Psoriatic Arthritis and Cancer Risk: What to Know

Psoriatic arthritis (PsA) is a type of inflammatory arthritis that affects the joints and the entheses (where tendons and ligaments connect to bone). It is common in people with the inflammatory skin disease psoriasis. Together, these conditions are called psoriatic disease. There is no cure for PsA or psoriasis, but both are manageable and treatable.

Some studies have found that PsA is linked to some types of cancer. That risk also extends to psoriasis. Other studies have disproved this and suggested that cancer risk is no different for people with PsA than for people without the condition.

This article will discuss the risk for different types of cancer that might affect people with psoriatic arthritis and psoriasis, prevention strategies, and when to reach out to your doctor.

Psoriatic Arthritis Cancer Risk

Many people with PsA believe some medicines used to treat it might increase their risk for different types of cancer. But the risk linked to conventional disease-modifying anti-rheumatic drugs (DMARDs) and biologic DMARDs and cancer is small in comparison with the link between PsA and cancer.

For example, a study reported in 2021 aimed to understand the risk for non-cutaneous (non-skin) cancers in people treated with different types of biologics for rheumatoid arthritis (RA), another type of inflammatory arthritis. In this study, researchers found biologic therapies for RA were not linked to increased cancer risk.

Many of the treatments used for PsA, including traditional DMARDs, biologic DMARDs, and Janus kinase (JAK) inhibitors, suppress the immune system, which might make it harder for the body to detect and destroy cancer cells.

The prescribing information for Janus kinase inhibitors such as Xeljanz (tofacitinib), Olumiant (baricitinib), and Rinvoq (upadacitinib) has a black box warning required by the Food and Drug Administration (FDA) that includes an increased risk of lymphoma or other cancers.

However, a study reported in 2014 found no link between PsA, PsA treatments, and cancer risk. Here, the researchers also concluded that the risk for cancer that did exist was similar to that which exists for others without PsA.

But an increased risk for nonmelanoma skin cancer was found in this study. Researchers concluded that risk was related to PsA, psoriasis, phototherapy, and/ or immune-modulatory treatments like Treaxall (methotrexate), Sandimmune (cyclosporine), Otezla (apremilast), and biologics.

Cancer Types Linked to PsA

Two types of cancer are believed to be linked to PsA:

• Nonmelanoma skin cancer
• Breast cancer

Nonmelanoma Skin Cancer

Nonmelanoma skin cancer refers to skin cancers that are not melanoma. Melanoma is cancer of the pigment-producing cells that give color to the skin. The two most common types of nonmelanoma skin cancer are basal cell carcinoma and squamous cell carcinoma.  

The first sign of nonmelanoma skin cancer is usually the appearance of a lump or discolored area of skin (the tumor) that persists and progresses. Nonmelanoma skin cancer often occurs in areas of the skin that are regularly exposed to the sun—the face, ears, hands, shoulders, or back—but any body area can be affected.

A 2019 review of studies looked at a total of 43,115 PsA patients among nine cohort studies who were treated with conventional DMARDs and biologic DMARDs. Here, the reviewers found that some, but not all, DMARDs were linked to certain skin cancers:

• Treating with methotrexate, Arava (leflunomide), Plaquenil (hydroxychloroquine), or Azulfidine (sulfasalazine) increased the risk for nonmelanoma skin cancer.
• Biologics, including Remicade (infliximab), Humira (adalimumab), Rituxan (rituximab), and Xeljanz (tofacitinib), did not appear to increase the risk for this type of skin cancer.

Breast Cancer

Studies have found a strong link between PsA and breast cancer. A 2016 retrospective analysis in the journal Clinical Rheumatology reviewed the patient records of 217 people with PsA and 434 people (control group) without the condition.

Here, the report’s authors found that people with PsA were significantly more likely to have malignant cancers (cancers that spread from one body area to another). That risk was for all cancers except nonmelanoma skin cancer. The risk for breast cancer was significantly higher in people with PsA compared with others in the general population.

Mixed Results

Other studies have found the overall risk for cancer malignancy in PsA to be similar to that of the general population. One long-term prospective follow-up study reported in 2021 found the overall risk for malignancy in people with PsA was no different than the risk in the general population.

That study also found an increased risk for nonmelanoma skin cancer. But it did not show sufficient data to suggest any link between biologic drugs and cancer malignancy.

Psoriasis Cancer Risk

Many people with PsA also have psoriasis. Researchers have found a stronger link between psoriasis and several types of cancer, which might further increase the risk for different types of cancer in people with both PsA and psoriasis.

A 2019 systemic review and meta-analysis of 58 studies found a link between psoriasis and increased risk of cancer. The report’s authors found that people with psoriasis had an increased risk for different cancers, including colon, colorectal, kidney, laryngeal, liver, lymphoma, esophageal, and pancreatic.

The researchers also found that people with psoriasis who developed cancer had an increased risk of dying across different cancer types. They admitted further research was needed to determine what lifestyle factors, treatment, and inflammatory processes in psoriasis might explain why the increased cancer risk exists.

Psoriasis and Cancer Types

Specific cancers linked to psoriasis might include:

• Nonmelanoma skin cancer and other skin cancers
• Lymphoma
• Lung cancer
• Blood cancers

Nonmelanoma Skin Cancer and Lymphoma

Lymphoma is a cancer of the lymphatic system. It can affect the lymphatic system and organs throughout the body. People with psoriasis have an increased risk for both nonmelanoma skin cancer and lymphoma.

A 2020 review of 112 studies published in the journal JAMA Dermatology looked to evaluate the link between psoriasis and PsA and the risk for specific cancer types. The overall cancer prevalence in people with psoriasis was nearly 5%, with an incidence rate of 11.75 per 1,000 person-years.

