The appearance of a growth is often unsettling, as it raises questions on what to do for the best going forward.
The main considerations when deciding whether to remove an abnormal lump as soon as possible, or to monitor for a while first, are as follows:
1. Is the mass likely to be malignant?
If so, it is best removed quickly to limit the potential for local reoccurrence, and spread to other parts of the body.
A biopsy (fine needle aspirate - FNA) is often advised by vets as a first step, to confirm the diagnosis and to assess if surgery should be performed sooner rather than later.
Pros of FNA
- Minimally invasive
- Quick
- Low risk when done correctly
- Helpful for confirming a specific diagnosis (subject to the extraction of undamaged, abnormal cells for cytology)
- Reasonable accuracy when samples are adequate (approximately 80% - 95% diagnostic for identifying malignant versus benign processes in canine mammary tumours, for example)
- Supports preoperative decision making
- Helps with staging of the disease
Cons of FNA
- High rate of non-diagnostic or inadequate samples (up to 25% - 28% of aspirates fail to yield suitable samples in mammary cancer due to the heterogeneous nature of the masses)
- Limited accuracy overall due to the above
- Does not provide a full diagnosis / prognosis given the results are based on a small sample(s) in isolated location(s) only
- Question mark as to whether this procedure (and others, such as a core / excisional biopsies) increase the risk of metastases
As always, the best way to proceed will depend on a range of different factors, which take into account a pet's own unique makeup and circumstances.
2. Is it more likely to be benign?
If a growth is:
- slow growing, intact (not ulcerated)
- well-defined (clear margins between it and adjacent, normal tissue) and
- not angry looking, friable or inflamed
it is reasonable to monitor for some time, as long as it is not causing any problems.
If there is a significant change in size or appearance, however - especially if this happens quickly - this suggests malignancy and the need to remove the mass quickly.
3. Where is it?
If a tumour is located near vital structures (important blood vessels or nerves, for example), even if it is benign it can cause serious problems (such as haemorrhage or paralysis). In these circumstances, surgical excision where practical, helps to minimise future complications.
The same is true if a growth is likely to become traumatised and infected on a regular basis, as is often the case when tumours appear in the mouth, on feet, in the rectum and similar parts of the body.
4. How much more difficult will removal be, if a cancer is left?
It's fairly easy to excise small growths in most parts of the body, as there is usually enough loose tissue in the surrounding area to close the incision. This becomes much harder however, the larger a mass becomes - especially where skin or mucous membranes are tight to the underlying tissues (as is the case on the lower limbs or in the mouth, for example).
And when a surgical site has to be left open, healing is slower and the risk of infection higher.
In such cases, the mass concerned is best removed when small.
Immune Support
Whenever a tumour appears in a previously healthy pet - whether this be a malignant cancer or a wart - it means the immune system has lost the ability to detect and destroy abnormal cells, and keep the body cancer free.
This being the case, it is vital if quality of life is to be maintained for as long as possible, that the body's natural defence mechanisms - especially the white blood cells responsible for anti-tumour activity - receive maximum nutritional support.
Guidelines on this can be found here