Brain metastases with poor vascular function are susceptible to pseudoprogression after stereotactic radiation surgery

Abstract

PurposeThis study aimed to investigate the hemodynamic status of cerebral metastases prior to and after stereotactic radiation surgery (SRS) and to identify the vascular characteristics that are associated with the development of pseudoprogression from radiation-induced damage with and without a radionecrotic component.Methods and materialsTwenty-four patients with 29 metastases from non-small cell lung cancer or malignant melanoma received SRS with dose of 15 Gy to 25 Gy. Magnetic resonance imaging (MRI) scans were acquired prior to SRS, every 3 months during the first year after SRS, and every 6 months thereafter. On the basis of the follow-up MRI scans or histology after SRS, metastases were classified as having response, tumor progression, or pseudoprogression. Advanced perfusion MRI enabled the estimation of vascular status in tumor regions including fractions of abnormal vessel architecture, underperfused tissue, and vessel pruning.ResultsPrior to SRS, metastases that later developed pseudoprogression had a distinct poor vascular function in the peritumoral zone compared with responding metastases (P < .05; number of metastases = 15). In addition, differences were found between the peritumoral zone of pseudoprogressing metastases and normal-appearing brain tissue (P < .05). In contrast, for responding metastases, no differences in vascular status between peritumoral and normal-appearing brain tissue were observed. The dysfunctional peritumoral vasculature persisted in pseudoprogressing metastases after SRS.ConclusionsOur results suggest that the vascular status of peritumoral tissue prior to SRS plays a defining role in the development of pseudoprogression and that advanced perfusion MRI may provide new insights into patients' susceptibility to radiation-induced effects.

Dynamic susceptibility contrast MRI may contribute in prediction of stereotactic radiosurgery outcome in brain metastases

“… 20 Furthermore, these studies report on measurements that are taken after treatment. 22 , 24 , 27–29 Treatment responders (ie, non-progressors) have previously been observed to have increased rCBV at baseline, 33 but pretherapeutic rCBV and rCBF are not always observed to correlate with treatment outcome. 20 , 32 , 35 Our findings are in agreement with this.…”

“… 32 However, none of these results were based on data from pre-SRS treatment, ie, baseline perfusion data. Using true baseline data, one study reported improved vascularization of the peritumoral tissue in treatment responders compared to pseudo-progressors, 33 and high rCBV prior to radiotherapy was identified as a predictor for survival in glioma. 34 Others did not find that pretherapeutic rCBV and rCBF correlated with treatment outcome.…”

Prolonged survival in advanced squamous cell lung carcinoma by rational and standardized treatment: A case report of long‐term survival in a patient with NSCLC

“…The overall effective rate of WBRT achieves to 80% and patient's median survival can extend to 3‐6 months 9 . Surgical treatment of NSCLC brain metastasis is associated with a high risk of recurrence and complication, and patient's quality of life may reduce after surgery 10‐12 . The treatment of lung cancer has entered into an era of precision medicine and full‐course management.…”

Management of complications from brain metastasis treatment: a narrative review

“…Typically, pseudoprogression occurs within 3 months of radiation treatment whereas radiation necrosis can occur months to years afterwards. Numerous studies have found MRI perfusion imaging to be helpful in differentiating pseudoprogression from tumor recurrence (50)(51)(52). By definition, most cases of pseudoprogression resolve spontaneously over 2-3 months and if suspected, can be closely monitored with short interval follow-up MRI.…”