COLUMBIA, SC—Limited data are available regarding the incidence, survival patterns, and long-term outcomes of natural killer/T-cell neoplasms in the United States.

A new study conducted to remedy that lack of information reported in Clinical Lymphoma, Myeloma & Leukemia that rates were rising significantly.1

A study team led by the University of South Carolina School of Medicine and including participation from the VA Nebraska Western Iowa Health Care System performed a retrospective study of patients with NK/T-cell neoplasms diagnosed from 2001 to 2014 using the Surveillance, Epidemiology, and End Results program database. The researchers estimated the overall survival difference among the subgroups and analyzed the data to determine the factors affecting survival.

They found that, for the 797 patients with NK/T-cell lymphoma, nasal type, the median age at diagnosis was 53 years, and males tended to be younger at diagnosis (P< .0001).

What was surprising was how much diagnosis of the disease had increased, study authors said pointing out that incidence increased from 0.4 in 2001 to 0.8 in 2014 per 1,000,000 individuals, with incidence significantly greater in Hispanic patients compared with that in non-Hispanic patients (rate ratio, 3.03; P= .0001).

The median overall survival, meanwhile, was 20 months (range, 2-73 months) and varied significantly according to the primary site (P< .0001) and the disease stage at diagnosis (P< .0001). NK/T-cell lymphoma patients also had an increased risk of acute myeloid leukemia (standardized incidence ratio, 18.77; 95% confidence interval, 2.27-67.81), the study said.

Specifically for the 105 NK/T-cell leukemia patients, the median age at diagnosis was 58 years (range, 4-95 years), and the overall incidence of the disease was 0.09 per 1,000,000 individuals, although significantly greater in males (rate ratio, 0.41; P< .0001). Unlike NK/T-cell lymphoma, no racial disparities were found in the incidence, researchers pointed out, adding that the median overall survival was 17 months (range, 0-36 months).

“The incidence of NK/T-cell lymphoma, nasal type, in the United States has at least doubled in the past decade, with the greatest predilection among Hispanics,” study authors concluded. “Patients with NK/T-cell lymphoma might have an increased risk of the subsequent development of acute myeloid leukemia.”

1. Kommalapati A, Tella SH, Ganti AK, Armitage JO. Natural Killer/T-cell Neoplasms: Analysis of Incidence, Patient Characteristics, and Survival Outcomes in the United States. Clin Lymphoma Myeloma Leuk. 2018 Jul;18(7):475-479. doi: 10.1016/j.clml.2018.04.009. Epub 2018 May 4. PubMed PMID: 29752210.