What Are the Stages of Multiple Myeloma?

What “staging” means in multiple myeloma

In many cancers, staging is mostly about where the cancer is and how far it has spread (think: tumor size and lymph nodes).
Multiple myeloma is different. It’s a blood and bone marrow cancer, so it doesn’t behave like a single lump that “moves” from Point A to Point B.

In myeloma, staging is less about geography and more about a mix of:

• Disease burden (how much myeloma is affecting the body)
• Disease biology (how aggressive the myeloma appears at a cellular/genetic level)
• Organ impact (especially kidneys, blood counts, and bones)

Bottom line: the “stage” helps estimate prognosis and guide conversations about treatment intensity, but it’s not a fortune cookie.
Two people can have the same stage and very different treatment journeysbecause myeloma is, politely speaking, a bit of an individualist.

The main system today: R-ISS staging (Stages 1–3)

Most U.S. cancer centers stage newly diagnosed multiple myeloma using the Revised International Staging System (R-ISS).
It’s widely used because it blends “how much disease” with “how risky the biology looks.”

The four R-ISS factors (the lab-and-genetics squad)

R-ISS staging uses four main pieces of information:

• Beta-2 microglobulin (B2M): a blood marker that often rises with higher myeloma burden and/or reduced kidney function.
• Albumin: a blood protein; lower levels can be linked with more inflammation and worse outcomes.
• LDH (lactate dehydrogenase): an enzyme; high LDH can signal more aggressive disease behavior.
• Cytogenetics (FISH/genetic changes): certain chromosome abnormalities are considered “high risk.”

R-ISS Stage 1: Lower risk profile

Stage 1 generally means the key markers look more favorable: lower B2M, normal LDH, and no “high-risk” cytogenetic findings.
Many people hear “Stage 1” and think, “So I’m fine, right?” Think of it more like: the numbers suggest the myeloma may be less aggressive.
It still needs careful management, and symptoms can still exist.

A common Stage 1 pattern looks like:

• B2M under 3.5 mg/L
• Albumin 3.5 g/dL or higher
• Normal LDH
• No high-risk cytogenetics

R-ISS Stage 2: The “middle bucket” (and yes, it’s broad)

Stage 2 is assigned when the disease doesn’t clearly fit Stage 1 or Stage 3.
This makes Stage 2 a large and diverse groupkind of like “miscellaneous” in your kitchen drawer.
Some Stage 2 cases behave closer to Stage 1, while others act more like Stage 3, depending on other risk factors and response to therapy.

If you’re Stage 2, don’t settle for vague explanations. Ask what pushed the staging into Stage 2:
Was it B2M? LDH? A borderline lab? A genetic finding? The details matter.

R-ISS Stage 3: Higher risk features and/or higher burden

Stage 3 typically indicates higher B2M and either high-risk genetics, high LDH, or both.
It often correlates with more aggressive disease behavior and can require more urgent or intensive treatment planning.

A common Stage 3 pattern includes:

• B2M 5.5 mg/L or higher
• High-risk cytogenetics and/or high LDH

R-ISS staging table (quick reference)

Which genetic changes count as “high risk” in R-ISS?

In plain English: doctors look at the chromosomes in myeloma cells (often via FISH testing on bone marrow samples).
Certain findings have been linked to worse outcomes, including:

• Deletion of part of chromosome 17 (often called del(17p))
• Translocation t(4;14)
• Translocation t(14;16)

Not every genetic abnormality is “high risk” in the R-ISS definition.
That’s one reason your oncologist may also talk about risk stratification beyond stage.

A note you may see: “R2-ISS”

Some centers are evaluating newer refinements (such as a “second revised” system) to split the big Stage 2 group into smaller risk categories.
If you see this on a report, it doesn’t mean your staging was “wrong”it means experts are trying to become more precise.

Example: How staging might look in real life

Here are simplified examples (not meant for self-diagnosis, but to make the logic less mysterious):

• Example A (often Stage 1): B2M 2.9 mg/L, albumin 4.0 g/dL, LDH normal, FISH shows no high-risk findings.
  This points to a more favorable R-ISS profile.
• Example B (often Stage 3): B2M 6.2 mg/L plus either high LDH or a high-risk FISH result like del(17p).
  This lands in the higher-risk bucket.
• Example C (often Stage 2): B2M 4.2 mg/L, albumin 3.4 g/dL, LDH normal, standard-risk genetics.
  Not Stage 1, not Stage 3so it becomes Stage 2.

