Clinical outcome after CyberKnife® radiosurgery re-irradiation for recurrent brain metastases

Stereotactic Body Radiotherapy Reirradiation Is Safe in Patients With Lung Cancer With In-Field Enlarged Tumor Recurrence

Introduction: Recurrence after stage III lung cancer treatment usually appears with a poor prognosis, and salvage therapy for these patients is challenging, with limited data for reirradiation. Materials and Methods: Fifteen patients with recurrent stage III lung cancer treated with stereotactic body radiotherapy (SABR) between October 2013 and December 2017 were retrospectively evaluated for local control as a first endpoint; overall survival, disease-free survival, and treatment-related toxicity were secondary endpoints. Results: The median age was 68 (IQR: 50-71) years, and the median tumor size was 3.3 cm (IQR: 3.0-4.5). The radiation field was all within the previous radiation (previous 80%-90% isodose line), and the median dose was 66 Gy/(2 Gy × 33 standard fractionation). For SABR, the median biologically effective dose at an α/β ratio of 10 (BED10) was 60.0 Gy (IQR: 39.38-85.0) and given in 3 to 5 fractions. Three patients experienced grade 3 or 4 toxicity but none experienced grade 5. The median follow-up period was 14 (IQR: 10-23) months. The local control rate was found as 86.7% in the first year, 80% in the second year, and 80% in the third year. The median disease-free survival was 8 (IQR: 6-20) months and the median overall survival was 14 (IQR: 10-23) months. The rate of overall survival was 66.6% for the first year and 33.3% for the second and third years. The disease-free survival rate was 46.6% for the first year and 40% for the second and third years. Nine patients who received doses of BED10 ≥ 50 Gy developed no local recurrence (P  =  .044). Discussion: In local local-regional recurrence of lung cancer, radiosurgery as reirradiation can be used at doses of BED10 ≥ 50 Gy and above to provide local control for radical or palliative purposes. SABR is an important and relatively safe treatment option in such recurrences.

Effectiveness of Robotic Stereotactic Radiotherapy in Patients Undergoing Re-irradiation: A Review

Stereotactic ablative radiotherapy (SABR) is a possible treatment option for patients who develop recurrence within or at the edge of a previously irradiated volume. Robotic stereotactic radiotherapy is the result of technological advances in robotic precision, real-time imaging, non-invasive, highly customizable treatment plan, and delivery with sub-millimeter accuracy. This article reviews the radiobiologic, technical, and clinical aspects of robotic-based SABR re-irradiation for various anatomical sites. An extensive literature search was performed to identify articles on the utilization of robotic stereotactic radiotherapy for patients undergoing re-irradiation. The reported prescription dose and fractionation data along with outcomes such as overall survival, local control rates, and toxicities were qualitatively reviewed. The findings consistently indicate that re-irradiation using robotic SABR provides encouraging survival rates with minimal toxicity in the clinical setting of various anatomical sites delivered using locally non-invasive means where other treatment options are scarce.

Automatically tracking brain metastases after stereotactic radiosurgery

Background and purpose

Patients with brain metastases (BMs) are surviving longer and returning for multiple courses of stereotactic radiosurgery. BMs are monitored after radiation with follow-up magnetic resonance (MR) imaging every 2-3 months. This study investigated whether it is possible to automatically track BMs on longitudinal imaging and quantify the tumor response after radiotherapy.

Methods

The METRO process (MEtastasis Tracking with Repeated Observations was developed to automatically process patient data and track BMs. A longitudinal intrapatient registration method for T1 MR post-Gd was conceived and validated on 20 patients. Detections and volumetric measurements of BMs were obtained from a deep learning model. BM tracking was validated on 32 separate patients by comparing results with manual measurements of BM response and radiologists' assessments of new BMs. Linear regression and residual analysis were used to assess accuracy in determining tumor response and size change.

Results

A total of 123 irradiated BMs and 38 new BMs were successfully tracked. 66 irradiated BMs were visible on follow-up imaging 3-9 months after radiotherapy. Comparing their longest diameter changes measured manually vs. METRO, the Pearson correlation coefficient was 0.88 (p < 0.001); the mean residual error was -8 ± 17%. The mean registration error was 1.5 ± 0.2 mm.

Conclusions

Automatic, longitudinal tracking of BMs using deep learning methods is feasible. In particular, the software system METRO fulfills a need to automatically track and quantify volumetric changes of BMs prior to, and in response to, radiation therapy.

Management of initial and recurrent radiation-induced contrast enhancements following radiotherapy for brain metastases: Clinical and radiological impact of bevacizumab and corticosteroids

Purpose

The appearance of radiation-induced contrast enhancements (RICE) after radiotherapy for brain metastases can go along with severe neurological impairments. The aim of our analysis was to evaluate radiological changes, the course and recurrence of RICE and identify associated prognostic factors.

