Immunotherapy-related arthritis

Immunotherapies, also called immune checkpoint inhibitors, release some of the natural brakes on the immune system so it attacks cancer cells more vigorously. The same boosted immune response can occasionally turn on healthy tissues, including the lining of the joints, producing inflammation. This is one of a family of so-called immune-related side effects, and it is the immune activity rather than the cancer itself that drives the joint problem.

Anyone receiving these treatments can be affected, and it is more often seen with certain checkpoint inhibitors or when two are combined. It can appear within weeks or only emerge months later. Unlike rheumatoid arthritis, it has a clear external trigger.

Joint symptoms related to immunotherapy can vary. Features may include:

• Pain, swelling and stiffness in one or several joints
• Morning stiffness
• Symptoms that develop during a course of immunotherapy, or sometimes after it has finished

Diagnosis brings together the history of immunotherapy treatment, the pattern of joint symptoms, an examination and appropriate tests. Recognising the link to the cancer treatment is important, and assessment also makes sure other causes are not missed.

Ultrasound can help confirm and assess joint inflammation accurately. Dr Borukhson uses point-of-care ultrasound during the consultation, so this can often be done in the same visit. You can read more on the ultrasound clinic page.

The aim is to control the joint inflammation and relieve symptoms while supporting the person's cancer care, since the two need to be balanced. Treatment is individual and is best coordinated closely with the oncology team. Where a particular joint is troublesome, an ultrasound-guided injection may help. The plan is agreed with you and your wider team.

This condition is managed with your cancer and rheumatology teams rather than alone, but day-to-day measures help. Keep gentle movement going, as activity within comfortable limits eases stiffness and protects joint function. Pace busier and quieter days, rest a flaring joint sensibly, and use warmth for stiffness. Keep a simple note of which joints are affected and how symptoms change, which is useful at appointments.

Attend your follow-up reviews, as the plan is adjusted as your cancer treatment and symptoms evolve. Mention any new joint, gut, skin, breathing or hormonal symptoms, since these can reflect immune effects elsewhere. With coordinated care, many people gain good control, and symptoms often settle once treatment is well established or completed.

Contact your cancer team promptly, ahead of your next routine appointment, if you develop new or worsening joint pain, swelling or stiffness while receiving or after finishing immunotherapy, so the cause can be confirmed early.

If you are on immunotherapy you should have a 24-hour acute oncology contact number. Use it urgently, the same day, if you also have:

• A high temperature, feeling shivery or generally unwell, which needs prompt review to exclude infection
• A single hot, very painful, swollen joint
• Severe symptoms badly limiting movement or daily life
• New breathlessness, diarrhoea, severe tummy pain, a marked rash, or unusual tiredness

These can signal immune effects elsewhere that need swift attention. If you cannot reach your team, ring NHS 111, and if you feel acutely unwell attend A&E.

Because this form of arthritis sits at the meeting point of rheumatology and cancer care, an assessment that works alongside the oncology team gives the best result. If you are receiving or have received immunotherapy and develop joint pain or swelling, a prompt specialist review is worthwhile.

How is immunotherapy-related arthritis diagnosed?

Diagnosis brings together your history of immunotherapy or checkpoint inhibitor treatment, the pattern of joint symptoms, an examination and appropriate tests. Recognising the link to the cancer treatment matters, and assessment also makes sure other causes are not missed. Ultrasound helps confirm and gauge joint inflammation accurately, and Dr Borukhson uses point-of-care ultrasound during the consultation, so this can often be done in the same visit.

How is it treated, and will I have to stop my cancer treatment?

The aim is to control the joint inflammation and ease symptoms while supporting your cancer care, since the two need to be balanced. Many people can continue their immunotherapy, though if symptoms are severe it may sometimes be paused. These decisions are made jointly with your oncology team rather than by rheumatology alone. Where a single joint is troublesome, an ultrasound-guided injection may help. The plan is always agreed with you and your wider team.

How is this different from ordinary rheumatoid arthritis?

The symptoms can look similar, with joint pain, swelling and morning stiffness, but the key difference is the trigger. Here the inflammation arises because immunotherapy has stimulated the immune system, rather than from arthritis developing on its own. It can begin during a course of treatment or sometimes after it has finished. Identifying this link shapes how it is assessed and managed, which is why coordinated rheumatology and oncology input is valuable.

When should I seek help if I develop joint symptoms?

If you are receiving or have received immunotherapy and develop joint pain, swelling or stiffness, it is worth mentioning promptly rather than waiting. Tell your cancer team, and a specialist rheumatology review is worthwhile. Early assessment helps confirm the cause, distinguish it from other problems, and start the right management sooner. Seek urgent advice through your cancer team if you feel generally unwell or develop other new symptoms alongside the joint pain.

What can I expect over time?

Symptoms vary from person to person, and the outlook depends on the joints involved, how the inflammation responds and your overall cancer care. Many people gain good control with treatment tailored to their situation and coordinated with oncology. Because this form of arthritis sits where rheumatology and cancer care meet, ongoing review alongside your cancer team gives the best result and lets the plan be adjusted as your treatment and symptoms change.