Patient selection: presentation with LEMS
Initial screening:
(1) CT scan of the thorax
(2) if negative, perform FDG-PET (18F-flurodeoxyglucose positron emission tomography) scan
If either is positive for a pulmonary lesion, then evaluate the lesion for small cell lung carcinoma.
If neither is positive, then perform a thoracic CT or FDG-PET scan in 6 months. If positive for a mass lesion evaluate the lesion for small cell lung carcinoma.
If neither is positive, then consider autoimmune myasthenia based on the presence of all of the following:
(1) age < 45 years
(2) no history of smoking
(3) HLA haplotype 8.1
If the patient does not have autoimmune myasthenia, then perform thoracic CT or FDG-PET scans every 6 months for 2 years (i.e., 3 more times). If any is positive then evaluate for small cell lung carcinoma.
If all imaging studies are negative to this point and if the patient does not qualify for autoimmune myasthenia syndrome, then the patient probably has LEMS due to a cause other than small cell carcinoma of the lung.
Limitations:
• The original protocol calls the person with a negative work up as "non-tumor LEMS".
• Tumors other than small cell lung carcinoma can cause LEMS. The group "non-tumor LEMS" in the protocol would include these patients as well.
• The cost of doing 5 FDG-PET scans would be very high.
