Optimization of hippocampus sparing during whole brain radiation therapy with simultaneous integrated boost-tutorial and efficacy of complete directional hippocampal blocking.

PURPOSE: Hippocampus-avoidance whole brain radiotherapy with simultaneous integrated boost (HA-WBRT+SIB) is a complex treatment option for patients with multiple brain metastases, aiming to prevent neurocognitive decline and simultaneously increase tumor control. Achieving efficient hippocampal dose reduction in this context can be challenging. The aim of the current study is to present and analyze the efficacy of complete directional hippocampal blocking in reducing the hippocampal dose during HA-WBRT+SIB. METHODS: A total of 30 patients with multiple metastases having undergone HA-WBRT+SIB were identified. The prescribed dose was 30 Gy in 12 fractions to the whole brain, with 98% of the hippocampus receiving ≤ 9 Gy and 2% ≤ 17 Gy and with SIB to metastases/resection cavities of 36-51 Gy in 12 fractions. Alternative treatment plans were calculated using complete directional hippocampal blocking and compared to conventional plans regarding target coverage, homogeneity, conformity, dose to hippocampi and organs at risk. RESULTS: All alternative plans reached prescription doses. Hippocampal blocking enabled more successful sparing of the hippocampus, with a mean dose of 8.79 ± 0.99 Gy compared to 10.07 ± 0.96 Gy in 12 fractions with the conventional method (p < 0.0001). The mean dose to the whole brain (excluding metastases and hippocampal avoidance region) was 30.52 ± 0.80 Gy with conventional planning and 30.28 ± 0.11 Gy with hippocampal blocking (p = 0.11). Target coverage, conformity and homogeneity indices for whole brain and metastases, as well as doses to organs at risk were similar between planning methods (p > 0.003). CONCLUSION: Complete directional hippocampal blocking is an efficient method for achieving improved hippocampal sparing during HA-WBRT+SIB.

Hippocampus-avoidance whole-brain radiation therapy with a simultaneous integrated boost for multiple brain metastases.

BACKGROUND: The current study was aimed at investigating the feasibility of hippocampus-avoidance whole-brain radiation therapy with a simultaneous integrated boost (HA-WBRT+SIB) for metastases and at assessing tumor control in comparison with conventional whole-brain radiation therapy (WBRT) in patients with multiple brain metastases. METHODS: Between August 2012 and December 2016, 66 patients were treated within a monocentric feasibility trial with HA-WBRT+SIB: hippocampus-avoidance WBRT (30 Gy in 12 fractions, dose to 98% of the hippocampal volume ≤ 9 Gy) and a simultaneous integrated boost (51 or 42 Gy in 12 fractions) for metastases/resection cavities. Intracranial tumor control, hippocampal failure, and survival were subsequently compared with a retrospective cohort treated with WBRT via propensity score matching analysis. RESULTS: After 1:1 propensity score matching, there were 62 HA-WBRT+SIB patients and 62 WBRT patients. Local tumor control (LTC) of existing metastases was significantly higher after HA-WBRT+SIB (98% vs 82% at 1 year; P = .007), whereas distant intracranial tumor control was significantly higher after WBRT (82% vs 69% at 1 year; P = .016); this corresponded to higher biologically effective doses. Intracranial progression-free survival (PFS; 13.5 vs 6.4 months; P = .03) and overall survival (9.9 vs 6.2 months; P = .001) were significantly better in the HA-WBRT+SIB cohort. Four patients (6.5%) developed hippocampal metastases after hippocampus avoidance. The neurologic death rate after HA-WBRT+SIB was 27.4%. CONCLUSIONS: HA-WBRT+SIB can be an efficient therapeutic option for patients with multiple brain metastases and is associated with improved LTC of existing metastases, higher intracranial PFS, a reduction of the neurologic death rate, and an acceptable risk of radiation necrosis. The therapy has the potential to prevent neurocognitive adverse effects, which will be further evaluated in the multicenter, phase 2 HIPPORAD trial.

Whole-brain irradiation with hippocampal sparing and dose escalation on metastases: neurocognitive testing and biological imaging (HIPPORAD) - a phase II prospective randomized multicenter trial (NOA-14, ARO 2015-3, DKTK-ROG).

