Patients with AIDS have a nearly twenty-fold higher chance of developing primary CNS lymphoma, than those who do not suffer from AIDS. The association of HIV/AIDS and primary CNS lymphoma is the one of the factors associated with the increasing number of primary CNS lymphomas around the world. The success of Highly Active Anti-Retroviral Therapy (HAART) has also resulted in a reduction in new cases of primary CNS lymphoma. However, primary CNS lymphoma also occurs in those without AIDS or a malfunctioning immune system.
AIDS itself does not cause lymphoma. It causes immunosuppression, or the malfunction of the immune system. The immune system protects our body from infections and harmful agents. Those with AIDS are thus at higher risk of developing infections, and some infections like the Epstein Barr Virus (EBV) have been shown to result in lymphoma. Those with the severest disease with the lowest counts of CD4 cells are at the highest risk of infections and of primary CNS lymphoma.
To make the final diagnosis, a brain biopsy is required in those suspected to have a lymphoma. This poses a risk in patients with AIDS as their blood CD4 counts are low, and they may catch an infection. Researchers have found that two other non-invasive tests may reduce the need to perform a biopsy in these ill patients. A PET or SPECT scan is done to check whether the brain tumor is hypermetabolic (full of active cells). A CSF tests for Epstein Barr Virus (EBV) DNA is also performed. If both tests are positive, the brain disease is extremely likely to be a lymphoma, and a biopsy can be avoided.
Most of the other tests for primary CNS lymphoma are the same for those who have AIDS and those who don’t. These include scans for the brain, chest and abdomen, as well as blood tests, bone marrow tests and a CSF examination.
Primary CNS lymphoma may show up differently on scans in patients with and without AIDS. Scans of those with AIDS may show some features that are not typical, making the diagnosis a bit more difficult. Patients with AIDS also can have infections in the brain, which can look just like lymphoma. It is important to diagnose lymphoma correctly, as the treatment of lymphoma is very different from the treatment of other diseases. Doctors may advise a PET or SPECT scan which can tell the difference between lymphoma and infections.
Treatment in patients with AIDS includes radiotherapy, steroids and occasionally chemotherapy. See the full article on Treatment of Primary CNS Lymphoma. Chemotherapy cannot always be used in those who have AIDS. There is already a severe immunosuppression, and chemotherapy may worsen it. This increases the toxicity of chemotherapy and many patients with AIDS may be unable to tolerate it. However, in those who are well, and don’t have other infections, chemotherapy has been tried with success.
Treatment for AIDS itself (HAART) plays a very important role in primary CNS lymphoma. Patients need to started on AIDS treatment, or the treatment may need to be modified. HAART improves the function of the immune system, and this may be critical in the success or failure of treatment for lymphoma.
