Imaging Findings within the first 12 months of Hepatocellular Carcinoma treated with Stereotactic Body Radiation Therapy (SBRT)

Publication date: Available online 24 August 2017
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Mishal Mendiratta-Lala, Everett Gu, Dawn Owen, Kyle C. Cuneo, Latifa Bazzi, Theodore S. Lawrence, Hero K. Hussain, Matthew S. Davenport
PurposeTo correlate the imaging findings of treated hepatocellular carcinoma (HCC) post stereotactic body radiation therapy (SBRT) with explant pathology and alpha-fetoprotein (AFP) response.MethodsFrom 2007-2015, of 146 patients treated with liver SBRT for Barcelona Clinic Liver Cancer (BCLC) Stage A hepatocellular carcinoma, 10 were identified with inclusion criteria and hadregular interval follow up MRI/triple phase CT and explant pathology or declining AFP values for radiology-pathology response correlation. Reference standards for successful response were: >90% necrosis on explant pathology or pre-treatment AFP >75 ng/mL normalizing to <10 ng/mL within 1 year post-SBRT without other treatment. Subjects were treated with 24-50 Gy in 3-5 fractions. Multiphasic MRI or CT was performed at 3, 6, 9 and 12 months post-SBRT was compared to pre-treatment imaging by two expert radiologists. Descriptive statistics were calculated.ResultsThere were 10 subjects with 10 treated HCCs, classified as 3 OPTN 5a, 4 OPTN 5b, and 3 OPTN 5x. All had successfully treated HCCs, based on explant pathology or declining AFP. Four of 10 HCCs had persistent central arterial hyperenhancement 3-12 months post-SBRT; persistent washout was common up to 12 months (9/10). 9/10 treated HCCs exhibited decreased size at 12 months. Liver parenchyma adjacent to the lesion showed early (3-6 months) hyperemia followed by late (6-12 months) capsular retraction and delayed enhancement. No patient had a significant decline in liver function.ConclusionIn the absence of increasing size, persistent central arterial hyperenhancement and washout can occur within the first 12 months post-SBRT in successfully treated HCCs, and may not represent residual viable tumor. Liver parenchyma adjacent to the treated lesion showed inflammation followed by fibrosis, without significant change in hepatic function. Until a radiological signature of tumor control is determined, freedom from local progression appears to be the best measure of HCC control after SBRT

Teaser

In the absence of increasing size, persistent arterial hyperenhancement with washout can occur within the first 12 months post-SBRT in successfully treated HCCs, and should not be confused with residual tumor. Liver parenchyma adjacent to the treated lesion showed inflammation followed by fibrosis, without significant change in hepatic function. Until a radiological signature of tumor control is determined, freedom from local progression appears to be the best measure of HCC control after SBRT.


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