Research on radiotherapy target volumes for glioblastoma is increasingly focused on exploring more limited yet effective irradiation fields, aiming to achieve local control while minimizing acute and long-term neurotoxicity. Previous retrospective analysis by investigators revealed that local recurrences of glioblastoma are predominantly confined to a narrow margin around the original lesion: 98.3% of recurrences occurred within 0.5 cm of the original T2-FLAIR abnormality, 94.8% within 1 cm of the original T1-enhanced region. These findings have been cited in the ESTRO-EANO treatment guidelines. Building on this evidence, investigators plan to conduct a single-arm, phase II clinical trial to systematically evaluate the efficacy and safety of a 1 cm radiotherapy target volume in post-operative glioblastoma patients.Eligible patients with glioblastoma who have undergone surgical resection will be selected to receive limited-field radiotherapy. The target volume will be defined based on the postoperative MRI enhancing lesion: a 1 cm margin will be added to form the clinical target volume (CTV), followed by a further 0.3 cm margin to create the planning target volume (PTV). A total dose of 60 Gy will be delivered in 30 fractions (2 Gy per fraction, 5 fractions per week). Concurrent and adjuvant chemotherapy will be administered per standard guidelines. The primary efficacy endpoints are the 6-month progression-free survival rate and the incidence of symptomatic radiation-induced brain necrosis of grade 3 or higher. Secondary endpoints include overall survival, patterns of recurrence, neurocognitive function, and quality of life.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
PREVENTION
Masking
NONE
Enrollment
79
limited-field radiotherapy + Concurrent and adjuvant TMZ chemotherapy
6m PFS
6-month progression-free survival rate
Time frame: up to 6 month
incidence of symptomatic radiation-induced brain necrosis of grade 3 or higher
Time frame: Up to 24 months
OS
overall survival
Time frame: Up to 24 months
Location of first recurrence relative to radiation field (in-field, marginal, or distant)
The spatial relationship between the first documented site of disease recurrence/progression and the original radiation treatment plan will be determined by a core imaging laboratory. Recurrent lesions will be co-registered with the original planning CT/MRI and radiation dose distribution. Classification is based on the volume of the recurrent lesion covered by the 95% isodose line of the original prescription dose: In-field recurrence: \>80% of the recurrent lesion's volume is within the 95% isodose line. Marginal recurrence: 20% to 80% of the recurrent lesion's volume is within the 95% isodose line. Distant recurrence: \<20% of the recurrent lesion's volume is within the 95% isodose line. This classification criteria is adapted from the dosimetric analysis methods commonly used in radiotherapy studies (e.g., Patterns offailure for glioblastoma multiforme following limited-margin radiation and concurrent temozolomide. Radiation oncology 2014, 9:130.)
Time frame: Up to 24 months
Cognitive function assessed by Mini-Mental State Examination (MMSE) score
Cognitive function assessed by the Mini-Mental State Examination (MMSE). Scores range from 0 to 30, with higher scores indicating better cognitive function.
Time frame: Up to 24 months
Cognitive function assessed by Montreal Cognitive Assessment (MoCA) score
Cognitive function assessed by the Montreal Cognitive Assessment (MoCA). Scores range from 0 to 30, with higher scores indicating better cognitive function.
Time frame: Up to 24 months.
Health-Related Quality of Life as assessed by the EORTC QLQ-C30 Global Health Status / QoL scale
Score on the Global Health Status / Quality of Life scale (Items 29 \& 30) of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). Scale range: 0-100. A higher score indicates a better overall quality of life.
Time frame: Up to 24 months
Disease-Specific Quality of Life as assessed by the EORTC QLQ-BN20 summary score
Summary score of the European Organization for Research and Treatment of Cancer Brain Cancer Module (EORTC QLQ-BN20). This scale assesses symptoms and issues specific to brain tumor patients (e.g., future uncertainty, visual disorder, motor dysfunction). Scale range and interpretation should be specified
Time frame: Up to 24 months
Quality of Life as assessed by the FACT-Br Total Score
Total score of the Functional Assessment of Cancer Therapy - Brain (FACT-Br). This questionnaire assesses physical, social, emotional, functional well-being, and additional concerns specific to brain tumor patients. Scale range: 0-200. A higher score indicates better quality of life.
Time frame: Up to 24 months
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