Your sister can be reassured, she doesn't have cancer. Chemotherapy drugs are sometimes used to treat diseases other than cancer.

Sarcoid disease, or sarcoidosis, is not a cancer. It is a condition where patches of inflammation, called granulomas, appear in different parts of the body. The lungs, lymph nodes, skin and eyes are the organs that are most often affected.

Inflammation often happens when the body's defence against infection, the immune system becomes overactive. This can often be helped with steroids but sometimes other drugs, including chemotherapy drugs, that make the immune system less active, are also needed.

The chemotherapy that is most often given to treat sarcoid is methotrexate. The dose that is given is much lower than that used for treating cancer. So side effects tend to be milder and much less of a problem.

Nevertheless it is still important that anyone being given chemotherapy drugs is seen regularly by their doctor and has blood tests to monitor the effect of the treatment on their body.

If your sister is unsure or worried about her treatment she can ask her doctor about this. They will be happy to explain more and answer any questions she may have.