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LEMS and Cancer

LEMS and Cancer

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LEMS may be caused by the immune system or cancer


Autoimmunea disorder caused by abnormally low activity or overactivity of the immune system LEMS occurs when the immune system mistakenly attacks a part of the nervous system called the neuromuscular junction. This is a part of the body where nerves communicate with muscles to control their movement.


Cancer-related LEMS occurs when a cancerous tumor, usually in the lung, causes the body to produce antibodiesa type of protein produced by the immune system to fight infections that attack not only the tumor, but also the neuromuscular junction.

Screening for cancer

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Once a diagnosis of LEMS is confirmed, your doctor may decide to run more tests. If your symptoms are severe—or have progressed very quickly—it could be a sign that your LEMS is related to cancer.


About 50%

of LEMS cases are caused by an underlying tumor—often small-cell lung cancer (SCLC).an aggressive, fast-growing cancer of the lungs

The majority of these cases occur in people with a history of smoking.

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Tests may include an x-ray or CT scan

If your doctor suspects SCLC, he or she may order an X-ray or a computer tomography (CT) scan of your chest to see if a tumor is present. Once the cause of your LEMS symptoms has been determined, your doctor will discuss the best treatment plan for you.

Signs and Symptoms of Underlying Cancer

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Specialists use a scoring system called DELTA-P to predict the likelihood that a patient’s LEMS symptoms are caused by an underlying tumor. The name is an acronym drawn from each of the signs associated with this type of LEMS.

D = Difficulty swallowing/neck weakness

E = Erectile dysfunction (in males)

L = Loss of weight

T = Tobacco use

A = Age of onsetthe age that symptoms first appeared 50 years and older

P = Performance status on the Karnofsky test a test that measures muscle weakness

If you’re seeing any of these signs or symptoms, reach out to your doctor to discuss.

Patients with tumor-related LEMS may face numerous daily challenges

Members of a panel of patients with cancer-related LEMS described their experiences and the effects on their lives and those around them.

  • Muscle pain
  • Extreme fatigue, which makes it difficult to do day-to-day tasks and climb stairs
  • Trouble chewing due to jaw fatigue, which also causes slurred speech and dryness
  • Vision trouble
  • Inability to sleep, which also disrupts their family members’ sleep
  • Difficulty with self-care and heavy reliance on caregiver support
  • Patients reported feelings of depression

Treating LEMS Related to Cancer

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In cancer-related LEMS, the treatment team usually includes oncologists and neurologists who may use a coordinated effort to determine the appropriate treatment for you.

  • The oncologists will treat the underlying cancer using chemotherapy and radiation therapy
  • The neurologists will typically manage the symptoms of LEMS

Stay informed

More content is on the way for LEMS Aware, including video stories with real patients who are living and thriving with LEMS. Sign up to stay informed about new additions to the website as well as other resources that become available.