Actual over 3-year survival after stereotactic body radiation therapy in patients with unresectable intrahepatic cholangiocarcinoma

Purpose: As a non-invasive treatment, stereotactic body radiation therapy (SBRT) has been an emerging and effective option for patients with unresectable intrahepatic cholangiocarcinoma (ICC). The Cyber Knife has an SBRT system, which can realize real-time tracking of tumors during treatment. It can protect the surrounding normal liver tissue while the tumor gets the therapeutic dose. The purpose of this study was to evaluate the factors affecting the local control rate for patients after SBRT treatment, and to predict the factors affecting survival rates, then to report the 3-year actual survival rates after treatment and identify the influencing factors of 3-year survival rate.

Materials and methods: We conducted a long-term follow-up of 43 patients with unresectable intrahepatic cholangiocarcinoma who underwent Cyber Knife in our hospital from January 2016 to December 2018. Regular medical check-ups were performed every 2-3 months after SBRT to evaluated the effect of treatment.

Results: The median follow-up time was 15 months (4-78 months), and the median progression-free survival (PFS) was 6 months (95% CI, 2.788-9.212) and the median overall survival (OS) was 12 months (95% CI, 3.434-20.566), respectively. Based on modified Response Evaluation and Criteria in Solid Tumor (mRECIST), response rate (RR) and disease control rate (DCR) of SBRT in unresectable ICC were 55.2% and 86%. The 1-, 2- and 3-years OS rate were 51.2%, 32.6% and 23.3%. Multivariate analysis based on competing risk survival analysis identified that patients with multiple nodules, large diameter, high level of CA199 and CEA, poor ECOG performance status had worse overall survival (p < 0.05). Patients who survived ≥3 years had significantly lower levels of CEA, CA199, smaller tumor diameters and lower number of lesions (p < 0.05).

Conclusion: The SBRT might be a candidate option for patients who unable to perform surgery. The rate of 3-year survival after SBRT for unresectable ICC can be expected with 23.3%.