What is cancer?
Cancer is caused when the cells in the body grow uncontrollably and invade surrounding tissue (Fig1).
Cancer cells can potentially spread to other parts of the body from the primary site and this is termed metastasis (Fig 2). This is either due to abnormal multiplication of cells by drivers of growth called proto-oncogenes, or when cells become old and damaged, and the mechanism by which they die naturally is impaired.
Cancer can start anywhere, in any cell in the body, and is usually named after the tissues or organs where they start. There are many different cancers; the two main types are divided into:
1. Solid tumour cancer which include carcinomas (skin, lung, breast, pancreas and other organs), sarcomas (arising from bone, muscle, cartilage, blood vessels or other connective tissues in the body) or melanomas that arise from pigmeneted cells in the skin.
2. Haematological (blood) cancer such as lymphomas, acute or chronic leukaemias or multiple myeloma.
Image source: cancer.org
STAGING OF CANCER
Staging is done to determine what your treatment intent is; if it’s curative or palliative (controlling the growth and symptoms of cancer).
Different cancers have different staging systems but in general there are usually four stages of cancer.
| Stage 1 | Very small tumour (usually <2cm) |
| Stage 2 | Larger tumour |
| Stage 3 | Spread to loco regional area, such as lymph nodes |
| Stage 4 | Spread to other organs from the primary tumour site |
Some cancers, that are Stage 4 can be curable if they are oligometastatic (few areas of spread or spread to a limited part of an organ). Sadly, most cancers if they spread, often have disease that is not curable but with new innovative treatments, patients can still live very long, good quality lives.
Different radiological imaging modalities are used to stage cancers. This will depend on the type of cancer usually. CT scans, bone scans, PET CT and MRI are some of the different scans that can be done. Your treating doctor will decide which scans are appropriate for the type of cancer, sometimes combinations of different scans can be used.
Image by stock.adobe.com