Updated 20 June 2007
Five percent to 10% of patients with lymphoma and an associated IgM monoclonal protein (usually lymphoplasmacytic lymphoma, also known as Waldenstrom’s macroglobulinemia) also develop anti-MAG (myelin-associated glycoprotein) antibodies and polyneuropathy. Such patients should be treated with standard chemotherapy for advanced stage indolent lymphoma (see Table 3.1) and approximately 50% will experience improvement in the neuropathy. However, some patients with IgM monoclonal protein and anti-MAG antibodies develop polyneuropathy without histologic evidence of underlying lymphoma despite the fact that the presence of the monoclonal IgM implies the existence of an underlying monoclone of malignant B-cells. Evidence concerning the usefulness of anti-lymphoma treatment in such patients is not definitive, with anecdotal series documenting improvement and the only randomized trial under-powered and not focused on the most relevant endpoints.
The BCCA Lymphoid Cancer Tumor Group recommends that patients with IgM-associated polyneuropathy be co-managed by an oncologist/hematologist and a neurologist experienced in the diagnosis and treatment of polyneuropathy as shown below. Such patients should undergo a careful search for underlying lymphoma, including a bone marrow biopsy, and all other conditions such as nutritional deficiency or spinal stenosis should be eliminated as possible causes before employing these treatment recommendations.
Clinical setting: IgM-associated polyneuropathy and histologically proven coincident indolent lymphoma
Recommended treatment: As for advanced stage indolent lymphoma, see Treatment section above
Clinical setting: IgM-associated polyneuropathy in the absence of histologically proven coincident indolent lymphoma
Recommended treatment: Single agent rituximab 375 mg/m2 IV weekly for 4 weeks (LYRITUX, requires Compassionate Access Program (CAP) approval)