Neurologic disorders in 203 consecutive patients with small cell lung cancer: Results of a longitudinal study

Abstract

Neurologic complications of small cell lung cancer (SCLC) are manifold. The incidence and course of the various metastatic and nonmetastatic neurologic disorders were studied prospectively in a cohort of SCLC patients. The 203 patients underwent neurologic examinations on a regular basis, prior to therapy, during and after treatment, from 1983 through 1994. Routine computer tomography or magnetic resonance imaging of the brain was performed before therapy and after 2 years' survival. Other auxiliary diagnostic tests were performed as required. The majority of the 174 neurologic disorders, diagnosed in 132 patients, were associated with metastases. A total of 79 patients developed brain metastases. The cumulative risk of brain metastases reached 47% for limited and 69% for extensive disease patients at 2 years from diagnosis. Survival following the diagnosis of brain metastases was significantly longer for patients with brain metastases at the initial diagnosis of SCLC than for patients with delayed brain metastases (P < 0.01, long rank test). The most frequent paraneoplastic syndrome with neurologic symptoms was that of inappropriate secretion of antidiuretic hormone (SIADH), which was diagnosed in 11 patients. Antibody-mediated paraneoplastic neurologic syndromes were diagnosed in five patients. Chemotherapy for SCLC caused SIADH to subside in most patients. In contrast, the antibody-mediated syndromes did not respond to SCLC therapy. Adverse effects of treatment included peripheral neuropathy, encephalopathy, radiation plexopathy, and steroid myopathy. However, unlike the other complications, peripheral neuropathy was reversible. This clinical investigation confirmed the frequency of central nervous system metastatic involvement as well as the diversity of the neurologic complications in SCLC. The high frequency of brain metastases justifies a reappraisal of prophylactic cranial irradiation in this patient group.