Why Doctors Don’t Use the Words ‘Benign MS’

The road to diagnosing and treating multiple sclerosis (MS) can be confusing. To start, symptoms look and feel different for everyone. It’s also a progressive chronic condition, which means your specific symptoms may first feel so mild you don’t really pay attention to them, only to find they are getting worse over time.

According to the National Multiple Sclerosis Society, approximately one million people in the U.S. have MS. “MS is an autoimmune disease that affects the central nervous system (CNS), including the brain, spinal cord, and optic nerves,” says Tirisham Gyang, M.D., a neurologist at The Ohio State University Wexner Medical Center in Columbus, OH.

Autoimmune diseases happen when the body’s immune system mistakenly attacks healthy cells. “In the case of MS, the target of that inflammatory response is myelin, the fatty coating that surrounds the nerves,” says Dr. Gyang. “It’s this abnormal inflammation happening in the CNS that attacks and destroys normal, healthy myelin, stripping it off cells in the CNS.”

Think of myelin similar to insulation around electrical wires. Without it (or with severely damaged insulation) nerve signals that travel through the CNS slow down significantly or stop completely, per the Cleveland Clinic.

There are a few different types of MS, per the National MS Society, clinically referred to as phenotypes. These different classifications inform treatment options to help slow down progression of the disease and minimize its impact on your quality of life.

You may also hear the term benign MS in older literature about the condition, used to describe a mild form with minimal or no symptoms. It’s important to know that this is an outdated term doctors largely consider inaccurate and potentially even dangerous. We talked with top experts about why benign MS is no longer used by clinicians, and what the current thinking is when it comes to understanding MS types and treatment.

A phenotype is the way MS presents in someone. There are three main types of MS:

• Relapsing-remitting MS (RRMS)

• Secondary progressive MS (SPMS)

• Primary progressive MS (PPMS)

RRMS is the most common phenotype. “It affects about 85% to 90% of people with MS at the onset of disease, and is prevalent in a younger population, 20s to 30s,” says Dr. Gyang.

With RRMS, people often experience an acute attack of neurologic symptoms. “They might not be able to see out of one eye, or one side of the body goes weak or numb, or they may have trouble walking or experience balancing issues,” says Dr. Gyang. “Typically, that happens very abruptly for days to a few weeks before they go into remission. In the future, they could have another attack that’s completely different from the first one.”

Someone who has had RRMS for a decade or longer may transition over time into secondary progressive MS. Dr. Gyang says this is a slow progression in baseline disability. “They may have trouble walking where they now need a cane or walker,” she says, adding that some people may progress to needing a wheelchair. There are also subsets within secondary progressive MS (such as active secondary progressive and nonactive).

The last major phenotype is primary progressive MS, which Dr. Gyang says accounts for 10% to 15% of people at the onset of disease. “From the get-go, these people never have any attack. They start off with very slow progression in some kind of disability, most often walking. They have maybe weakness on one leg that's very subtle. Then they start falling, and it progresses very slowly over time.”

You’ll notice in the phenotypes mentioned above, benign MS isn’t one of them. That’s because it’s a controversial term in the medical community, and one that many neurologists and MS specialists now steer away from.

“The way I think of the term benign MS is that its origins really were before there were any disease-modifying therapies (DMTs),” says Barry Hendin, M.D., the chief medical officer of the Multiple Sclerosis Association of America (MSAA) and a neurologist specializing in MS based in Phoenix, AZ. “There were no treatments for MS that changed the course of the disease until 1993. Before that time, only 5% of the MS population seemed to do fine without treatment and that was known as having benign MS.”

People with what used to be called benign MS often still had symptoms, but they were less intrusive in daily life that someone with more severe MS. “Benign MS implied that there was mild disability as measured by the Expanded Disability Status Scale (EDSS) after 10 to 15 years after diagnosis,” adds Dr. Hendin. The EDSS scores from zero to 10; benign MS was categorized as a three or less, he notes.

