Incidence of radionecrosis in single-fraction radiosurgery compared with fractionated radiotherapy in the treatment of brain metastasis.

Introduction: Radiation-induced brain necrosis ["radionecrosis" (rn)] is a relatively uncommon but potentially severe adverse effect of stereotactic radiosurgery (srs) for brain metastasis. Although dose, volume, and hypofractionation have been suggested to affect rn rates, patient and treatment variability in this population make it difficult to clearly delineate the risk. We set out to establish the effect of fractionation on rn rates by reviewing patients receiving simultaneous multi-fraction and single-fraction treatment at our centre. Methods: Patients receiving simultaneous (within 1 month) 1-fraction (ssrs) and 3-fraction (fsrs) radiosurgery treatments during 2012-2015 were identified in our institution's database. Serial post-srs magnetic resonance imaging (mri) was reviewed to determine rn and local recurrence. The effect of maximum dose, volume, whole-brain radiotherapy (wbrt), and fractionation on rn development was assessed using logistic regression for paired data. Results are reported using odds ratios (ors) and corresponding 95% confidence intervals (cis). Results: Of 90 patients identified, 22 had at least a 6-month mri follow-up. Median follow-up was 320 days. The most common primary tumour type was non-small-cell lung cancer, followed by breast and rectal cancer. Radionecrosis developed in 16 patients [21 of 62 lesions (34%), with 4 being symptomatic (20%)]. Of the 21 lesions in which rn developed, 11 received 3 fractions, and 10 received 1 fraction. The or for the association between the incidence of rn and maximum dose was 1.0 (95% ci: 0.9 to 1.1); for fractionation it was 1.0 (95% ci: 0.3 to 3.6); for previous wbrt, it was 0.4 (95% ci: 0.2 to 1.2); and for a 10-unit increase in volume, it was 3.1 (95% ci: 1.0 to 9.6). Local recurrence developed in 8 patients (12%), 6 of whom belonged to the ssrs group. Conclusions: Our results indicate that patients receiving srs for multiple brain metastases experience a higher rate of rn than is reported in the literature and poorer survival despite having equivalent local control. Maximum dose did not appear to be associated with rn risk in our cohort, but volume was significantly associated with rn risk. Although fractionated treatment did not directly lower the rate of rn in this population, it might have played a role in reducing the magnitude of the rn risk in large-volume lesions. Further investigation will help to delineate optimal dose and fractionation so as to minimize rn while maintaining local control in this group.

Comparative survival in patients with brain metastases from non-small-cell lung cancer treated before and after implementation of radiosurgery.

INTRODUCTION: Survival after a diagnosis of brain metastasis in non-small-cell lung cancer (nsclc) is generally poor. We previously reported a median survival of approximately 4 months in a cohort of patients treated with whole-brain radiotherapy (wbrt). Since that time, we implemented a program of stereotactic radiosurgery (srs). In the present study, we examined survival and prognostic factors in a consecutive cohort of patients after the introduction of the srs program. METHODS: Data from a retrospective review of 167 nsclc patients with brain metastasis referred to a tertiary cancer centre during 2010-2012 were compared with data from a prior cohort of 91 patients treated during 2005-2007 ("pre-srs cohort"). RESULTS: Median overall survival from the date of diagnosis of brain metastasis (4.3 months in the srs cohort vs. 3.9 months in the pre-srs cohort, p = 0.74) was not significantly different in the cohorts. The result was similar when the no-treatment group was excluded from the srs cohort. Within the srs cohort only, significant differences is overall survival were observed between treatment groups (srs, wbrt plus srs, wbrt, and no treatment), with improved survival being observed on univariate and multivariate analysis for patients receiving srs compared with patients receiving wbrt alone (p < 0.001). CONCLUSIONS: No improvement in survival was observed for nsclc patients with brain metastases after the implementation of srs. Selected patients (younger age, female sex, good performance status, fewer brain metastases) treated with srs appeared to demonstrate improved survival. However, those observations might also reflect better patient selection for srs or a greater tendency to offer those patients systemic therapy in addition to srs.

Clinical surveillance compared with clinical and magnetic resonance imaging surveillance for brain metastasis: a feasibility survey.

INTRODUCTION: After stereotactic radiosurgery (srs) for brain metastases, patients are routinely monitored with magnetic resonance imaging (mri). The high rate of new brain metastases after srs treatment alone might not be as concerning with modern mri and target localization treatment. Intensive surveillance might induce anxiety, lowering the patient's quality of life (qol). The present work is the feasibility component of a prospective study evaluating the role of surveillance mri on qol in patients with limited (1-3) brain metastases. METHODS: Patients with limited brain metastases treated with srs alone, an Eastern Cooperative Oncology Group performance status of 2 or less, and documented stability in treated lesions, with no new lesions seen on mri at weeks 6-10 after srs, were eligible. All were asked about their interest in participating in the control (mri and clinical surveillance) or the experimental arm (symptom-directed mri and clinical surveillance). If 33% or more agreed to participate in the experimental arm, it would be considered feasible to conduct the prospective study. RESULTS: From November 2014 to July 2015, 45% of patients (10 of 22) agreed to participate in the experimental arm. Subgroup analyses found that the decision to participate has no statistically significant association with time of presentation (p = 0.696), display of symptoms (p = 0.840), age (p = 0.135), or number of lesions (p = 0.171). CONCLUSIONS: Results show that it is feasible to conduct the prospective cohort study. Because of the small sample size, we are limited in the conclusions able to be drawn in the subgroup analyses. However, the future study would allow for a better understanding of the attitudes of patients toward mri and its effect on qol.