LEUKEMIAS, MYELOMA, AND OTHER LYMPHORETICULAR NEOPLASMS

Background. The purpose of this study was to assess the occurrence of various morphologic types of leukemia and myeloma within patient demog raphic groups and to correlate findings with data-reporting periods an d other variables, such as 5-year relative survival. Methods. Data fro m 31,850 cases of multiple subgroups of acute and chronic leukemia, 12 ,237 cases of myeloma, and 321 cases of ''other'' lymphoreticular neop lasms were collected by the National Cancer Institute's Surveillance, Epidemiology; and End Results (SEER) program. The data were examined b y age, sex, race, age-specific and age-adjusted incidence rate, and pa tient 5-year relative survival during three reporting periods: 1973-19 77, 1978-1982, and 1983-1987. Results. The age-adjusted incidence rate for all categories of leukemia combined has been constant, but there has been an increase in the relative frequency (percentage) of acute l ymphoid leukemia (ALL) in the general population and a rising incidenc e rate of myeloid leukemia in the black population. The increase of AL L is offset by a decline of acute myeloid leukemias (AMLs) and acute l eukemia, not otherwise specified. The age-adjusted rate of ALL in whit es, 1.5 per 100,000 per year, is twice that of blacks, 0.8. The rates for each of the major categories of leukemia are considerably higher i n males than in females. Five-year survival rates changed very little for leukemias over the 15 years of the study except for ALL, in which there was a marked improvement between the first (1973-1977) (39.1%) a nd second (1978-1982) (51.3%) reporting period. The SEER data confirm that multiple myeloma is predominantly a disease of late adulthood and occurs more frequently in blacks and males. The incidence rate of mul tiple myeloma has not changed during the 15 years surveyed. The 5-year relative survival rate has remained nearly constant for multiple myel oma. There is a marked difference in 5-year relative survival rates fo r patients with plasmacytoma of bone marrow (45.7%), multiple myeloma (25.9%), and plasma cell leukemia (13.0%). Conclusions. Shifts in the relative frequencies of leukemia types may have been affected by chang es in classification criteria, changes in the use of histologic terms over time, and the expanded use of immunophenotyping and other technol ogy to characterize acute leukemias. Incidence rates and 5-year relati ve survival rates for myeloma have remained stable.