Stereotactic body radiotherapy (SBRT) in combination with surgery for primary and metastatic liver tumors.

Abstract

347 Background: Evaluate the feasibility, safety, and efficacy of SBRT in combination with surgery for primary and metastatic liver tumors. Methods: 12 patients completed hepatectomy and SBRT for either hepatocellular carcinoma (HCC) (3) or metastases from colorectal (4), neuroendocrine (2), uterine (2), or sarcoma (1) primary. All patients with metastases completed chemotherapy. Most patients (7) had resection of their operable metastases, total of 19, and gold fiducials placed in the unresectable lesions, total of 9, to facilitate definitive adjuvant SBRT. One patient with an unresectable metastasis received preoperative SBRT. Two patients with HCC had SBRT as a bridge to liver transplant. Two patients had salvage SBRT for recurrence after surgery. All patients completed 4D-CT for ITV definition and SPECT/CT to define functional normal liver parenchyma volume (NLV). MV-fluoro was performed to confirm tumor/fiducial respiratory motion within the PTV. Results: All patients successfully completed a combination of hepatectomy and SBRT. Seventeen hepatic lesions (≤ 2/patient) were treated with SBRT with a mean PTV 186.0 cc (15.1-803.5). The mean dose was 49.3 Gy (39-60) prescribed to the PTV in 5-6 fractions. With median follow-up of 9.2 months (2.8-15.3) there was no RILD > Grade 1 observed. The most common toxicity was Grade ≤ 2 fatigue. Nine patients had reduced SPECT-NLV vs. calculated NLV by a mean of 487.5 cc (p = 0.0004). In 6 of these, the SPECT-NLV vs. the CT-NLV was reduced by a mean of 253.9 cc (44.6 - 1076.2) reflecting the importance of SPECT functional imaging for SBRT planning. Postoperative morbidity was ≤ Grade 1. All surgical margins were negative. Three patients developed intrahepatic failures post SBRT. However, on follow-up imaging no in-field failures have occurred. Conclusions: The combination of liver SBRT with hepatic resection is safe and effective. It can be used preoperatively to increase resectability or to salvage surgical failures. We also report on the combination of limited hepatectomy for peripheral (including bilobar) hepatic metastases with planned SBRT to unresectable metastatic lesion(s). SBRT planning with SPECT/CT allows identification and preservation of the NLV.