One of the complexities of cancer care is that the effects of a growth, lesion or tumour can vary significantly depending on where it originated, how long it has been there and how far it has spread.
Regardless of the specific type of cancer, a general rule is that the sooner it is diagnosed the more treatments that are available and the greater the likelihood that they will be effective.
One particular aspect of a cancer diagnosis that can often be confusing is the idea of stages, such as when Sky Sports presenter Jo Wilson announced that she has been diagnosed with Stage 3b cervical cancer, she along with other people following her story were unsure as to what that meant initially.
To help with this, ease fears and ensure people know what a diagnosis means for them, here is a brief guide on cancer stages.
Why Are They Used?
There are two main staging systems used; there is the traditional numbered stage system as well as the TNM system. Most doctors will use both depending on the particular type of diagnosis, as the latter can make more complex cancers easier to understand.
Both types are used to signify the size of growths and tumours and whether they have spread, as this can affect the types of treatments that can be used and their effectiveness.
For example, if a tumour is localised in one place, it can be removed with surgery or a targeted radiotherapy system such as stereotactic radiosurgery.
The Stage Numbers
The most common way in which cancers are described is in a series of stages from 0 to 4, traditionally written down in Roman numerals.
These highlight a cancer’s behaviour, although exactly what that can mean in terms of treatment options depends on the type of cancer that is diagnosed.
Typically, however, the stages mean the following:
- Stage 0: Often known as ‘in situ neoplasm’ or ‘carcinoma in situ’, this is an abnormal cluster of cells that have developed somewhere in the body that could potentially develop into cancer but have not yet currently done so nor are they large enough to form a tumour. In many cases, a carcinoma will never develop into cancer and, in certain organs, are too small to even be picked up by a scan.
- Stage I: The first stage of cancer usually indicates a cancer that is contained within the organ it originated in, is small in size and has not spread.
- Stage II: At this stage, the cancerous tumour has grown, but has not spread into surrounding tissues, although it can, in some cases, have spread into nearby lymph nodes depending on the cancer type.
- Stage III: By this stage, the cancer has grown larger and cancer cells may have started to spread into lymph nodes or surrounding tumours.
- Stage IV: Also known as metastatic cancer, stage IV cancer has spread to other organs
The TNM System
Alongside the standard numbering system, there is an additional staging system that can quickly and precisely be used to document the progression of cancer known as TNM, or Tumour, Node, Metastasis.
- Tumour is used to document the size of the cancer and how far it has spread and uses the same 1-4 stage system as the numerical system.
- Node is used to document if the cancer has spread to nearby lymph nodes, graded by intensity from 0 (no lymph node cancer cells) to 3 (a significant amount of cancer cells in lymph nodes).
- Metastasis is the medical term used when a cancer spreads, and in the TNM system is a simple binary code; 0 means the cancer has not spread and 1 means that it has.