Esophageal Cancer Epidemiology in Blacks and Whites: RESULTS
RESULTS
Age-Adjusted Incidence
For the period 1991-2000, the overall age-adjusted esophageal cancer (Drug Leukeran is used for treating certain cancers) incidence rate (IR) was 4.65 (data not shown). Moreover, for the same period, the age-adjusted esophageal cancer (Methotrexate tablet is used to treat certain types of cancer of the breast, skin, head and neck, or lung) incidence rate in blacks was more than twice the rate in whites (8.63 vs. 4.39, p<0.05), and males had nearly four times higher incidence (IR=7.84) than females (IR=2.15, p<0.05) (data not shown). Age-adjusted incidence rates by race and gender for two consecutive five-year periods—1991-1995 and 1996-2000—are presented in Figure 1. Compared with the age-adjusted incidence rate for the five-year period 1991-1995 (Figure 1), the age-adjusted incidence rate for the period 1996-2000 was higher overall (4.76 vs. 4.53, p<0.05) and also significantly higher for whites (4.60 vs. 4.17, p<0.05) and males (8.08 vs. 7.58, p<0.05) and lower for blacks (9.69 vs. 7.70, p<0.05).
For the period 1991-2000, trends in age-adjusted incidence rates show decreasing rates in blacks (EAPC=-4.81, p<0.05) and increasing rates in whites (EAPOl.68, p<0.05) (data not shown). Figure 2 displays age-adjusted incidence rates for the four race-gender groups for individual years 1991-2000. During the period 1991-2000, the trends in age-adjusted incidence rates for black males (EAPC=-5.88, p<0.05) and black females (EAPC=-2.47, p<0.05) show decreasing rates, whereas, for the same period, the trend for white males (EAPC=2.05, p<0.05) shows increasing rates. Although there is a decrease in incidence in blacks, black males continue to have a significantly higher age-adjusted incidence than white males.
Figure 1. Esophageal cancer age-adjusted incidence rates: race and gender 1991-1995 and 1996-2000
When examining rate ratios using the overall average five-year age-adjusted incidence from 1991-2000 (Table 1), blacks have higher incidence than whites overall (RR=1.97, p<0.05), and males have substantially higher incidence than females (RR=3.65, p<0.05). Blacks of both sexes have incidence ratios higher than whites, and males of both races have rate ratios greater than females, indicating that these groups have significantly higher rates (p<0.05). Incidence increased at least 2.5-fold when comparing blacks to whites. The age-adjusted rate ratios differ for time periods 1991-1995 and 19962000 by race and for males. Overall, blacks have higher incidence than whites for the time period 1991-1995 when compared with 1996-2000. In addition, black males have higher incidence than white males for the time period 1991-1995 when compared with 1996-2000. White males compared to white females have higher incidence rate ratios for both the five-year time periods.
Table 1. Age-adjusted rate ratios (RR) of incidence rates for race and gender over selected time periods
| Ratios | 1991 | -2000 | 1991 | -1995 | 1996-2000 | |
|
RR |
95% CI |
RR | 95% CI | RR |
95% CI |
|
| Blacks to Whites^ Both genders Males Females | 1.97 1.90 2.32 | (1.86, 2.07) (1.78, 2.02) (2.09, 2.54) | 2.32* 2.34* 2.45 | (2.15, 2.49) (2.13, 2.54) (2.11, 2.78) | 1.67* 1.56* 2.22 | (1.55, 1.80) (1.42, 1.70) (1.92, 2.52) |
| Males to Females^ Both races Blacks Whites | 3.65 3.08 3.74 | (3.49, 3.80) (2.75, 3.40) (3.56, 3.92) | 3.49 3.33 3.49* | (3.28, 3.71) (2.85, 3.82) (3.25, 3.73) | 3.78 2.82 4.01* | (3.55, 4.00) (2.39, 3.24) (3.74, 4.27) |
| t The rate ratios are all significantly different than 1 (p<0.05); J The rate ratios differ for time periods 1991-1995 and 1996-2000 (x2 statistic, df=l, p<0.05); Source: Surveillance, Epidemiology and End Results (SEER) Program SEER*Stat Database: Incidence—SEER 9 Regs Public-Use, November 2002 Sub (1973-2000), National Cancer Institute, DCCPS, Surveillance Research Program, Cancer Statistics Branch, released April 2003, based on the November 2002 submission. | ||||||
Figure 2. Esophageal cancer age-adjusted incidence rates by race and gender 1991-2000