EXTENDED FIELD AND TOTAL CENTRAL LYMPHATIC RADIOTHERAPY IN THE TREATMENT OF EARLY-STAGE LYMPH-NODE CENTROBLASTIC-CENTROSYTIC LYMPHOMAS - RESULTS OF A PROSPECTIVE MULTICENTER STUDY

BACKGROUND, A prospective multicenter trial was performed to evaluate survival, patterns of relapse, and toxicity for clinically staged pati ents with lymph node centroblastic-centrocytic (cb/cc) lymphomas in St ages I-IIIA after large extended field irradiation (EFI) or total cent ral lymphatic irradiation (TCLI). METHODS. Between January 1986 and Au gust 1993, 117 adults with clinical Stage I-IIIA lymph node cb/cc lymp homa (Kiel classification) were recruited. Patients in Stages I or II with mediastinal, hilar, periaortic, iliac, or mesenteric involvement and in Stage IIIA received TCLI, whereas patients with more peripheral ly located cb/cc lymphomas were treated with EFI. TCLI and EFI were ad ministered to a total dose of 26 gray (Gy) with 2 Gy per daily fractio n, with the exception of the whole abdomen, which was irradiated to a total dose of 25.5 Gy with 1.5 Gy per fraction. A boost of 10 Gy with 2 Gy per fraction was administered to enlarged and involved lymph node s at the start of radiotherapy. RESULTS, Sixty, 40, and 17 patients ha d Stage I, II, and limited IIIA disease (no bulk and less than 6 invol ved lymph node regions), respectively. Overall survival was 86% at 5 a nd 7 years; median follow-up was 68 months. The probabilities of relap se at any site, recurrences in lymph nodes, and in-field lymph node re currences after TCLI were 17% in Stage I; 56%, 43%, and 40% in Stage I I, respectively; and 44%, 35%, and 35% in Stage IIIA, respectively. Th e risk of disseminated extralymphatic relapses was 9% at 7 years. The most important adverse prognostic factor for in-held lymph node recurr ences was a deviation of >20% from the assigned total radiation dose. After EFI, patients in Stage I had a significantly lower risk of recur rences in adjuvant irradiated lymph node regions than in unirradiated lymph node regions. Acute toxicity of EFI and TCLI was moderate. CONCL USIONS. In-field lymph node recurrences remained the main risk after T CLI, and a deviation of >20% from the assigned radiation dose was the major risk factor for in-field recurrences. From these data, a total d ose of 40-44 Gy in conventional fractionation for the treatment of mac roscopic cb/cc lymphomas and 30 Gy for the treatment of subclinical di sease is recommended. A randomized study comparing TCLI with EFI is no w being organized by this group. (C) 1997 American Cancer Society.