Blood Cancer

Multiple Myeloma, a Type of Blood Cancer

Plasma cell myeloma, also known as multiple myeloma, is a cancer of the bone marrow.

What Is Multiple Myeloma?

Multiple myeloma is a type of blood cancer that starts in plasma cells; white blood cells found in your bone marrow, which is the soft, spongy tissue inside your bones. Plasma cells help your body fight infections by producing antibodies. In multiple myeloma, these cells become abnormal, multiply uncontrollably, and crowd out healthy blood cells. They also produce a faulty antibody called monoclonal protein (or M-protein), which builds up in the body and causes damage.

Multiple myeloma affects the immune system and bones. Healthy plasma cells make helpful antibodies, but cancerous plasma cells make large amounts of a single, abnormal antibody (M-protein), which cannot fight infections and instead harms organs.

This disease can:

Decrease normal blood cell production, leading to fatigue, infections, and bleeding issues
Damage bones and cause fractures
Lead to kidney failure from protein buildup
Weaken your immune system

How Multiple Myeloma Affects the Body

1. Low Blood Counts, When plasma cells overtake your bone marrow, they stop your body from making enough healthy blood cells:

Anemia (low red blood cells): Causes tiredness, weakness, and shortness of breath
Thrombocytopenia (low platelets): Increases risk of bruising and bleeding
Leukopenia (low white blood cells): Makes you more likely to get infections

2. Bone and Calcium Problems

Healthy bones are constantly being broken down and rebuilt. Myeloma cells speed up the breakdown but stop new bone from forming.
This leads to bone pain, fractures, and osteolytic lesions (weakened areas in the bone).
Bone breakdown releases calcium into the blood (hypercalcemia), which can cause nausea, constipation, confusion, and dehydration.

3. Weakened Immune System: Cancerous plasma cells make abnormal antibodies that don’t fight infections, and they crowd out healthy cells that do. This increases your risk of getting sick.

4. Kidney Problems: The abnormal M-protein can collect in your kidneys and damage them. Over time, this may lead to kidney failure.

Plasma Cell Disorders

Not all abnormal plasma cell conditions are full-blown myeloma. Some are earlier stages or related diseases:

1. Monoclonal Gammopathy of Undetermined Significance (MGUS)

A condition where abnormal plasma cells produce M-protein but don’t cause symptoms or damage.
MGUS is not cancer, but it can develop into multiple myeloma over time.
Risk of progression: about 1% per year

2. Smoldering Multiple Myeloma (SMM)

A more advanced condition than MGUS, but still without symptoms.
Has higher levels of M-protein or plasma cells in the bone marrow.
Requires regular monitoring because it can progress to active myeloma.

3. Solitary Plasmacytoma

A single tumor made of abnormal plasma cells, often found in bone.
Treated with radiation or surgery.
May develop into multiple myeloma later, so patients are monitored.

4. Light Chain Amyloidosis (AL Amyloidosis)

Caused by excess light chains (a part of antibodies) building up in organs like the heart and kidneys.
Can lead to heart failure, kidney damage, and other problems.
Treated similarly to myeloma.

Causes and Risk Factors

Multiple myeloma usually begins as a condition called monoclonal gammopathy of undetermined significance (MGUS). In MGUS, abnormal plasma cells make M-proteins but do not cause damage. Around 1% of people with MGUS go on to develop myeloma each year.

Multiple myeloma occurs when a genetic mutation changes a healthy plasma cell into a myeloma cell. This mutated cell begins multiplying rapidly and avoids dying when it should. Over time, these cells crowd out healthy cells in the bone marrow and release large amounts of M-protein, which harms organs like the kidneys and bones.

These gene changes are usually not inherited, meaning they do not run in families. Most develop spontaneously over time, which may explain why multiple myeloma is more common in older adults.

Scientists believe certain risk factors may increase your chances of developing multiple myeloma:

Age: Most people are diagnosed in their late 60s or older
Sex: More common in men than in women
Ethnicity: Higher rates in people of African descent
Family history: Having a close family member with myeloma slightly increases your risk
MGUS: People with MGUS are at higher risk of developing myeloma
Exposure to radiation or certain chemicals: May increase mutation risk, although this is less common

It's important to know: Nothing you did caused this disease, and there's currently no known way to prevent it.

Symptoms of Multiple Myeloma

Many people don’t notice symptoms early on. As the disease progresses, symptoms may include:

Bone pain (especially in the back or ribs)
Fatigue (due to anemia)
Frequent infections (due to low white blood cells)
Kidney problems (caused by protein buildup)
Unexplained weight loss
Thirst, nausea, confusion (caused by high calcium levels)
Numbness or weakness (if the spine is affected)

Diagnosis

Doctors use several tests to diagnose multiple myeloma:

1. Blood Tests: Look for M-protein, high calcium, low blood counts, and signs of kidney damage

2. Urine Tests: Check for light chains (also called Bence Jones proteins)

3. Bone Marrow Biopsy: A sample of bone marrow is tested to measure the percentage of plasma cells and check for genetic abnormalities

4. Imaging Tests: X-rays, MRI, CT, or PET scans are used to look for bone damage or tumors

Staging

Doctors use the Revised International Staging System (R-ISS) to describe how advanced the disease is:

Stage I: Low M-protein levels, normal blood markers, no high-risk genetic changes
Stage II: Moderate markers, doesn’t meet Stage I or III exactly
Stage III: High M-protein levels, high-risk genes, or high LDH levels

Treatment Options

Treatment depends on your symptoms, stage of disease, and overall health.

Common Treatments for Active Myeloma:

Chemotherapy: Drugs that kill cancer cells throughout the body
Corticosteroids (like dexamethasone): Help reduce inflammation and kill myeloma cells
Immunomodulatory drugs (IMiDs): Help the immune system find and kill cancer cells (e.g., lenalidomide, thalidomide)
Proteasome inhibitors: Stop myeloma cells from breaking down waste, causing them to die (e.g., bortezomib, carfilzomib)
Monoclonal antibodies: Lab-made proteins that target myeloma cells and help the immune system destroy them (e.g., daratumumab)
Stem Cell Transplantation: Healthy stem cells are used to rebuild bone marrow after high-dose chemo
Bisphosphonates: Help protect bones from breaking down

For Relapsed or Refractory Myeloma: