Cyberknife stereotactic body radiation therapy for nonresectable tumors of the liver: preliminary results

Abstract

Purpose: Stereotactic body radiation therapy (SBRT) has emerged as a treatment option for local tumor control of primary and secondary malignancies of the liver. We report on our updated experience with SBRT in patients with non-resectable tumors of the liver.

Methods: Our first 17 consecutive patients (mean age 58.1 years) receiving SBRT for HCC (n = 6), IHC (n = 3), and LM (n = 8) are presented. Mean radiation dose was 34 Gy delivered over 1-3 fractions.

Results: Treated patients had a mean decrease in maximum pretreatment tumor diameter from 6.9 +/- 4.6 cm to 5.0 +/- 2.1 cm at three months after treatment (P < .05). The mean total tumor volume reduction was 44% at six months (P < .05). 82% of all patients (14/17) achieved local control with a median follow-up of 8 months. 100% of patients with HCC (n = 6) achieved local control. Patients with surgically placed fiducial markers had no complications related to marker placement.

Conclusion: Our preliminary results showed that SBRT is a safe and effective local treatment modality in selected patients with liver malignancies with minimal adverse events. Further studies are needed to define its role in the management of these malignancies.

Figure 1

Tumor response in patients with nonresectable liver tumors treated with Stereotactic Body Radiation Therapy (SBRT). All patients with hepatocellular carcinoma (HCC) responded to SBRT with a mean decrease in tumor volume of 60% at 3 months after therapy (P < .05 by paired t-test). Similar response was observed in patients with liver metastases (LMs) treated with SBRT with a mean decrease tumor volume of 59% at 3 months posttreatment (P < .05 by paired t-test). It was difficult to be certain of the tumor response of patients with intrahepatic cholangiocarcinoma (IHC) due to the multicentricity of these tumors and the ill-defined edges.

Figure 2

Tumor response in a patient with nonresectable and large ICC treated with Stereotactic Body Radiation Therapy (SBRT). (a) CT scan of the liver showed tumor compromising the liver outflow (right, middle, and left hepatic veins) with a satellite lesion in segment 3. (b)and (C) CT scans of the ICC before and after fiducial markers placement. (d) Tumor response by Ct scan and PET scan before (e) and at 3 months after SBRT (f). Note a “hot” liver mass before SBRT and same liver mass “cold” after treatment. It was found that the precise definition of the mass contour was difficult to establish. Although the gross total volume of the mass and its diameter appears to be similar when sizes were compared before and after treatment, its active tumor load has decreased.

Figure 3

Tumor response in a patient with nonresectable and large HCC treated with Stereotactic Body Radiation Therapy (SBRT). (a) The patient underwent laparoscopy, liver biopsy, intraoperative US and fiducial markers placement. (b) The contour of liver tumor was performed and the development of the SBRT plan was approved. (c) Tumor response at 3 months after surgery. Tumor volume decreased from 1,293 cc to 258 cc.