Anal cancer incidence and survival: the surveillance, epidemiology, and end results experience, 1973-2000.

BACKGROUND: Anal cancer is a rare malignancy of the anogenital tract that historically has affected women at a greater rate than men.
METHODS: The authors analyzed changing trends in incidence rates and 5-year relative survival percentages for patients with anal cancer. The publicly available data used in the current study were obtained from the Surveillance, Epidemiology, and End Results (SEER) Program, a system of population-based tumor registries in the United States.
RESULTS: The incidence of anal cancer was similar for men and women between 1994 and 2000 (2.04 per 100,000 and 2.06 per 100,000, respectively), the most recent period for which data were available, whereas men had lower rates than did women between 1973 and 1979 (1.06 per 100,000, compared with 1.39 per 100,000), the earliest period for which data were available. In addition, recently, black men had higher incidence rates than did other race-specific and gender-specific groups (2.71 per 100,000). From the earliest period for which data were available to the most recent period, relative 5-year survival improved from 59% to 73% among women, was unchanged among men ( approximately 60%), and decreased from 45% to 27% among black men. Eighteen percent of patients who had distant disease were alive at 5 years, compared with 78% of patients who had localized disease.
CONCLUSIONS: The incidence of anal cancer in the United States increased between 1973 and 2000, particularly among men. There were higher incidence rates and lower survival rates for black men compared with other race-specific and gender-specific groups. Later disease stage was inversely associated with the survival rate, indicating that earlier detection may improve the survival of patients with anal cancer. Copyright 2004 American Cancer Society.