Cancer cells have the potential to spread from the mesothelium to other parts of the body where they can grow into new tumours. This process is called metastasis. The tumours are also called metastasis (singular) or metastases (plural). Metastases are also called secondary tumours.
Understanding the usual progression of cancer helps the doctor to predict its probable course, plan treatment and anticipate further care.
The most common sites where pleural mesothelioma spreads are:
- mediastinum (the space in the chest between the lungs) and organs within the mediastinum
- pericardium (the sac that surrounds the heart)
- lymph nodes
- chest wall
- lung on the opposite side of the chest from the original tumour (contralateral)
- diaphragm (the muscle below the lungs and heart that separates the chest cavity from the abdomen)
- peritoneum (the membrane that lines the walls of the abdomen and pelvis, and covers and supports most of the abdominal organs)
- adrenal gland
Metastasis outside of the chest occurs late in the course of the disease.
The most common sites where peritoneal mesothelioma spreads are:
- outermost layer (serosa) that covers the small and large intestine – can cause a bowel obstruction
- one or both pleural cavities (the space between the lungs and the walls of the chest that is lined by the pleura)
- other organs in the abdomen
Peritoneal mesothelioma does not usually spread to the lymph nodes or distant organs.