|Year : 2015 | Volume
| Issue : 5 | Page : 95-96
Lambert-Eaton myasthenic syndrome in patients with small cell lung cancer: Report of five cases
Yueqiao Hao1, Jinmeng Hu2, Yajun Zhang3, Weichao Liu4, Shanshan Lu5, Min Zhang1
1 Department of Electromyography, Henan University, Huaihe Hospital, Henan 475000, PR China
2 Department of Electromyography, Zhejiang Province, Taizhou Central Hospital, Taizhou 318000, PR China
3 Department of Respiratory, Henan University, Huaihe Hospital, Henan 475000, PR China
4 Department of Thoracic Surgery, Henan University, Huaihe Hospital, Henan 475000, PR China
5 Department of Electromyography, Shandong Province, Qianfoshan Hospital, Jinan, Shandong 25000, PR China
|Date of Web Publication||31-Aug-2015|
Dr. Min Zhang
Department of Electromyography, Henan University, Huaihe Hospital, 475000
Source of Support: None, Conflict of Interest: None
Objective: To further evaluate the clinical characteristics of small cell lung cancer (SCLC) with Lambert-Eaton syndrome.
Methods: We reviewed the patient database of our hospital from 2001 to 2013 to evaluate and analyze the patients of SCLC with Lambert-Eaton syndrome. The clinical characteristics and prognosis of the patients were analyzed in this retrospective study.
Results: From reviewing our hospital database, we included 5 SCLC patients with Lambert-Eaton syndrome from 202 SCLC subjects with an incidence rate of 2.5%. The median age of the 5 patients was 52 (41-71) with 4 male and 1 female. The myasthenia symptom can be detected in 2-20 months before the pathology confirmation for small cell lung carcinoma. The general electromyography characteristics of Lambert-Eaton syndrome was reduction in action potential amplitude after repetitive peripheral never stimulation at low frequency and increased amplitude at high frequency.
Conclusion: Lambert-Eaton syndrome was sometimes found in patients with SCLC which was useful for diagnosis of non-small cell lung carcinoma in a relatively early stage.
Keywords: Characteristics, electromyography, Lambert-Eaton myasthenic syndrome, small cell lung cancer
|How to cite this article:|
Hao Y, Hu J, Zhang Y, Liu W, Lu S, Zhang M. Lambert-Eaton myasthenic syndrome in patients with small cell lung cancer: Report of five cases. J Can Res Ther 2015;11, Suppl S1:95-6
|How to cite this URL:|
Hao Y, Hu J, Zhang Y, Liu W, Lu S, Zhang M. Lambert-Eaton myasthenic syndrome in patients with small cell lung cancer: Report of five cases. J Can Res Ther [serial online] 2015 [cited 2020 Sep 27];11:95-6. Available from: http://www.cancerjournal.net/text.asp?2015/11/5/95/163853
Yueqiao Hao and Jinmeng Hu contribute equally to this work.
| > Introduction|| |
Lambert-Eaton myasthenic syndrome (LEMS), also named Lambert-Eaton syndrome, or Eaton-Lambert syndrome, is a rare autoimmune disorder that is characterized by muscle weakness of the limbs. It is the result of an autoimmune reaction in which antibodies are formed against presynaptic voltage-gated calcium channels (VGCCs), and likely other nerve terminal proteins, in the neuromuscular junction.  LEMS can occur as remote effect of a neoplasm, in the paraneoplastic form, usually in association with small-cell lung cancer (SCLC). Generally speaking, LEMS is relatively rare in the general population with an incidence rate of 0.48/million.  However, the incidence is on the rising because of its improved recognition by doctors. And it has been reported that about 50% of LEMS patients had a kind of carcinoma.  SCLC accounting for 20% of all diagnosed lung cancer is the major type of cancer which occurs in patients with LEMS. Several articles have reported the clinical characteristic and treatment strategy for patients of SCLC with LEMS. We retrospectively analyzed the patient database and found 5 SCLC patients with LEMS. We evaluate the clinical characteristics of SCLC with Lambert-Eaton syndrome in order to enhance the acknowledgement for health providers.
| > Methods|| |
We reviewed the patient database of our hospital from 2001 to 2013 to evaluate and analyze the patients of SCLC with Lambert-Eaton syndrome. The clinical characteristics and prognosis of the patients were analyzed in this retrospective study. The general characteristics were recorded by two authors. The general characteristics include age, gender, duration of LEMS before the diagnosis of SCLC, treatment modality, and prognosis.
| > Results|| |
The general characteristics of the five cases
From reviewing our hospital database, we included five SCLC patients with Lambert-Eaton syndrome from 202 SCLC subjects with an incidence rate of 2.5%. The median age of the five patients was 52 (41-71) with four male and one female. The myasthenia symptom can be detected in 2-20 months before the pathology confirmation for small cell lung carcinoma [Table 1].
The general electromyography characteristics of Lambert-Eaton syndrome
The general electromyography characteristics of Lambert-Eaton syndrome was reduction in action potential amplitude after repetitive peripheral never stimulation at low frequency and increased amplitude at high frequency [Figure 1].
|Figure 1: The general electromyography characteristics of Lambert- Eaton syndrome|
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Treatment and prognosis
Four of the five patients received chemotherapy or chemoradiation, and one of the patients received operation after diagnosis of SCLC. The prognosis was recorded in three patients with two symptoms improved, two not available, and one died of multiple metastases.
| > Discussion|| |
LEMS is a rare autoimmune disorder of neuromuscular transmission. It is characterized clinically by muscle weakness, hyporeflexia or areflexia, and autonomic dysfunction. LEMS develops as a result of antibodies directed at the presynaptic VGCC. , LEMS was firstly reported by Anderson et al. in the year 1953.  In that report, they described a 47-year-old man with progressive muscle weakness and diminished tendon reflexes. They found a tumor in patient's lung, which was surgically removed. The tumor was pathology diagnosis of SCLC. After the operation, the muscle weakness symptom was significantly improved. Several years after, American neurologists named Lambert-Eaton described six similar cases with a distinctive electrophysiological pattern seen with repetitive nerve stimulation.  Thereafter, this syndrome, with or without SCLC, has become known as LEMS, and the diagnosis is still based on these electrophysiological criteria. ,
In our retrospective study, we reviewed the patient database of our hospital from 2001 to 2013 and found five typical cases of SCLC with LEMS. The incidence of LEMS in small cell cancer patients was 2.5% which is smaller than the previous studies reported. , The general treatment modality for SCLC patients with LEMS was chemotherapy. After chemotherapy, most of the cases had symptom relief. In this study, two patients received chemotherapy, but the prognosis was not available. Two patients received chemoradiation with improved symptom, and one died of multiple metastases. Because of a smaller number of cases in this study, the prognosis of small cell cancer patients with or without LEMS was not compared. Hence, whether LEMS is associated with the prognosis of small lung cancer is not clear.
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Conflicts of interest
There are no conflicts of interest.
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