The Complex Link Between Tattoos and Cancer

A recent study suggests that tattoos may increase the risk of lymphoma by 21%. Scientists say such a link is possible, but it may be too early to draw definitive conclusions.

The practice of getting tattoos dates back thousands of years and is still widespread — one-third of Americans have at least one tattoo, often made to honor or remember someone or something important, according to a survey by Pew Research Center.

Despite their long-standing use, the risks of tattoos may not be fully understood. A recent study published in eClinical Medicine suggests that tattoos may raise the risk of lymphoma, a cancer of the lymphatic system.

The study included 11,905 people. Of these, 2,938 people had been diagnosed with lymphoma when they were between 20 and 60 years old. Among them, 1,398 people answered the questionnaire, while the control group comprised 4,193 participants.

In the group of people with a history of lymphoma, 21% were tattooed, compared to 18% in the control group without the lymphoma diagnosis.

However, the researchers say that lymphoma is a rare disease, and the study findings apply only at the group level, underscoring the need for further investigation.

The study also rejected the hypothesis that the size of the tattoo would affect lymphoma risk — the area of the tattooed body surface does not appear to matter.

"We do not yet know why this was the case. One can only speculate that a tattoo, regardless of size, triggers a low-grade inflammation in the body, which in turn can trigger cancer. The picture is thus more complex than we initially thought," Christel Nielsen, the researcher at Lund University who led the study, said in a statement.

Tattoo ink can migrate to lymph nodes

Ash A. Alizadeh, M.D., a professor of medicine, oncology, and hematology at Stanford University, says the study requires a closer examination by lymphoma and statistical epidemiologists, particularly focusing on the methods and potential confounding factors.

However, the link between tattoos and lymphomas is biologically plausible because autopsy studies have reproducibly shown the migration of tattoo pigments into lymph nodes.

Vital dyes and inks that are introduced into skin and soft tissues are routinely used to identify 'sentinel' draining lymph nodes during cancer surgeries for melanoma, breast, and head and neck cancers.

Alizadeh

Moreover, tattoos may induce profound lymphoid proliferations, including allergic reactions and dermatopathic lymphadenopathy, which has been linked to malignant lymphoma.

Alizadeh says tattoos can also be a risk factor for the hepatitis C virus, which can play a role in lymphoma development.

Nevertheless, addressing the possible mechanisms underlying the link between tattoos and lymphoma would be speculative. Alizadeh points out that the direct effects of tattoos, such as contamination with polycyclic aromatic hydrocarbons (PAHs) or indirect effects like hepatitis C virus, are unclear in vivo.

He says, "I suspect that genomic and genetic profiling of lymphomas associated vs. not associated with tattoos could help address mechanisms. This could be done by comparing tattoo-associated mutation signatures from lymphomas to known genotoxins."

What is in the tattoo ink?

Tattoo ink may introduce a large number of unknown ingredients into the skin, such as PAHs, heavy metals, and primary aromatic amines (PAAs).

They are either unintentionally introduced along with the ink or produced inside the skin by different processes. If present beyond permissible limits, these ingredients may pose toxicological risks to human health.

For example, benzo(a)pyrene, one of the PAHs, is present in carbon ink and is known to be highly carcinogenic. Moreover, exposure to PAAs, especially occupational, may play a role in developing bladder, lung, and breast cancers.

Meanwhile, heavy metals like cadmium, lead, and mercury, among others, have been associated with a wide variety of conditions, ranging from cancer to neurodegenerative and cardiovascular diseases.

What are the symptoms of lymphoma?

The study does not prove that tattoo ink definitely causes lymphoma, and there are many other risk factors associated with the disease, including certain infections, tobacco smoking, and obesity.

Regardless of whether you have a tattoo or not, it is essential to know and recognize the symptoms of lymphoma:

• Swollen lymph nodes, usually in the neck, armpit, or groin, which are normally painless.
• Fatigue without any obvious reason.
• Unexplained weight loss.
• Getting infections more easily and having difficulty getting rid of them.
• Sweats, especially at night.
• Itching without a rash.
• Temperatures above 100.4°F (38°C).

While tattoos may raise the risk of lymphoma, it is important to address other risk factors, including smoking and excess body weight.