Myeloma is a type of marrow cancer in which there is an overproduction of plasma cells. As a result of these elevated plasma cells, there is an abnormal amount of immunoglobulin (Ig) protein in the blood and/or in the urine. However, in about 1- 5% of myeloma cases, the cancerous plasma cells do not secrete Ig. This type of myeloma is called nonsecretory myeloma (NSM).
The Nonsecretory Myeloma Diagnosis
Classic myeloma and NSM present themselves in much the same way. NSM causes the same type of bone damage called osteolytic lesions, elevated levels of calcium in the blood, abnormal blood cell counts and damage to the kidneys. But without the hallmark sign of an elevated level of Ig in the blood and/or urine, called M-protein, diagnosis of NSM can be delayed or missed.
Serum free light chain assay, a more sensitive blood test that can detect tiny fragments of Ig protein, may be able to confirm a diagnosis in some cases.
Bone marrow biopsy and biopsy of the bone lesions will show evidence of the disease and are used to arrive at a diagnosis.
NSM can be divided into two different categories:
- Producer Type (also called true nonsecretory or nonexcretory myeloma): In this type, the cancerous plasma cells produce Ig, but do not secrete it into the blood. Scientists believe that about 85% of NSM cases fall into this category.
- Nonproducer Type: In this type of NSM, the plasma cells do not produce Ig at all and there is no evidence of M-protein even within the cancerous cells.
Due to the nature of NSM, blood and urine tests will not be helpful in diagnosing or monitoring the disease. Specialists rely heavily on bone marrow tests, magnetic resonance imaging (MRI), positron emission tomography (PET scan) and X-rays to keep track of this condition.
Interestingly, some patients with classic myeloma may become non-secretory when they relapse. Therefore, it is important that follow-up of patients with myeloma include a PET or MRI, even when their laboratory results do not indicate the presence of M-protein.
Treatment of Nonsecretory Myeloma
Treatment options for NSM are identical to those for classic myeloma. Consideration to your age, the stage of your cancer, and other health issues will factor into the decision-making process.
Your doctor may offer you chemotherapy, radiation therapy, stem cell transplant or a combination of these modalities.
Prognosis of Nonsecretory Myeloma
There is some conflicting information about NSM prognosis in the literature. Patients with NSM are less likely to have kidney damage as a result of abnormally high amounts of protein being filtered from the blood, theoretically improving survival outcomes. However, there is often a delay in the diagnosis of NSM and the condition may be more advanced once it is discovered.
Even with consideration to these two factors, the survival rates and prognosis for classic myeloma and NSM are the same.
Summing it Up
NSM patients will show many of the same signs and symptoms as people with classic myeloma. Bone pain and damage, low blood cell counts, and kidney problems may be present in both conditions. However, NSM will not show the hallmark evidence of elevated levels of Ig in the blood and/or urine.
Treatment options and survival outcomes are the same for both types, but diagnosing the condition and monitoring progress in patients with NSM may be more challenging.
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Caldas, A., Brandao, M., Marinho, A. Non- Secretory or Light Chain- Producing Multiple Myeloma: A Case Report. Journal of Medical Cases June 2011. 2: 97-100.
Middela, S., Kanse, P. Nonsecretory multiple myeloma. Indian Journal of Orthopaedics Oct- Dec 2009. 43: 408- 411.