The Community Resource in Targeted Therapies
Driving Knowledge. Empowering Change. Optimizing Outcomes.
ONCAlert | Upfront Therapy for mRCC
Publications  >  HCC Monitor  >  2016  >  September 2016  >  

Despite Growing Evidence for SBRT, the Jury Is Still Out

Published Online: Sep 19,2016
The jury is still out on whether stereotactic body radiation therapy (SBRT) should truly be considered a preferred frontline treatment modality for patients with hepatocellular carcinoma (HCC) who are not candidates for surgery, despite an ever-growing body of evidence supporting this approach.
 
In a recent retrospective study of patients with inoperable, nonmetastatic HCC, 1- and 2-year freedom from local progression (FFLP) rates were greater with SBRT versus radiofrequency ablation (RFA). The results of the study were reported in the Journal of Clinical Oncology by Daniel Wahl, MD, PhD, and colleagues with the University of Michigan Medical Center.1 Prior to this publication, data comparing SBRT and RFA were lacking.
 
While surgical resection is the preferred first-line therapeutic intervention for patients with a single HCC lesion and preserved liver function, many patients with multifocal disease, poor liver function, or major vascular invasion need to be managed with other locoregional therapy. These alternative therapeutic strategies may include RFA, SBRT, microwave ablation, percutaneous ethanol injection, or various embolization techniques.2,3
 
Previous reports have shown similar local recurrence rates between SBRT and RFA, ranging from 10% to 30% for small tumors.4,5 However, specific outcomes and treatment failure in various patient and tumor populations, especially those with large tumors, was unknown. With retrospective results in hand, the next step will be a prospective comparison of the two approaches, if it is deemed feasible.
 
Support of SBRT as a Frontline Therapy in HCC

In the study by Wahl et al, 249 lesions in 161 patients were treated with RFA, and 83 lesions in 63 patients were treated with SBRT. Compared with patients who had received SBRT, those treated with RFA had significantly lower alpha-fetoprotein levels, higher rates of cirrhosis, fewer previous liver-directed treatments, and longer follow-up. Median maximum tumor diameter was similar between treatment groups.1
 
Freedom from local progression rates were greater for tumors treated with SBRT compared with those treated with RFA. The 1-year and 2-year FFLP rates were 97.4% versus 83.6% and 83.8% versus 80.2% for SBRT and RFA, respectively.
 
To account for any imbalances in treatment assignment, authors used an inverse probability of treatment weighting (IPTW) to the Kaplan-Meier and Cox models for FFLP. Using the IPTW univariate analysis, patients who received RFA had a significant association with local progression compared with SBRT (HR, 2.63; P = .016). Among all of the variables analyzed, only tumor size was predictive of local progression (HR, 1.36; P = .029). Larger tumor size was predictive of treatment failure with RFA but not with SBRT.1
 
Further stratification of data was performed to identify additional differences between treatments. Although FFLP was similar in tumors smaller than 2 cm, significantly worse FFLP was associated with RFA (HR, 3.35; 95% Cl, 1.17-9.62, P = .025). One- and 2-year overall survival (OS) rates were similar between treatment groups.
 
The rates of grade ≥3 adverse events (AEs) were 11% for the RFA cohort and 5% for the SBRT cohort. Radiofrequency ablation complications included bleeding (n = 3), duodenal and colonic perforation (n = 2), sepsis (n = 2), and pneumothorax (n = 1). Stereotactic body radiation therapy complications included radiation-induced liver disease (RILD; n = 1), gastrointestinal bleeding (n = 1), and worsening ascites (n = 1). Radiofrequency ablation-associated complications resulted in 2 deaths, 1 from hemothorax and 1 from gastrointestinal bleeding, while no deaths resulted from SBRT.
 
“These results suggest that both SBRT and RFA are excellent choices for smaller tumors but that SBRT may be preferred for larger tumors,” the authors concluded. “Prospective, randomized clinical trials are needed to compare these two modalities, especially for larger tumors, although we are unaware of any such ongoing trials.”1
 
Opposition to SBRT

Not everyone is in agreement regarding the frontline use of SBRT in HCC, despite the growing evidence of its clinical utility. In response to the retrospective study by Wahl et al, international clinicians have voiced their concerns over the endorsement of SBRT as the “preferred treatment for larger HCC.”
 


Continue Reading (Page 2) >>

Clinical Articles

Despite Growing Evidence for SBRT, the Jury Is Still Out
Copyright © TargetedOnc 2018 Intellisphere, LLC. All Rights Reserved.