There was also an increased risk for several cancers, including nonmelanoma skin cancer, lymphomas, lung cancer, and bladder cancer. The risk was highest for nonmelanoma skin cancer and lymphoma. Biologic drug use was not linked to an increased risk for cancer.

Skin and Blood Cancers

Skin cancer refers to the abnormal growth of skin cells, usually the result of sun exposure. It is the most common type of cancer. There are three major types of skin cancer—basal cell carcinoma, squamous cell carcinoma, and melanoma.

Blood cancers (hematologic cancers) occur in the blood due to abnormal or excessive production of red or white blood cells. Examples of blood cancers are leukemia, lymphoma, and myeloma.

A 2017 study found a connection between psoriasis and skin and blood cancers. Here, researchers used case-control and retrospective cohort designs to make sense of the risk of melanoma and blood cancer in people with psoriasis and the association with different treatments used to treat psoriasis.

Researchers found a 1.53 times greater risk of developing malignancy in people with psoriasis than in those without psoriasis. There was no additional increase in malignancy risk in people using topical medicines, phototherapy, systemic drugs, or biologics. Neither psoriasis nor malignancy led to significantly worse survival.

Lung Cancer

Lung cancer is cancer that starts in lung tissues, usually the cells lining air passages. There are two main types of lung cancer—small cell lung cancer and non-small cell lung cancer—which grow differently and need different treatments.

A 2016 population-based study found a slightly higher risk in psoriasis patients for lung cancer, lymphoma, and nonmelanoma skin cancer. When adjusting for age, sex, and smoking status, people with moderate to severe psoriasis had a 60% increased risk of developing lung cancer compared with people without psoriasis.

Some studies discussed in this report show a positive association between psoriasis and lung cancer while others do not, noting that adjustments for smoking might need to be made. The study’s authors note that the relationship between smoking, lung cancer, and psoriasis might be much more complex than the relationship between smoking and lung cancer.

Prevention

It is not possible to prevent every type of cancer or eliminate every risk factor. It is, therefore, important to talk to your doctor about your risk factors for certain types of cancer and what you can do to reduce your risk.

Most types of skin cancer are caused by too much exposure to ultraviolet (UV) rays from the sun, tanning beds, and sunlamps. UV rays can damage skin cells. The best way to reduce your risk for skin cancer is to protect your skin from UV rays.

Use sunscreen, limit your time in the sun, and dress appropriately to protect your skin from the sun. Be extra cautious when taking medicines that make you more sensitive to the sun.

Methotrexate, which has been used to treat both PsA and psoriasis, can make skin sun-sensitive. People who have psoriasis and take methotrexate should be especially careful outdoors because sun exposure can worsen skin symptoms.

If you have an increased risk for skin cancer from factors like family history, personal history, or being an older adult, you should check in with your doctor to have your skin examined regularly for changes. Reach out to a dermatologist if you notice any abnormal skin areas.

Lung cancer prevention tools include quitting smoking, eating a healthy diet, and avoiding repeated exposure to chemicals like radon and asbestos.

Breast cancer risk can be reduced with good nutrition and regular exercise, which will improve your overall health and help you maintain a healthy weight.

Blood cancers can be prevented by reducing exposure to chemicals, such as pesticides, and by not smoking or using tobacco in any form. Lifestyle behaviors, including staying active and eating a healthy diet, can help reduce your risk for blood cancer and other cancers.

Alcohol can increase the risk for different types of cancer, including breast, throat, liver, colon, and rectal. The more alcohol you consume, the higher your risk.

Regular screening can help catch some types of cancer early, when they are small, have not spread, and are still easier to manage. With some types of cancer, including cervical cancer, testing can help prevent cancer from developing. Talk to your primary care provider about regular breast, cervical, colon, prostate, and lung cancer screenings.

When to Talk to a Doctor

People with PsA should follow up with their doctors regularly and follow their treatment plans exactly as prescribed. Be sure to discuss any new or increased symptoms with your doctor.

It is also important to discuss your cancer risk with your doctor, especially if certain cancers run in your family, you have a personal cancer history, or you have other risk factors.

Early signs of cancer are not always noticeable, and sometimes symptoms experienced may not be specific. You should never wait to get medical attention. Early diagnosis is vital and can lead to more effective treatment.

Some of the earliest signs of cancer are:

• Unexplained weight loss
• Severe fatigue
• Fever
• Pain
• Skin changes

The National Cancer Institute recommends people see their doctors if they experience symptoms that last longer than two weeks. This is especially important for people with a family history or other risk factors. You should seek out immediate medical attention for any symptoms that interfere with your quality of life.

Summary

Both psoriatic arthritis and psoriasis are linked to an increased risk for some types of cancer, especially nonmelanoma skin cancer. In addition, treatments for these conditions might also increase your risk. Fortunately, the risk is quite small, and the benefits of PsA treatments outweigh the risk in this case.

If you have a family history of cancer or other risk factors, it is important to discuss these with your doctor and take the necessary steps to prevent these conditions. It is also wise to ask about routine cancer screenings and get those done as recommended by your doctor.

A Word From Verywell

There is an increased risk for some types of cancer among people with psoriatic arthritis, but that risk is small for most people. But it is still important to talk to your healthcare professional about ways to reduce your risk for certain types of cancer and to discuss routine cancer screenings.

You should also take the necessary steps to reduce behaviors that might increase your risk for cancer, such as smoking, consuming too much alcohol, and getting too much sun exposure. Also, make sure you are staying active, eating healthy, and maintaining a healthy weight.