Cancer Incidence Rates in Eddy and Lea Counties

New Mexico, 1970-1994

Prostate

In 1993 in New Mexico, prostate cancer was the most frequently diagnosed cancer in men of all ethnicities (Figures 1 and 3).

During the period between 1986 and 1990, men aged 65 years and over were diagnosed with this cancer about forty times more often than men under 65 years (NCI 1993). Risk factors may include having a family history of prostate cancer, a diet including high consumption of fat or animal fat, multiple sexual partners, certain occupations, and possibly, having a vasectomy.

Nationally, invasive prostate cancer incidence rates have doubled over the last several decades from 64.1 per 100,000 in 1973 to 128.9 in 1990 (NCI 1993). In New Mexico, incidence rates of invasive prostate cancer were comparable to, or higher than, US rates, more than doubling over the period of study, from approximately 70 per 100,000 in 1971 to 160 in 1992 (Figure 40). Much of this increase appears to have occurred after 1987, and rates began to level off in 1990 and to drop in 1992.

Spatial Variation

Spatial variation of incidence rates for prostate cancer, for the period between 1970 and 1992, among males residing in New Mexico, Eddy County, and Lea County, is presented in Tables 37.

Non-Hispanic Whites: During the period studied, the incidence rate for prostate cancer among non-Hispanic white males was 105 per 100,000 statewide, and ranged from a low of 44.6 in Harding County to a high of 154 in Los Alamos County. Prostate cancer incidence rates among non-Hispanic white males in Eddy and Lea counties were below the statewide rate.

Hispanic Whites: During the period studied, the incidence rate for prostate cancer among Hispanic white males was 77.1 per 100,000 statewide, and ranged from a low of 19.1 in De Baca County to a high of 109 in McKinley County. Prostate cancer incidence rates among Hispanic white males in Eddy and Lea counties were below the statewide rate.

Temporal Variation

Temporal variation of incidence rates for prostate cancer, for the period between 1970 and 1994, among males residing in Eddy County and Lea County is presented in Figures 41 and 42.

Males: Statewide, prostate cancer incidence rates more than doubled over the period of study from approximately 70 per 100,000 in 1971 to 160 in 1992. Much of this increase occurred after 1987, and rates began to level off in 1990 and drop in 1992. In Eddy and Lea counties, prostate cancer incidence rates were lower than statewide rates during the study period. In Eddy County, prostate cancer incidence rates followed the same patterns as statewide rates, increasing from approximately 60 per 100,000 in 1971 to 145 in 1992, and then decreasing to 130 in 1993. In Lea County, prostate cancer incidence rates increased from approximately 65 per 100,000 in 1971 to 145 in 1992, and then dropped to 135 in 1993. However, the characteristic of prostate cancer incidence rates of rising rapidly appears to have started a few years later in Lea County than statewide.

By Ethnicity: Statewide, prostate cancer incidence rates during the period studied increased among non-Hispanic whites from approximately 80 per 100,000 in 1971 to 160 in 1993, and among Hispanic whites from approximately 50 per 100,000 in 1971 to 124 in 1993. These rates increased more smoothly for Hispanic whites than non-Hispanic whites. On the county level, prostate cancer incidence rates for non-Hispanic whites were generally higher than for Hispanic whites over the period studied, and appear to have determined the variation and magnitude of incidence rates for all ethnicities. In Eddy County, prostate cancer incidence rates among non-Hispanic whites increased from approximately 60 per 100,000 in 1971 to 140 in 1993, and rates among Hispanic whites increased from approximately 17 per 100,000 in 1971 to 120 in 1993. A major portion of this increase in incidence rates among both ethnicities occurred after 1987. In Lea County, prostate cancer incidence rates among non-Hispanic whites increased from approximately 65 per 100,000 in 1971 to 145 in 1993, with much of this increase after 1989. Prostate cancer incidence rates among Hispanic whites varied widely during the period studied, with no cases reported for many years.

Factors Affecting Rates: The rapid increase of prostate cancer incidence rates in New Mexico, Eddy County, and Lea County are associated with a change in diagnostic practices (the use of a blood test for prostate specific antigen) (Gilliland 1995).