BACKGROUND: Whole brain radiation therapy (WBRT) is the standard therapy for multiple brain metastases. However, WBRT has a poor local tumor control and is associated with a decline in neurocognitive function (NCF). Aim of this trial is to assess the efficacy and safety of a new treatment method, the WBRT with hippocampus avoidance (HA) combined with the simultaneous integrated boost (SIB) on metastases/resection cavities (HA-WBRT+SIB). METHODS: This is a prospective, randomized, two-arm phase II multicenter trial comparing the impact of HA on NCF after HA-WBRT+SIB versus WBRT+SIB in patients with multiple brain metastases. The study design is double-blinded. One hundred thirty two patients are to be randomized with a 1:1 allocation ratio. Patients between 18 and 80 years old are recruited, with at least 4 brain metastases of solid tumors and at least one, but not exceeding 10 metastases ≥5 mm. Patients must be in good physical condition and have no metastases/resection cavities in or within 7 mm of the hippocampus. Patients with dementia, meningeal disease, cerebral lymphomas, germ cell tumors, or small cell carcinomas are excluded. Previous irradiation and resection of metastases, as well as the number and size of metastases to be boosted have to comply with certain restrictions. Patients are randomized between the two treatment arms: HA-WBRT+SIB and WBRT+SIB. WBRT is to be performed with 30 Gy in 12 daily fractions and the SIB with 51 Gy/42 Gy in 12 daily fractions on 95% of volume for metastases/resection cavities. In the experimental arm, the dose to the hippocampi is restricted to 9 Gy in 98% of the volume and 17Gy in 2% of the volume. NCF testing is scheduled before WBRT, after 3 (primary endpoint), 9, 18 months and yearly thereafter. Clinical and imaging follow-ups are performed 6 and 12 weeks after WBRT, after 3, 9, 18 months and yearly thereafter. DISCUSSION: This is a protocol of a randomized phase II trial designed to test a new strategy of WBRT for preventing cognitive decline and increasing tumor control in patients with multiple brain metastases. TRIAL REGISTRATION: The HIPPORAD trial is registered with the German Clinical Trials Registry (DRKS00004598, registered 2 June 2016).

Molecular Imaging in Photon Radiotherapy.

Nowadays, more than ever before, the treatment of cancer patients requires an interdisciplinary approach more than ever. Radiation therapy (RT) has become an indispensable pillar of cancer treatment early on, offering a local, curative treatment option and symptom control in palliative cases.

Hippocampus-Avoidance Whole-Brain Radiation Therapy Is Efficient in the Long-Term Preservation of Hippocampal Volume.

BACKGROUND AND PURPOSE: With improved life expectancy, preventing neurocognitive decline after cerebral radiotherapy is gaining more importance. Hippocampal damage has been considered the main culprit for cognitive deficits following conventional whole-brain radiation therapy (WBRT). Here, we aimed to determine to which extent hippocampus-avoidance WBRT (HA-WBRT) can prevent hippocampal atrophy compared to conventional WBRT. METHODS AND MATERIALS: Thirty-five HA-WBRT and 48 WBRT patients were retrospectively selected, comprising a total of 544 contrast-enhanced T1-weighted magnetic resonance imaging studies, longitudinally acquired within 24 months before and 48 months after radiotherapy. HA-WBRT patients were treated analogously to the ongoing HIPPORAD-trial (DRKS00004598) protocol with 30 Gy in 12 fractions and dose to 98% of the hippocampus ≤ 9 Gy and to 2% ≤ 17 Gy. WBRT was mainly performed with 35 Gy in 14 fractions or 30 Gy in 10 fractions. Anatomical images were segmented and the hippocampal volume was quantified using the Computational Anatomy Toolbox (CAT), including neuroradiological expert review of the segmentations. RESULTS: After statistically controlling for confounding variables such as age, gender, and total intracranial volume, hippocampal atrophy was found after both WBRT and HA-WBRT (p < 10-6). However, hippocampal decline across time following HA-WBRT was approximately three times lower than following conventional WBRT (p < 10-6), with an average atrophy of 3.1% versus 8.5% in the first 2 years after radiation therapy, respectively. CONCLUSION: HA-WBRT is a therapeutic option for patients with multiple brain metastases, which can effectively and durably minimize hippocampal atrophy compared to conventional WBRT.

Survival and Prognostic Predictors of Anaplastic Meningiomas.

BACKGROUND: Anaplastic meningiomas are rare tumors with a poor prognosis, even after complete surgical resection and radiotherapy. There has been limited evidence with respect to the clinical factors and their effects on the course of the disease. Various retrospective studies have not been able to provide clear evidence of standardized treatment, usually presenting contradictory results. The aim of this study was to evaluate the prognostic factors influencing the progression-free survival (PFS) and overall survival (OS) of anaplastic meningiomas, with a particular focus on the roles of the extent of resection and postoperative adjuvant radiotherapy. METHODS: Between October 2001 and March 2016, 36 patients with anaplastic meningiomas were treated in our Department of Neurosurgery, of whom 11 underwent gross total resection (GTR) and 18 subtotal resection. Twenty-one patients received postoperative adjuvant radiotherapy, and 8 were treated with surgery alone. GTR (Simpson grades I and II) was associated with significantly improved PFS (P = 0.01) and OS (P = 0.004). Furthermore, adjuvant radiotherapy showed an improvement in PFS (P = 0.01) but not in OS (P = 0.16). CONCLUSIONS: The extent of resection in anaplastic meningiomas is correlated with a better outcome. However, resection alone is not sufficient for the long-term control of anaplastic meningiomas. Adjuvant radiotherapy is an essential component in the adjuvant treatment of anaplastic meningiomas, including for patients undergoing GTR. Further investigations through which to improve adjuvant therapy options are necessary to improve meningioma therapy.