Methods

We retrospectively identified patients diagnosed with brain metastases, who were treated with radiotherapy and subsequently developed RICE. Patient demographic and clinical data, radiation-, cancer-, and RICE-treatment, radiological results, and oncological outcomes were reviewed in detail.

Results

A total of 95 patients with a median follow-up of 28.8 months were identified. RICE appeared after a median time of 8.0 months after first radiotherapy and 6.4 months after re-irradiation. Bevacizumab in combination with corticosteroids achieved an improvement of clinical symptoms and imaging features in 65.9% and 75.6% of cases, respectively, both significantly superior compared to treatment with corticosteroids only, and further significantly prolonged RICE-progression-free survival to a median of 5.6 months. Recurrence of RICE after initially improved or stable imaging occurred in 63.1% of cases, significantly more often in patients after re-irradiation and was associated with high mortality of 36.6% after the diagnosis of flare-up. Response of recurrence significantly depended on the applied treatment and multiple courses of bevacizumab achieved good response.

Conclusion

Our results suggest that bevacizumab in combination with corticosteroids is superior in achieving short-term imaging and symptom improvement of RICE and prolongs the progression-free time compared to corticosteroids alone. Long-term RICE flare-up rates after bevacizumab discontinuation are high, but repeated treatments achieved effective symptomatic control.

Radiosurgery effects and adverse effects in symptomatic eloquent brain-located Cavernomas

In this study, the dose schedule efficacy, safety and late adverse effects of stereotactic radiosurgery (SRS) were evaluated for patients with symptomatic cavernomas who were not eligible for surgery and treated with SRS. Between January 2013 and December 2018, 53 patients with cavernomas were treated using SRS with the CyberKnife® system. Patients' diseases were deeply located or were in subcortical functional brain regions. In addition to bleeding, 23 (43.4%) patients had epilepsy, 12 (22.6%) had neurologic symptoms and 16 patients (30.2%) had severe headaches. The median volume was 741 (range, 421-1351) mm3, and the median dose was 15 (range, 14-16) Gy in one fraction. After treatment, six (50%) of 12 patients with neurologic deficits still had deficits. Rebleeding after treatment developed in only two (3.8%) patients. The drug was completely stopped in 14 (60.9%) out of 23 patients who received epilepsy treatment, and the dose of levetiracetam decreased from 2000 mg to 1000 mg in four (17.3%) of nine patients. Radiologically, complete response (CR) was observed in 13 (24.5%) patients, and partial responses (PR) were observed in 32 (60.2%) patients. Clinical response of CR was observed in 30 (56.6%) patients, PR was observed in 16 (30.2%), stable disease (SD) was observed in three (5.7%) and four (7.5%) patients progressed. In conclusion, SRS applied in the appropriate dose schedule may be an effective and reliable method in terms of symptom control and prevention of rebleeding, especially in patients with inoperable cavernomas.

Stereotactic radiosurgery for brain metastases from pelvic gynecological malignancies: oncologic outcomes, validation of prognostic scores, and dosimetric evaluation

INTRODUCTION

Stereotactic radiosurgery is a well-established treatment option in the management of brain metastases. Multiple prognostic scores for prediction of survival following radiotherapy exist, but are not disease-specific or validated for radiosurgery in women with primary pelvic gynecologic malignancies metastatic to the brain. The aim of the present study is to evaluate the feasibility, safety, outcomes, and impact of established prognostic scores.

METHODS

We retrospectively identified 52 patients treated with radiotherapy for brain metastases between 2008 and 2021. Stereotactic radiosurgery was utilized in 31 patients for an overall number of 75 lesions; the remaining 21 patients received whole-brain radiotherapy. Kaplan-Meier survival analysis and the log-rank test were used to calculate and compare survival curves and univariate and multivariate Cox regression to assess the influence of cofactors on recurrence, local control, and prognosis.

RESULTS

With a median follow-up of 10.7 months, overall survival rates post radiosurgery were 65.3%, 51.3%, and 27.7% for 1, 2, and 5 years, respectively, which were significantly higher than post whole-brain radiotherapy (p=0.049). Five local failures (6.7%) were detected, resulting in 1 and 2 year local cerebral control rates of 97.4% and 94.0%, respectively. Univariate factors for prediction of superior overall survival were high performance status (p=0.030) and application of three prognostic scores, especially the Recursive Partitioning Analysis score (p=0.028). Uni- and multivariate analysis revealed that extracranial progression prior to radiosurgery was significant for inferior overall survival (p<0.0001). Radionecrosis was diagnosed in five women (16%); long-term neurotoxicity was significantly worse after whole-brain radiotherapy compared with radiosurgery (p=0.023).

CONCLUSION

Stereotactic radiosurgery for brain metastases from pelvic gynecologic malignancies appears to be safe and well tolerated, achieving promising local cerebral control. Prognostic scores were shown to be transferable and radiosurgery should be recommended as primary intracranial treatment, especially in women with no prior extracranial progression and Recursive Partitioning Analysis class I.