News from Cancer: Risk factors for deadly form of lymphoma

A new study indicates that the incidence of mantle cell lymphoma, an aggressive type of non-Hodgkin's lymphoma, is on the rise, most frequently striking men, Caucasians and older individuals. The study, published in the August 15, 2008 issue of CANCER, a peer-reviewed journal of the American Cancer Society, also reveals that most patients are diagnosed with advanced stages of the disease. While research has documented a steady increase in non-Hodgkin's lymphoma over the past several decades, the prevalence of mantle cell lymphoma, an uncommon yet distinct subtype of this cancer, remains unknown.

Mantle cell lymphoma was first established as a type of lymphoma in 1992. It is a fast-growing cancer of the immune system that is characterized by small- to medium-size cancer cells that may be in the lymph nodes, spleen, bone marrow, blood or gastrointestinal system. Despite the availability of many different types of therapies, the cancer remains incurable.

To determine how many people have been diagnosed with mantle cell lymphoma since it was first recognized, Dr. Michael Wang of the University of Texas M.D. Anderson Cancer Center and colleagues examined cancer registry data from 1992 to 2004, the most recent year for which complete data are available.

The researchers analyzed the records of 2,459 patients (2.8 percent of all patients with non-Hodgkin's lymphoma) diagnosed with mantle cell lymphoma during the time period. They found men were more than twice as likely to be diagnosed with the disease as women, and Caucasians had the highest risk of all ethnic groups. Age was a significant risk factor, with people between the ages of 70 to 79 more likely to be diagnosed with mantle cell lymphoma than all other age groups. The data also revealed that almost three-quarters of all mantle cell patients were diagnosed with advanced disease (stage III and IV).

When looking at trends during the study period, Drs. Wang and Du and their team found that the incidence rates increased progressively over time. In 1992, only 2.7 people per 1,000,000 were diagnosed, compared with 6.9 people per 1,000,000 in 2004. The investigators noted that the cause of this remarkable increase in the incidence rate of the disease over the past 13 years is unknown.

Because mantle cell lymphoma often goes undetected until later stages, it has the poorest prognosis of all lymphomas. Despite the recent discovery of new anti-cancer therapies that have improved the survival rates of patients with various types of non-Hodgkin's lymphoma, there is no clear standard approach for treating mantle cell lymphoma.

"A better understanding of the epidemiology of mantle cell lymphoma, the development of novel agents, more research funding and increased public awareness are all needed," the authors write.

Source: American Cancer Society