Hodgkin's disease.

BACKGROUND

Over three time periods, 1973-1977, 1978-1982, and 1983-1987, 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 trends that emerged over the time intervals of this study.

RESULTS

Hodgkin's disease had a bimodal distribution of age-specific incidence rates with two peaks in the age groups of 15-34 years and older than 55 years. Since 1973, the incidence of Hodgkin's disease in the younger age group increased progressively as a result of a marked increase in the incidence of the nodular sclerosis subtype. From the period 1973-1977 to 1983-1987, the age-adjusted incidence rate of nodular sclerosis rose from 1.1 to 1.6 per 100,000. In 1983-1987, nodular sclerosis represented 57.7% of Hodgkin's disease and occurred most often in whites, with an equal sex ratio. In females, this increase in incidence over time was most dramatic in young adult women. The overall incidence of the mixed cellularity subtype, 23.4% of Hodgkin's disease, remained stable 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 lymphocytic depletion subtype, 3.8% of Hodgkin's disease, occurred predominantly in the elderly; its incidence decreased, most likely the result of changes in diagnostic criteria, with many cases being reclassified as non-Hodgkin's lymphoma (NHL). Similarly, unclassifiable cases of Hodgkin's disease designated as miscellaneous, 9.1% of Hodgkin's disease, decreased over time, probably the result of improved classification. Nevertheless, a subset of cases of Hodgkin's disease remained difficult to subclassify. The human immunodeficiency virus (HIV) epidemic appears to be associated with an increased incidence of Hodgkin's disease in San Francisco County in adult males age 30-49 years, a population known to have a high prevalence of HIV infection.

CONCLUSION

The SEER data suggest that Hodgkin's disease is a heterogeneous entity composed of at least two different diseases--nodular sclerosis and mixed cellularity. Over the time course of this study, the incidence of nodular sclerosis increased dramatically, particularly in adolescents and young 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 Hodgkin's disease. This decrease in Hodgkin's disease occurred predominantly in the lymphocytic depletion and miscellaneous groups.