Malignant carcinoids in the USA, SEER 1992-1999. An epidemiological study with 6830 cases.

Most of our knowledge on the epidemiology of carcinoid tumours in the USA relies on studies updated during the 1980s. The aim of this study was to describe USA population-based case-series incidence in the period 1992-1999. Data were retrieved from a Surveillance Epidemiology and End Results (SEER) Program public-use file. Incidence rates, male-to-female standardized ratios, estimated annual percentage changes and 5-year relative survival rates were computed, and 6830 malignant carcinoid incident during 1992-1999 were analysed. The overall age-adjusted incidence rates were 1.9 per 100 000 for men and women. There was an excess in women for lung and stomach carcinoids, while rates were higher among men for carcinoids of the small intestine and rectum. From 1992 to 1999, incidence rates showed a 3% estimated annual increase. Thirteen per cent of the cases had metastasis at diagnosis. In the present series, 24% of carcinoid patients had more than one tumour. The overall 5-year relative survival rate was 82%. In conclusion, improvements in diagnostic techniques seem to have influenced the epidemiology of carcinoid tumours, leading to a slightly different site distribution and a better stage distribution at diagnosis. Increasing incidence and improving survival rates were shown.