Thyroid abnormalities associated with treatment of malignant lymphoma

Abstract

The effects on the thyroid of radiation therapy to the neck and/or chemotherapy were investigated in 54 Hodgkin's and 72 non-Hodgkin's lymphoma patients. These patients had received radiation therapy with doses ranging from 2000 to 4000 rad (median 3600 rad) to the cervical or mantle fields and/or multiple-agent chemotherapy following usual staging procedures. Palpable abnormalities of the thyroid were found in 15 patients. The patients with irradiation to the neck had a higher incidence of hypothyroidism than those patients treated with chemotherapy alone (31/74 vs. 8/52, P < 0.001 for TSH and 10/74 vs. 1/52, P < 0.025 for T4). A higher frequency of elevated serum TSH levels and antithyroid antibodies were also observed in patients receiving radiation therapy alone to the neck than in those receiving both radiation therapy and chemotherapy (19/33 vs. 12/41, P < 0.025 for TSH and 16/33 vs. 7/41, P < 0.01 for antibodies), suggesting that chemotherapy agents may reduce the thyroid dysfunction induced by irradiation. There was nodifference in prevalence of elevated TSH levels following irradiation to the neck between patients in whom lymphangiogram was or was not performed (21/51 vs.

Hypothyroidism

“…18 More recently, DeGroot 19 and Hancock et al 20 suggested that radiation doses to the thyroid in the range of 3000 -8000 rads were required to induce hypothyroidism, and hypothyroidism after mantle irradiation of 3500 -4500 rads for patients with Hodgkin lymphoma has been well documented. [21][22][23] Hancock et al 23 examined 1787 patients with Hodgkin disease and found that patients who were treated with radiation had a 43% actuarial risk of developing hypothyroidism at 20 years. The postulated mechanisms by which hypothyroidism develops include direct thyroid cell injury from radiation, vascular injury from radiation, and possible immune-mediated damage.…”

Transition of thyroid autoantibodies by rituximab treatment for thyroid MALT lymphoma

“…After rituximab monotherapy, thyroid autoantibody levels decreased and thyroid functions were normalized gradually. There was a report that the patients with thyroid malignant lymphoma who received irradiation to the neck had a higher incidence of hypothyroidism than those treated with chemotherapy [16]. Although case 3 had a recurrence of thyroid MALT lymphoma after radiation and rituximab therapy, we thought that rituximab monotherapy was better than radiation therapy in terms of thyroid function.…”

“…Because prednisolone and cyclophosphamide are known to be immunosuppressive agents, it could be speculated that chemotherapy suppressed the thyroid autoantibody levels in Hashimoto's thyroiditis [16]. In case 2, TPOAb levels were reduced by R-THP-COP, and TPOAb levels were further reduced by the subsequent rituximab monotherapy.…”

Autoimmune Disorders and Lymphomas

“…Involved field radiotherapy is associated with a 5-year OS of 90% (Laing et al, 1994). Nonetheless, patients with thyroid malignant lymphoma treated with radiotherapy seem to have a higher incidence of hypothyroidism than those treated with chemotherapy (Tamura et al, 1981). Localized treatment plays a minor role in DLBCL, which requires aggressive anthracycline-based chemotherapy regimens (CHOP or CHOP-like), associated with rituximab, a monoclonal antibody directed against B-cell specific antigen CD20, and followed by involved-field radiotherapy.…”