“Benign” MS: Is Disability Just a Matter of Time?

Patients with multiple sclerosis (MS) who don’t experience disabling symptoms or loss of function are often diagnosed with benign MS and informed that the symptoms associated with the disease are unlikely to occur to the same extent as in other patients with MS.

However, a recent study by Ana-Luiza Sayao, MD, of the University of British Columbia in Vancouver, and colleagues suggests that with time, symptoms associated with benign MS can in fact progress from mild to severe in certain patients.

The findings, which were published in the February 13 Neurology, came after Dr. Sayao and her colleagues evaluated disease progression in patients 20 years after symptom onset.

For the study, 200 patients with benign MS for 10 years or longer were selected from the British Columbia MS clinics database. The researchers defined benign MS as a score of 3 or less on the Expanded Disability Status Scale (EDSS). The cohort was pared down when researchers were able to obtain a 20-year history of EDSS scores in only 169 patients; this cohort had a mean age of 39.8 at the beginning of the study and a median EDSS score of 2. Other factors included in the evaluation were gender, age at onset, symptom type, and whether patients used immunomodulatory drugs.

After evaluating clinical progression of the disease at 20 years, the researchers determined that the median EDSS score had increased to 3, noting that more than 50% of those evaluated had progressed in disease severity, with more than 21% requiring the use of a cane to walk. Most patients had the relapsing-remitting form of the disease; however, 20% of patients developed secondary progressive MS.

The researchers noted that unlike previous studies, which have suggested that “manifestations of optic neuritis or sensory symptoms at onset, female sex, and younger age at onset are all associated with benign status, whereas pyramidal symptoms at onset have been associated with a poor outcome,” they “did not find onset symptoms to have a predictive effect on disease severity, as also indicated by other studies. Also, age at onset and sex were not significantly associated with benign status in our study when we controlled for other factors.” In fact, they said that only the EDSS scores at 10 years remained significantly predictive in the 20-year score.

The results prompted Dr. Sayao to urge clinicians to use caution when speaking to patients with the less severe form of MS. “We need to be careful what we tell people and not give them false hope that their symptoms may never get worse,” she said.

In an accompanying editorial, Sean J. Pittock, MD, advises clinicians to treat patients presenting with MS symptoms with a “watchful waiting” approach and to refrain from administering disease-modifying agents “until better methods exist to individualize therapeutic decision making.” He noted that this is not to be misconstrued as a “never treat” approach and added  that if a decision is made to delay treatment in a patient with a favorable disease profile, it’s necessary to follow up with yearly clinical and radiologic surveillance and to administer disease-modifying agents when appropriate.“The MS prognostic glass is half full for a high proportion of these most benign cases,” he concluded.

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