295 - Prospective Study of Combined Stereotactic Body Radiotherapy and Immunotherapy in Locally Advanced Hepatocellular Carcinoma - Five-Year Survival Update
Presenter(s)
C. L. Chiang1, S. K. Chan2, W. H. K. Chiu3, F. A. Lee4, N. S. M. Wong5, R. L. M. Ho6, V. W. Y. Lee7, K. Man8, F. M. Kong9, and A. C. Y. Chan8; 1Department of Clinical Oncology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China, Hong Kong, Hong Kong, 2Department of Clinical Oncology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China, 3Department of Diagnostic Radiology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China, Hong Kong, Hong Kong, 4Department of Clinical Oncology, Tuen Mun Hospital, Tuen Mun, Hong Kong, 5Department of Clinical Oncology, Tuen Mun Hospital, Hong Kong, China, Hong Kong, Hong Kong, 6Gleneagles Hospital, Hong Kong, Hong Kong, 7Medical Physics Unit, Department of Clinical Oncology, Tuen Mun Hospital, Hong Kong, China, Hong Kong, Hong Kong, 8Department of Surgery, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China, Hong Kong, Hong Kong, 9The University of Hong Kong, Hong Kong, China
Purpose/Objective(s):
We have previously reported promising 3-year survival outcome in patients with locally advanced unresectable hepatocellular carcinoma (uHCC) treated with combined stereotactic body radiotherapy and immunotherapy (SBRT-IO) (JAMA Oncol. 2024 Nov 1;10(11):1548-1553). Herein we reported an updated analysis of OS after 5 years of follow-up, including survival by multiple tumor response measures.Materials/Methods:
This prospective study included patients with uHCC who treated with SBRT-IO between January 2018 and December 2022. The updated data cutoff was 31 Jan 2026. The overall survival (OS) and depth of response (DpR) were assessed. The tumor response was measured per modified RECIST. The DpR was defined as maximum tumor shrinkage from baseline per modified RECIST. Factors predictive of long-term survivors (=48 months) were analyzed using multi-variable analyses.Results:
A total of 63 patients were enrolled (58 male [92.1%]; median age, 69 years [range, 18-90]); 38 patients (60.3%) had macrovascular invasion, and the median tumor diameter was 10 cm (range, 3.8-31.1). The median follow-up time was 63.7 months (95% CI, 57.5-69.9). At the time of data cutoff, 39 patients (61.9%) had died. Twenty-nine patients (46.0%) achieved CR. The overall 5-year OS rate was 41.3% (95% CI: 28.5-55.7) and local control was 87.5% (95% CI: 78.9-96.0). The 5-year OS rate of CR vs. non-CR was 71.4% (95% CI, 55.4-88.1) vs. 11.6% (95% CI, 1.2-25.3) (p<0.001). Tumor shrinkage occurred in 92.5% (60/63) patients with mean DpR was -52.9% (SD: 34.5%). For those with tumor shrinkage of 0% to <30%, =30% to <50% or =50% to 100%, the 5-year OS rate was 16.7% (0-37.6), 20.0% (1.1-44.0), 60.4% (44.1-77.2) respectively (p<0.001). The treatment response (odds ratio: 10.9 [95% CI, 3.0-38.9]) was independent predictor of long-term survivors. No late-onset treatment related serious adverse events were observed.Conclusion:
This is the first prospective series to report a 5-year OS in patients with uHCC treated with SBRT-IO. The observed 5-year OS rate of 40% in the overall population and 70% among CR patients suggest that SBRT-IO warrants further evaluation as a potentially curative approach. Abstract 295 – Table 1| Tumor shrinkage | 36-month OS rate (%, 95% CI) | 48-month OS rate (%, 95% CI) | 60-month OS rate (%, 95% CI) |
| 0% to <30% | 16.7% (0%-37.6%) | 16.7% (0%-37.6%) | 16.7% (0%-37.6%) |
| =30% to <50% | 50% (22.4%-77.7%) | 20% (1.1%-44.0%) | 20.0% (1.1%-44.0%) |
| =50% to 100% | 66.9% (51.2%-83.0%) | 63.7% (41.4%-80.2%) | 60.4% (44.1%-77.2%) |