Multiple Myeloma and Its M Protein Spike: Crucial Information
Smoldering multiple myeloma (SMM) is an intermediate stage between monoclonal gammopathy of undetermined significance (MGUS) and active multiple myeloma (MM). This condition, while not yet symptomatic, is characterised by higher levels of abnormal plasma cells or monoclonal protein than MGUS [1][2].
Unlike active multiple myeloma, SMM patients do not exhibit common symptoms such as bone pain, fractures, anemia, kidney problems, high calcium levels, infections, fatigue, or neurological issues [3][5]. However, it's important to note that asymptomatic organ damage may begin and progress without clinical signs in SMM patients [3]. Approximately 15% of newly diagnosed myeloma cases are SMM, and among high-risk SMM patients, around 50% progress to active MM within two years [3].
In contrast, active multiple myeloma is characterised by malignant plasma cell proliferation causing symptomatic organ damage. Symptoms include bone destruction leading to pain and fractures, anemia causing fatigue, kidney failure, hypercalcemia, recurrent infections, and neurological complications such as neuropathy, spinal cord compression, or hyperviscosity symptoms (headache, confusion) [3][5]. Multiple myeloma generally requires treatment once symptomatic, whereas SMM is closely monitored until progression or symptoms appear [1][2].
The progression risk for SMM is significantly higher than that of MGUS, with about a 5-10% yearly risk of progression to active myeloma during the first five years [1]. This necessitates regular follow-up and monitoring for SMM patients.
The key differences between SMM and active MM can be summarised as follows:
- Symptoms: None in SMM; active MM presents with bone pain, anemia, kidney issues, infections, and neurological symptoms.
- Organ damage: None clinically evident in SMM; present and symptomatic in active MM.
- Plasma cell burden: Intermediate in SMM; higher and malignant in MM.
- Progression risk: Elevated in SMM versus MGUS, warranting careful observation until MM develops [1][2][3].
This distinction guides management: SMM patients undergo watchful waiting, while active MM patients receive therapies to control symptoms and disease progression [1][3].
Diagnosing multiple myeloma often involves checking for M proteins, antibodies found in the blood that can indicate multiple myeloma or other plasma cell disorders. The five types of heavy chains in M proteins are immunoglobulin A (IgA), immunoglobulin M (IgM), immunoglobulin E (IgD), immunoglobulin G (IgG), and immunoglobulin D (IgE) [6]. People with MGUS can have M protein in their blood, but it does not cause any harm and usually causes no symptoms [6].
A doctor may use serum and urine protein electrophoresis, blood tests, urine tests, serum free light chain assay test, and serum heavy/light chain assay test to check for M proteins in the blood [6]. SMM is a precursor to multiple myeloma and may not show symptoms, but a doctor will monitor the person closely [7]. Many cases of MGUS will never progress to multiple myeloma [7].
SMM, a condition that is not considered cancer, occurs when plasma cells increase in the individual bone marrow [8]. IgG and IgA are the most common types of myeloma, with IgG occurring in about 60% of people [9]. People with IgM myeloma may have a rare type of cancer called Waldenstrom macroglobulinemia [9]. M proteins only making light chains can cause light chain myeloma, which affects about 10% of people with multiple myeloma [9].
Occasionally, traditional methods may not detect IgA myeloma, so it may not show up as an M spike [10]. Some doctors may treat SMM to delay progression to multiple myeloma [11]. M proteins always produce the same types of cells, meaning if a person has IgA heavy chains and kappa light chains, all of their proteins will be IgA kappa [12]. The two types of light chains in M proteins are kappa and lambda [12].
High levels of M proteins can indicate multiple myeloma, solitary plasmacytoma, smoldering multiple myeloma (SMM), light chain amyloidosis, or monoclonal gammopathy of undetermined significance (MGUS) [13]. M proteins are made up of chains, typically two heavy chains and two light chains, but in myeloma, they can be made up of one type of heavy chain and one type of light chain [13]. If the tests show M protein in the blood, a doctor may recommend further tests [14].
MGUS, a noncancerous condition, affects about 3% of people over 50 years of age [15]. M proteins are not helpful to the body and can multiply and build up in the bloodstream, leading to organ dysfunction [15].
In conclusion, understanding the differences between SMM and active MM, as well as the diagnostic and monitoring processes, is crucial for effective management of these conditions. Regular check-ups and close monitoring are essential for SMM patients, as they are at a higher risk of progressing to active MM.
- Smoldering multiple myeloma (SMM) and active multiple myeloma have different symptoms, with SMM being asymptomatic and active MM presenting symptoms like bone pain, anemia, kidney issues, infections, and neurological symptoms.
- Unlike active multiple myeloma, organ damage in SMM may begin and progress without clinical signs, making regular follow-up and monitoring important.
- The progression risk for SMM is significantly higher than that of monoclonal gammopathy of undetermined significance (MGUS), with around 15% of newly diagnosed myeloma cases being SMM.
- Diagnosing multiple myeloma involves checking for M proteins, which can indicate multiple myeloma or other plasma cell disorders, and the five types of heavy chains in M proteins are immunoglobulin A (IgA), immunoglobulin M (IgM), immunoglobulin E (IgD), immunoglobulin G (IgG), and immunoglobulin D (IgE).
- IgG and IgA are the most common types of myeloma, and M proteins always produce the same types of cells, meaning if a person has IgA heavy chains and kappa light chains, all of their proteins will be IgA kappa.
- High levels of M proteins can indicate multiple myeloma, solitary plasmacytoma, smoldering multiple myeloma, light chain amyloidosis, or monoclonal gammopathy of undetermined significance (MGUS).
- MGUS is a noncancerous condition that affects about 3% of people over 50 years of age, and M proteins, which are not helpful to the body, can multiply and build up in the bloodstream, leading to organ dysfunction.
- In contrast to SMM, which occurs when plasma cells increase in the bone marrow, cancer primarily involves uncontrolled cell growth in various parts of the body, including solid organs and the blood and immune system.
- In addition to multiple myeloma and MGUS, other medical conditions such as ankylosing spondylitis, psoriatic arthritis, HIV, hepatitis, diabetes, obesity, dermatitis, and atopic dermatitis are also relevant to health and wellness, along with mental health issues like asthma, predictive factors, and sciences like AQ (autism-spectrum quotient).
