Management of localized non-Hodgkin's lymphoma.

Non-Hodgkin's lymphomas (NHLs) are a heterogeneous group of disorders that vary widely in response to therapy. In Canada the modified Rappaport classification is used to categorize NHL. To facilitate the reporting and comparison of treatment results all cases should also be categorized in the terminology of the National Cancer Institute's working formulation. The choice of therapy should be guided by specific prognostic factors: stage and bulk of the disease, patient's age, presence of systemic symptoms and histologic subtype. Of these, the last appears to be the most important. Radiotherapy (RT) is the treatment of choice in localized low-grade lymphomas with favourable prognoses, while bimodal therapy (RT and chemotherapy [CT]) is warranted in presentations with unfavourable prognoses. Regional irradiation alone is indicated in intermediate-grade lymphomas with good prognoses (i.e., pathological stage I or II or clinical stage IA or IIA localized disease of small bulk in young patients). All other patients require CT followed by RT. The results of CT alone are encouraging but remain experimental. Aggressive therapy with multidrug regimens that include central nervous system prophylaxis is the foundation for successful treatment of high-grade NHL such as lymphoblastic lymphoma and diffuse small-noncleaved-cell lymphomas. Low-dose RT should be given to sites of bulky disease.