Summary

• In a study of 453 people described as having radiologically isolated syndrome (specific areas of damage on MRI scans with no accompanying symptoms), about 12% eventually developed primary-progressive MS. This mirrors the frequency of primary-progressive MS seen in other studies of people with MS.
• Those who developed primary-progressive MS were more likely to be men, were significantly older, and were more likely to have MS-like lesions in the spinal cord compared to those who went on to develop clinically isolated syndrome (CIS) or relapsing-remitting MS.
• This study provides a rare glimpse of a very early stage of disease even before progression begins, and provides additional evidence of the value of research into radiologically isolated syndrome. Finding a way to identify and track primary-progressive MS earlier may help to improve access to care for those who have it.
• The team (Dr. Orhun Kantarci, Mayo Clinic and Foundation, and national and international collaborators) published their findings in Annals of Neurology (published online, December 29, 2015).

Background: Diagnosing MS can be challenging, and it often happens in stages. The term “clinically isolated syndrome” (CIS) is used to describe a first episode of neurologic symptoms  that lasts at least 24 hours and is caused by inflammation and demyelination in one or more sites in the brain and spinal cord. Individuals who experience a CIS may or may not go on to develop definite MS. However, clinical trials of specific disease-modifying therapies have led to approvals for their use to treat CIS.

Some people have specific, “clinically silent” lesions (areas of inflamed or damaged tissue) on MRI, meaning that they are experiencing no symptoms and only have imaging findings. There has been growing research on this phenomenon, called “radiologically isolated syndrome (RIS),” which like CIS may or may not go on to develop into definite MS. There is debate as to whether people with RIS would benefit from early treatment with disease-modifying therapies.

Primary-progressive multiple sclerosis is a relatively rare form of MS, with about 10% of all people with MS receiving this diagnosis. It is characterized by steady worsening of neurologic functioning, without any distinct relapses (also called attacks or exacerbations) or periods of remission.

The Study:  This team examined data from 453 people with RIS collected from 22 investigators in five countries; a database of 210 people with MS in Olmsted County, Minnesota; and a cohort of 754 people with progressive MS.

Of the 453 people with RIS, 128 (28%) went on to develop a first neurological event consistent with CIS or relapsing MS. Of these, 15 (11.7%) developed primary-progressive MS. Those who developed primary-progressive MS were more commonly men, and older at diagnosis by approximately 10 years, than the 113 people who developed CIS/MS. The frequency of primary-progressive MS and age comparisons were similar to those identified in other groups of MS. Of the 15 who went on to develop primary-progressive MS, 12 had MRI scans of the spinal cord, and all 12 had lesions in the spinal cord, compared with 64% of those who developed CIS/MS.

The team (Dr. Orhun Kantarci, Mayo Clinic and Foundation, and national and international collaborators) published their findings in Annals of Neurology (published online, December 29, 2015).

Conclusions: This study provides a rare glimpse of a very early stage of disease even before progression begins, and provides additional evidence of the value of research into radiologically isolated syndrome. Finding a way to identify and track primary-progressive MS earlier may help to improve access to care for those who have it.

Read more about primary-progressive MS