[Results of radiation therapy in extranodal non-Hodgkin's lymphoma of the head and neck--a study of the Japan Lymphoma Radiation Therapy Study Group].

Extranodal non-Hodgkin's lymphoma (NHL) in the head and neck except Waldeyer's ring treated with radiation were analyzed. No definite difference was observed both in actuarial and relapse-free five-year survival rate between stage I and II. There was a high survival rate with orbital NHL in which most of the patients occupied with favorable histology. Prognosis of the disease was highly influenced by the histologic subtype; five-year survival was 91.4% in DWDL, 77.2% in the DM, 52.0% in DPDL and 51.7% in DH. Application of histologic classification with the Working Formulation was also recommended. There was a high incidence of extranodal relapses to bone and/or soft tissue from the lesions with nasal cavity, paranasal sinus and oral cavity.