Thyroid Lymphoma Treatment & Management

Large cell lymphoma

The management of thyroid lymphoma is not different from any other lymphoma presenting in a nodal site. Literature data point out that the best results are obtained when combined-modality therapy with the CHOP (cyclophosphamide, hydroxydaunorubicin, Oncovin, prednisone) regimen and radiation are used. Results at the M.D. Anderson Cancer Center, as well as those from Matsuzuka et al, reveal that approximately 90% are failure free after this approach.^[13]

The current trend in the management of large-cell lymphoma, however, is to select treatment based on prognostic factors. Those whose IPI is favorable would be treated by most investigators with the standard CHOP regimen, which consists of cyclophosphamide, doxorubicin, vincristine, and prednisone, followed by radiation therapy consolidation in those who present with Ann Arbor stage I-II disease. The number of courses of chemotherapy administered ranges from 3-6.^[14] Cases with Ann Arbor stage I, an IPI of 0, and at less than 5 cm diameter could be managed with 3 courses of CHOP followed by local radiation. All others would receive 6 courses. In those with an IPI of greater than 0, the management should be with experimental regimens whenever possible, but recent data point out that the addition of rituximab for those older than 60 years with large cell lymphoma provides further benefit in survival and disease-free survival.

At the M.D. Anderson Cancer Center, the tumor-score system is used to select the treatment for aggressive lymphomas in general.^[15] The management of thyroid lymphomas is based on the same principles. With this system, patients with favorable prognostic features are identified and are treated with standard chemotherapy/radiotherapy protocols, while those with poor prognoses are treated with experimental protocols. With this system, 1 point is assigned for any bulky site greater than or equal to 7 cm, Ann Arbor stage III or IV, B-symptoms, LDH greater than or equal to 110% of the upper normal limit, and beta2-microglobulin greater than or equal to 150% of the upper normal limit. This system classifies the patients into 2 prognostic groups: one with low risk who have a tumor score of 0, 1, or 2 (85% cure rate when treated with CHOP) and one with 3 or more points, whose prognosis is very poor (only 20% cure rate).

Radiation therapy is used most commonly after 3-6 courses of chemotherapy. The radiation fields most commonly used are either involved field or modified mantle, which includes the thyroid, bilateral neck and supraclavicular, and the mediastinum.^[6] The importance of radiation therapy consolidation for patients with large-cell lymphoma has been well established by 2 prospective randomized clinical trials.^{[16, 17]}

MALT lymphomas

Although in theory thyroid diffuse large-cell lymphomas arise from previously existing low-grade MALT lymphomas, the latter are relatively uncommon in the thyroid gland, and, for that reason, there are few data on their management. Local management with radiation therapy appears to be adequate treatment.^[18] It appears that patients with intermediate or high-grade lymphoma arising from MALT lymphoma have a worse prognosis and these patients need to be treated more aggressively with combined-modality therapy as discussed above. According to recent data from the M.D. Anderson Cancer Center, a diagnosis of thyroid MALT lymphoma should prompt a gastroscopy to rule out involvement of the stomach. MALT lymphomas tend to home to other areas of MALT.

Relapsed thyroid lymphoma

Due to the excellent outcome related to the front-line management of MALT thyroid lymphoma, there are very few data on the salvage management of this cell type. The management of relapsed thyroid large cell lymphoma is based on similar principles as the salvage management of any recurrent large cell lymphoma. If circumstances allow, high-dose chemotherapy with stem cell transplantation would be considered the treatment of choice.