Primary CNS lymphomas
Primary CNS lymphomas in immunocompetent patients is a rare disease occurring in only 1-2% of all new non-Hodgkin lymphomas. The incidence is increasing, mainly because the condition is relatively common in immune-compromised patients, especially AIDS patients. The median age at diagnosis is 62 years based on a large Danish population-based study. Debut symptoms are the same as for other brain tumors.
CNS prophylaxis and treatment for systemic CNS involvement
Highly malignant lymphomas may recur in the meninges. The following indications are currently used in Norway for prophylactic treatment with CNS-active regimens including chemotherapy given instraspinally according to specific protocols:
- Lymphoblastic lymphoma and Burkitt's lymphoma regardless of stage (Hammersmith-82, BFM regimen).
- Diffuse large cell B-cell lymphomas, mediastinal large cell B-cell lymphomas, and mature T-cell lymphomas (exception: cutaneous T- and B-cell lymphomas and mycosis fungoides) with at least 4 of 5 of the following risk factors:
- Elevated LDH
- Age < 60 years
- Albumin < 35 g/l
- Retroperitoneal node tumor
- More than one extranodal localization
In addition, involvement of testicles (stage II-IV) or structures near the CNS (such as ethmoid sinus, skull, intraspinal extradural manifestation), will initiate active CNS-directed prophylaxis.
Patients in this group may require systemic treatment with chemotherapy with adequate penetration to the CNS, for example high-dose methotrexate. This is possible with CHOP21 or the BFM regimen, but is difficult with CHO(E)P14. Since some CNS recurrences appear with simultaneous systemic recurrences, it is likely that more effective systemic treatment will also give fewer CNS recurrences. When CHO(E)P14 is given, only triple prophylaxis is given for the first 6 courses (methotrexate 15 mg, cytarabine 40 mg, prednisolon 10 mg). With CHOP21, instraspinal chemotherapy is also given, high-dose methotrexate 2 g/m2 with leucovorin rescue on day 15 (MmCHOP) for the first four cycles instead of only intraspinal prophylaxis.
Treatment of CNS involvement at diagnosis
Treatment should be managed by a university hospital. Patients under 50 years should be given BFM-based chemotherapy. Patients under 60 years or those having significant comorbidity are given CHOP21 with triple intraspinal chemotherapy administration day 1 and high-dose methotrexate 2 g/m2 with leucovorin rescue and triple intraspinal chemotherapy administration on day 15 (MmCHOEP). This applies for the first 6 courses. Triple intraspinal therapy may be considered instead of longer-lasting cytarabine (Depocyte®) intraspinally for this group, especially when malignant cells are confirmed in spinal fluid. Elderly patients are treated on an indvidual treatment plan.
The prognosis for patients with primary CNS involvement is very serious. Indviduals reaching complete remission after primary treatment should be considered for radiation therapy to the entire spinal axis. A dose of 2 Gy x 9 is given to the entire target volume followed by an additional 2 Gy x 3 to the whole brain. For details around planning of this treatment, visit the chapter on radiation therapy. It may also be appropriate to give consolidation treatment with HDT with SCS to younger patients instead of radiation therapy.
Lymphoma in the gastrointestinal tract
Around 40% of aggressive non-Hodgkin lymphomas occur primarily extranodally (non-lymphoid organs). The most common localization is the stomach in 25%. These patients generally have a good prognosis. Intestinal lymphomas (most often small intestine) have the worst prognosis.
Extra nodal lymphoma of the ear-nose-throat area
Extra nodal lymphomas of the ENT area are the next most common localization after GI lymphomas. Tonsils and lymphoid tissue in Waldeyer's ring are considered nodal manifestations. The disease is usually confined and the prognosis is good. The patient should be referred to a university hospital.
It is not uncommon for this diagnosis to be found after an orchiectomy for suspicion of germinal cell tumor. Histologically, testicular lymphoma is often aggressive, either of diffuse large cell B-cell type, Burkitt's lymphoma, or lymphoblastic lymphoma. Diffuse large cell B-cell lymphoma is the most common in elderly patients.
Lymphoma in bone
Primary origin of lymphoma in bone is very rare. The prognosis is not much different from other lymphomas with the same histological subgroup, and treatment follows the specific treatment programs. Diffuse large cell B-cell lymphoma is the most common.