[Radiotherapy in (localized) non-Hodgkin's lymphoma of the orbit]

Orbital NHLs are rare and manifest themselves primarily in localized stages. The value of radiotherapy is discussed, reviewing retrospectively the treatment results obtained in 41 patients irradiated for orbital NHL between 1958 and 1966. All were histologically verified. There were 15 lymphomas of low and nine of high malignancy according to the Kiel classification. Among the 17 remaining patients, 15 cases had been classified as reticulum cell sarcoma and two as lymphosarcoma. Fourteen cases were in stage IE, 19 in stage IIE, and eight in stage IIIE/IVE. After surgical biopsy (n = 25) or resection (n = 5), megavoltage irradiation was delivered in conventional fractionation from 20 Gy up to a total dose of 50 Gy. During the last decade treatment has been based on CT scans and corresponding computer assisted treatment planning. Clinically, complete remission was achieved in 13 out of 14 patients (93%) with stage IE, in 17 out of 19 patients (90%) with stage IIE, and in five out of eight patients (63%) with stage IIIE/IVE. The nonrecurrence rate is 65% (10 out of 14) for stage IE and 75% (13 out of 17) for stage IIE after a mean follow-up time of 36 months. As regards lymphomas of low and high malignancy, the nonrecurrence rate is 89% and 43% respectively. Recurrence (n = 8) and dissemination (n = 6) occurred only twice more than two years after radiotherapy had been discontinued. The incidence of side effects was low. Two patients developed a "dry eye." In two eyes the lens had to be removed because of progressive cataract. Radiotherapy with individual treatment planning based on CT scans is the curative treatment of choice fo localized orbital NHL.