Study examines quality of life, survival outcomes in Lambert-Eaton myasthenic syndrome

Patients with nontumor Lambert-Eaton myasthenic syndrome had survival rates comparable to the general population, according to the results of an observational study conducted in the Netherlands.

Further, patients with small cell lung cancer-associated Lambert-Eaton myasthenic syndrome experienced improved tumor-related survival, even after correction for tumor stage, according to the study findings, which were published in Neurology.

“Associated tumors are found in 50% to 60% of patients with [Lambert-Eaton myasthenic syndrome (LEMS)], almost invariably small cell lung cancer (SCLC),” the researchers wrote. “Limited data suggest some improvement of symptoms in patients with LEMS with SCLC after treatment of the tumor. Previous studies have shown a profound improved tumor survival in SCLC-LEMS, but no data exist on the quality of life of this period of improved survival. Hardly any data are available determining survival and quality of life of patients with LEMS without associated tumors.”

Alexander F. Lipka, MD, of Leiden University Medical Center and Groene Hart Hospital in the Netherlands, and colleagues aimed to classify functional impairments over the LEMS disease course as well as their quality of life. They also examined survival rates for all patients with LEMS, including those with and without associated tumors.

The researchers gathered data prospectively from all consecutive Dutch patients with LEMS from July 1, 1998, to Oct. 1, 2015. They added several patients to the study retrospectively, for a final cohort of 150 patients with LEMS. An associated lung cancer was identified in 85 patients (59%).

The 65 patients with LEMS and no associated tumor experienced a life expectancy that was similar to the average life expectancy in the Netherlands (adjusted for sex, age and year of diagnosis HR = 1.16; 95% CI, 0.59–2.27). The researchers observed significantly longer tumor survival in 81 patients with SCLC-LEMS compared with patients with non-LEMS SCLC (overall median survival, 17 vs. 7 months; P < .0001).

At the time of diagnosis, 39 of 63 patients (62%) with complete follow-up data were independent for activities of daily living, improving to 85% at the 1-year follow-up. The physical health-related quality of life composite score (55.9) was lower than in the general population (76.3; P < .0001) and comparable to that of patients with myasthenia gravis (60.5). The mental health-related quality of life composite score was 71.8 in patients with LEMS, a figure comparable to the general population (77.9) and patients with myasthenia gravis (70.3).

“This study provides detailed information on long-term prognosis and limitations in LEMS. This can guide expectations of doctors and patients and be of potential relevance for treatment choices,” the researchers wrote. “Although LEMS is usually a chronic disease with long-term physical limitations and reduced quality of life, appropriate treatment results in a relevant decrease in functional impairments for most patients.”