Role of Particle Therapy for Intrahepatic Cholangiocarcinoma; Meta-Analysis for Comparison with Standard Therapy: TRP-Intrahepatic Cholangiocarcinoma 2025.

Introduction: Particle therapy (PT) for intrahepatic cholangiocarcinoma is expected to provide good local control. However, it is difficult to compare PT with the current standard treatment modalities, surgery, and chemotherapy. Therefore, we conducted a meta-analysis and systematic review of the literature to compare PT with surgery and drug therapy.

Methods: A meta-analysis was performed using studies from 2010 to 2024 in which PT or surgery or drug therapy was performed for intrahepatic cholangiocarcinoma. 40 articles (7 PT, 13 surgery, 19 drug therapy, one surgery, and drug therapy) were selected based on used of radial surgery or first-line drug therapy. PT was basically for unresectable cases, and 80% of drug therapy cases had distant metastases.

Results: Forty selected articles found 1-3-year OS rates (PT vs. surgery vs. drug therapy) of 70.7% (95% CI: 64.2-76.1%) vs. 78.6% (74.2-82.3%) ( = 0.1198) vs. 49.0% (43.4-54.4%) ( = 0.0001); 47.1% (40.9-53.0%) vs. 56.3% (48.8-63.1%) ( = 0.1265) vs. 25.3% (19.7-31.3%) ( = 0.0011); and 36.6% (27.0-46.3%) vs. 46.8% (41.7-51.6%) ( = 0.1213) vs. 14.7% (8.3-22.7%) ( = 0.0021), respectively. And the 1-3-year local control rates for PT were 89.4% (95% CI: 81.3-94.1%), 74.6% (63.0-83.1%) and 67.1% (51.4-78.7%), respectively. Meta-regression analysis was performed using modality (PT vs. surgery vs. drug therapy), male: female ratio, and median age as risk factors. The results showed no significant difference between surgery and PT, but drug therapy showed significantly lower 1- and 2-year OS rates and median survival time, and a trend toward lower 3-year OS.

Conclusion: The results of this analysis suggest that PT for intrahepatic cholangiocarcinoma may be one of the standard treatments in unresectable cases and in combination with drug therapy.