Do Biologics Increase Your Risk of Cancer?

For most people taking a biologic for arthritis, psoriasis, or bowel disease, the drug itself adds little or no overall cancer risk. The warning on the label isn’t empty, though: the risk that does exist clusters in specific situations. And the disease being treated carries its own cancer risk, which makes the drug’s share harder to pin down.¹

What Large Studies Show About Overall Cancer Risk

Biologics are injected or infused drugs made from living cells. Each one blocks a single immune signal that drives inflammation. The most widely used kind are TNF blockers: adalimumab (Humira), infliximab (Remicade), and etanercept (Enbrel). In long-term follow-up of people on TNF blockers, overall cancer risk was no higher than in comparable patients once other factors were accounted for.²

Other biologics look similar. In a nationwide Swedish study of people with rheumatoid arthritis, rates of new cancer were similar, roughly 1 in 100 people per year, whether they took TNF blockers, tocilizumab, abatacept, rituximab, or no biologic.³ A Danish study of over 20,000 treatment starts found no rise in overall cancer with tocilizumab, sarilumab, abatacept, or rituximab.⁴

Studies of people on a drug can mislead, because the people with the most severe, active disease are often the ones given biologics. If severe disease carries its own cancer risk, a simple comparison can make the drug look worse than it is. Researchers try to correct for this by comparing people with similar disease type, age, sex, smoking, and other medicines. That’s why the Swedish and Danish findings carry weight: they compared biologic users with similar patients who weren’t on these drugs, not with the general public. No observational study removes every difference between groups, so the reassurance rests on many studies pointing the same way.

The disease matters as much as the drug. Immune diseases themselves are linked to about an 8% higher overall cancer risk, and that link barely changes when medicine use is accounted for.⁵ An 8% rise is relative, so for someone with a low baseline the extra chance is small in real numbers.

Researchers have also noted that cancer risk in autoimmune disease peaks early in the illness and falls over time, which points to inflammation rather than treatment as a key driver.⁶ Long-running inflammation is itself linked to cancer, which is one reason doctors treat untreated disease as a risk, not a safe default.

So why does the label still carry a cancer warning? Warnings were written early, before long-term data from thousands of patients existed, and labels must mention possible risks even when later studies find little or none. The warning reflects the specific situations covered below, not a general rise for everyone.

Does the Type of Biologic Make a Difference

IL-17 blockers such as secukinumab and IL-23 blockers such as ustekinumab and guselkumab are mainly used for psoriasis. They look reassuring. Most studies of ustekinumab found no higher cancer rate than in the general population, even with long-term use.⁷ In one large international study, people on IL-17 or IL-23 blockers had lower rates of several cancers, including lymphoma and basal cell skin cancer, than similar patients not on biologics.⁸

Lower rates are hard to interpret, though. Doctors often steer people with other serious illnesses or past cancer away from a new drug, so the people who get it may be healthier from the start. That kind of selection can make a drug look protective when it is only being given to people who were already at lower risk. The sensible reading is no sign of harm, not proof that these drugs prevent cancer.

If you have psoriasis, it’s reasonable to ask whether an IL-17 or IL-23 blocker fits your type of psoriasis. Joint involvement can steer the choice toward other drugs, and your skin doctor will balance effectiveness against these safety findings.

Lymphoma is the cancer people ask about most with TNF blockers. Trials are short and may miss rare cancers that take years to appear, so large patient registers that follow people for years add weight. In clinical trials, lymphoma rates were not clearly different between rheumatoid arthritis patients on TNF blockers and those on standard treatment.⁹ In Sweden, people with rheumatoid arthritis on TNF blockers had lymphoma at rates similar to other rheumatoid arthritis patients, though about 2.7 times the general population.¹⁰ The higher rate therefore comes largely from rheumatoid arthritis itself, not the TNF blocker. Risk also didn’t climb with longer treatment or differ by which TNF blocker was used.¹¹

Skin Cancer Is the Clearest Risk

Non-melanoma skin cancers are basal and squamous cell cancers, the most common and usually easily treated skin cancers. People on biologics for arthritis, psoriasis, or bowel disease had about 25% higher rates of these than people not on biologics.¹² The rise showed up in rheumatoid arthritis and psoriasis but was not clearly seen in bowel disease.¹³ Abatacept was the one arthritis biologic linked to more squamous cell skin cancer in Sweden.¹⁴ Melanoma, the more dangerous skin cancer, occurred at similar rates across psoriasis drugs.¹⁵ The skin is constantly exposed to ultraviolet damage, and the immune system helps find and clear damaged cells before they turn into tumors.

A yearly skin check is the practical answer. A dermatologist looks over your whole body, including scalp and back, and spots that have changed, bleed, or won’t heal are checked or removed. Many psoriasis patients already see a skin doctor, so this can be folded into visits. Ask how often you need checks based on your skin and sun history.

Between visits, watch for a pearly bump or a sore that doesn’t heal over weeks, or a rough, scaly patch or growing crusted bump on sun-exposed skin. These cancers are slow and curable when caught early.

Sun protection helps too. Use broad-spectrum sunscreen daily on face, ears, and hands, wear a hat, and avoid midday sun. Fair skin or past sunburns makes this especially important.

Combining Biologics With Other Immune Drugs

In Crohn’s disease and colitis, doctors often pair a TNF blocker with azathioprine or 6-mercaptopurine (from here, azathioprine-type pills). A TNF blocker alone can lose effectiveness because the body may make antibodies against it. The added pill lowers the chance of those antibodies forming, and the combination also tends to work better at the start in some people, especially with infliximab.

