Primary mediastinal lymphomaDescriptionPrimary mediastinal B-cell lymphoma is a subset of Diffuse Large B-cell lymphoma, which arises in the thymus, and presents as a mass in the mediastinum.
It primarily affects younger patients in their 30's and 40's, and is more common in women than men. It closely resembles Hodgkin's lymphoma, and has a similar prognosis to similarly staged DLBC.
PMBCL is an aggressive lymphoma which often presents with symptoms related to its location. Breathing problems, shortness of breath, pleural effusions, superior vena cava syndrome, fevers. etc. On initial diagnosis it is almost always limited to the mediastinal mass, but if a relapse occurs it is likely to occur in the kidneys, liver, central nervous system.
Diagnosis and PrognosisPMBCL therapy and prognosis are the same for similarly staged patients with diffuse large b-cell lymphoma. The International Prognostic Index can assist with determining the overall prognosis. TreatmentsTreatment consists of aggressive combination chemotherapy with the goal of curing the disease. In the event of a relapse a stem cell transplant is the preferred treatment option as is the case with other relapsed aggressive lymphomas. The addition of Rituxan to chemotherapy appears to have negated the need for more intensive chemotherapy, and therefore R-CHOP may be preferred over regimens such as MACOP-B.
The role of radiotherapy is uncertain. Some studies suggest there is an added benefit to radiation to the primary mass, while other studies show no such benefit. Here again, the addition of Rituxan to chemotherapy may eliminate the need for radiation due to the dramatic survival benefit Rituxan adds. The choice of whether or not to use radiotherapy should be made in consultation with the doctor and after a review of the post chemotherapy CT and/or PET scans. Here are some studies regarding the use of radiation. The first indicates a benefit from adding radiation.
This next study shows that the addition of Rituxan eliminates the need for radiation.
This next one also shows that the addition of Rituxan eliminates the need for radiation therapy.
Here is a study that looks at Proton Beam Radiation instead of traditional radiation. It appears to show there is significantly less radiation delivered to the major organs like the heart and lungs, when radiating a mediastinal mass. Rationale for and Preliminary Results of Proton Beam Therapy for Mediastinal Lymphoma.
Other informationFor more reading about PMBCL please read the following articles. A highly detailed look at primary mediastinal lymphoma from The Oncologist Journal
Primary mediastinal lymphoma from e-medicine
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