Lung cancer in Hodgkin's disease: association with previous radiotherapy.

Seven cases of lung cancer were observed in patients with Hodgkin's disease (HD) since 1970. The risk ratio for the development of lung cancer among HD patients was 5.6 times that expected in the general population. The pertinent clinical data from these patients are described and compared to 28 additional patients reported from other institutions. Small-cell lung cancer represented the predominant histologic type of lung cancer encountered in both smoking and nonsmoking patients with HD, accounting for 42% of cases overall and greater than 55% of cases reported in reviews of second malignancies. Tobacco use was noted in only 53% of patients. Twenty-eight (94%) of 30 patients developing metachronous lung cancer received supradiaphragmatic irradiation as primary therapy for HD. Nineteen (68%) of these patients received subsequent chemotherapy salvage. The median age at diagnosis of HD and lung cancer was 39 and 45 years, respectively. The interval between diagnosis of HD and metachronous lung cancer averaged seven years but appeared to vary inversely with age. HD patients treated with supradiaphragmatic irradiation or combined modality therapy may be at increased risk for developing lung cancer. The high frequency of in-field malignancies that we observed and the prevalence of small-cell lung cancer in both smoking and nonsmoking patients suggests that chest irradiation may influence the development of metachronous lung cancer in these patients. The finding of a mean latent interval in excess of seven years emphasizes the need for close long-term observation.