Radiologically isolated syndrome (RIS) is a clinical finding that describes individuals with magnetic resonance imaging (MRI) patterns similar to those seen in multiple sclerosis patients. However, affected patients do not show a clinical history of neurological symptoms and the finding usually happens incidentally.1 The syndrome, which has an incidence of around 0.1% in adults, has raised many questions in the past, including the prognosis for affected individuals.2,3 Even though a multinational study has reported the probability of a clinical event of occurring in 5 years to be an estimated 34%, no risk assessment over a longer period of time has been performed so far.3,4 Therefore, Christine Lebrun-Frenay (Côte d’Azur University, France) and her team recently performed a retrospective analysis to estimate the risk for a clinical event occurring in 10 years. In addition, the authors aimed to determine potential risk associations with demographic, clinical and radiological characteristics.
Retrospective collection of long-term 10-year data
The authors included long-term follow-up data from 277 individuals with RIS that were followed longitudinally within a worldwide cohort study.3 The subjects were previously identified based on MRIs according to 2009 RIS criteria,1 and were overlapping with those that were analysed in the previously published 5-year study.4 Data were collected out of 21 databases from 5 countries, and the median reported follow-up time in the analysed individuals was 6.7 years.
Probability of clinical events higher than after 5 years
The collected data showed that individuals with diagnosed RIS had a 51.2% cumulative probability of a clinical event at 10 years. The team around Dr Lebrun-Frenay was also able to identify a list of independent predictors associated with clinical events, including positive cerebrospinal fluid for oligoclonal bands, infratentorial or spinal cord lesions and young age. In addition, they reported an increased risk for a clinical event with the occurrence of gadolinium-enhancing lesions during follow-up.
New data may lead to new guidance
This retrospective analysis of follow-up data from individuals diagnosed with RIS showed that around half of affected individuals experience a clinical event within 10 years after diagnosis. According to the authors, it is currently the longest and largest study published that investigated RIS. The authors further stated in their publication that these findings, and in particular the identification of independent predictors for an event, may lead to the guidance of clinical management and education. Treatment of individuals with RIS is currently being studied in randomised clinical trials and will further pave the way for optimal clinical management in the future.