One of the first questions many people with systemic mastocytosis (SM) ask after diagnosis is how the disease will affect their lifespan. As with many aspects of SM, there’s no one answer. It’s different for everyone, because it depends on a handful of separate factors.
Why life expectancy in SM varies
The life expectancy of someone living with SM can vary significantly because it depends on a number of different factors. Subtype, overall health, other existing diseases and how successfully you’re able to control symptoms all influence how long you can live with SM.
A patient diagnosed with a nonadvanced form of the disease who responds well to treatment and prioritizes a healthy lifestyle can generally live a normal lifespan, while someone diagnosed with an advanced form of the disease might only live a few years, even with treatment.
Read more about SM prognosis
How each SM subtype affects life expectancy
When diagnosed with SM, your disease will receive a subtype classification. The 2016 WHO classification includes five subtypes, categorized into a nonadvanced group and an advanced group. Each one means a different prognosis for your health.
Nonadvanced subtypes
The most common subtype of SM is indolent systemic mastocytosis (ISM), which is generally mild and doesn’t affect life expectancy. Found in 90% to 95% of people living with SM, in ISM mast cells are slow to accumulate and organs are less severely impacted.
Compared to ISM, smoldering systemic mastocytosis (SSM) causes more damage to the organs. While it can remain stable for a number of years, it can slowly progress to a more advanced form of SM, so patients need careful monitoring. Life expectancy can be affected, especially if the disease progresses to a different subtype.
Advanced subtypes
Aggressive systemic mastocytosis (ASM) is marked by debilitating symptoms and organ dysfunction. It heavily impacts lifespan: the median survival rate for people living with ASM is 5.7 years.
Systemic mastocytosis with an associated hematological neoplasm (SM-AHN) affects one in five SM patients, and means SM occurs alongside an associated blood malignancy. Its prognosis can differ based on the specific blood malignancy: life expectancy can vary from 11 months to 31 months.
Mast cell leukemia, the most aggressive form of SM, is very rare; it affects less than 1% of SM cases. Life expectancy can be as low as a few months following diagnosis.
How lifestyle changes and medication affect lifespan
How well a patient controls SM also has a major impact on their lifespan.
Following a diagnosis, you will quickly become familiar with the different physical, emotional and environmental triggers of SM. When mast cells are activated, the chemicals they release don’t just provoke symptoms — they also damage the organs. This means that controlling symptoms through medications and by avoiding triggers helps your health both now and in the long term.
For the best chance at a longer, healthier life, stay on top of your medications and avoid contact with symptom triggers. Seeing a specialist for care and prioritizing your overall health can also make a difference.
Sign up here to get the latest news, perspectives, and information about SM sent directly to your inbox. Registration is free and only takes a minute.