The original ISS staging (still shows up in reports)

Before R-ISS, the International Staging System (ISS) was the go-to approach. You’ll still see it because it’s simple and widely recognized.
ISS is based on two blood tests:

• Beta-2 microglobulin (B2M)
• Albumin

ISS Stage 1

Lower B2M and higher albumin. In many summaries, it’s listed as B2M < 3.5 mg/L and albumin ≥ 3.5 g/dL.

ISS Stage 2

Middle rangepatients who don’t fit the Stage 1 or Stage 3 definitions.

ISS Stage 3

Higher B2M (often defined as ≥ 5.5 mg/L).

Why ISS isn’t the whole story: ISS doesn’t include LDH or genetics, which can be crucial for understanding aggressiveness.
That’s why R-ISS took over as the more modern tool.

The older Durie-Salmon staging (tumor burden-focused)

The Durie-Salmon Staging System is older but still comes up in some discussions and resources.
It focuses on tumor burden and the body’s measurable “wear and tear,” using things like:

• Hemoglobin level (anemia severity)
• Calcium level (a clue to bone breakdown)
• Bone lesions on imaging
• Monoclonal (M) protein levels in blood/urine
• Kidney function subclassification (A vs B in some versions)

Durie-Salmon Stage 1 (low tumor burden)

Generally includes a higher hemoglobin, normal/near-normal calcium, limited bone damage, and lower M protein production.

Durie-Salmon Stage 2

The in-between category: fits neither Stage 1 nor Stage 3.

Durie-Salmon Stage 3 (high tumor burden)

Includes one or more stronger signals of heavy disease burdenmore anemia, higher calcium, more extensive bone lesions, or higher M protein levels.

Why many clinicians prefer R-ISS now: Durie-Salmon can be more complex and doesn’t capture the genetic “personality” of the myeloma as directly.
It’s helpful historically and conceptually, but R-ISS tends to be more practical for prognosis discussions today.

MGUS, smoldering myeloma, and when myeloma becomes “active”

When people ask about “stages,” they sometimes mean something different from R-ISS staging.
They might be asking: Is this early? Is it active? Do I need treatment now?

MGUS (Monoclonal Gammopathy of Undetermined Significance)

MGUS isn’t cancer, but it can be a precursor condition where an abnormal monoclonal protein is present.
Most people with MGUS never develop myeloma, but it requires monitoring.

Smoldering multiple myeloma (SMM)

Smoldering myeloma sits between MGUS and active myeloma. It typically involves higher M protein and/or more plasma cells in the bone marrow,
but without the organ damage that defines symptomatic myeloma.
Monitoring can be intense, because the risk of progression is higher than in MGUSespecially in higher-risk smoldering cases.

Active (symptomatic) multiple myeloma: CRAB and SLiM criteria

Modern diagnostic criteria recognize that some patients are at such high risk of near-term organ damage that treatment should begin
before classic complications become severe.

Traditionally, doctors looked for CRAB features (organ damage attributed to myeloma):

• Calcium elevation (hypercalcemia)
• Renal (kidney) dysfunction
• Anemia
• Bone lesions

Updated criteria also include certain “myeloma-defining events” sometimes summarized as SLiM:

• S: ≥ 60% clonal plasma cells in bone marrow
• Li: involved/uninvolved free light chain ratio ≥ 100 (with involved light chain high enough)
• M: more than one focal lesion on MRI (each typically at least 5 mm)

These features don’t replace stagingthey help determine whether myeloma is “active” and needs treatment now.
After diagnosis of active myeloma, R-ISS staging helps estimate prognosis.

What your stage doesand doesn’ttell you

What staging helps with

• Prognosis discussions: staging provides a standardized way to talk about expected outcomes across large groups.
• Clinical trial matching: many trials stratify results by stage or risk.
• Planning intensity: stage and risk features may influence how aggressive treatment needs to be and how closely doctors monitor you.

What staging does NOT fully capture

• Your symptoms and organ function today: two patients with the same stage can feel wildly different.
• Response to treatment: how quickly and deeply the disease responds can be as important as initial stage.
• Other biologic details: additional genetic changes (beyond the “big three” high-risk markers) can matter.
• Your overall health: age, fitness, other medical conditions, and frailty influence treatment options.

