Fat Tissue Levels of Pesticides and Polychlorinated Biphenyls: Risk of Non-Hodgkin's Lymphoma

Susan Korrick, MD
Harvard School of Public Health
P42ES05947

Background: Non-Hodgkin's lymphoma (NHL) is a type of cancer in B or T cells, which are immunologic cells in the human lymphatic system. NHL encompasses a collection of diseases that together are the sixth leading cause of cancer-related deaths. According to the National Cancer Institute (NCI), NHL has increased 75 percent over the last 20 years, making it the most rapidly rising cancer after lung cancer and melanoma, NCI says. Mortality from the disease also increased from 4.8 per 100,000 people in 1973 to 6.5 per 100,000 in 1991. Although recent studies have provided some intriguing clues, the cause of what some experts call the "NHL epidemic" is not known. Fortunately, advances in treatment seem to be keeping pace; the five-year survival rate for NHL rose from 31 percent to 51 percent over the past 30 years, according to NCI.

Exposure to organochlorine pesticides has been proposed as a risk factor for NHL. These compounds accumulate in the fat stores of the body. Organochlorine compounds have been found to be carcinogenic in animal studies and the use of pesticides has been associated with increased risk of NHL in farmworkers and other occupationally exposed populations. Data on exposure to specific pesticides and risk of NHL are very limited. These investigators used a unique database of human fat tissue samples that were analyzed for organochlorine pesticides and polychlorinated biphenyls (PCBs) to investigate whether exposure to organochlorine compounds is associated with increased risk of developing NHL.

Advance: A number of specific pesticides were found to be associated with increased NHL risk. They included dieldrin, heptachlor, chlordane, DDT, and hexachlorobenzene. The risks varied based on concentration of the pesticide metabolite in the tissue; they ranged from two to more than three times the risk as that of a control group.

Implication: The pesticides studied in this report although once commonly used, are no longer in use in the United States. However, given the persistence of these pesticides in the environment and their continued use in other countries, these findings are still relevant. Other researchers have shown links between organochlorine exposure and cancer severity; therefore it is possible that exposure to the pesticides studied may result in a more aggressive type of NHL or worsen the disease course and prognosis.

Citation: Quintana PJ, Delfino RJ, Korrick S, Ziogas A, Kutz FW, Jones EL, Laden F,Garshick E. Adipose tissue levels of organochlorine pesticides and polychlorinated biphenyls and risk of non-Hodgkin's lymphoma. Environ Health Perspect. 2004 Jun;112(8):854-61.