Multiple myeloma is a type of blood cancer that starts inside a bone. Like other types of cancers, myeloma can spread to other parts of the body in stages. In a process known as staging, doctors can assess how far cancer has spread.
Myeloma is cancer that forms in a type of white blood cell, known as a plasma cell. The spongy tissue inside bones, known as bone marrow, makes healthy plasma cells. However, as with other cancers, these cells can become abnormal and start dividing rapidly. This causes too many plasma cells to accumulate inside the bone marrow, which can cause tumors to develop.
At first, the abnormal cells reproduce in the bone marrow of your spine. From there, the cells enter your bloodstream and travel to bone marrow in other parts of your body. Once inside another bone, the cells can collect in the marrow of the bone or in the bone’s hard outer part to cause multiple tumors.
Your doctor or oncologist may diagnose multiple myeloma when plasma cells account for 10% or more of all the cells in your bone marrow, or when you have multiple tumors.
After you receive a diagnosis of multiple myeloma, your oncologist will determine how far your blood cancer has spread. This staging process helps your doctor create your treatment plan. Multiple myeloma in its early stage responds to different treatments than it does at a later stage.
As multiple myeloma progresses, it begins to affect your bones or kidneys. When staging multiple myeloma, then, your doctor will perform a number of tests to evaluate the health of your bones or kidneys. The staging helps your doctor develop a treatment plan.
When staging your multiple myeloma, your doctor will order several blood tests, including the levels of serum albumin and beta-2 microglobulin (β2-M). Albumin is a protein that transports various substances in your blood; a low albumin level can indicate a problem in your liver or kidneys
Your doctor might measure the level of Beta-2-microglobulin, also known as β₂ microglobulin or β2-M. Cancer cells like myeloma shed β2-M into the bloodstream, so high levels of β2-M suggest the presence of cancer.
The oncologist might order an LDH level. Serum lactate dehydrogenase (LDH) is a protein that helps your body make energy. Nearly all body tissues, including those in the kidneys, contain LDH. When damaged, these tissues release LDH into the blood. This makes LDH a reliable biomarker, or indicator, of tissue damage.
Your doctor may order other blood tests measuring your kidney function or your platelets, which are a type of blood cells that stops bleeding.
Your doctor might also order imaging studies that create detailed pictures of your bones. These imaging studies may include computed tomography (CT) and magnetic resonance imaging (MRI). Imaging tests are painless and typically take an hour or less to perform.
Patients with multiple myeloma may not experience common symptoms, which may include bone pain in the spine or chest, constipation, loss of appetite and weight loss, frequent infections, mental fogginess or confusion. Patients who are in the earlier stages of multiple myeloma are frequently symptom-free.
Patients with no symptoms are often in the earlier stages of the disease and may be in one of the following stages:
Smoldering is the earliest stage of multiple myeloma. People with smoldering myeloma are often symptom- free. They may not show any signs of the disease, such as bone damage. At this stage, your oncologist will likely recommend “watchful waiting,” in which your doctor watches your condition closely. Your cancer doctor may suggest a therapy to slow the growth of blood cancer cells. Your physician will likely recommend that you undergo testing every three months to monitor the development of tumors in your bones and signs of kidney problems.
During Stage I, your β2-M will be less than 3.5 mg/L and your serum albumin will measure 3.5 g/dL or more. If you are still symptom-free, your oncologist may recommend continued watchful waiting and monitoring. Your cancer doctor may recommend treatment if you have symptoms during Stage I.
Your lab results may change when you enter Stage I. Multiple myeloma may damage your kidneys in ways that prevent them from clearing calcium from your bloodstream; this causes your calcium levels to go up. Calcium levels in blood, known as serum calcium levels, are normally 2.2 to 2.7 mmol/L. You may be in Stage I if your serum calcium levels are greater than 2.75 mmol/L.
Damage from multiple myeloma can also prevent the kidneys from clearing creatinine from your bloodstream. Creatinine is a waste product produced by your muscles. You may be in Stage I if your creatinine level is higher than normal.
Multiple myeloma often interferes with the blood-making activities of bone marrow, which can prevent your body from making the red blood cells (RBCs) it needs. RBCs contain hemoglobin, a protein that transports oxygen from your lungs to the various tissues in your body, and carries carbon dioxide from your body cells to your lungs. Anemia is a condition in which there is not enough hemoglobin to deliver oxygen to your body cells or carry away carbon dioxide. You may be in Stage I multiple myeloma if your hemoglobin level is lower than 10 g/dL.
Myeloma can cause areas of bone damage, known as lytic lesions, in Stage I. The blood cancer can also cause osteoporosis, or thinning of the bone. Furthermore, multiple myeloma can cause a compression fracture of the spine, which is a condition where the bones of the spine collapse.
In Stage II, the blood cancer is spreading to cause multiple symptoms. You enter Stage II when your β2-M is between 3.5 mg/L and 5.5 mg/dL or when your albumin is less than 3.5 g/dL.
In Stage III multiple myeloma, blood cancer is in several parts of your body and you will likely experience complex symptoms. You enter Stage III when your β2-M is greater than 5.5 mg/L.
Because multiple myeloma spreads through your bloodstream, it can reach different parts of your body quickly, which makes this form of cancer difficult to treat. Staging helps your cancer doctor create the best treatment plan for your stage of multiple myeloma.