SCLC and anti‐GABABR encephalitis: A retrospective analysis of 60 cases in China

Abstract Background Anti‐gamma aminobutyric acid B receptor (anti‐GABABR) encephalitis is a rare autoimmune neurological syndrome observed in lung cancer patients. More research on the clinical characteristics of small cell lung cancer (SCLC) and anti‐GABABR encephalitis should be carried out to improve diagnosis and treatment. Methods We retrospectively investigated the clinical characteristics, auxiliary examination results, and treatment responses in patients with SCLC and anti‐GABABR encephalitis at Beijing Chaoyang Hospital from January 2010 to December 2020. The study also retrospectively analyzed cases of SCLC and anti‐GABABR encephalitis well documented in China. Results A total of 60 cases of SCLC and anti‐GABABR encephalitis were analyzed in the study, two in our hospital, and 58 previously reported in the literature. The male:female ratio was 3:1, with a median age at presentation of 61 years (range: 40–81 years). Twenty‐eight patients initially presented with seizures, four with cognitive disorder, and three with psychiatric symptoms. The major symptoms were epileptic seizures (n = 56; 96.9%), cognitive impairment (n = 47; 81.0%), psychiatric disorders (n = 45; 77.6%), and conscious disturbance (n = 32; 55.2%). Fifty‐five patients underwent immunotherapy, and 23 patients underwent oncologic treatment in the literature. After a median follow‐up duration of 8.8 (range, 0.5–37.0) months, nine patients showed good outcomes (modified Rankin Scale score, mRS ≤2), eight patients showed poor prognosis (mRS > 2), and 18 patients died. Conclusions The clinical characteristics of SCLC and anti‐GABABR encephalitis are seizures, cognitive impairment, and psychiatric disorders which affect middle‐aged to elderly men in China. The long‐term prognosis is relatively poor.