Is Hippocampal Avoidance During Whole-Brain Radiotherapy Risky for Patients With Small-Cell Lung Cancer? Hippocampal Metastasis Rate and Associated Risk Factors

Kıraklı, Esra Korkmaz; Öztekin, Özgür

doi:10.1177/1533034617742301

Cited by 13 publications

(9 citation statements)

References 30 publications

(82 reference statements)

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“…Dose to hippocampi could be minimised if the PTV locates far from the hippocampi. In Korkmaz Kirakli and Oztekin (2017) study, the distance between multiple brain metastases and hippocampi were measured to evaluate the risk of recurrence after whole brain radiotherapy 28 . While in this study, primary single tumour was treated.…”

Section: Discussionmentioning

confidence: 99%

Non-coplanar VMAT plans for postoperative primary brain tumour to reduce dose to hippocampus, temporal lobe and cochlea: a planning study

Lee

Lau

et al. 2021

BJR|Open

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Objectives: This study aimed to compare radiotherapy plan quality of coplanar VMAT (CO-VMAT) and non-coplanar VMAT (NC-VMAT) for postoperative primary brain tumour. Methods: A total of 16 patients who were treated for primary brain tumours were retrospectively selected for this study. For each patient, identical CT sets with structures were used for both CO-VMAT and NC-VMAT planning. For CO-VMAT, one full arc and two coplanar half arcs were used. For NC-VMAT, one full coplanar and two non-coplanar half arcs with couch rotation of 315° or 45°. Dose constraints were adhered to the RTOG0614 and 0933. Dose volumetric parameters were collected for statistical analysis. Results: There were no significant differences for the PTV, HI, CN and μ between the CO-VMAT and NC-VMAT. For the brainstem, Dmean of CO-VMAT and NC-VMAT were 6.04 ± 3.94 Gy and 4.69 ± 2.56 Gy respectively (p < 0.05). For the ipsilateral OARs including temporal lobe, TM joint and cochlear, Dmean of CO-VMAT and NC-VMAT were 31.80 ± 12.78 Gy and 25.51 ± 17.54 Gy (p < 0.01) ; 14.12 ± 8.6 Gy and 3.35 ± 4.12 Gy (p < 0.001); 11.96 ± 11.68 Gy and 6.62 ± 9.74 Gy (p < 0.01) respectively. For contralateral OARs including hippocampus, temporal lobe, TM joint, Optic nerve, lens, eyeball and cochlear, the Dmean of CO-VMAT and NC-VMAT were 6.16 ± 2.44 Gy and 4.49 ± 2.00 Gy (p < 0.01) ; 6.48 ± 2.76 Gy and 3.68 ± 1.76 Gy (p < 0.0001); 11.96 ± 11.68 Gy and 6.62 ± 9.74 Gy (p < 0.01) respectively. Conclusion: The proposed NC-VMAT showed more favourable plan quality than the CO-VMAT for primary brain tumours, in particular to OARs located to the contralateral side-of tumours. Advances in knowledge: For primary brain tumours RT, NC-VMAT can reduce doses to the brainstem, ipsilateral temporal lobe, TM joint and cochlear, as well as OARs located to the contralateral side-of tumours.

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Section: Discussionmentioning

confidence: 99%

Non-coplanar VMAT plans for postoperative primary brain tumour to reduce dose to hippocampus, temporal lobe and cochlea: a planning study

Lee

Lau

et al. 2021

BJR|Open

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“…Studies demonstrate that sparing the hippocampus from radiation without altering the coverage of the rest of the brain decreases early NCF decline without compromising disease control. Dosimetric studies utilizing various techniques to spare the hippocampus including both intensity modulated radiotherapy (IMRT) and helical TomoTherapy treatment first demonstrated the feasibility of hippocampal avoidance during WBRT 9–13 . RTOG 0933 was a multi‐institutional phase II trial of HA‐WBRT for brain metastases 7 .…”

