Lymphoma Prevention: Environmental Exposures

In this series on lymphoma prevention, I'll be looking at some of the known risk factors for lymphoma from a prevention angle. However, the reader should always be aware of the reality that preventing cancer generally, and lymphoma specifically, is a very gray and uncertain area in medicine.

At best, cancer prevention comes to us in the form of behavioral modifications, notably by eating fruits and vegetables, by getting some exercise, and by not smoking.

Experts can be vague

According to Dr. Julie Vose of Nebraska Medical Center University Hospital:

"In any one patient there is usually not a known cause for the non-Hodgkin or Hodgkin lymphoma. If you don't know the cause of lymphoma, you can't say how to prevent it."

Uncertainty of this kind tends to frustrate patients. They want to know how and why they developed lymphoma. Uncertainty is the mark of maturity in a physician, so patients should be very wary of anyone who says they can tell them how they got cancer.

With all that in mind, what we can do is look at lymphoma incidence from an epidemiological standpoint and draw some general conclusions.

Lymphoma and Environmental Exposures

Regarding lymphoma and exposure to the likes of herbicides, what do the big-shot sites say?

The National Cancer Institute says "High quantities of some pesticides have been linked to cancer."

The Leukemia & Lymphoma Society is even less assertive, saying only that "Studies suggest there might be a link to some ingredients in herbicides and pesticides."

Vietnam Vets, Agent Orange, & the Institutes of Medicine

This is a whimper when set against the Institutes of Medicine's Committee to Review the Health Effects in Vietnam Veterans of Exposure to Herbicides. In 1994 this influential committee wrote that "the two specific types of cancer most closely linked to herbicide exposure in the scientific literature [are] soft tissue sarcoma (STS) and non-Hodgkin's lymphomas."

In a 2004 update, they wrote:

"The committee …concluded that there was sufficient information to determine an association between exposure to at least one of the compounds of interest [2,4-D, 2,4,5-T or its contaminant TCDD, picloram, or cacodylic acid] and NHL. Additional information available to the committees responsible for Update 1996, Update 1998, Update 2000, and Update 2002 did not change that conclusion."

While noting that the association with Hodgkin's was not as strong as it was with non-Hodgkin's, they still wrote that:

"On the basis of its evaluation of the epidemiologic evidence reviewed here and in previous [Veterans and Agent Orange] reports, the committee concludes that there is sufficient evidence to state that an association exists between exposure to at least one of the compounds of interest and [Hodgkin's lymphoma]."

Herbicide 2,4-D

Nobody does it better than the National Pesticide Information Center, which has a gloriously detailed and easy-to-read information page on the commonly used herbicide 2,4-D. This, along with 2,4,5-T, is what's known as a chlorophenoxy herbicide. Hundreds of commercial fertilizers with several different names use these herbicides.

If you live in the United States, you can determine what pesticides are legal in your state by going to the State Pesticide Regulatory Agency page. Living in Texas, I learned that my state permits the use of over 15,000 such products; further, that a full 73 of them use 2,4-D as an active ingredient, including:

• Two brands from Miracle-Gro
• Nine brands from Scott's
• Five brands from Turf Builder
• Four brands from Preen
• Four brands from Vigoro

What does this knowledge get you? The less you are exposed to certain pesticides, the lower your risk of developing lymphoma from those pesticides.

The President's Cancer Panel

In 2009, The President's Cancer Panel issued the annual report "Reducing Environmental Cancer Risk". At that time I searched the document and found all mentions of lymphomas, which you can see here. It includes Benzene, Styrene, PCBs, hair dyes and other carcinogens.

What does that knowledge get you? You could avoid buying and using products that contain these chemicals. Since some of these chemicals are used in the manufacture of plastics, you could choose not to buy plastics. You could use a filter on your tap water to cut down the amount of chemicals like these that get into tap water.

Conclusion

You could take these steps and you might lower your risk of developing lymphoma from these factors. You won't eliminate the risk.

Either way, most experts suggest worrying less about these specific factors and putting more focus on changing your diet to include more fruits and vegetables and on changing your routine to get more exercise, if you don't currently get much.

And if you smoke, quit. It makes absolutely no sense to go out of one's way to avoid exposure to certain herbicides while heading to the store to buy cigarettes.

Photo of crop dusting by EPA photographer Charles O'Rear