A total of 151 patients with previously untreated Hodgkin's disease, clinical stages III-IV A & B, were randomized to receive CVPP for 6 cycles, or CVPP plus RT 3000 cGy to previously involved areas between the 3rd and 4th cycles. CVPP consists of cyclophosphamide 600 mg/m2/i.v., vinblastine 6 mg/m2/i.v. on day 1, procarbazine 100 mg/m2/p.o. and prednisone 40 mg/m2/p.o. on days 1 to 14. Both groups displayed similar clinical characteristics at diagnosis. Sixty-six were treated with CVPP + RT (52 St III and 14 St IV) and 85 with CVPP alone (68 St III and 17 St IV). Complete remission was obtained in 57 (86%) of 66 patients who received CVPP plus RT, and in 62 (73%) of 85 patients treated with CVPP. Five and sixteen patients, respectively, achieved partial responses, while 2 in each group died during treatment. At 7 years, duration of complete remission and failure-free survival were: 51% and 45% for those treated with CVPP plus RT, and 23% and 21% with CVPP alone (p = 0.0150 and P = 0.0016, respectively). Overall survival at 7 years was 71% and 58%, respectively (p = 0.1488). A dose analysis performed in 84 pts showed that 91% and 88% received full protocol doses of CPM and PCZ, respectively, in the CVPP + RT group, and 95% and 94% for CVPP. The WBC nadir was 3.5 and 3.7 x mm3, respectively. Of 25 pts on CVPP + RT who relapsed, 9 are now disease-free, 5 are alive with disease and 11 have died, and with CVPP, of 37 relapsing pts, 18 are disease-free, 5 are alive with disease and 14 are dead.(ABSTRACT TRUNCATED AT 250 WORDS)