Because the word “benign” incorrectly signaled to people with MS that their disease required less management, doctors realized fewer of these people were therefore seeking treatment, raising the risk of disease progression. In the last decade, the term has been phased out of use by most reputable physicians. “With all the innovations and treatments that we have now, we don't want to not treat people adequately only for them to have an adverse outcome,” says Dr. Gyang. “We don’t want to under-treat because there’s some notion where we think they have a benign form of the disease. There are cases where people could appear to be stable, but there’s a lot of inflammation going on without having any larger symptoms.”

The problem with calling any type of MS benign is that although symptoms may be milder than in more advanced stages of the disease, there are still significant challenges in managing the condition. “These people may walk OK and have good coordination, but they may suffer from cognitive symptoms,” says Dr. Hendin.

According to Dr. Hendin, some symptoms of mild MS include:

• Anxiety

• Cognitive dysfunction, including problems with memory, focus, and concentration.

• Depression

• Fatigue

• Vision problems

Although the term “benign MS” is no longer used among clinicians today, in the years prior to modern treatment, it was a way of distinguishing between lesser and more severe symptoms.

“We’re now in a treatment era,” says Dr. Hendin. “We’ve moved on from when there was only one agent, Betaseron (interferon beta-1b) to now more than 25 agents, with more on the horizon.” In fact, with today’s DMTs, many people with MS are able to live with minimal to no symptoms for years. “After 10 to 15 years post-MS diagnosis on these high-efficacy therapies, people are doing quite well in terms of motor functions and performing in society,” he adds.

Dr. Hendin notes some people who have milder physical symptoms may still be dealing with cognitive symptoms like fatigue and mood issues. No matter the severity of your symptoms, if you’ve been diagnosed with MS, it’s important to make sure you are receiving treatment, adds Dr. Gyang. “Once a disability from MS sets in, there’s no way to reverse it,” she notes. “If you classify someone as having benign MS and they don’t get treatment for decades, they may end up with a progressive form later in life, such as having to use a wheelchair. That leads to the question no one wants to ask: Could a doctor have prevented that by treating them from the start?”

Certain aspects of MS can stay mild for many years, says Dr. Hendin. When discussing disability, specialists use two terms: relapse associated worsening (RAW) and progression independent of relapse activity (PIRA). With PIRA, the concept is that progression is present in all forms of MS, whether or not there are noticeable relapses.

“We’ve gotten much better with reducing relapses,” says Dr. Hendin. “The newest agents reduce the likelihood of a relapse to maybe one every 10 years. But what we haven’t done a good job with is reducing PIRA, which is the degenerative aspects of MS.” This includes lesion and plaque buildup, neurodegeneration, nerve damage, and more.

In fact, PIRA causes disability more often than RAW–47.3% compared to 26.9%—in people with RRMS, according to research in NEJM Journal Watch. In secondary progressive MS, PIRA sustained disability was present in 77.7% of patients, and in primary progressive MS the number was 83.4%.

Additional research published in Brain states that PIRA begins early in RRMS, and while RAW can contribute to disabilities over time, the use of disease-modifying therapies can delay relapses, making PIRA the dominant driver for disabilities.

But there is some good news: A new group of medicines called Bruton's tyrosine kinase (BTK) inhibitors has recently been successfully trialed, according to Dr. Hendin. While not yet approved by the Food and Drug Administration (FDA), these drugs have shown progress in slowing down PIRA activity.

Changing the perception of life with MS starts by tossing out incorrect terminology, and in recent years, the idea of benign MS has been dismissed by doctors who realize all MS is serious and requires treatment. As a result, more people today experience mild symptoms due to appropriate management of their disease.

“Before 1993, too many people with MS experienced too much disability,” says Dr. Hendin. “There wasn’t much a specialist could do. Over the past 30 years we've developed therapies that create much better outcomes for people with MS with less disability, even 10 to 15 years after a diagnosis.”

Dr. Hendin adds that an increased focus on overall health habits is also helping those with MS better manage their symptoms. “We are smarter in non-pharmacologic therapies, concentrating on eating better, exercising more, general wellness, and brain health,” he says. “We are now able to help people avoid and delay serious disability over their adult years.”