Learn how subtle weakness and autonomic signs in small cell lung cancer may signal LEMS—and why early neurology referral improves outcomes.
Back
Lambert-Eaton Myasthenic Syndrome in Small-Cell Lung Cancer: Bridging Oncology and Neurology to Achieve Earlier Diagnostics and Coordinated Care
Dr. Misty Shields from Indiana University moderated a discussion with Dr. Ditte Primdahl, neuro-oncologist at Northwestern University, and Dr. Triparna Sen from The Ohio State University Comprehensive Cancer Center on cancer-associated Lambert-Eaton myasthenic syndrome (CA LEMS) in small cell lung cancer (SCLC). CA LEMS is a paraneoplastic neuromuscular junction disorder characterized by proximal muscle weakness, hyporeflexia, and autonomic dysfunction, arising from autoantibodies against presynaptic voltage-gated calcium channels (VGCCs). Despite estimated prevalence of 3% to 6% in SCLC, CA LEMS is diagnosed in under 1% of patients in real-world practice. The program addresses clinical recognition, differential diagnosis from treatment-related toxicities, VGCC antibody testing including seronegative cases, electrodiagnostic studies, the 2025 NCCN guideline update, amifampridine (Firdapse) as FDA-approved symptomatic treatment, immune checkpoint inhibitor safety considerations, and optimal multidisciplinary care models. Evidence gaps including prospective prevalence data, immune checkpoint inhibitor safety in CA LEMS, and validated patient-reported outcome instruments are identified as priority research needs.
Lambert-Eaton Myasthenic Syndrome in Small-Cell Lung Cancer: Bridging Oncology and Neurology to Achieve Earlier Diagnostics and Coordinated Care
Episodes
All
All
Dr. Primdahl describes what CA LEMS looks like clinically for oncologists with limited exposure to this diagnosis. Patients are unlikely to self-report proximal weakness in clinical terms; they more commonly describe difficulty with everyday tasks, such as climbing stairs, getting in and out of a car or chair.
Dr. Sen addresses the striking gap between CA LEMS prevalence in prospective studies (3-6% of SCLC) and real-world diagnosis rates (under 1%), citing the Drapkin et al. published dataset.
Dr. Primdahl describes the diagnostic delays and misattributions that characterize the CA LEMS journey in patients with SCLC.
Dr. Sen recommends against testing VGCC antibodies in isolation when CA LEMS is suspected in SCLC.
Dr. Sen explains VGCC antibody testing in depth.
Dr. Primdahl addresses management of seronegative CA LEMS in a patient with SCLC and a compelling clinical picture.
Dr. Primdahl walks through clinical differentiation of CA LEMS from the most important diagnostic mimics encountered in SCLC.
Dr. Sen explains how to manage discordant serologic and electrodiagnostic results without allowing disagreement between tests to paralyze decision-making.
Dr. Sen addresses the significance of the 2025 NCCN SCLC guideline update explicitly naming CA LEMS symptom recognition (proximal weakness paired with autonomic dysfunction) and recommending P/Q-type and N-type VGCC antibody testing under the neurologic workup section, with early subspecialty consultation recommended.
Dr. Primdahl details amifampridine (Firdapse), FDA-approved in 2018 for CA LEMS based on 2 randomized placebo-controlled studies demonstrating clinically meaningful functional improvement with a favorable safety profile.
Dr. Primdahl describes optimal multidisciplinary CA LEMS care models.
Advertisement
Advertisement
Trending on OncLive
1
Pumitamig Plus Elfetabart Drozuntecan Elicits 70% ORR Across Lines of Therapy in SCLC
2
SERENA-4 Misses Primary PFS End Point With Camizestrant Plus Palbociclib in First-Line ER+ Advanced Breast Cancer
3
FDA Extends Review Period for Zanzalintinib Plus Atezolizumab NDA in Pretreated mCRC
4
Dibotatug Is Safe and Yields Durable Responses in Large Granular Lymphocytic Leukemia
5