When it comes to lung cancer, medical guidelines change as doctors learn more. It’s important to stay on top of these changes because they can directly impact your care. Recently, the National Comprehensive Cancer Network (NCCN) updated its guidelines for small cell lung cancer (SCLC) to include important information about a rare condition called Lambert–Eaton Myasthenic Syndrome (LEMS). Here’s what you need to know. 

What is LEMS? 

LEMS is a rare condition where the body’s own immune system mistakenly attacks the connection between nerves and muscles. This makes it harder for nerves and muscles to communicate with each other, which causes muscle weakness, dizziness, and other symptoms. Because LEMS is rare, it can be overlooked or misdiagnosed.  

What is the connection between LEMS and SCLC? 

Out of every 100 people diagnosed with SCLC, about 3 people will also have LEMS. For people with SCLC, recognizing LEMS symptoms allows your healthcare team to diagnose and manage the condition early, which can improve your quality of life. For people with LEMS but no cancer, it’s important to ask your healthcare team about annual lung cancer screening. This is because LEMS can sometimes appear years before SCLC is found and can sometimes be an early warning sign.  

What are the symptoms of LEMS? 

LEMS symptoms often occur over time and can be mistaken for other health issues. Symptoms of LEMS can include: 

Muscle weakness 

  • Usually starts in the hips and legs, making it hard to climb stairs, get out of a chair, or walk far 
  • Can also affect the arms and shoulders, making it tough to lift objects or reach overhead 
  • Muscles may actually feel stronger after you use them for a while, which is different from other muscle conditions 

Other body changes 

  • Very dry mouth (one of the most common complaints) 
  • Constipation 
  • Blurry vision or trouble focusing your eyes
  • Dizziness when standing up too quickly 
  • Less sweating than normal 
  • Erectile problems in men 

Fatigue 

Many people with LEMS feel tired all the time, even after rest. 

Other possible signs 

  • Tingling or numbness in the hands or feet 
  • Trouble with balance (less common)

If you or a loved one has these symptoms, it’s crucial to talk to your healthcare team. 

What do these new guidelines mean for people with SCLC? 

The updated NCCN guidelines give your healthcare team a clear roadmap for how to recognize and manage LEMS in people with SCLC: 

  • Better testing: Doctors are now encouraged to test for specific antibodies (VGCC antibodies) if you have muscle weakness or other possible LEMS symptoms. 
  • Faster referrals: Early consultation with a neurologist is recommended. 
  • Improved treatment: Firdapse (amifampridine) is highlighted as the first treatment for LEMS. It can improve muscle strength and is the only FDA-approved drug for this condition. 
  • Team-based care: Your oncologist and neurologist are encouraged to work together, so both SCLC and LEMS are managed effectively.

What are the next steps?  

If you have been diagnosed with SCLC and have symptoms of LEMS, talk to your healthcare team about your symptoms and ask for a referral to an experienced neurologist to be tested for LEMS.  

If you have been diagnosed with LEMS, ask your healthcare team about annual lung cancer screenings.