Use of Involved Fields

Use of Involved or Regional Fields

Carefully planned radiation therapy to limited fields with modest doses can significantly reduce the risk for significant damage to the marrow reserve, the risk for developing a treatment-related malignancy, and the risk for long-term toxicity to other normal tissues such as the salivary glands, lungs, heart, kidneys, and bowel.

The recommended dose is 30 to 36 Gy with a boost to areas of initial involvement to 36 to 40 Gy. Bulky disease should be treated to the upper end of the range; 30 to 36 Gy should suffice for smaller-volume disease.

Use of Radiation Therapy to Involved Nodal Regions or Extranodal Sites

Doses of 30 Gy result in a near 100% local control rate. Although there are limited data with lower doses such as 25 Gy (except for orbital MALT), local control rates can also be high with this dose. This should allow for modification of dose in settings where the risk for injury to normal tissue is higher (orbit, salivary glands).

Although there are high complete response rates with chemotherapy for marginal zone lymphoma, there is little evidence that it is curative. Therefore, outside of clinical trials, chemotherapy should be reserved for patients with stage III-IV disease. Asymptomatic individuals with generalized disease may be considered for observation, similar to patients with generalized follicular lymphoma.

CHOP, Cyclophosphamide, hydroxydaunomycin, vincristine (Oncovin), and prednisone; MALT, mucosa-associated lymphoid tumor; R-CHOP, rituximab-CHOP.

Table 23-1 Randomized Trials Comparing Chemotherapy Alone and Chemotherapy Followed by Radiation Therapy in Localized Diffuse Large B-Cell Lymphoma

ACVBP, Doxorubicin (Adriamycin) cyclophosphamide, vindesine, bleomycin, prednisone; CHOP, cyclophosphamide, hydroxydaunomycin, vincristine (Oncovin), and prednisone; CR, complete response; ECOG, Eastern Cooperative Oncology Group; EFS, event-free survival; FFS, failure-free survival; nl LDH, normal lactate dehydrogenase; OS, overall survival; PFS, progression-free survival; PR, partial response; PS, performance status; RT, radiation therapy.

^*2001 Abstract update: Median follow-up of 8.2 years: OS and PFS of two arms overlapped.