Colorado State University Extension
SafeFood Rapid Response Network
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Food Safety Issues for Cancer and Organ Transplant Patients
Edited by: Mary Schroeder, M.S., R.D. & Pat Kendall, Ph.D., R.D., Colorado State - Winter/Spring 2005
Cancer and organ transplant patients are included on the list of immune compromised persons at highest risk of foodborne illness. Cancer and bone marrow patients are especially susceptible to infection during periods of "neutropenia," resulting either from the underlying condition or the medical treatment used. Organ transplant patients are at high risk for infection during medical treatment and at continuing risk for the rest of their lives due to drug treatment used to prevent rejection of the transplanted organ.
The clinical marker for immune suppression is termed neutropenia, defined as a deficiency of circulating lymphocytes or neutrophils. Neutropenia results during radiation therapy or chemotherapy when beneficial white blood cells are destroyed along with targeted cancer cells.
Cancer and Bone Marrow Transplant
There are three main medical treatments used for cancer: radiation therapy, chemotherapy and bone marrow transplants. All result in some level of neutropenia, created as the cytotoxic agent attacks rapidly dividing cells. Whenever neutrophil counts drop below 500 cells/microliter, the patient is considered at high risk for opportunistic infection. Patients receiving intermittent cycles of chemotherapy will have 3-5 days of neutropenia post therapy. Patients receiving myeloablative therapies in preparation of a bone marrow transplant or to treat leukemia will experience periods of neutropenia lasting 23-27 days after treatment. Persons receiving bone marrow transplants are most susceptible to opportunistic infections during the 2-4 weeks before and following transplantation. Most patients will be prescribed a low microbial diet during this period to minimize the chance of infection from foodborne pathogens. When the neutrophil count returns to 500 cells/l, the risk of opportunistic infection has begun to subside. Immunosuppressive drugs are not necessary to maintain bone marrow transplants. Therefore, if all other co-morbidities are resolved and if there are no other lifespan or pharmacological reasons for immune suppression, most cancer and bone marrow patients fully recover their immune function and risk of opportunistic infection returns to that of a healthy individual within 6 to 18 months following treatment. Particular concern for food handling behavior also returns to the usual precautions used by all individuals.
Solid Organ Transplants
The absolute neutrophil count is also used to monitor immune suppression in persons with organ transplants. Opportunistic infection can be caused by any type of microorganism from either the environment or food. The greatest susceptibility to infection occurs during the first month following the transplant.
To help prevent rejection of the transplanted organ, most patients need to take drugs like cyclosporine, azathioprine, or mycophenolate for the rest of their lives. Drug therapy suppresses immune function to a "low normal" level, enough to prevent rejection but still provide some protection against opportunistic infection. Transplant patients are most susceptible to infections during the first 6 months post transplantation due to higher doses of immunosuppressive drugs. They will remain at risk of opportunistic infections, at least to some degree, for as long as they are on the medical treatment. For this reason, organ transplant patients need to be cautious about food handling practices for life since foodborne pathogens could be the cause of an opportunistic infection.
Pathogens
Pathogens of particular concern to cancer and transplant patients include Norovirus, Shigella spp., E. coli 0157, Salmonella spp., Campylobacter jejuni, Yersinia enterocolitica, Toxoplasma gondii, Vibrio spp., and Listeria monocytogenes. Severe foodborne illnesses or consequences resulting from the illnesses may occur in cancer and transplant patients if care is not taken in food selection and handling.
The majority of cases of Listeria monocytogenes occur in individuals with suppressed immune systems. Compared with the general population, cancer patients with solid tumors are 66 to 229 times more susceptible to becoming infected with Listeria monocytogenes, and individuals with blood-borne cancers have a 1,364 times greater risk. Transplant patients are at the top of the list with a risk that is over 2,500 times greater than a healthy adult. This high relative risk justifies the guidance that cancer and transplant patients should avoid the following risky foods, especially during times of greatest immune suppression:
- Raw or undercooked meat, poultry, eggs, fish, and shellfish
- Unpasteurized milk and chilled fruit juices
- Raw sprouts (like alfalfa)
- Soft cheeses made with raw milk
- Hot dogs and luncheon meats that have not been reheated to steaming hot
- Refrigerated pates and meat spreads
- Refrigerated smoked fish and pre-cooked seafood, such as shrimp and crab
Education Materials
Food safety materials designed specifically for persons with cancer or organ transplant can be found on the Colorado State University SafeFood website.
- Online continuing education course: Food Safety for High Risk Populations; Pilot Oct. 2004. Available at http://www.hec.osu.edu/highriskfoodsafety/. Presenter: Hillers, V. Professor, Extension Specialist. Washington State University.
- Kendall P, Medeiros LC, Hillers V, Chen G, DiMascola S. Food handling behaviors of special importance for the pregnant, young, elderly and immune compromised. J Amer Diet Assoc. 2003;103:1646-1649.
