Study finds cancer patients may face increased risk of food-borne illness listeria

In collaboration with Adfero

People with cancer face an increased risk of developing the food-borne illness listeria, UK scientists have reported in the journal Emerging Infectious Diseases.

There have been more cases of listeria in recent years, with 3.6 cases per million people between 2001 and 2009, compared to just 2.1 per million people between 1990 and 2000.

The illness is caused by the bacterium Listeria monocytogenes and is rare, but can be serious if caught by pregnant women, unborn or newborn babies, elderly people, or those with a weak immune system.

Researchers at the Health Protection Agency (HPA) reviewed 1,413 people who had listeria between 1999 and 2009. Pregnant women and their unborn or newborn children were not included in this study.

Two-thirds (936) of patients had one or more underlying conditions and, among these patients, over-60s were found to have a higher rate of listeria than younger people.

The researchers observed that the rate of listeria was nearly five times higher for cancer patients than for those with other underlying conditions.

Patients with blood cancers were found to have the greatest risk.

Overall, one in three cases of listeria involved a patient with cancer - of these, over 40 per cent were patients with blood cancers.

Dr Bob Adak, head of epidemiology services in the HPA's gastrointestinal diseases department, said: "Our research has shown that those receiving cancer treatment or suffering from a variety of conditions, including diabetes, kidney or liver disease, should be offered appropriate health advice on how to avoid listeria. At present this is given passively and mainly to pregnant women, but clearly there are other groups of people who need to be advised on what they can do to protect their health."

Dr Adak noted that listeria can cause serious illness and may prove fatal in patients with certain underlying health conditions, such as cancer.

"Taking steps to avoid infection is a very important part of managing their health and these groups need to be made aware of how they should do this," he advised.

People can reduce their risk of listeria infection by avoiding certain foods, including pre-packed and sliced delicatessen meats; soft cheeses; smoked fish; pate; pre-prepared cooked and chilled meals; pre-prepared sandwiches; and un-pasteurised milk.

Martin Ledwick, head information nurse at Cancer Research UK, said: "Currently patients who are receiving high doses of chemotherapy should be advised to take precautions to avoid food-borne infections.

"This study may suggest that this advice should be extended to all cancer patients having any type of treatment that compromises their immunity. But, as it is not clear from the work what type of treatments the cancer patients with listeria were having, it's not certain whether this precaution is absolutely necessary for all cancer patients."

References

  • Piers Mook, Sarah J. O’Brien, and Iain A. Gillespie - Concurrent Conditions and Human Listeriosis, England, 1999–2009 DOI: 10.3201/eid1701.101174