Trend and Geographic Variations in the Incidence of Mantle Cell Lymphoma in the United States over 30 Years from 1975 to 2004.

Abstract

Background: Mantle cell lymphoma (MCL) is an uncommon subtype of non-Hodgkin's lymphoma (NHL). To better understand the incidence and epidemiological features of MCL in the United States, we conducted a population-based study with 2635 patients (pts) of MCL identified from 9 Surveillance, Epidemiology, and End Results (SEER) tumor registries over 30 years.Methods: From SEER public database, we identified 111 424 pts of all ages diagnosed with NHL between 1975 and 2004 in 9 SEER areas. Of these pts, 2635 had histologically confirmed MCL, accounting for 2.36% of NHL. The incidence with 95% confidence intervals were generated from SEER*Stat Software. Incidence was age-adjusted to the U.S. 2000 standard population. Annual percent change (APC) for the incidence was calculated and considered to be statistically significant if P<0.05. The crude 1-year survival rate was calculated as the ratio of the number of pts who survived over 1 year and the number of pts diagnosed with MCL.Results: Of 2,635 pts with MCL, 68.1% were late-stages (stages III IV), 25.6% were early-stages (stages I–II), and 6.3% were unstaged. Median age at diagnosis for MCL was 68.0. Overall incidence was 0.41/100,000/year, which increased by age from 0.06 in pts aged <50 to 2.11 for 70–79 and 2.02 in pts aged 80 or older. The age-adjusted incidence increased from 0.08 in 1975 to 0.67 in 2004. APC was 4.64% (P<0.05). Incidence of MCL was higher in men (0.60) than in women (0.27) (P<0.05). Annual increase was greater in men (5.67%) than in women (2.93%). There were also substantial geographic variations (P<0.05) in the incidence of MCL. The age-adjusted incidence was highest in Seattle (0.49) and the lowest in Hawaii (0.33). The incidence appeared to be higher in Caucasians (0.44) than in African-Americans (0.25) and other races (0.25). Annual increase(from 1987–2004) was 8.68% in Caucasians, and 1.64% in African-Americans and other races.Conclusions: The incidence of MCL increased progressively from 1975 to 2004, and was significantly higher in males and in Caucasians. There were substantial geographical variations in the incidence of MCL.