Multiple myeloma in L'Aquila and Avezzano, Italy, 1970-89. Changes in incidence rates, symptoms at diagnosis, and survival.

From 1970 to 1989, multiple myeloma was diagnosed in 184 residents in the counties of L'Aquila and Avezzano, two cities of the Region Abruzzo in Central Italy. The data were analysed for variations by sex, classes of age, urban and residence areas, symptoms and clinical stages at presentation, causes of death, and survival curves. The average annual incidence rate in the period 1970-89 was 5.8 per 100,000 residents. This increase in trend is statistically-significant (p less than 0.01). The average incidence was consistently higher among males, the age group 61-70 years old, and residents in urban areas for the decades 1970-79 and 1980-89. The increase in incidence rates of multiple myeloma was evident in all population categories, without significant differences (p greater than 0.05) in any evaluated class. The patients diagnosed in 1970-79 presented significantly (p less than 0.05) higher percentage of bone involvement at first diagnosis with respect to the patients diagnosed in 1980-89. A significant difference (p less than 0.05) was also observed in the clinical stage distribution. Patients from the 1980-89 decade survived for a significant (p less than 0.0001) longer period of time than the diagnosed between 1970-79. No differences (p greater than 0.05) were noted regarding causes of death. These results confirm the recent data of an increased incidence of multiple myeloma in the world. This trend could be due to an improvement in diagnosis and recording of multiple myeloma. On the other hand, environmental and occupational factors may play an important role in this increase.(ABSTRACT TRUNCATED AT 250 WORDS)