Dr Ajai Chari Explains MGUS and How to Discuss It With Patients

Monoclonal gammopathy of undetermined significance is a diagnosis of exclusion, but even once it has been identified, patients should not obsess over this precancerous condition, said Ajai Chari, MD, associate professor of medicine, Hematology and Medical Oncology, Mount Sinai Hospital.

Transcript

How should clinicians handle it when they identify monoclonal gammopathy of undetermined significance in patients?

Monoclonal gammopathy of undetermined significance, or MGUS, always is a diagnosis of exclusion, which means we shouldn’t label somebody as MGUS unless we’ve done due diligence. So, broadly speaking, first we want to think about plasma cell disorders and non—plasma cell disorders. So, within the plasma cell disorders, of course, we have myeloma, which is easy CRAB [calcium (elevated), renal failure, anemia, and bone lesions] symptoms, smoldering myeloma, and plasmacytomas are also important not to miss. Because those can be resected or radiated.

But also, there’s other conditions that may not be as common, but also may not be picked up or thought about. So, AL [amyloid light-chain] amyloidosis should be thought about, and particularly in anybody who has multisystem failure symptoms; POEMS syndrome, which is polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and sclerotic bone lesions; there’s other rarer conditions like Schnitzler’s syndrome, and also there’s a whole group of patients, now we understand there’s 2 groups of patients where we need to think about before just labelling somebody as MGUS, which are MGRS, which is monoclonal gammopathy of renal significance, and so these patients can include light-chain deposition disorders, heavy-chain deposition disorders, so for these conditions we need to work closely with nephrologists and consider kidney biopsy in somebody who has a new renal insufficiency.

And finally, there’s also monoclonal gammopathy with neuropathy. So, this includes conditions like POEMS syndrome, amyloid, but we also know that some patients with MGUS have neuropathy just from having MGUS, where the antigens of these proteins are directed against nerve antigens.

So, I think if you’ve thought about a lot of those, and then also the non—plasma cell disorders, like CLL [chronic lymphocytic leukemia], can also have a lot of paraproteins, posttransplant lymphoproliferative disease, etc. But if you’ve gone through all of that, MGUS is the diagnosis of exclusion.

When monoclonal gammopathy of undetermined significance is identified, how should clinicians explain it to patients and what it means?

I think the way to explain MGUS to a patient is that this is a precancerous condition. So, if we’ve gone through all of that intellectual exercise and laboratory work-up, and we’ve found no other problems, this is a premalignancy. So, I try to tell patients, “Look, MGUS is like a mole on your skin. And you’re not going to hack it out, you’re not going to obsess over it, but you’re going to pay attention to make sure it’s not growing and changing. And if you notice that it’s getting bigger quickly, you may want to reassess it.”

And spo, that’s I think the analogy I use in my practice to reassure patients that, “pay attention, come to your appointments, but don’t live your life revolving around this mole.”