Optimizing prophylactic cranial irradiation for patients with lung cancer

Prophylactic cranial irradiation is an effective method to reduce the incidence of brain metastases in patients with lung cancer. However, it is associated with a risk of memory decline. This thesis aimed to optimize prophylactic cranial irradiation for patients with lung cancer by identifying patients who are more likely to develop brain metastases and who are at high risk to experience memory impairment. It found that the type of radiotherapy (twice-daily) to the lung tumor, younger age, and a larger tumor are associated with a higher risk to develop brain metastases. Besides this, special characteristics of the lymph nodes on a CT scan of the chest are also related to a higher chance to get brain metastases. As a novel finding, it was shown that memory impairment is dynamic in individual patients, evolving from sustained, reversible, recurring, and alternating. Patients having memory impairment before radiotherapy is the more likely to experience diminishing mind functions later.