – 1376 cc). Large lesions (>5cm or >100cc) comprised 65% (n=39) patients. The median BED radiation dose was 80 Gy₁₀ (range -- 58.5 Gy₁₀ to 100 Gy₁₀). For the entire cohort, 10 patients had local recurrence with a LC rate of 83.3%. The 1 yr and 2 yr actuarial LC was 80% and 77% respectively. The 1 yr and 2 yr actuarial OS was 51% and 42% respectively for the entire cohort. On multivariate analysis (MVA), viral etiology (p=0.034), CP-A class (p<0.001) and low volume (p<0.005) were significant prognostic factors with improved OS. Large volume tumors had inferior 1 yr LC (64% vs 93%) and 1 yr OS (75.4 % vs 85.4%) compared to small volume tumors. On MVA of large volume tumors, CP-A class (p<0.001) and RT dose more than 80 Gy₁₀ (p=0.019) were significant favorable prognostic factors for OS, while presence of viral etiology showed a favorable trend towards significance (p=0.053).
Conclusion: Large volume tumors have inferior LC and OS as compared to small volume HCC treated with HFRT. Viral etiology showed a trend towards better OS. CP-A class and biological radiation dose greater than 80 Gy10 are significant prognostic factors for OS in large volume tumors. This information can help in better personalization and decision-making regarding intensifying the radiation treatment and adding additional therapy to improve the oncological outcomes.