Supplementary Material for: Stable disease without tumor shrink cannot benefit from surgery following immune-based therapy in potentially resectable hepatocellular carcinoma

Background
The criteria for identifying patients with potentially resectable hepatocellular carcinoma (HCC) at the baseline stage have helped identify patients who are more likely to achieve successful conversion. However, the suitable timing and selection of candidates for conversion surgery after systemic therapy remained underexplored.
Methods
Based on real-world evidence, we analyzed a cohort of 222 patients with potentially resectable HCC treated with immune-based therapy between January 2019 and May 2024. The treatment response was assessed using the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) and modified RECIST (mRECIST). Depth of response (DpR) was defined as the maximum tumor shrinkage from baseline, based on the sum of the longest diameters, as assessed by an independent review facility per RECIST v1.1. Conversely, stable disease (SD) with a DpR < 0% / > 0% was categorized as SD_shrink / SD_non-shrink. Survival outcomes were compared between patients who underwent surgery and those who did not, with different DpRs, and assessed using Kaplan–Meier methods.
Results
A total of 85 patients with partial response (PR), 86 with SD_shrink, and 51 with SD_non-shrink were included in this study. Generally, patients who underwent surgery had a better prognosis than those who did not (P < 0.001). Patients with PR and SD_shrink significantly benefited from the surgery in both OS and EFS. However, patients with SD_non-shrink failed to obtain the same benefits. Additionally, surgical patients with a DpR < 0% had a better prognosis than those with a DpR > 0% (P < 0.001 and P = 0.004 respectively), whereas the survival of patients who did not undergo surgery did not differ.
Conclusion
DpR is an important factor in choosing the right candidates and the timing of conversion therapy. Patients only at a DpR < 0% receiving various immune-based treatments who met the ‘potentially resectable’ criteria can benefit from surgical resection. These findings can help increase the success rate of conversion therapy in patients with advanced HCC.