Section: Introductionmentioning

confidence: 99%

Hippocampus segmentation on noncontrast CT using deep learning

et al. 2020

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Purpose: Accurate segmentation of the hippocampus for hippocampal avoidance whole-brain radiotherapy currently requires high-resolution magnetic resonance imaging (MRI) in addition to neuroanatomic expertise for manual segmentation. Removing the need for MR images to identify the hippocampus would reduce planning complexity, the need for a treatment planning MR imaging session, potential uncertainties associated with MRI-computed tomography (CT) image registration, and cost. Three-dimensional (3D) deep convolutional network models have the potential to automate hippocampal segmentation. In this study, we investigate the accuracy and reliability of hippocampal segmentation by automated deep learning models from CT alone and compare the accuracy to experts using MRI fusion. Methods: Retrospectively, 390 Gamma Knife patients with high-resolution CT and MR images were collected. Following the RTOG 0933 guidelines, images were rigidly fused, and a neuroanatomic expert contoured the hippocampus on the MR, then transferred the contours to CT. Using a calculated cranial centroid, the image volumes were cropped to 200 9 200 9 35 voxels, which were used to train four models, including our proposed Attention-Gated 3D ResNet (AG-3D ResNet). These models were then compared with results from a nested tenfold validation. From the predicted test set volumes, we calculated the 100% Hausdorff distance (HD). Acceptability was assessed using the RTOG 0933 protocol criteria, and contours were considered passing with HD ≤ 7 mm. Results: The bilateral hippocampus passing rate across all 90 models trained in the nested cross-fold validation was 80.2% for AG-3D ResNet, which performs with a comparable pass rate (P = 0.3345) to physicians during centralized review for the RTOG 0933 Phase II clinical trial. Conclusions: Our proposed AG-3D ResNet's segmentation of the hippocampus from noncontrast CT images alone are comparable to those obtained by participating physicians from the RTOG 0933 Phase II clinical trial.

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“…Studies have shown that the metastasis rate of SCLC in the hippocampus is approximately 3–5.1% [ 10 – 13 ]. Modern radiotherapy modalities include conventional three-dimensional conformal radiation therapy (3D-CRT) and intensity-modulated radiation therapy (IMRT) [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Comparison of whole brain radiation therapy for synchronous brain metastases with irradiation protecting the hippocampus versus whole brain radiotherapy for sequential brain metastases to boost irradiation in the treatment of brain metastases from SCLC: study protocol for a randomized controlled trial

Zhang

Wang

et al. 2022

Trials

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Background This study is in regard to the comparison of whole brain radiation therapy for synchronous brain metastases with irradiation protecting the hippocampus versus whole brain radiotherapy for sequential brain metastases to boost irradiation in the treatment of brain metastases from small cell lung cancer (SCLC). Therapeutically, they have notably varying dose distributions. Based on theoretical and model studies, it has long been speculated that these modes may result in different prognostic outcomes. We aim to assess the efficacy of tomotherapy in the treatment of SCLC brain metastases while protecting the key functional area, the hippocampus, and minimizing any neurocognitive impairments incurred by radiation. Methods This is a randomized, controlled, prospective study including 102 SCLC patients with brain metastases randomized (1:1) to the experimental (whole brain radiation therapy for synchronous brain metastases with irradiation to protect the hippocampus) or control (whole brain radiotherapy for sequential brain metastases to boost irradiation) group. The sample size is calculated through a single-sided test; 102 participants will be required for the main results to have statistical and clinical significance. We aim to provide clinical trial data support for better prognostic treatment options in patients with SCLC and brain metastases. The clinical trial data include both the primary and secondary outcomes; the primary outcome is the intracranial progression-free survival time after the new technology application. The secondary study outcomes include the assessment of neurological function, the quality of life, and the overall survival rate. Follow-up consultations will be conducted every 2 months. After the final patient completes follow-up, the Statistical Product and Service Solutions software will be used for scientific and rigorous data analysis. Version 1.0 of the protocol was implemented on January 1, 2021; the recruitment process for this clinical trial commenced on April 1, 2021, and will end on March 31, 2024. Discussion The study will provide high-quality clinical evidence to support the efficacy and safety of whole brain radiation therapy for synchronous brain metastases with dose irradiation protecting the hippocampus versus whole brain radiotherapy for sequential brain metastases with push volume irradiation for the treatment of patients who have lung cancer as well as brain metastases. This has not been previously reported. Trial registration This trial is registered with the Chinese Clinical Trial Registry (ChiCTR1900027539; November 17, 2019) (URL: https://www.chictr.org.cn/hvshowproject.aspx?id=20515).

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Is Hippocampal Avoidance During Whole-Brain Radiotherapy Risky for Patients With Small-Cell Lung Cancer? Hippocampal Metastasis Rate and Associated Risk Factors

Cited by 13 publications

References 30 publications

Non-coplanar VMAT plans for postoperative primary brain tumour to reduce dose to hippocampus, temporal lobe and cochlea: a planning study

Non-coplanar VMAT plans for postoperative primary brain tumour to reduce dose to hippocampus, temporal lobe and cochlea: a planning study

Hippocampus segmentation on noncontrast CT using deep learning

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