Treatment of brain metastases in patients with small-cell lung cancer: lessons from treatment of other tumors.
Brain metastases are common in patients with small-cell lung cancer (SCLC) and are usually fatal. About half of all patients who develop brain metastases will remain symptomatic at their time of death, even if the immediate cause of death is not neurologic. While it has been argued that the obtundation that sometimes comes with brain metastases may be a relatively easy way to die, studies which have examined the quality of life of individuals developing brain metastases dispute this. For most patients and their families, the impairment of physical, cognitive, and affective function which accompanies most brain metastases is highly distressing and can be seen as a "loss" of the patient even before his/her death. Thus, improved treatment of overt brain metastases will be of palliative value, and eradication of microscopic disease in the brain may cure patients whose disease in other sites has been eradicated. Prophylactic cranial irradiation (PCI) for patients who have achieved a complete response to induction therapy markedly reduces the risk of central nervous system relapse and modestly but significantly improves survival. Despite the use of PCI, many patients with SCLC will develop brain metastases, and there is increasing interest in surgical treatment of patients with solitary lesions and the use of systemic chemotherapy in treating patients, with both SCLC and non small-cell lung cancer, who have multifocal brain metastases which are minimally symptomatic, particularly when these patients also have extracranial metastatic disease.