Dosimetric Analysis of Liver Toxicity Post Liver Metastasis Stereotactic Body Radiotherapy

Publication date: Available online 9 March 2017
Source:Practical Radiation Oncology
Author(s): A. Barry, A. McPartlin, P. Lindsay, L. Wang, J Brierley, J Kim, J Ringash, R Wong, R Dinniwell, T. Craig, L.A. Dawson
PurposeThe aim of this study is to describe the incidence and type of liver toxicity seen following liver metastases stereotactic body radiotherapy (SBRT) and the corresponding clinical and dosimetric factors associated with toxicity.Methods and MaterialsBetween 2002 and 2009, 81 evaluable patients with liver metastases were treated on two prospective studies assessing SBRT, with prescription doses based on the effective liver volume irradiated evaluated. Toxicity was defined as grade≥2 classic or non-classic radiation induced liver disease (RILD). Specific toxicity endpoints evaluated were worsening transaminases and albumin levels, within 3months of SBRT.ResultsSeventy percent of patients had colorectal carcinoma, 55% had extra-hepatic disease, 1 patient had Hepatitis B and 54% had received prior chemotherapy. Baseline transaminases were elevated at CTCAE V4.0 grade 1, 2 and 3 levels in 33 (41%), 2 (2%) and 0 (0%) of patients. The mean prescription dose was 43Gy (27.7 – 60Gy) in 6 fractions. The mean liver (minus GTV) dose (MLD) was 16Gy (3–25.6Gy) in 6 fractions. No classic or non-classical ≥ grade 2 RILD was observed. Within 3months of SBRT, 49 (61%) patients had worsening of grade of transaminase and 23 (28%) patients had a reduction in albumin, all transient (majority grade≤2 toxicity) without subsequent clinical toxicity. Seventeen patients exceeded QUANTEC MLD guidelines (≤20Gy), 13 (76%) of whom had worsening of transaminase grade. On multivariate analysis, worsening of liver enzymes was more likely in patients with higher doses to the spared 700cc of liver (p=0.026), and reduction of albumin was more likely with higher effective liver volume (OR 1.53 (1.08, 2.16)) p=0.016).ConclusionLiver metastases SBRT is safe with a low risk of transient biochemical liver toxicity, more likely in patients with a higher effective liver volume and higher doses to the spared uninvolved liver volume.



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