Background Cutaneous T-Cell Lymphomas (Mycosis Fungoides and its leukemic variant, Sézary Syndrome) are rare malignancies. Reports of occurrence of Mycosis Fungoides in married couples and families raise the possibility of an environmental trigger for this cancer. While it was suggested that CTLC arises from inappropriate T cell stimulation, currently no preventable trigger has been identified. Methods We analyzed by region, zip code, age, sex and ethnicity the demographic data of 1047 patients from Texas, who were seen in a CTCL clinic at the MD Anderson Cancer Center during 2000-2012 (the MDACC database) and 1990 patients that were recorded in the population-based Texas Cancer Registry (TCR) between 1996-2010. Subsequently data from both databases was cross analyzed and compared. Results Our findings, based on the MDACC database, document geographic clustering of patients in three communities within the Houston metropolitan area, where CTCL incidence rates were 5-20 times higher than the expected population rate. Analysis of the TCR database defined the CTCL population rate for the state to be 5.8 [95% CI 5.5, 6.0] cases per million individuals per year, confirmed the observations from the MDACC database and further highlighted additional areas of geographic clustering and regions spared by CTCL in Texas. Conclusions Our study documents geographic clustering of CTCL cases in Texas and argues for the existence of yet unknown external causes/triggers for this rare malignancy.

Cutaneous T-cell lymohomas (CTCLs) are rare, but potentially devastating malignancies, with Mycosis fungoides and Sézary Syndrome being the most common. In our previous study, we identified and described regions of geographic clustering of CTCL cases in Texas by analyzing ∼1990 patients using two distinct cancer registries. In the current work, we describe in detail demographic patterns for this malignancy in our study population and apply logistic regression models to analyze the incidence of CTCL by sex, race, age, and clinical stage at the time of diagnosis. Furthermore, using Fisher's exact test, we analyze changes in incidence over time in the identified Houston communities with unusually high CTCL incidence. While CTCL primarily affects Caucasian individuals >55 years old, we confirm that it presents at a younger age and with more advanced disease stages in African-American and Hispanic individuals. Also, we demonstrate a significant increase in CTCL incidence over time in the identified communities. Spring, Katy, and Houston Memorial areas had high baseline rates. Furthermore, a statistically significant disease surge was observed in these areas after ∼2005. This report supplements our initial study documenting the existence of geographic clustering of CTCL cases in Texas and in greater detail describes demographic trends for our patient population. The observed surge in CTCL incidence in the three identified communities further argues that this malignancy may be triggered by one or more external etiologic agents.

OBJECTIVES. This study uses Indian Health Service inpatient data to estimate cancer incidence among American Indians and Alaska Natives. METHODS. Hospital discharge data for 1980 through 1987 were used to identify cases of cancer for 21 sites in women and 18 sites in men. Estimates of incidence were directly standardized to data from the Surveillance, Epidemiology, and End Results Program for the same time frame. RESULTS. Cancers of the gallbladder, kidney, stomach, and cervix show generally high rates among many American Indian and Alaska Native communities, and cancers of the liver and nasopharynx are high in Alaska. Of the relatively common cancers in Whites, American Indians and Alaska Natives experience lower rates for cancers of the breast, uterus, ovaries, prostate, lung, colon, rectum, and urinary bladder and for leukemia and melanoma. Variation among geographic areas and among tribal groups is observed for many important cancer sites. CONCLUSIONS. This study demonstrates significant variations of cancer rates among American Indians and Alaska Natives, with important implications for Indian Health Service cancer control programs. The study also supports the potential use of hospital discharge data for estimating chronic disease among diverse American Indian and Alaska Native communities.

Although cancer incidence and mortality rates are known to be higher in urban populations, more unstaged tumors and later staged cancer are diagnosed in rural populations. Most investigators have used a dichotomous definition of urban and rural in studying these populations, and they have not considered whether a more detailed categorization of rural areas could influence their findings. The objective of this study was to evaluate colorectal cancer incidence and mortality rates in Texas from 1990 to 1992 by using a dichotomous definition (Metropolitan Area vs. Nonmetropolitan Area [MA/non-MA]) and two more detailed rural classifications (the Rural-Urban Continuum Code [RUCC] and the Urban Influence Code [UIC]). Cancer data were obtained from the Texas Cancer Registry for 1990 to 1992 and supplemented with data from the Texas State Department of Vital Statistics (mortality), the US Census Bureau (age, gender, race) and the Area Resource File (rural and urban definitions). Incidence and mortality rates, age-adjusted to the 1970 US standard population, were calculated for non-Hispanic White, African American, and Hispanic males and females. Results revealed a nonlinear relationship between rural category and colorectal cancer incidence or mortality for all races. Applying the MA definition yielded rates in the middle of the ranges obtained with using RUCC or UIC classifications and most closely reflected the result for non-Hispanic Whites using the more detailed scales. Our results suggest that a dichotomous definition of rural and urban may mask important variation in colorectal cancer incidence and mortality rates within rural areas.

We conclude that it is feasible to develop state-specific cancer incidence and survival estimates for American Indians in at least some states in different regions of the United States. Collaboration between the IHS and a state tumor registry is likely to improve the case ascertainment achieved by either agency alone.