HODGKINS-DISEASE

Background. Over three time periods, 1973-1977, 1978-1982, and 1983-19 87, the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute collected all cases of Hodgkin's disease in designated geographic regions representative of the United States as a whole. Methods. The authors reviewed the data pertaining to 9418 microscopically confirmed cases of Hodgkin's disease and focused on tr ends that emerged over the time intervals of this study. Results. Hodg kin's disease had a bimodal distribution of age-specific incidence rat es with two peaks in the age groups of 15-34 years and older than 55 y ears. Since 1973, the incidence of Hodgkin's disease in the younger ag e group increased progressively as a result of a marked increase in th e incidence of the nodular sclerosis subtype. From the period 1973-197 7 to 1983-1987, the age-adjusted incidence rate of nodular sclerosis r ose from 1.1 to 1.6 per 100,000. In 1983-1987, nodular sclerosis repre sented 57.7% of Hodgkin's disease and occurred most often in whites, w ith an equal sex ratio. In females, this increase in incidence over ti me was most dramatic in young adult women. The overall incidence of th e mixed cellularity subtype, 23.4% of Hodgkin's disease, remained stab le although the age-specific incidence rate increased progressively in black males older than age 40 years. The incidence of the lymphocytic predominance subtype, 6.0% of Hodgkin's disease, remained stable over time, with a slight increase in adults older than age 50 years. The l ymphocytic depletion subtype, 3.8% of Hodgkin's disease, occurred pred ominantly in the elderly; its incidence decreased, most likely the res ult of changes in diagnostic criteria, with many cases being reclassif ied as non-Hodgkin's lymphoma (NHL). Similarly, unclassifiable cases o f Hodgkin's disease designated as miscellaneous, 9.1% of Hodgkin's dis ease, decreased over time, probably the result of improved classificat ion. Nevertheless, a subset of cases of Hodgkin's disease remained dif ficult to subclassify. The human immunodeficiency virus (HIV) epidemic appears to be associated with an increased incidence of Hodgkin's dis ease in San Francisco County in adult males age 30-49 years, a populat ion known to have a high prevalence of HIV infection. Conclusion. The SEER data suggest that Hodgkin's disease is a heterogeneous entity com posed of at least two different diseases-nodular sclerosis and mixed c ellularity. Over the time course of this study, the incidence of nodul ar sclerosis increased dramatically, particularly in adolescents and y oung adults, whereas mixed cellularity remained stable. The incidence of Hodgkin's disease in the elderly decreased, most likely the result of our improved ability to diagnose both Hodgkin's disease and NHL and the realization that many cases of NHL had been misclassified as Hodg kin's disease. This decrease in Hodgkin's disease occurred predominant ly in the lymphocytic depletion and miscellaneous groups.