Cancer Incidence Rates in Eddy and Lea Counties

New Mexico, 1970-1994

Non-Hodgkin's Lymphoma

Lymphomas are a group of cancers of the lymphatic system (NCI 1993). Hodgkin's lymphomas are separated from this group, and all other lymphomas are termed non-Hodgkin's lymphomas. In 1993 in New Mexico, lymphomas (both Hodgkin's and non-Hodgkin's) were the fifth most commonly diagnosed cancer among all men combined and among Hispanic white men (Figures 1 and 3). In 1994 in New Mexico, 216 new cases of non-Hodgkin's lymphomas were diagnosed, accounting for 3.3% of all cancers (NMTR 1996).

In general, males are diagnosed with non-Hodgkin's lymphomas more often than females; however, males and females over 65 years of age are diagnosed at the same rate (NCI 1993). Risk factors are not well known, but may include viruses such as HIV, human T-cell leukemia virus-1, and Epstein-Barr virus; health conditions such as asthma, allergies, arthritis, rheumatic fever, tuberculosis, and infectious mononucleosis; drugs such as certain agents used for chemotherapy and common steroids; and certain chemicals including pesticides.

Nationally, the incidence rates of non-Hodgkin's lymphomas increased by about 150% over the last two decades, from 8.5 per 100,000 in 1973 to 14.9 in 1990 (NCI 1993). Rates among males increased more than among females (males by 83% and females by about 61%). The incidence rates of non-Hodgkin's lymphomas were substantially higher among males between 20 and 54 years old residing in the San Francisco/Oakland area. However, even if this group is not included, the incidence of non-Hodgkin's lymphomas increased among men in this age group. HIV accounts for only part of the increase in incidence rates of non-Hodgkin's lymphomas, although it may account for more of these increases in the future. Other risk factors probably account for less than 50% of the incidence rate increases of the last four decades. In New Mexico, incidence rates of non-Hodgkin's lymphomas increased over the period of study, from approximately 6 per 100,000 in 1971 to 11 in 1993 (Figure 34), but are generally lower than US rates.

Spatial Variation

Spatial variation of incidence rates for non-Hodgkin's lymphomas, for the period between 1970 and 1992, among residents of New Mexico, Eddy County, and Lea County, is presented in Tables 33, 34 and 35.

Non-Hispanic Whites: During the period studied, the incidence rate for non-Hodgkin's lymphoma among non-Hispanic white males and females combined was 10.6 per 100,000 statewide, and ranged from a low of 3.6 in Guadalupe County to a high of 18.1 in Taos County. The incidence rate among non-Hispanic white females in Lea County was below the corresponding statewide rate.

Hispanic Whites: During the period studied, the incidence rate for non-Hodgkin's lymphoma among Hispanic white males and females combined was 6.7 per 100,000 statewide, and ranged from a low of no cases in Catron, De Baca, and Los Alamos counties to a high of 11.6 in Eddy County. Incidence rates of non-Hodgkin's lymphoma among Hispanic white males in Eddy County were above the corresponding statewide rates. The incidence rate for Hispanic white males in Eddy county was 15.7 per 100,000 (the highest county rate among Hispanic white males in New Mexico), and for Hispanic white females in Eddy County was 7.8 per 100,000 (the fourth highest county rate among Hispanic white females in New Mexico). These incidence rates of non-Hodgkin’s lymphoma among Hispanic white males and Hispanic white females in Eddy County were higher than the corresponding rates in Lea County. The incidence rate for non-Hodgkin’s lymphoma among Hispanic white females in Lea County was below the corresponding statewide rates, and the incidence rate among Hispanic white males in Lea County (2.7) was higher than among Hispanic white females (no cases).

Temporal Variation

Temporal variation of incidence rates for non-Hodgkin's lymphomas, for the period between 1970 and 1994, among residents of Eddy County and Lea County is presented in Figures 35 and 36.

By Sex: Statewide, incidence rates of non-Hodgkin's lymphomas increased among both sexes over the period studied. Incidence rates among males were higher than among females, and increased from approximately 8 per 100,000 in 1971 to 13 in 1993. Rates among females residing in New Mexico increased from approximately 5 per 100,000 in 1971 to 10 in 1993. In Eddy County, incidence rates of non-Hodgkin's lymphoma increased overall during the study period for both sexes combined, from approximately 9 per 100,000 in 1971 to 15 in 1993. Rates also increased among males, from 7 in 1971 to 19 in 1993, and among females, from 10 in 1971 to 13 in 1993. Rates among males dropped below rates among females for several years around 1974 and experienced peaks beginning in the early 1970s and early 1980s. In Lea County, incidence rates for non-Hodgkin's lymphoma decreased overall during the study period for both sexes combined, from approximately 8 per 100,000 in 1971 to under 4 in 1993. Rates also increased among males, from approximately 12.5 per 100,000 in 1971 to under 4 in 1993. Rates for females began and ended the study period at approximately 4 per 100,000, but ranged for the intervening years from a low of no cases between 1987 and 1989 to a high of approximately 14 per 100,000 in 1985. Incidence rates for non-Hodgkin's lymphoma showed several notable peaks, for males, around 1973 and 1981, and for females, around 1976 and 1985.

By Ethnicity: Statewide, incidence rates for non-Hodgkin's lymphoma among non-Hispanic whites and Hispanic whites increased steadily during the period studied. Incidence rates for non-Hispanic whites increased from approximately 7.5 per 100,000 in 1971 to 13 in 1993, and for Hispanic whites increased from approximately 4 per 100,000 in 1971 to 9 in 1993. In general, incidence rates for non-Hodgkin's lymphoma during the period studied were higher among non-Hispanic whites than among Hispanic whites. In Eddy County, incidence rates for non-Hodgkin's lymphoma increased among non-Hispanic whites during the period studied from approximately 9 per 100,000 in 1971 to 15 in 1993, and among Hispanic whites, from approximately 5 per 100,000 in 1975 to 23 in 1993. In Lea County, the incidence rates among non-Hispanic whites decreased during the period studied, from approximately 8 per 100,000 in 1971 to under 5 in 1993. No Hispanic whites were diagnosed with non-Hodgkin's lymphoma in Lea County for many of the years studied.