Cancer Incidence Rates in Eddy and Lea Counties

New Mexico, 1970-1994

Uterine (Corpus) Cancer

The uterus has three distinct regions: the cervix, the lower uterine segment, and the corpus (Crum 1994). Cancer of the corpus uterus is the most commonly diagnosed cancer of the female genital system in the US (NCI 1993). The most common type of corpus uterine cancer is cancer of the endometrium, comprising 7% of all cancers diagnosed in females (not including skin cancers) (Crum 1994). In New Mexico in 1993, invasive cancer of the corpus uterus was the fourth most frequently diagnosed cancer in women (Figure 1).

Cancer of the corpus uterus is rare in women under 40 years of age, and in the period between 1986 and 1990, women aged 65 years and over were diagnosed with this cancer about eight times more than women under 65 (NCI 1993). Risk factors for cancer of the corpus uterus include obesity as well hormonal factors such as estrogen use, infertility, early age at menarche, never giving birth, and late age at menopause (NCI 1993; Mettler 1995).

Nationally, incidence rates of invasive cancer of the corpus uterus decreased over the last two decades, from 28.4 per 100,000 in 1973 to 21.2 in 1990 (NCI 1993). In New Mexico, incidence rates of cancer of the corpus uterus were lower than US rates, decreasing over the period of study from approximately 18 per 100,000 in 1971 to 16 in 1993 (Figure 49).

Spatial Variation

Spatial variation of incidence rates for uterine cancer, for the period between 1970 and 1992, among female residents of New Mexico, Eddy County, and Lea County, is presented in Table 44.

Non-Hispanic Whites: During the period studied, the incidence rate for uterine cancer among non-Hispanic white females was 21.2 per 100,000 statewide, and ranged from a low of no cases in Mora County to a high of 32.8 in Harding County. The uterine cancer incidence rate among non-Hispanic white females in Lea County was lower than the corresponding statewide rate.

Hispanic Whites: During the period studied, the incidence rate for uterine cancer among Hispanic white females was 10.7 per 100,000 statewide, and ranged from a low of 1.5 in Lea County to a high of 16.8 in Torrance County. The uterine cancer incidence rate among Hispanic white females in Lea County was below the corresponding statewide rate, and below the incidence rate among non-Hispanic white females in that county. The uterine cancer incidence rate among Hispanic white females in Eddy County was 14.8 per 100,000 (the fourth highest county rate among Hispanic white females in New Mexico).

Temporal Variation

Temporal variation of incidence rates for uterine cancer, for the period between 1970 and 1994, among female residents of Eddy County and Lea County is presented in Figures 50 and 51.

Females: In Eddy County, while incidence rates for uterine cancer were higher in 1993 than in 1971, rates for intervening years varied widely, and no clear increasing trend was discernible. In Lea County, incidence rates for uterine cancer decreased during the period studied, from approximately 16 per 100,000 in 1971 to 7 in 1993.

By Ethnicity: Statewide, uterine cancer incidence rates were higher for non-Hispanic whites than for Hispanic whites. While rates for non-Hispanic whites decreased over the study period, from approximately 23 per 100,000 in 1971 to 18 in 1993, rates for Hispanic whites increased slightly, from approximately 10 per 100,000 in 1971 to 13 in 1993. In Eddy and Lea counties, the magnitude and variation of incidence rates for uterine cancer during the study period appear to have been determined by incidence rates for non-Hispanic whites. Rates for Hispanic whites were variable, and no incidence of uterine cancer was reported for many of the years studied.