In gratitude of the loyal support of our members, the CNS is offering complimentary 2021 Annual Meeting registration to all members! Learn more.

  • Quantitative Volumetric Response After Gamma Knife Radiosurgery For Meningiomas

    Final Number:
    186

    Authors:
    Gillian Harrison BS; Hideyuki Kano MD PhD; L. Dade Lunsford MD; John Flickinger MD; Douglas Kondziolka MD MSc FRCS(C) FACS

    Study Design:
    Other

    Subject Category:

    Meeting: Congress of Neurological Surgeons 2012 Annual Meeting

    Introduction: This study attempts to quantitatively define the early radiobiologic response of meningioma following Gamma Knife stereotactic radiosurgery (SRS) and evaluate early tumor response as a predictor of long-term tumor control.

    Methods: We reviewed serial T1-weighted contrast-enhanced MRIs of patients undergoing SRS for meningioma from 2002-2010. Volume percent change from baseline, absolute rate of change, and percent rate of change were compared at 3-month intervals for patients classified by ultimate tumor outcome (progressed, stable, regressed). A total of 252 patients with mean age of 56 years (14-87), baseline tumor volume of 5.8 cm3 (0.2-33.8), and follow-up time of 28.6 months (0.1-106.1) were evaluated.

    Results: Mean regression of -40.2% occurred in 168 (67%) patients, progression of +104% occurred in 17 (7%) patients, and stability (-2.7%) was maintained in 67 (27%) patients (p<0.001). In patients who ultimately regressed, mean shrinkage of -18.2% and maximum rate of change (mean -0.6 cm3/month, -6.4%/month) were observed at 3 months. In patients who ultimately progressed, initial regression was observed in the first 3 months (mean -0.1 cm3/month, -0.9%/month), with progression observed by 6 months. Transient progression was observed in 15 (9%) tumors before eventual decrease and transient regression was observed in 6 (35%) tumors before eventual increase. Skull base tumors regressed significantly more than non-skull base tumors (mean -25% vs. -16%, p=0.036). On multivariable analysis, volume percent change, slope of volume change, and slope of percent change were significant predictors of progression after 6 months.

    Conclusions: Meningioma volume response after SRS is dynamic; early changes may not be indicative of final response. Tumors that ultimately regress often shrink in the first 3 months, whereas tumors that ultimately progress may shrink in this period, then progress by 6 months post-treatment. Tumor rate of change 6-12 months post-SRS is predictive of long-term tumor response.

    Patient Care: A more thorough understanding of meningioma response to radiosurgery will aid clinician decision-making during the early follow-up period. Quantification of volume changes, with characterization of the variable nature of response trends and identification of important time points in the natural history of tumor response, can support post-treatment management decisions

    Learning Objectives: By the conclusion of this session, participants should be able to describe the dynamic volumetric response demonstrated by meningiomas following Gamma Knife radiosurgery.

    References:

We use cookies to improve the performance of our site, to analyze the traffic to our site, and to personalize your experience of the site. You can control cookies through your browser settings. Please find more information on the cookies used on our site. Privacy Policy