Résumé
Objective:To evaluate the efficacy and safety of hippocampal avoidance whole-brain irradiation with simultaneous integrated boost in the treatment of brain metastases of lung cancer.Methods:Forty lung cancer patients with brain metastases who received whole-brain radiotherapy with simultaneous integrated boost and hippocampal avoidance in Cancer Hospital, Chinese Academy of Medical Sciences from 2014 to 2020 were enrolled in this study. Brain MRI, survival follow-up and evaluation of side effects were performed before radiotherapy and at 1, 3, 6 and 12 months after radiotherapy, respectively. Overall survival (OS), progression-free survival (PFS) and changes in cognitive function were analyzed. Continuous data were described as Mean ± SD. Categorical data were described by frequency and composition ratio or percentage. Survival analysis was conducted by Kaplan-Meier method. Influencing factors of survival were identified by univariate and multivariate Cox's regression analyses.Results:A total of 40 patients were enrolled in the study. The median follow-up time was 14.2 months and the median OS, PFS and intracranial PFS of all patients were 14.8 months, 6.7 months and 14.8 months, respectively. Multivariate analysis showed that male gender and newly diagnosed stage Ⅳ disease were associated with worse OS and PFS, respectively. The Hopkins verbal learning test-revised (HVLT-R) scores at baseline and 1, 3 and 6 months after radiotherapy were 21.94±2.99, 20.88±3.12, 20.03±3.14, and 19.78±2.98, respectively. The HVLT-R score at 6 months after radiotherapy was decreased by approximately 9.8% compared with the baseline. No grade 3 or above toxic and side effect occurred in the entire cohort.Conclusion:Hippocampal avoidance whole-brain irradiation with simultaneous integrated boost is a safe and effective treatment for brain metastases of lung cancer, which is expected to reduce the impact of radiotherapy on cognitive function.
Résumé
With the advancement of imaging diagnosis and the development of modern radiotherapy, the survival of cancer patients has been prolonged and the incidence rate of brain metastases (BM) has been significantly increased. The quality of life of patients and potential radiotherapy-induced neurocognitive impairment have gradually captivated widespread attention. Whole brain radiotherapy (WBRT) is one of the common local therapies for BM patients. However, the application of WBRT is controversial because it may lead to neurocognitive impairment. The incidence of metastatic tumors in hippocampus and radiation-induced neurocognitive impairment can accelerate the implementation of hippocampal-avoidance WBRT (HA-WBRT). In this article, the feasibility of HA-WBRT was discussed and research progress in recent years was reviewed.
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Objective Whole brain radiotherapy ( WBRT) remains the primary treatment for patients with multiple brain metastases ( BM). Hippocampal avoidance WBRT ( HA-WBRT) offers the feasibility of less cognitive function impairment than conventional WBRT.WBRT yields better control rate of intracranial distant progression than stereotatic body radiotherapy (SBRT).This study aims to understand the distribution characteristics of BM within the cranial structures by analyzing imaging features and define the safe margin during HA-WBRT. Methods Clinical data of patients diagnosed with BM by enhanced MRI in Ruijin Hospital from July 2011 to July 2016 were retrospectively analyzed. The distance between the intracranial lesion closest to the hippocampus and the hippocampus was measured. Results A total of 146 patients (90 male and 56 female) with 630 BM lesions were reviewed. Sixty-four patients were diagnosed with non-small-cell lung cancer complicated with BM during the initial admission. In the other 82 patients, the average time from the initial diagnosis to the diagnosis of BM was (14.5±14. 3) months. In total,486 (77. 1％) BM lesions were situated beyond the tentorium. The average diameter of the largest intracranial lesion was (12.5± 10. 3) mm (95％CI:10. 8-14. 2). All 630 BM lesions were distributed as follows:138 (21. 9％) in the cerebellum, 182 ( 28. 9％) in the frontal lobe, 114 ( 18. 1％) in the temporal lobe, 78 (12. 4％) in the parietal lobe,87(12. 7％) in the occipital lobe,28(4. 4％) in the thalamus and 10(1. 6％) in the brainstem. The frequency of hippocampal involvement was 3. 4％(5 mm),4. 8％(10 mm) and 8. 2％(20 mm). The univariate and multivariate logistic analyses indicated that with the risk of hippocampal involvement in patients aged> 60 years was significantly increased (OR= 11. 576 P= 0. 042). Conclusions The probability of brain metastasis within 10 mm around the hippocampus is low. HA-WBRT can control the intracranial lesions and reduce cognitive impairment,which is a safe and feasible treatment method.
Résumé
Objective To investigate the dosimetric characteristics of hippocampal?avoidance prophylactic cranial irradiation ( HA?PCI ) in fixed?field intensity?modulated radiotherapy ( IMRT ) and volumetric modulated arc therapy ( VMAT) and the feasibility and risks of hippocampal avoidance. Methods Prophylactic cranial irradiation (PCI) was performed for 16 patients with localized small cell lung cancer ( SCLC) who were treated in our hospital from January to August, 2014, and achieved complete response ( CR) after chemoradiotherapy, with a prescribed dose of 25 Gy in 10 fractions. CT localization image was fused with brain MRI image to contour the hippocampus on the fused image, and the boundary of the hippocampus was extended 5 mm outward to form the area for reduced dose. IMRT and VMAT plans with hippocampal avoidance were developed separately, and the dose distribution in the whole brain, the hippocampus, and the 5?mm area outside the hippocampus was evaluated for these two plans. Independent?samples t test was applied to evaluate the difference between the two groups. Results The mean hippocampal volume in the 16 patients was 2. 76 cm3 ( range 2. 56 ?3. 01 cm3 ) . The mean radiation dose ( Dmean ) in the hippocampus during IMRT and VMAT was 9. 04± 0. 20 Gy and 10. 32± 0. 28 Gy, respectively, reduced by 66. 0% and 61. 2%, respectively, compared with the prescribed dose ( P=0. 55);Dmean in the area for reduced dose during IMRT and VMAT was 13. 57± 0. 90 Gy and 14. 86± 0. 60 Gy, respectively, reduced by 49. 0% and 44. 1%, respectively, compared with the prescribed dose (P=0. 88). Conclusions HA?PCI in IMRT and VMAT meets the clinical requirements, and can reduce the dose in the hippocampus while ensuring the whole?brain radiation dose, and therefore can be applied in PCI and provide a technical support to protect the patient’ s neurocognitive function.