Second solid malignancies after combined modality therapy for Hodgkin's disease.

Objective: To determine the actuarial incidence (AI) and relative risk (RR) of second solid malignancies (SSM; solid tumors and non-Hodgkin's lymphoma) in patients with Hodgkin's disease who were treated with chemotherapy and adjuvant, low-dose radiation (combined modality therapy; CMT).

Methods: From 1969 to 1983, 102 patients with previously untreated advanced Hodgkin's disease (group A) and 81 patients with recurrent disease after radiation (group B) were treated with CMT. Patients were observed for the development of solid tumors (ST) and non-Hodgkin's lymphoma (NHL), and the AI and RR were calculated.

Results: Nearly half of the patients entering remission were observed for greater than 15 years. At 20 years, the AI for SSM was 12% in group A versus 41% in group B (P = .009). The overall RR for developing a ST in group A was 1.88 (not significant) versus 8.84 in group B (95% confidence interval, 5.3 to 15.4). The difference in the RR between groups A and B was significant (P < .001). The RR for developing NHL was significantly increased in both groups, but the difference between groups was not significant.

Conclusions: Previously untreated patients with advanced disease who were treated with CMT (group A) had a modest but not significant increase in the RR of ST; however, patients treated with CMT for recurrent disease (group B) had a highly significant increase in the RR of ST. Possible explanations for the increase in ST in group B include more cumulative radiation or a greater carcinogenic effect of chemotherapy in previously irradiated patients, but it also is possible that the increase is due to a longer follow-up time.