A research team at Samsung Medical Center proved the effectiveness of proton beam therapy in a large-scale study of liver cancer patients for whom standard treatment is difficult. The team secured meaningful treatment outcomes in a patient group long considered a "blind spot" in liver cancer care, suggesting new treatment possibilities.
Samsung Medical Center said on Apr. 8 that a research team led by professors Park Hee-chul and Yoo Jeong-il and resident Lee Jeongha in the Department of Radiation Oncology analyzed 2,000 cases (1,823 patients) of liver cancer treated with proton therapy and published the results in the latest issue of the European Journal of Cancer.
Proton therapy is a type of particle radiation that has the physical property of releasing concentrated energy upon reaching a specific depth in the body and then dissipating. This allows high doses to be delivered to tumors while minimizing impact on surrounding normal tissue, especially healthy liver. However, highly sophisticated treatment planning and technology that precisely account for tumor location and organ motion due to breathing are essential.
This study is a large single-institution analysis based on about 10 years of accumulated treatment data since the introduction of the proton therapy system at the end of 2015.
The study subjects were patients for whom standard treatments such as surgery or radiofrequency ablation are difficult under the Barcelona Clinic Liver Cancer (BCLC) guideline criteria. They are a so-called unmet-need group with limited access to existing treatments due to tumor location, impaired liver function, underlying disease, advanced age, and other reasons.
The team selected patients through a multidisciplinary collaborative system involving gastroenterology, surgery, radiology, medical oncology, and radiation oncology, and applied high-precision proton therapy. In particular, they analyzed organ motion using four-dimensional CT before treatment and applied techniques that account for breathing during treatment to improve accuracy.
As a result, the two-year freedom from local progression (FFLP) rate exceeded 90% across all stages. By stage, it was 95.5% for stage 0, 93.9% for stage A, 98.5% for stage B, and 87.6% for stage C. At three years, the rates remained high at 91.1%, 91.3%, 95.0%, and 83.3%, respectively.
Stage 0 is a very early stage with a high likelihood of cure; stage A is an early stage confined to the liver; stage B is an intermediate stage with multiple tumors; and stage C is an advanced stage with vascular invasion or metastasis.
Overall survival was also favorable. Three-year survival rates were 81.1% for stage 0, 65.5% for stage A, 45.5% for stage B, and 37.2% for stage C, showing meaningful results even in advanced patients.
Professor Yoo Jeong-il said, "Building a large cohort based on multidisciplinary care and standardized treatment protocols underpinned this achievement," adding, "Proton therapy can be a key means of improving outcomes for liver cancer patients."
Professor Park Hee-chul also said, "It has taken root as an alternative that can deliver high local control and survival rates in patients for whom existing treatments are difficult," and noted, "Its role will further expand through prospective studies going forward."
Meanwhile, the Proton Therapy Center at Samsung Medical Center surpassed a cumulative 8,000 patients as of 2025, with liver cancer accounting for about 30% of all treatments, the largest share. Recently, the center also began full-scale research on "FLASH" therapy, which delivers ultra-high-dose radiation in a short time.
References
European Journal of Cancer (2026), DOI: https://doi.org/10.1016/j.ejca.2026.116593