Aflatoxin exposure may up gallbladder cancer risk in Chilean women

Last Updated: 2015-05-28

By Joan Raymond

NEW YORK (Reuters Health) - Exposure to aflatoxin may be associated with an increased risk of gallbladder cancer, researchers in Chile say.

This possibility was "only suggested in previous discussions, and never evaluated directly," Dr. Catterina Ferreccio, of the School of Medicine, Pontifical Catholic University of Chile, Santiago, told Reuters Health by email.

In Chile, gallbladder cancer is a leading cause of cancer deaths in women, the authors wrote. Contamination with aflatoxin, a known liver carcinogen, has been identified in Chile, including in red chili peppers.

"Aflatoxin forms adducts with albumin in peripheral blood that accumulate up to 30-fold higher with chronic versus single exposure," the authors wrote.

As reported online May 26 in a research letter in JAMA, they assessed aflatoxin B1-lysine adduct (AFB1 adduct) in 36 gallbladder cancer cases, 29 controls with gallstones, and 47 community controls. Red chili pepper consumption was determined via questionnaire.

Cases and controls had similar characteristics except for red chili pepper consumption, the authors wrote.

In their analysis, the researchers detected AFB1-adducts in 23 cases (64%), seven controls with gallstones (18%), and nine community controls (23%).

Levels were highest in cases (median, 7.6 pg/mg) who were more likely to have detectable AFB1 adducts than controls with gallstones (odds ratio 9.4) or community controls (OR 13.2).

Restricted to participants with AFB1 adducts, cases with gallbladder cancer had higher levels per change of 10 pg/mg of albumin than controls with gallstones (OR 4.0) or community controls (OR 2.5).

"Our study is the first to suggest that mycotoxins are a causal factor for a digestive cancer other than hepatocellular carcinoma," Dr. Ferreccio told Reuters Health.

"If confirmed, GBC (gallbladder cancer) would be at least in part preventable," she said, adding that public health authorities would have to initiate strong food safety control programs as a primary prevention strategy.

"Despite the small number of participants, the associations between aflatoxin exposure and gallbladder cancer were statistically significant. Recall bias may affect self-reported variables, but not exposure measurement," the authors wrote.

"We cannot rule out reverse causation (i.e., cancer may affect AFB1 adduct detection) using cross-sectional data," they wrote.

The next steps would be "to conduct population-based studies in Chile to characterize the sources of aflatoxin exposure, including foods and occupational exposures, and to confirm and more precisely measure the association of aflatoxin with GBC in a larger case-control study and in a prospective population-based cohort of gallstones patients," Dr. Ferreccio said.

The researchers would also like to explore the association of aflatoxin with stomach cancer.

"The incidence rate of this cancer is high in the same regions affected by GBC, suggesting that aflatoxins may be a common risk factor," Dr. Ferreccio said.

Although surgical resection is the only potentially curative management of gallbladder cancer, "recurrences in the liver or lymph nodes after surgery are not uncommon, and the clinical course can quickly deteriorate despite systemic treatment with chemotherapy," Dr. Marissa Hill, of Rush University Medical Center in Chicago, told Reuters Health by email.

Dr. Hill, a medical oncologist who was not involved in the study, added, "These results are based upon a small number of patients, so they are hypothesis-generating, and if larger studies produced similar results, one could make the association between aflatoxin and gallbladder cancer with more confidence."

The National Cancer Institute supported this research. The authors reported no disclosures.

SOURCE: http://bit.ly/1EALNKk

JAMA 2015.