BACKGROUND AND OBJECTIVE(#br)Patients affected by Hodgkin's disease (HD) in pathologic stage IA-IIA have a strong possibility of remission and long-term survival when treated with radiotherapy to extended fields. However, 20-30% of cases relapse in the five years following treatment and consequently need further therapy. This study examines the occurrence of relapse and other complications in patients with pathologic stage IIA Hodgkin's disease and mediastinal involvement treated in different ways: radiotherapy alone vs radiotherapy plus one cycle of adriamycin, bleomycin, vinblastine and dacarbazine (ABVD).(#br)DESIGN AND METHODS(#br)Our series consisted of 73 HD patients with mediastinal involvement treated by the Department of Radiation Oncology and the Hematology Department of "La... Sapienza" University of Rome from 1983 to 1989. The patients were randomized into two groups according to their initial treatment. The first group contained 37 patients treated, initially, with supradiaphragmatic radiotherapy and para-aortic irradiation (STNI); the second group was made up of 36 patients treated, initially, with supradiaphragmatic radiotherapy and para-aortic irradiation (STNI) combined with one course of adriamycin, bleomycin, vinblastine and dacarbazine (ABVD). For 28 (38%) of the patients, the follow-up period was longer than 10 years. The average follow-up period was 114 months (range 22-174 months). Overall survival and relapse-free survival were assessed using the Kaplan and Meier method, while differences were tested by the log-rank test.(#br)RESULTS(#br)We recorded twelve cases of relapse after initial treatment. The period of time which elapsed between the end of treatment and the evidence of relapse ranged from 6 to 51 months, with an average of 22 months. Ten relapses occurred in the STNI group and two in the ABVD/STNI group. No statistically significant differences emerged between the two groups in the overall survival analysis but did in the relapse-free survival analysis (p<0.01). In the group treated with ABVD and STNI one patient developed acute non-lymphocytic leukemia and another patient treated at the age of 44 developed primary breast cancer. X-ray-related asymptomatic pulmonary fibrosis was observed in 12 patients: 10 cases in the STNI and ABVD group and 2 cases in the group treated with RT alone. The other sequelae of combined CT/RT treatment in our study were thyroid dysfunction (2 cases, hypothyroidism), whereas the sequela of RT treatment was cardiac disease (2 cases).(#br)INTERPRETATION AND CONCLUSIONS(#br)We conclude that one cycle of ABVD and radiotherapy in early-stage HD patients with mediastinal involvement may reduce the risk of relapse. Moreover, the combination of low-toxicity CT and RT, administered preferably to limited fields, in patients who have not undergone laparotomy could be a valid alternative to current treatment for early-stage HD. However, additional data and a longer follow-up are mandatory in order to evaluate late toxicity and the potential risk of treatment.