Predicting and implications of target volume changes of brain metastases during fractionated stereotactic radiosurgery. (January 2020)

• Record Type: Journal Article
• Authors: Hessen, Eline; Nijkamp, Jasper; Damen, Pim; Hauptmann, Michael; Jasperse, Bas; Dewit, Luc; Lutkenhaus, Lotte; Lamers, Emmy; van der Heide, Uulke; Damen, Eugène; Hanssens, Patrick; Borst, Gerben
• Is Part Of: Radiotherapy and oncology. Volume 142(2020)
• Page Start: 175
• Page End: 179
• Publication Date: 2020-01
• Subjects: MR0 planning MRI -- MR1 repeated MRI -- fSRS fractionated stereotactic radiosurgery -- T1_c T1 sequence after contrast administration (gadolinium) -- postop postoperatively -- dMR1-MR0 maximum distance between the target delineation on MR1 and MR0 -- VMR1-MR0 target volume on MR1 outside target volume on MR0 -- Dmin minimum dose; SRS -- Stereotactic radiotherapy -- Brain metastases -- Target volume changes -- Target coverage; Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2019.07.011
• Languages: English
• ISSNs: 0167-8140

Abstract

Highlights: Patients received a new MRI during fractionated SRS for brain metastases. The observed target volume changes deteriorated the target dose coverage. Tumor volume changes before treatment may predict changes during treatment. Abstract: Objective: To study the impact of target volume changes in brain metastases during fractionated stereotactic radiosurgery (fSRS) and identify patients that benefit from MRI guidance. Material and methods: For 15 patients (18 lesions) receiving fSRS only (fSRSonly ) and 19 patients (20 lesions) receiving fSRS postoperatively (fSRSpostop ), a treatment planning MRI (MR0) and repeated MRI during treatment (MR1) were acquired. The impact of target volume changes on the target coverage was analyzed by evaluating the planned dose distribution (based on MR0) on the planning target volume (PTV) during treatment as defined on MR1. The predictive value of target volume changes before treatment (using the diagnostic MRI (MRD)) was studied to identify patients that experienced the largest changes during treatment. Results: Target volume changes during fSRS did result in large declines of the PTV dose coverage up to −34.8% (median = 3.2%) for fSRSonly patients. For fSRSpostop the variation and declines were smaller (median PTV dose coverage change = −0.5% (−4.5% to 1.9%)). Target volumes changes did also impact the minimum dose in the PTV (fSRSonly ; −2.7 Gy (−16.5 to 2.3 Gy), fSRSpostop ; −0.4 Gy (−4.2 to 2.5 Gy)). Changes in target volume before treatment (i.e. seen between the MRD and MR0) predicted which patients experienced the largest dose coverage declines during treatment. Conclusion: Target volume changes in brain metastases during fSRS can result in worsening of the target dose coverage. Patients benefiting the most from a repeated MRI during treatment could be identified before treatment.