This study assessed efficacy, optimal dosage and timing, and toxicity of involved-field radiotherapy used in conjunction with high-dose chemotherapy and stem cell transplantation for patients with refractory/relapsed Hodgkin's disease and non-Hodgkin's lymphoma.
Methods and materials: 306 patients with refractory or relapsed Hodgkin's disease and non-Hodgkin's lymphoma were analyzed. Forty-one patients underwent involved-field radiotherapy in conjunction with high-dose chemotherapy and bone marrow or peripheral stem cell transplantation. Thirty-three patients received involved-field radiotherapy prior to stem cell transplantation directed at symptomatic and/or bulky sites; eight patients received involved-field radiotherapy after stem cell transplantation directed at sites of persistent disease. The other 265 patients with refractory/relapsed non-Hodgkin's lymphoma and Hodgkin's disease received high-dose chemotherapy/stem cell transplantation, but not involved-field radiotherapy. Data were analyzed using Cox proportional hazards regression to determine the risk of death among patients treated with stem cell transplantation compared with that among patients treated with stem cell transplantation and involved-field radiotherapy.
Results: There were 124 deaths during the follow-up period, including 17% of the patients treated with involved-field radiotherapy and 44.2% of the patients receiving chemotherapy without involved-field radiotherapy. Multivariate analysis found that patients who did not receive involved-field radiotherapy were 2.09 times more likely to die during the follow-up period than patients who received involved-field radiotherapy (P = 0.066; adjusted for age, stem cell transplantation type, stage I/II vs stage III/IV, refractory vs relapsed, and Hodgkin's disease vs non-Hodgkin's lymphoma). When patients were treated with involved-field radiotherapy prior to stem cell transplantation, 27 (79.4%) of the 34 patients achieved local control; when involved-field radiotherapy followed stem cell transplantation, 6 (85.7%) of the 7 patients experienced local control. Timing of involved-field radiotherapy prior to or following stem cell transplantation did not affect patient survival. Five of the 41 patients treated with involved-field radiotherapy developed toxicity subsequent to treatment. All but one of these patients had been treated with doses greater than 30 Gy.
Conclusions: Although of borderline significance in this small sample, results of this study suggest that patients who receive involved-field radiotherapy in conjunction with stem cell transplantation may have increased survival when compared with patients who do not receive involved-field radiotherapy. Further follow-up of this cohort is necessary to confirm these findings.