Abstract
BackgroundWhole brain radiotherapy (WBRT) plus sequential focal radiation boost is a commonly used therapeutic strategy for patients with brain metastases. However, recent reports on WBRT plus simultaneous in-field boost (SIB) also showed promising outcomes. The objective of present study is to retrospectively evaluate the efficacy and toxicities of WBRT plus SIB with image guided intensity-modulated radiotherapy (IG-IMRT) for inoperable brain metastases of NSCLC.MethodsTwenty-nine NSCLC patients with 87 inoperable brain metastases were included in this retrospective study. All patients received WBRT at a dose of 40 Gy/20 f, and SIB boost with IG-IMRT at a dose of 20 Gy/5 f concurrent with WBRT in the fourth week. Prior to each fraction of IG-IMRT boost, on-line positioning verification and correction were used to ensure that the set-up errors were within 2 mm by cone beam computed tomography in all patients.ResultsThe one-year intracranial control rate, local brain failure rate, and distant brain failure rate were 62.9%, 13.8%, and 19.2%, respectively. The two-year intracranial control rate, local brain failure rate, and distant brain failure rate were 42.5%, 30.9%, and 36.4%, respectively. Both median intracranial progression-free survival and median survival were 10 months. Six-month, one-year, and two-year survival rates were 65.5%, 41.4%, and 13.8%, corresponding to 62.1%, 41.4%, and 10.3% of intracranial progression-free survival rates. Patients with Score Index for Radiosurgery in Brain Metastases (SIR) >5, number of intracranial lesions <3, and history of EGFR-TKI treatment had better survival. Three lesions (3.45%) demonstrated radiation necrosis after radiotherapy. Grades 2 and 3 cognitive impairment with grade 2 radiation leukoencephalopathy were observed in 4 (13.8%) and 4 (13.8%) patients. No dosimetric parameters were found to be associated with these late toxicities. Patients received EGFR-TKI treatment had higher incidence of grades 2–3 cognitive impairment with grade 2 leukoencephalopathy.ConclusionsWBRT plus SIB with IG-IMRT is a tolerable and effective treatment for NSCLC patients with inoperable brain metastases. However, the results of present study need to be examined by the prospective investigations.
Highlights
Whole brain radiotherapy (WBRT) plus sequential focal radiation boost is a commonly used therapeutic strategy for patients with brain metastases
Treatment planning and delivery All patients received WBRT at a dose of 40 Gy/20 f (5 f/ week), and simultaneous in-field boost (SIB) with IG-intensity-modulated radiotherapy (IMRT) at a dose of 20 Gy/5 f concurrent with WBRT in the fourth week. Under this schedule of radiotherapy, intracranial lesions had received total boost dose of 30 Gy/5 f, and the biological effective dose (BED) value based on linear-quadratic (LQ) model (BED = nd [1 + d/(α/β)], α/β = 10 Gy) was close to the Stereotactic radiosurgery (SRS) boost of 15-18Gy/1f used to apply in our department
Score index for radiosurgery in brain metastases (SIR) score >5, number of intracranial lesions
Summary
Whole brain radiotherapy (WBRT) plus sequential focal radiation boost is a commonly used therapeutic strategy for patients with brain metastases. Image guided intensity-modulated radiotherapy (IGIMRT) is a new technique of radiotherapy It improves the accuracy of treatment delivery by using cone beam computed tomography (CBCT) with x-ray volumetric images (XVI) to give the 3-dimensional anatomic information in the treatment position and to reduce setup uncertainty [6]. With these advantages, it is possible to administer hfSRT with IG-IMRT to brain metastases with noninvasive head fixation such as thermoplastic mask [6,7]
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