Cancer of the thymus is a cancer of the thymus gland which lies behind the breastbone. Tumours in the thymus gland are generally also termed as thymoma. The term thymoma includes benign and malignant tumours of the thymus gland. Like malignant tumours, benign thymoma must be surgically removed as they can develop into cancer of the thymus.
The thymus gland plays an important role in the development of the immune system in childhood. T-lymphocytes, important immunity cells against bacteria and viruses, occur in the thymus gland, for example. In adulthood, the thymus gland recedes until only a small amount remains.
Cancer of the thymus or thymoma are rare diseases. Around 30 people are diagnosed with cancer of the thymus in Switzerland every year. Cancer of the thymus is mostly diagnosed after the age of 50; however, it can principally occur at every age.
It is not known why cancer of the thymus or a thymoma occurs. Sometimes a connection with other diseases of the immune system is observed. For example, with the muscle weakness myasthenia gravis or with ulcerative colitis.
Tumours of the thymus gland grow very slowly and are thus often discovered coincidentally when x-raying the chest. Symptoms usually only occur if the tumour presses on neighbouring organs such as the trachea or the oesophagus due to its size. Then difficulties swallowing, coughing, hoarseness or also breathing difficulties can occur. Sometimes there is visible blockage of the neck veins if the tumour presses on the upper vena cava veins in the chest.
If there is suspected cancer of the thymus, computed tomography or an MRI examination is carried out. Tumour cells are also taken via a biopsy and examined in the laboratory to confirm the diagnosis.
The first and most important step of the treatment is the surgical removal of the tumour. Depending on the type of tumour and the stage of the disease, radiation treatment or chemotherapy is required before and after the surgery. Benign thymoma must also be surgically removed as they can become malignant or too large over time. The majority of tumours of the thymus gland only grow in the surrounding tissue without forming metastases. The chances of recovery after surgical removal of the tumour are therefore generally good. Find out more on the surgery in the Thymus gland surgery section.