Primary central nervous system (CNS) lymphoma is defined as lymphoma limited to the cranial-spinal axis without systemic disease. An increasing incidence of this disease has been seen among patients with acquired immunodeficiency syndrome (AIDS) and among other immunocompromised persons. The natural history of this disorder differs between patients with AIDS and those without AIDS. Computed tomographic (CT) scans may show ring enhancement in 50% of AIDS patients while patients without AIDS almost always show only homogeneous enhancement. Both groups do equally poorly without therapy (1–3 month mean survival), but the overall survival for treated patients is much better for patients without AIDS (18.9 months) than for those with AIDS (2.6 months).[1,2]
Poor prognostic factors include the following:[3,4,5]
Mistletoe is a semiparasitic plant that grows on several types of common trees such as apple, oak, pine, and elm. Mistletoe extract has been used since ancient times to treat many ailments (see Question 1).
Mistletoe is one of the most widely studied complementary and alternative medicine therapies in people with cancer. In certain European countries, preparations made from European mistletoe are among the most prescribed drugs for patients with cancer (see Question 1).
Performance status greater than 1 or Karnofsky performance status less than 70.
Elevated serum level of lactate dehydrogenase.
Elevated cerebrospinal fluid protein concentration.
Involvement of nonhemispheric areas of the brain (periventricular, basal ganglia, brainstem, and cerebellum).
When tumor progression occurs, it is usually confined to the CNS and/or the eye. Occult systemic disease can be excluded by staging with bone marrow biopsy and CT scans of the chest, abdomen, and pelvis.[6,7]
In one prospective, case series of 282 patients, 17% were found to have meningeal dissemination by cytomorphology, polymerase chain reaction of rearranged immunoglobulin heavy-chain genes, or meningeal enhancement on magnetic resonance imaging. The clinical impact of meningeal involvement on prognosis and therapy remains to be evaluated.
Although more than 95% of patients with primary CNS lymphoma have lymphoma of B-cell origin, 45 patients with CNS lymphoma of T-cell origin showed no difference in presentation or outcome in a retrospective series with data collected from 12 cancer centers. Almost all primary CNS lymphomas are aggressive neoplasms of the diffuse large B-cell type. In a retrospective case series derived from 18 cancer centers in five countries of 40 patients with low-grade primary CNS lymphoma, a better long-term outcome was shown (7-year median survival) than is associated with the usual aggressive CNS lymphoma.[Level of evidence: 3iiiDiv] Anecdotal cases of primary CNS Hodgkin lymphoma have also been reported.