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Prophylactic (Preventative) Radiation of the Brain

Prophylactic (Preventative) Radiation of the Brain

Question

Dear OncoLink "Ask The Experts,"

Could you please give me some information on the use of preventative radiation therapy to the brain? My daughter is in remission from lung cancer, and the doctor suggests radiation therapy to the brain as a preventative measure. Thank you.

Answer

Robert Lustig MD FACR, Clinical Associate Professor, Department of Radiation Oncology, University of Pennsylvania, responds:

In the adult population, and excluding diagnoses of leukemia/lymphoma, the only clear indication for prophylactic cranial radiation (PCI) is in the setting of small cell lung carcinoma (aka oat cell). If the patient presents with limited stage disease, has a complete remission after chemotherapy/local lung radiation, and is restaged with no evidence of disease, then whole brain radiation is indicated. This will decrease the risk of intra-cranial recurrence ( brain metastasis ) and improve overall survival. Studies have found significant decreases in rates of future brain metastases in patients with small cell lung cancer (55% rate in patients without radiation down to 19% with radiation at 2 years; from 56% down to 35% at 5 years).

There have been some studies suggesting that prophylactic cranial radiation may be a benefit in adenocarcinoma and large cell carcinoma of the lung. PCI continues to be tested in this setting in clinical trials, but to date it is not standard of care in these subtypes as it is with small cell lung cancer.

Some have suggested that there may be long-term neurologic damage from this treatment, but this has not been demonstrated in studies.