Background
A phase 3 Radiation Therapy Oncology Group (RTOG) study subset analysis demonstrated improved overall survival (OS) with the addition of stereotactic radiosurgery (SRS) to whole brain radiation therapy (WBRT) in non-small cell lung cancer (NSCLC) patients with 1 to 3 brain metastases. Because temozolomide (TMZ) and erlotinib (ETN) cross the bloodbrain barrier and have documented activity in NSCLC, a phase 3 study was designed to test whether these drugs would improve the OS associated with WBRT + SRS.
Methods and Materials
NSCLC patients with 1 to 3 brain metastases were randomized to receive WBRT (2.5 Gy×15 to 37.5 Gy) and SRS alone, versus WBRT + SRS + TMZ (75 mg/m2/day× 21 days) or ETN (150 mg/day). ETN (150 mg/day) or TMZ (150–200 mg/m2/day ×5 days/month) could be continued for as long as 6 months after WBRT þ SRS. The primary endpoint was OS.
Results
After 126 patients were enrolled, the study closed because of accrual limitations. The median survival times (MST) for WBRT + SRS, WBRT + SRS + TMZ, and WBRT + SRS + ETN were qualitatively different (13.4, 6.3, and 6.1 months, respectively), although the differences were not statistically significant. Time to central nervous system progression and performance status at 6 months were better in the WBRT þ SRS arm. Grade 3 to 5 toxicity was 11%, 41%, and 49% in arms 1, 2, and 3, respectively (P<.001).
Conclusion
The addition of TMZ or ETN to WBRT + SRS in NSCLC patients with 1 to 3 brain metastases did not improve survival and possibly had a deleterious effect. Because the analysis is underpowered, these data suggest but do not prove that increased toxicity was the cause of inferior survival in the drug arms.
Accurate and automatic brain metastases target delineation is a key step for efficient and effective stereotactic radiosurgery (SRS) treatment planning. In this work, we developed a deep learning convolutional neural network (CNN) algorithm for segmenting brain metastases on contrast-enhanced T1-weighted magnetic resonance imaging (MRI) datasets. We integrated the CNN-based algorithm into an automatic brain metastases segmentation workflow and validated on both Multimodal Brain Tumor Image Segmentation challenge (BRATS) data and clinical patients' data. Validation on BRATS data yielded average DICE coefficients (DCs) of 0.75±0.07 in the tumor core and 0.81±0.04 in the enhancing tumor, which outperformed most techniques in the 2015 BRATS challenge. Segmentation results of patient cases showed an average of DCs 0.67±0.03 and achieved an area under the receiver operating characteristic curve of 0.98±0.01. The developed automatic segmentation strategy surpasses current benchmark levels and offers a promising tool for SRS treatment planning for multiple brain metastases.
Treatment at institutions with higher clinical trial accrual volume is associated with longer OS among patients with LA-NSCLC participating in a phase III trial.
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