The response of cerebral metastases in small cell lung cancer to systemic chemotherapy

Abstract

Although small cell lung cancer (SCLC) is very chemosensitive, cerebral metastases are treated with radiotherapy in the belief that they are protected from chemotherapy by the blood-brain barrier (BBB). The validity of this assumption has not been tested in clinical practice. In a randomised trial of treatment in 610 patients with SCLC, 19 patients who had symptomatic cerebral metastases at presentation were treated initially with chemotherapy, and cranial irradiation withheld. Chemotherapy was cyclophosphamide 1 g m-2 i.v. day 1, vincristine 2 mg i.v. day 1 and etoposide 100 mg tds p.o. days 1-3, repeated every 21 days, with response assessed objectively by computerised tomography (CT) or radionuclide brain scan, and by clinical examination. A post-chemotherapy scan was obtained in 14 patients, eight of whom achieved a partial remission and one a complete remission of the cerebral metastases. The radiologically proven responses were sustained and accompanied by rapid neurological improvement. Of the remaining five patients who were assessed by clinical examination alone, one had improved neurological function after chemotherapy. The response rate for SCLC cerebral metastases treated with chemotherapy was therefore 10/19 (53%). Chemotherapy has the advantage over cranial irradiation of simultaneously treating both cerebral metastases and extracranial disease. The place of chemotherapy in the management of cerebral metastases in this and other chemosensitive tumours should be reconsidered since these findings indicate that the BBB does not prevent response to chemotherapy.