According to a new study published in the issue of the New England Journal of Medicine, patients with monoclonal gammopathy of undetermined significance (MGUS) are at risk of progressing to multiple myeloma or a related cancer—even after 30 years of stability.

Monoclonal gammopathy of undetermined significance (MGUS) is a condition in which an abnormal protein, known as monoclonal protein, is found in the blood. Monoclonal gammopathy of undetermined significance usually causes no problems but may develop, over time, into multiple myeloma—a form of blood cancer.

S. Vincent Rajkumar, M.D., a hematologist at Mayo Clinic and senior author of the study said, monoclonal gammopathy of undetermined significance (MGUS) is present in more than 3% of the general population age 50 and older. In some cases, people with monoclonal gammopathy of undetermined significance go on to develop multiple myeloma.

The study research team studied 1,384 patients with two major types of monoclonal gammopathy of undetermined significance: IgM monoclonal gammopathy of undetermined significance and non-IgM monoclonal gammopathy of undetermined significance, and associated risk factors health professional use to counsel patients.

Dr. Rajkumar and his colleagues, during the study, found that the overall risk of progression to myeloma or a related disorder is relatively small at 1% each year; however, the risk persists indefinitely. Researchers also noted that risk of myeloma or related cancer was relatively small, compared to other general causes of death.

As a result, the Mayo Clinic researchers have recommended that patients who are followed for monoclonal gammopathy of undetermined significance (MGUS) not only be checked for presence or absence of progression, but also receive all other routine preventive services appropriate for patients as they age.

The team found that patients with monoclonal gammopathy of undetermined significance (MGUS) had shorter survival rate than comparable people without the condition, which raises the possibility there may be other disorders associated with monoclonal gammopathy of undetermined significance (MGUS) that still need further study, Dr. Rajkumar said.