A Prospective, Multicenter Study of Involved-Field Radiation Therapy With Autologous Stem Cell Transplantation for Patients With Hodgkin Lymphoma and Aggressive Non-Hodgkin Lymphoma (ALLG HDNHL04/TROG 03.03)

Abstract

The role of involved-field radiation therapy (IFRT) with autologous stem cell transplantation (ASCT) for lymphomas remains uncertain. In this prospective, multicenter study, patients undergoing ASCT for relapsed/refractory lymphoma received peritransplant IFRT to disease sites identified at study registration (SR) (before salvage chemotherapy [SC]). Radiation dose was adapted to SC response. Survival, relapse rates/pattern, toxicity, and prognostic factors were evaluated. Forty-five patients were enrolled (23 with Hodgkin lymphoma, 22 with aggressive non-Hodgkin lymphoma). Three-year overall survival and cumulative incidence of posttransplant progression rates were 72% (95% confidence interval [CI], 59%-87%) and 42% (95% CI, 27%-57%), respectively. Stage (P=.03) and elevated lactate dehydrogenase (P=.05) were significant risk factors for disease progression on multivariable analysis. Three-year actuarial in-field, marginal, and distant progression rates were 7% (95% CI, 0%-15%), 9% (95% CI, 0%-18%), and 36% (95% CI, 21%-51%), respectively. Progression occurred in 8 of 30 patients with all sites irradiated and in 13 of 15 patients without all sites irradiated. There were 117 disease sites at SR and 64 post-ASCT progression sites, of which 15 were involved at SR and 12 only at initial diagnosis. Posttransplant relapse occurred in 3 of 83 irradiated and 12 of 34 unirradiated involved sites. Of 28 sites in complete response to SC on computed tomography, there was no relapse in any of the 21 irradiated sites and in 1 of 7 unirradiated sites. Of 72 sites in complete response on positron emission tomography, relapse occurred in 1 of 50 irradiated and 10 of 22 unirradiated sites. No grade 4 nonhematologic radiation therapy toxicities were observed. IFRT was well tolerated and associated with a low rate of in-field progression. Progression rates were lower for patients with all disease sites irradiated. Response to SC on both computed tomography and positron emission tomography warrants further study to select sites for IFRT.