That cost is measurable. In nearly 190,000 people with bowel disease, lymphoma risk rose with an azathioprine-type pill alone, a TNF blocker alone, and most with both together.¹⁶ In Crohn’s disease, people on adalimumab plus another immune drug had nearly three times the risk of cancers other than skin cancer compared with adalimumab alone.¹⁷

That nearly threefold figure applies to Crohn’s disease on adalimumab plus another immune drug, so it shouldn’t be applied to every biologic or condition. A threefold relative rise on a small starting risk is still a small absolute risk for most people. The study design also can’t rule out that people on combinations had more severe disease to begin with. Combination therapy often controls severe Crohn’s better and can help prevent surgery, and your age, sex, and disease severity shift the balance.

One lymphoma deserves separate mention. Hepatosplenic T-cell lymphoma is a very rare, almost always fatal lymphoma of the liver and spleen.¹⁸ It has been linked to infliximab plus azathioprine-type pills in young people with bowel disease.¹⁹ Of 25 reported cases with TNF blockers, 24 also took azathioprine, 6-mercaptopurine, or methotrexate, and most were men.²⁰ Still, the disease is so rare that only about 100 cases had been published worldwide by 2006.²¹

If you’re offered combination therapy, ask why the second drug is needed and for how long. Ask whether checking drug levels could let you use a TNF blocker alone. Young men with Crohn’s may be steered away from azathioprine-type pills because of this rare lymphoma. Don’t stop either drug yourself, since sudden flares carry their own dangers.

How JAK Inhibitor Pills Compare

JAK inhibitors such as tofacitinib, baricitinib, and upadacitinib are pills, not biologics, and are often offered as an alternative. They work inside the cell, blocking enzymes that pass inflammation signals along, whereas biologics block a signal outside the cell. Because they block signals more broadly, they affect more parts of the immune system than a single-target biologic does.

Most comparisons found more cancer in people on these JAK pills than on TNF blockers or other biologics, especially in rheumatoid arthritis and with tofacitinib.²² In a German register, people on JAK pills had about 40% higher cancer risk than those on biologics.²³ That extra risk appeared only after more than about 16 months of treatment.²⁴ Basal and squamous cell skin cancers were also more common with JAK pills than biologics in psoriasis patients.²⁵

The warning on these pills reached beyond cancer. A large safety trial of tofacitinib in older rheumatoid arthritis patients with heart risk factors found more cancers and more serious heart events than with TNF blockers. Regulators responded with warnings covering the whole group of these pills. That’s why doctors weigh age, smoking, and heart risk when choosing a JAK pill, not cancer concerns alone. For a younger person without those risks, the balance may look different. If you’re already on a JAK pill, discuss whether switching makes sense rather than stopping abruptly.

Taking a Biologic After You’ve Had Cancer

In people with a past cancer, TNF blockers, ustekinumab, and vedolizumab did not raise the risk of new or returning cancer compared with standard treatment or none.²⁶ Among psoriasis patients with active or recent cancer, about 86% stayed free of cancer progression after one year on either biologics or standard drugs.²⁷ The stage of the cancer and overall health predicted recurrence far more than the psoriasis treatment did.²⁸

This group was thinly studied for a long time. Drug trials usually excluded people with recent or past cancer, which left doctors cautious and some patients undertreated for years, even though their inflammatory disease was active. Later studies that followed real patients filled part of the gap. They are more reassuring than the old caution suggested, but they are still observational and the groups are modest in size.

Timing matters. Guidelines advise seeing a cancer specialist before starting a biologic if your cancer was treated in the last five years.²⁹ A cancer treated long ago with a low chance of returning raises fewer concerns than one treated recently, and some cancers are more likely to return late or are more sensitive to immune function than others. The general reassurance doesn’t replace a decision based on your own cancer.

Bring your cancer type, stage, and treatment dates to the appointment, and ask both doctors to talk directly before you start. Ask which biologic class has the best record for your cancer type, and plan how often you’ll be monitored for recurrence.

Steps to Lower Your Risk Before and During Treatment

Before starting, your doctor should take a full history and examine your lymph nodes, liver, spleen, and skin for signs of cancer.³⁰ Tell your doctor about any past cancer and family history, since guidelines ask doctors to assess both.³¹ Name which relatives had cancer, what type, and roughly at what age. A strong family history doesn’t rule out a biologic, but it may affect which drug is chosen and how closely you’re checked, and it can prompt earlier screening, such as colon checks for someone with bowel disease.

The same workup usually includes tests for tuberculosis and hepatitis B, because these infections can flare when the immune system is dampened. That’s a separate safety step from cancer assessment.

Keep up with routine national screenings such as mammograms, cervical tests, and colon checks.³² Stopping smoking cuts the risk of many cancers and helps inflammatory disease. Sun protection matters more on any immune-calming drug, and staying up to date on vaccines like HPV reduces virus-linked cancers.

Some symptoms are worth reporting promptly: swollen lymph nodes in the neck, armpits, or groin that don’t go away; night sweats, unexplained fevers, or weight loss; or a new or changing skin spot. Mention these rather than waiting for the next routine visit.

Fear shouldn’t drive dosing. People with stronger worries about their biologic were more likely to skip doses,³³ yet uncontrolled inflammation carries its own cancer risk, as described earlier. Cost may also come up. Biosimilars, cheaper close copies of brand biologics, have shown no safety differences from the originals after more than 10 years in Europe.³⁴ Switching to a biosimilar shouldn’t change your cancer risk.