A Case of a 12-cm Huge Hepatocellular Carcinoma Treated Successfully With Two-Stage CyberKnife Stereotactic Body Radiation Therapy.

Determining the optimal treatment for patients with huge hepatocellular carcinoma (HCC) remains challenging. Although surgical resection is the preferred option, it is feasible only in selected cases. Transarterial chemoembolization is commonly used but often provides insufficient local control. Advanced radiation therapy methods, such as real-time tumor tracking and inverse planning, have enabled the safe delivery of high-dose radiation via stereotactic body radiotherapy (SBRT), achieving excellent local control. However, alternative strategies may be necessary for difficult cases. We report the case of an 81-year-old male with a 12-cm unresectable HCC who was successfully treated with two-stage CyberKnife SBRT. Due to the tumor size and proximity to the gastrointestinal tract, single-stage SBRT was considered infeasible. The first-stage SBRT (25 Gy in three fractions, maximum dose of 55 Gy) induced tumor shrinkage, allowing for the second-stage SBRT (25 Gy in five fractions, maximum dose of 50 Gy) six months later. The only adverse event was transient radiation-induced fatigue two weeks post-treatment. A significant reduction in tumor volume was achieved, with no recurrence and preserved liver function for 44 months after initial treatment. This case highlights the potential of two-stage SBRT with real-time tumor tracking as an effective treatment strategy for unresectable huge HCC.