Still No Evidence That Preventive Radiation to Brain Improves Survival
For patients with Stage III non-small cell lung cancer, prophylactic (preventive) radiation therapy to the brain reduces the risk of brain metastases but carries a risk of memory problems and doesn’t appear to improve overall survival. These results were published in the Journal of Clinical Oncology.
Lung cancer remains the leading cause of cancer death in the United States. Non–small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancers.
One of the sites to which NSCLC can spread (metastasize) is the brain. Brain metastases can have a profound effect on survival and quality of life.
Prophylactic cranial irradiation (PCI) refers to the administration of radiation to the brain before brain metastases become apparent. The goal of PCI is the prevention of brain metastases. Previous studies have suggested that PCI can reduce the occurrence of brain metastases, but PCI has not become a part of routine NSCLC care because of concern about side effects and lack of evidence that PCI improves survival.
To further explore the role of PCI in the management of locally advanced NSCLC, researchers conducted a Phase III clinical trial among patients with Stage IIIA or IIIB NSCLC. The researchers initially planned to enroll more than 1000 patients, but because of slow accrual they were only able to enroll 356 patients. Study participants were assigned to receive either PCI or observation. The primary objective of the study was to determine whether PCI improved overall survival.
- Brain metastases developed in 7.7% of patients in the PCI group and 18% of patients in the observation group.
- One-year overall survival was 75.6% among patients in the PCI group and 76.9% among patients in the observation group.
- Patients in the PCI group were more likely to experience a decline in memory.
Although there was no significant survival difference between the groups, the researchers note “It is possible that a survival advantage may become evident with longer follow-up.”
In summary, although preventive radiation therapy reduces the risk of brain metastases among patients with NSCLC, it may cause memory problems and may not improve overall survival. The researchers note that at this time, “PCI is not recommended as standard therapy on the basis of this study or the available data, because there is no evidence of a survival benefit in patients with [locally advanced] NSCLC.”
Gore EM, Bae K, Wong SJ et al. Phase III comparison of prophylactic cranial irradiation versus observation in patients with locally advanced non-small-cell lung cancer: primary analysis of Radiation Therapy Oncology Group Study RTOG 0214. Journal of Clinical Oncology. 2011;29:272-278.
Sun A, Bae K, Gore EM et al. Phase III trial of prophylactic cranial irradiation compared with observation in patients with locally advanced non-small-cell lung cancer: neurocognitive and quality-of-life analysis. Journal of Clinical Oncology. 2011;29:279-286.
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