Scientists Validate New Tool for Estimating Cancer Risk in LEMS Patients

A new scoring tool can be used to effectively estimate the risk of developing small cell lung cancer (SCLC) for a person with Lambert-Eaton myasthenic syndrome (LEMS), according to a new study.

Smoking, being age 50 or older, and significant weight loss within three months of LEMS onset all predict the development of SCLC.

The research, “Lung cancer prediction in Lambert-Eaton myasthenic syndrome in a prospective cohort,” was published in the journal Scientific Reports.

LEMS affects the neuromuscular junction — the place where motor nerve cells and muscle fibers communicate — leading to muscle weakness, reduced reflexes, and extreme fatigue.

The rare autoimmune disorder is often associated with cancer, in particular SCLC, which is responsible for nearly 60% of all cases of LEMS.

To better understand a LEMS patient’s risks of SCLC, a team from the Netherlands and the U.K. had previously developed and validated a cancer prediction scoring tool. It enabled the differentiation between SCLC-LEMS and LEMS not associated with cancer.

Now, the same researchers sought to further validate their cancer prediction tool, called the Dutch-English LEMS Tumour Association Prediction (DELTA-P) score. The tool was tested among a second group of patients newly diagnosed with LEMS to assess the DELTA-P’s utility in a real-world setting.

The study included 87 people with LEMS — 54 women and 33 men. Clinical data collected within three months following the onset of LEMS was used to calculate the individual DELTA-P score.

A total of 44 patients (51%) had SCLC associated with LEMS, while the remaining 43 (49%) had no underlying tumor.

Notably, the median age at LEMS diagnosis was 65 in patients with SCLC and 58 in participants without cancer. In addition, the group with SCLC had a greater proportion of participants ages 50 or older (91% vs. 70%), of smokers (66% vs. 16%), and of participants who lost at least 5% of their body weight within three months of LEMS onset (61% vs. 19%).

After comparing DELTA-P scores between the two groups, the investigators found that the median scores were significantly higher among participants with SCLC-LEMS compared with those without cancer (3.5 vs. 2).

Higher DELTA-P scores were associated with an increased risk of SCLC. Patients with DELTA-P scores ranging from 0 to 1 had a low risk of having SCLC (0-18.8%), while those with scores ranging from 4 to 6 were at a high risk of having lung cancer (85.7-100%)

Statistical analyses also identified being age 50 or older at LEMS onset, smoking, and weight loss of at least 5% as independent predictors for the development of SCLC among people with LEMS.

Overall, the DELTA-P score, calculated at the time of LEMS diagnosis, is an effective way to screen for cancer, the scientists said.

“Using clinically validated data from a large prospective cohort, we have confirmed that the use of the DELTA-P scoring system at LEMS diagnosis is a robust measure of the risk of developing SCLC,” they wrote.

“Confirmation of the validity of the DELTA-P scoring system by other international investigators would be of great clinical value,” the team added.