Clinical characteristics and long term follow-up of Lambert-Eaton myasthenia syndrome in patients with and without small cell lung cancer.

In order to describe the clinical characteristics, treatment response and long-term follow up in Lambert-Eaton myasthenic syndrome (LEMS) patients with and without small cell lung cancer (SCLC) in East China, patients seen in Huashan Hospital from January 1997 to December 2017 were included. Clinical information was collected retrospectively and quantitative MG (QMG) score, manual muscle testing (MMT), activities of daily living (ADL) scale were evaluated when the patients were followed up. Of 50 patients, 23 (46%) were SCLC-LEMS and 20 (40%) were nontumor LEMS (NT-LEMS). The median onset age was 55.5 (18-86) years old and the gender ratio was about 1.8:1. It took less time to make the diagnosis (median time: 6 vs 22.5 months, p = 0.0003) and there were more patients with other paraneoplastic syndromes in SCLC-LEMS group than in NT-LEMS group (8/23 vs 0/20, p = 0.0042). Electrophysiologically, the peroneal compound motor action potential (CMAP) of rest showed difference between SCLC-LEMS and NT-LEMS (0.8 vs 1.6 mV, p = 0.0499). The median survival time of 19 SCLC-LEMS patients since the diagnosis of SCLC was 30 months. According to their survival time, SCLC patients with LEMS showed a more favorable prognosis than those without LEMS. In the time of follow-up, most NT-LEMS showed improvement or obtained status of CSR/PR/MM after immunosuppressive therapy and no significant difference in proportion of achieving CSR/PR/MM was found between SCLC-LEMS and NT-LEMS patients (0/5 vs 6/13, p = 0.114).

Long-term survival in paraneoplastic Lambert-Eaton myasthenic syndrome.

OBJECTIVE: To establish whether improved tumor survival in patients with Lambert-Eaton myasthenic syndrome (LEMS) and small-cell lung cancer (SCLC) was due to known prognostic risk factors or an effect of LEMS independently, perhaps as a result of circulating factors. METHODS: We undertook a prospective observational cohort study of patients with LEMS attending Nottingham University Hospitals, UK, or via the British Neurological Surveillance Unit. In parallel, patients with a new diagnosis of biopsy-proven SCLC were enrolled, examined for neurologic illness, and followed up until death or study end. RESULTS: Between May 2005 and November 2014, we recruited 31 patients with LEMS and SCLC and 279 patients with SCLC without neurologic illness. Allowing for known SCLC survival prognostic factors of disease extent, age, sex, performance status, and sodium values, multivariate Cox regression analysis showed that the presence of LEMS with SCLC conferred a significant survival advantage independently of the other prognostic variables (hazard ratio 1.756, 95% confidence interval 1.137-2.709, p = 0.011). CONCLUSIONS: Improved SCLC tumor survival seen in patients with LEMS and SCLC may not be due solely to lead time bias, given that survival advantage remains after allowing for other prognostic factors and that the same degree of survival advantage is not seen in patients with paraneoplastic neurologic syndromes other than LEMS presenting before SCLC diagnosis.

Small-cell lung cancer, paraneoplastic cerebellar degeneration and the Lambert-Eaton myasthenic syndrome.

Several cancers, especially lung, ovarian and breast, can cause paraneoplastic cerebellar degeneration. The presence of different antineuronal antibodies associated with different cancers and paraneoplastic cerebellar degeneration suggests that several immunological mechanisms may result in the same neurological disorder. In patients with small-cell lung cancer, paraneoplastic cerebellar degeneration may occur with or without Hu antineuronal antibodies (HuAb), indicating that patients with the same tumour can develop paraneoplastic cerebellar degeneration by different immunological mechanisms. Furthermore, paraneoplastic cerebellar degeneration sometimes occurs in association with the Lambert-Eaton myasthenic syndrome. In order to try to understand the clinical implication of antineuronal antibodies in patients with small-cell lung cancer, we examined the serum of 57 patients with presenting symptoms of paraneoplastic cerebellar degeneration for the presence of HuAb and P/Q- and N-type voltage-gated calcium channel antibodies. Patients with paraneoplastic cerebellar degeneration who were HuAb positive were compared with HuAb negative patients with respect to neurological symptoms, course of the neurological disorder, response to treatment, tumour prognosis, pathological findings, and cause of death. The tumour outcome and serological findings of these patients were also compared with those of 109 small-cell lung cancer patients without paraneoplastic syndromes of the CNS. Titres of HuAb were classified as 'high' (immunoblot titre > 1:10,000) or 'low' (< 1:10,000), the latter similar to the antibody titres detected in some small-cell lung cancer patients without paraneoplastic symptoms. Twenty-five patients with paraneoplastic cerebellar degeneration (44%) had high titres of HuAb, four (7%) had low titres of HuAb, and 28 (49%) were HuAb negative; for clinical comparisons with the patients with high titres of HuAb, the four patients with low antibody titres were included in the HuAb negative cohort. None of the 109 small-cell lung cancer patients without paraneoplastic symptoms had high titres of HuAb. The presence of high titres of HuAb defined a subset of patients who differed from the HuAb negative paraneoplastic cerebellar degeneration cohort, HuAb positive patients were more likely to be female (P < 0.01), to have multifocal neurological disease (brainstem encephalopathy and sensory neuropathy being common extracerebellar manifestations) (P < 0.002), and be severely disabled (P < 0.005). A total of nine patients (16%) from both paraneoplastic cerebellar degeneration groups developed electrophysiologically confirmed Lambert-Eaton myasthenic syndrome. Seven of these nine patients had serum available for P/Q-type voltage-gated calcium channel antibody testing and all seven were positive. In addition, 20% of HuAb negative paraneoplastic cerebellar degeneration patients without clinically identified Lambert-Eaton myasthenic syndrome had P/Q-type voltage-gated calcium channel antibodies, while only 2% of small-cell lung cancer patients without paraneoplastic symptoms had these antibodies. Treatment of the tumour and/or immunomodulation did not alter the course of paraneoplastic cerebellar degeneration, but improved Lambert-Eaton myasthenic syndrome symptoms. At the time of death, in 60% of HuAb positive and 20% of HuAb negative paraneoplastic cerebellar degeneration patients, the tumour was either not evident or localized to the chest (P < 0.007); neurological disease was the cause of death of 65% HuAb positive paraneoplastic cerebellar degeneration and 10% HuAb negative paraneoplastic cerebellar degeneration patients (P < 0.001). (ABSTRACT TRUNCATED)