By: Bo Zhao, MD, PhD
Monoclonal gammopathy is a medical condition caused by abnormal proteins in the blood. These proteins grow from a small number of plasma cells, a type of white blood cell, found in the bone marrow. The most common condition linked with these abnormal proteins is monoclonal gammopathy of undetermined significance (MGUS). It is not cancer but does put these patients in a higher risk category for developing cancer in the blood or bone marrow.
MGUS is somewhat common, affecting about 3% of people over age 50. Risk for the condition, which is more common in men, climbs with age, reaching 3% for ages 60 to 69, greater than 4% for ages 70 to 79, and 6% for those ages 80 and above.
MGUS can be a precursor of multiple myeloma, or a lymphoproliferative disorder such as lymphoplasmacytic lymphoma (Waldenström Macroglobulinemia), marginal zone lymphoma, or chronic lymphocytic leukemia. It is often diagnosed during the work up of chronic kidney disease (CKD) or peripheral neuropathy.
Besides cancer, there are other medical conditions that can be caused by MGUS including nerve damage, kidney damage, or a weakened heart.
How Do Doctors Identify MGUS in Their Patients?
Sometimes, identifying the problem can be di cult because symptoms are very subtle, not present, or could be associated with other conditions. For example, in patients with underlying hypertension and diabetes, progression of chronic kidney disease may or may not
be related to MGUS.
In addition, rare conditions such as systemic capillary leak syndrome, TEMPI syndrome, or some skin manifestations are underdiagnosed unless evaluation of the M-protein is specifically pursued.
Symptoms of MGUS
Most MGUS patients will experience no symptoms.
Multiple Myeloma
In cases where MGUS progresses to multiple myeloma, a bone marrow cancer, common problems include anemia, kidney damage, high blood calcium level, and bone fractures.
Lymphoma
For MGUS that progresses into lymphoma, symptoms may include a persistent low-grade fever, night sweats, or progressive lymphadenopathy (persistent swelling of the lymph nodes).
Waldenström Macroglobulinemia
Patients with Waldenström Macroglobulinemia may develop a bleeding diathesis (bruising or bleeding easily), vision problems, and neurologic symptoms (ie, headaches, dizziness).
In recent years, a novel concept of monoclonal gammopathy of clinical significance (MGCS) has been developed to provide some guidance for physicians. The National Comprehensive Cancer Network (NCCN) guidelines also included monoclonal gammopathy of renal significance (MGRS) and monoclonal gammopathy of neurologic significance (MGNS). Recognizing these categories and related findings will help physicians avoid missed cases of MGCS.
Watchful Waiting for MGUS Patients
Most MGUS cases will not progress to cancer. For instance, about 1% of MGUS patients a year progress to myeloma. Since progression to cancer typically happens slowly, watchful waiting is often the chosen approach.
There is no specific treatment right now for MGUS. Rather, regular follow-up is done as part of watchful waiting. Visiting the doctor every three to six months is typically recommended to start.
Each visit should include a physical, review of symptoms, blood work, and/or urinalysis to monitor changes. Depending on test results and protein levels in individual patients, the risk of progression to a cancerous condition can be determined. If at a higher risk, more frequent follow-up appointments may be recommended.
If watchful waiting shows MGUS is progressing, you may receive treatment from one or more of the following types of physicians: a nephrologist (renal/kidney specialist), a neurologist (brain/spine and nerve specialist), and/or a hematologist (blood and bone marrow specialist).
If you have been diagnosed with MGUS, be sure you have a regular check-up plan in place with a specialist such as a hematologist. The hematologists at Virginia Oncology Associates are available for a consultation to see if a watchful waiting program is right for you and to assess your risk for developing blood or bone marrow cancers.
Dr. Zhao is a Medical Oncologist and Hematologist at Virginia Oncology Associates, a regional practice that partners on clinical trials with the U.S. Oncology Network.
