Treatment Lymphoma

The treatment of lymphoma depends primarily on the histologic subtype and the stage. HL is treated with chemotherapy, or for more limited-stage disease, combination chemotherapy and radiotherapy. In this situation, the dose of both radiation and chemotherapy is less than if either modality is used alone. The advantage is a reduction in toxicity of each modality used alone. In some cases of very limited disease without B symptoms, radiation alone may be used. The current standard chemotherapy regimen is doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD) (adriamycin, bleomycin, vinblastine, and dacarbazine), administered every two weeks for six months (one cycle equals one month). Two to four cycles of ABVD may be given, followed by involved field radiation, for more limited disease.

Of the NHL, indolent lymphomas, including follicular Grade-1 and -2 small lymphocytic lymphoma and lymphoplasmacytic lymphoma (sometimes associated with WM), are generally considered incurable. Although many active chemotherapeutic agents and combination regimens are available, in many cases, in the absence of symptoms, treatment is withheld until there is evidence of disease progression. Earlier treatment has not been shown to impact survival compared to the "watch and wait" approach (41). The anti-CD20 monoclonal antibody rituximab is a very active agent in this group of disorders, either as a single agent or combined with chemotherapy (42,43). It is noteworthy that lymphoma affecting head and neck sites in a localized fashion can be treated with involved field irradiation. Such an approach can be associated with low morbidity and prolonged disease-free intervals (44,45).

For the higher grade lymphomas, chemotherapy is indicated. The CHOP (cyclopho-sphamide, adriamycin, vincristine, and prednisone) regimen is generally administered with rituximab (46). For aggressive Stage-1 or -2 lymphomas involving most head and neck sites, localized irradiation used to be a reasonable option. However, a high rate of relapse has been observed, mostly at distant sites, probably due to the frequent occurrence of occult disease at presentation. For limited-stage disease, abbreviated (three to four cycles) combination anthracycline-based chemotherapy with monoclonal antibody therapy, followed by involved field radiotherapy, is administered with curative intent in most cases (47-53). This approach is modeled on data comparing combined modality therapy with radiation therapy alone for limited-stage nodal-based disease (54). For more extensive disease, six to eight cycles of immunochemotherapy are generally administered (46). For patients who relapse, a salvage chemotherapy regimen is indicated in appropriate candidates for further therapy. This is frequently a platinum-containing regimen, and for responsive patients, high-dose chemotherapy with autologous stem-cell transplantation may be curative (55).

Surgery when dealing with lymphoma is generally limited to biopsy, but, rarely, may have a role in debulking of particular sites for relief of symptoms. In the head and neck region, surgery is most often used to relieve airway obstruction, dysphagia, or bleeding. Plasmacytomas may be controlled by surgery alone when adequate margins can be obtained; however, when margins are close or tumor-free margins cannot be obtained, postoperative radiation therapy should be given. A large retrospective statistical analysis indicated that plasmacytomas treated with combined surgery and radiation had a better survival outcome than those treated with either of the modalities alone (56).

NK-/T-cell lymphomas are particularly aggressive and are also frequently managed with a combined modality approach. Recent Chinese studies suggest that involved field radiation as initial therapy may be sufficient, and, if given with chemotherapy, should be sequenced so that the irradiation is administered first (57,58).

The high-grade lymphomas, Burkitt's, Burkitt's-like, and lymphoblastic lymphoma, are treated with aggressive, intensive, multicycle chemotherapy, including CNS prophylaxis with intrathecal chemotherapy (59). Prophylaxis against tumor lysis syndrome is important when treating these aggressive tumors. Localized radiation therapy alone, even for limited-stage disease, is not appropriate for the high-grade tumors.

Solitary plasmacytomas are managed with localized irradiation. For involvement of head and neck sites, regional lymph nodes may be included.

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