Image-based response assessment of liver metastases following stereotactic body radiotherapy with respiratory tracking

Abstract

ObjectiveTo describe post-CyberKnife® imaging characteristics of liver metastases as an aid in assessing response to treatment, and a novel set of combined criteria (CC) as an alternative to response according to change in size (RECIST).Subjects and MethodsImaging data and medical records of 28 patients with 40 liver metastases treated with stereotactic body radiotherapy (SBRT) were reviewed. Tumor size, CT attenuation coefficient, and contrast enhancement of lesions were evaluated up to 2 years post SBRT. Rates of local control, progression-free survival, time to progression, and overall survival according to RECIST and CC were estimated.ResultsComplete response (CR) was 3.6% (95% CI: 0.1–18%) and 18% (95% CI: 6–37%) according to RECIST and combined criteria, respectively. Two progressive diseases and two partial responses according to RECIST were classified as CR by the combined criteria and one stable response according to RECIST was classified as progressive by CC (Stuart-Maxwell test, p = 0.012). The disease control rate was 60.7% (95% CI: 41–78%) by RECIST and 64% (95% CI: 44%–81%) by CC.ConclusionUse of response criteria based on change in size alone in the interpretation of liver response to SBRT may be inadequate. We propose a simple algorithm with a combination of criteria to better assess tumor response. Further studies are needed to confirm their validity.

Computed Tomography Imaging Assessment of Postexternal Beam Radiation Changes of the Liver

“…An intriguing new concept, called lobulated enhancement (LE) [31], may provide some additional clues when differentiating and predicting risk of tumor progression. Developed in Lille, France, this change is defined as an irregular, thick (>1 mm) and distinct peripheral enhancement with more than or equal to three lobulations ( Figure 5) [32]. These lobulations, similar to petals of a daisy, seem to be highly predictive of progression.…”

“…Approach to distinguishing tumor from normal postradiation changes [32] • If a lesion is shrinking, received a dose higher than 35 Gy and has a thin halo, then the lesion is considered controlled. Note that at lower doses (<35 Gy), there should be no halo.…”

Evaluation of response after SBRT for liver tumors

“…Price et al 16 Liver primary tumors Jarraya et al began in 2013 by describing post-therapeutic CT transformations of secondary hepatic lesions treated with cyberknife. 35 Following the example of the work by Chun on the hepatic metastases treated by bevacizumab, 8 they described four types of responses according to the evolution in size, the occurrence of a lobulated enhancement or total necrosis. According to that work, the use of RECIST criteria may be inadequate.…”

Suivi après radiothérapie stéréotaxique des tumeurs hépatiques : revue de la littérature et recommandations

“…Les études évaluant les différentes échelles de mesures disponibles sont limitées. Les modification après radiothérapie stéréotaxique observées correspondent à des modifications vasculaires, à de la nécrose et à des réactions inflammatoires locales, pouvant mimer des réponses pseudo-progressives [60,61]. Lors d'analyse comparative entre critères radiologiques et analyse histologique, il existait 87 % de corrélation entre les critères de l'EASL, contre seulement 29 % pour les critères de l'OMS et RECIST [62][63][64].…”

“…Ils représentent probablement le même type de réaction qui se modifie au cours du temps. Ces changements morphologiques peuvent cependant être confondus avec une progression tumorale [60,66]. Ces données sont égale-ment rapportées après radiothérapie stéréotaxique des carcinomes hépatocellulaires.…”