Think of staging as a map. It’s usefulbut it’s not the weather forecast, the road conditions, and your car’s gas tank all at once.
You need the full dashboard.

Questions to ask your doctor about your myeloma stage

If you want to get the most out of your staging appointment (and avoid leaving with 17 new acronyms and no clarity),
consider asking:

• Which staging system are we usingR-ISS, ISS, or something else?
• What were my key numbers (B2M, albumin, LDH), and what do they suggest?
• What did my FISH/cytogenetic tests show? Do I have any high-risk abnormalities?
• Do I have CRAB or SLiM criteria that define active disease?
• How does my stage affect my recommended treatment plan right now?
• What monitoring schedule makes sense for my situation?
• Should I consider a second opinion at a myeloma specialty center?

Bonus tip: ask for a copy of your key labs and pathology summary. Myeloma care is a marathon, and having your data helps you stay oriented.

Patient & caregiver experiences: what staging feels like (and what people wish they’d known)

The clinical definition of “stage” is clean: lab values, genetics, criteria, categories. The lived experience is… less tidy.
People often describe the staging conversation as the moment myeloma becomes “real,” even if symptoms started months earlier.
You can feel oddly calm during the appointment, then get hit laterwhile microwaving leftoversby the thought:
Wait. What does Stage 2 actually mean for me?

One of the most common experiences is confusion between stage and severity today.
A person with Stage 1 can still have real symptomsbone pain, fatigue, infectionsbecause stage reflects a risk profile, not a daily comfort rating.
Meanwhile, someone with Stage 3 may respond beautifully to therapy and feel better faster than expected.
Many patients say the best emotional “upgrade” came when their doctor explained that myeloma is treated based on a combination of
stage, symptoms, organ function, and responsenot a single number.

Another common theme: the shock of Stage 2. Because Stage 2 is a broad category, patients often report leaving with a frustratingly vague sense of where they stand:
“Not the best, not the worst.” Some describe it as getting graded “average” without seeing the rubric.
In practice, people feel more grounded when they learn which factor nudged them into Stage 2.
For example, if B2M is modestly elevated but LDH is normal and genetics are standard-risk, the outlook may differ from a case where
LDH is high or a high-risk cytogenetic abnormality is present.
Patients frequently say that understanding the why behind the stage turned anxiety into a plan.

Caregivers often experience staging as a sudden shift into project-manager mode. There are labs to track, appointments to schedule,
medications to organize, and insurance calls that could qualify as an endurance sport.
Many caregivers say the staging details helped them prioritize: “Okay, if this is higher risk, we’ll push harder for a specialist consult,”
or “If this is lower risk, we still take it seriously, but we breathe a little and focus on building routines.”
The most helpful reframing caregivers mention is: staging is information, not a verdict.

People also talk about the “acronym fatigue.” CRAB. SLiM. R-ISS. FISH. LDH. It can feel like your health became a group chat you weren’t invited to.
A practical tip many patients share: bring a notebook (or your phone notes) and ask the clinician to write down the stage criteria in plain language.
Some even ask, “If my best friend had this diagnosis, how would you explain their stage in one minute?”
That single question often triggers the clearest explanation of the day.

Finally, many long-term survivors say the biggest mindset shift was realizing that myeloma care evolves.
Staging is often done at diagnosis, but your disease course is also shaped by response, maintenance strategies, and new therapies.
Hearing your stage can be scarybut it can also be empowering: it’s a starting point for personalization.
Patients frequently describe a moment, weeks after diagnosis, when they stop asking only “What stage am I?”
and start asking “What’s our strategy?” That’s when the numbers become tools instead of threats.

Wrap-up

The stages of multiple myeloma are most commonly defined using the R-ISS staging system, which places patients into Stage 1, 2, or 3
based on B2M, albumin, LDH, and cytogenetic risk. The older ISS system (B2M + albumin) and the Durie-Salmon system (tumor burden/organ impact)
may still appear in resources or records.

If there’s one takeaway to keep: staging matters, but it’s not the whole story.
Your symptoms, organ function, genetics, and response to therapy all shape what happens next.
Ask questions, get clarity on your specific numbers, and don’t hesitate to request explanations in everyday language.
Myeloma is complexbut your understanding of it doesn’t have to be.