Tattoos and Lymphoma: Should You Be Worried About a Link to Ink?

Before we get into this research, can you explain what lymphoma is and what causes it?

It’s a cancer of the lymphatic system and the lymphocytes. The immune system has a complex network of cells that play different roles, and lymphocytes – B cells in particular – play a key role in how the immune system adapts to and protects against new threats encountered in the environment. One of the ways they do this is by making antibodies to help fight infection, but these cells can also give rise to B cell lymphomas.

We can’t really know what drives the development of cancer in any one individual. As part of the biology of lymphocytes, they mutate their DNA as the individual cells develop – this is how they are able to create such a rich diversity of antibodies – but that process can be error prone, which can play a role in the development of lymphoma. Inherited genetic variants may play a minor role. But environmental factors, such as chemicals in the environment, diet, alcohol, smoking, and so on, likely contribute to the development of these cancers.

What’s your take on this recent research about tattoos and lymphoma?

I’ve seen a few other studies that suggested an association between tattoos and the risk of developing lymphoma. The Danish study was a cohort study with large enough group of participants to allow for some certainty in the results. The investigators designed this study in particular to control for the genetic aspects I mentioned earlier. This is probably the largest and most rigorous study to date trying to address the association between tattoos and cancer risk.

But the study has limitations. There were several other variables that the investigators didn’t adequately control for – things like sun exposure, alcohol intake, or other behaviors that might theoretically impact cancer risk. And it’s a survey-based study, while the gold standard in medicine is a randomized, controlled trial. For obvious reasons, however, we can’t randomize 6,000 people to get tattoos or not get tattoos, and then just watch what happens for years and years. The best we can do is look for associations in studies such as this one.

I would say that among my own lymphoma patients, fewer than one in four have tattoos.

I take it we need more research before we can say people with tattoos definitely face an increased risk of cancer.

A large percentage of Americans have tattoos, which is why this has generated interest and concern, so it’s certainly a relevant public health problem that warrants more discussion and study.

One of the key challenges in studying the link between tattoos and cancer is the lack of good data. Although we have many medical databases that we can use to study many different risk factors, the challenge here is finding a large database that captures tattoo data. In order to have more certainty around these results, you’d need exposure data on tens of thousands of individuals.

Also, an important piece of this is that these types of studies only tell us there may be an association between a risk factor and an outcome. You might look at this research and say, “Oh, tattoos cause lymphoma.” That’s not what it says. It says there’s an association, which could mean that tattoos cause lymphoma, or there could be other risk factors or behaviors in this population that might be the cause. That’s where I think this latest study is wanting in terms of not adequately capturing other potential risk factors.

We know that there are chemicals contained in tattoo ink that can cause an inflammatory processes in the skin. These same chemicals can theoretically induce an inflammatory response in lymphocytes and other immune cells. And many cancers are probably driven by inflammation, at least in part, and we think that’s true for some lymphomas as well. So it makes sense to me, just from a mechanistic standpoint, that there could be a link. This data is compelling, but the issue warrants further research.

You mentioned genetic factors playing a role, but are there things a person can do that are within their control to reduce the risk of lymphoma or improve the outcome?

There are not any specific, alterable risk factors specific to lymphoma that have been well validated. There are many other behavioral changes that may alter overall cancer risk and that have a lot of other health benefits, like eating a well-balanced diet that’s low in processed foods, exercise, etc.

Is there a way to screen for lymphoma? Are there signs we should look out for?

There are no current screening tests for lymphoma, although there’s a lot of interesting science going on around very sensitive blood tests that can detect disease at a very low level. For patients with a family history of certain types of lymphoma, they should see their primary care doctor for a physical exam once a year.

Things to notice that might be a red flag include swelling in the neck, groin, or armpit, which are the most common places where someone might have an enlarged lymph node. Also, unexplained fevers, drenching night sweats, or weight loss without another clear reason, persisting for more than a couple weeks, are things that should be evaluated.

What if someone reads this who is considering getting a tattoo?

If someone feels really strongly about getting a tattoo, I don’t think that these results are compelling enough to say they should absolutely not get one. But if someone is on the fence about getting a tattoo, they might want to think a little bit more about it before getting one. Hopefully, over time, we will accumulate more studies that help us understand this issue with greater certainty.