According to a study published in the scientific journal Neurology, the survival rates of patients with Lambert-Eaton myasthenic syndrome (LEMS) were compared to that of the general population as well as patients with small cell lung cancer (SCLC). Quality of life and various measures of functionality were also evaluated. The study included patients with comorbid tumors (always SCLC) and those without. The study found that patients without tumors had normal survival and those with SCLC had improved tumor survival.
Lambert-Eaton Myasthenic Syndrome
Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disease which is characterized by weakness of the limb muscles. In this autoimmune disease, the immune system develops antibodies against an ion channel that plays a vital role in neuromuscular function. Lambert-Eaton myasthenic syndrome commonly appears as the result of cancer, often small cell lung cancer. Genetic variants are often the cause when cancer is not involved. The disease presents with muscle weakness of the upper arms and legs, with the legs usually being most affected. Other symptoms include difficulty swallowing, double vision, drooping eyelids, orthostatic hypotension, ataxia, and reduced reflexes. Weakness may be temporarily relieved after exercise; hot temperatures seem to worsen symptoms. Treatment of comorbid cancer can resolve the disease; other treatments include immune system suppressors (IVIG and prednisone) and drugs that improve neuromuscular function. To learn more about Lambert-Eaton myasthenic syndrome, click here.
The study ultimately included a total of 150 patients with Lambert-Eaton myasthenic syndrome. The 65 patients without comorbid tumors had survival that was comparable to the general population. For the patients with SCLC, tumor survival was a median of 17 months vs 7 months for other SCLC patients. When diagnosed, 39 of the 63 patients that had complete follow up data were functionally independent for daily living activities; at one year follow up, this improved to 85 percent of patients.
Using a measure called health-related quality of life (HRQOL), the researchers found that patients scored substantially lower than the general population (55.9 vs 76.3) on the physical assessment. On the mental assessment, scores were more similar (71.8 vs 77.9).
The authors drew several conclusions from the study. Most patients appear to have a fairly stable course of disease; most are able to live fairly independently though typically with some degree of physical impairment; and patients without comorbid SCLC tend to have normal life expectancy. In addition, Lambert-Eaton myasthenic syndrome patients with SCLC tend to have better survival compared to other SCLC patients. Overall, the study provides useful information about the course of the disease and long-term outcomes.