Why Do U.S. Asians Suffer More and Deadlier Enteropathy-associated T-cell Lymphoma?

Celiac.com 08/24/2015 - A new study reveals that U.S. Asians experience higher rates of deadlier cases of Enteropathy-associated T-cell lymphoma EATL.

Enteropathy-associated T-cell lymphoma is a rare primary intestinal non-Hodgkin lymphoma (NHL) strongly associated with celiac disease. It is an aggressive disease with a median survival of approximately 10 months (Ferreri et al, 2011).

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Previous studies suggest that EATL may be more common in Europe and among Whites, among whom celiac disease is prevalent (Delabie et al, 2011; Ferreri et al, 2011). However, a second type of EATL (Type II) not associated with celiac disease is increasingly reported in Asia (Lee et al, 2005; Sun et al, 2011; Tan et al, 2013).

To date, there have been no comparative epidemiological study in a racially diverse large population. A team of researchers recently set out to conduct such a study. The research team included Pawan K. Karanam, Mohammed Al-Hamadani, and Ronald S. Go. They are variously associated with the Departments of Medical Education and Medical Research at the Gundersen Medical Foundation in La Crosse, USA, and with the Division of Hematology at the Mayo Clinic, and the Mayo Clinic's Robert D, and Patricia E. Kern Center for the Science of Health Care Delivery, Rochester, MN, USA.

The team turned to the two largest public cancer databases in the US: the Surveillance, Epidemiology, and End Results (SEER) database (Open Original Shared Link); and the National Cancer Data Base (NCDB; Open Original Shared Link).

Using these databases, the research team was able to find and compare the cases of EATL by race. They were also able to describe the clinical features and overall survival (OS) for these cases. 

The team's study included all patients with an EATL diagnosis according to International Classification of Diseases for Oncology (ICD-O: 9717). The team used SEER-18 registries from 2000 to 2011 to calculate incidence.

To describe clinical outcomes, they used the NCDB NHL-PUF with patients diagnosed between 1998 and 2012 for clinical characteristics and those diagnosed between 1998 and 2006 for OS. Because CoC-accredited programs report survival data only once every 5 years, OS analysis was possible only for patients diagnosed between 1998 and 2006.

From the data, the team calculated the incidence rate (case/1 000 000), age-adjusted to the 2000 standard US population, according to race (White, Black, Asian/Pacific Islander, American Indian/Alaska native) using seer*stat software version 8.1.5 (National Cancer Institute, Bethesda, MD, USA) and performed risk ratio comparisons using Poisson regression.

They analyzed OS using the Kaplan–Meier method and used log-rank tests to compare survival distributions between race cohorts. The prognostic effect of pertinent clinical variables were studied using multivariate Cox proportional hazards models.

They found that, for the years 2000–2010, the overall age-adjusted incidence rate of EATL in the US was 0·111 per 1,000,000. Asians/Pacific Islanders had a higher incidence rate (0·236) compared with other races [White (0·101), Black (0·107), American Indian/Alaska native (0·128)].

The risk ratio of Asians/Pacific Islanders compared with non–Asians/Pacific Islanders was 2·32 [95% confidence interval (CI) 1·39–3·69; P = 0·002].

The incidences for Asians and Pacific Islanders were combined in seer*stat, therefore we could not provide separate incidences for Asians and Pacific Islanders.
All tests of statistical significance were two-sided and P < 0·05 was considered significant.

Source:

• Open Original Shared Link