The fibrosarcoma is the most common tumour in cats. It is a serious cancer, and one to tackle early. This guide explains what it is, how serious it really is, the treatments available, and how we support you and your cat through it.
What is it?
A fibrosarcoma is a malignant (cancerous) tumour that develops from the supporting tissue beneath the skin. It shows up as one or more nodules — firm lumps under the skin — often painless at first, usually on the back, between the shoulder blades, on the flanks or on the limbs. Later, the skin over it may break down (ulcerate). Cats of any age can be affected.
Is it serious?
It is a locally aggressive cancer: it invades the neighbouring tissue and tends to come back after surgery (what we call a recurrence). It does, on the other hand, spread to distant organs — so-called metastases — fairly rarely, in about one case in ten. So it is mainly its local behaviour that makes the outlook uncertain. One key point: the smaller the tumour and the earlier it is treated, the better the chances.
How is it diagnosed?
The diagnosis is confirmed by taking a small piece of the mass to examine under the microscope (a biopsy). Before surgery, imaging (X-rays, sometimes a CT scan) helps to measure exactly how far the tumour extends.
What treatments are there?
The main treatment is surgery, with the aim of removing the tumour very widely, taking a margin of healthy tissue all around to limit recurrence. Depending on the case, this may be combined with:
- a course of radiotherapy (targeted beams) to reduce the risk of the tumour coming back;
- less often, chemotherapy, above all when there is a risk of spread.
There is no ‘miracle’ treatment, and a permanent cure cannot always be guaranteed. But the right care can often buy time and preserve the animal’s comfort. We take the time to explain the options and to decide together with you, at your own pace.
Can it be prevented?
Your best asset is watchfulness: show us any lump that appears, grows or persists, especially if it is bigger than a pea or sits at an injection site. A mass picked up early is far easier to treat. Vaccination protocols have in fact evolved to reduce this risk — so there is no reason to stop protecting your cat, but do talk it over with us.
The key points: the fibrosarcoma is a serious cancer, but one whose metastases remain rare; it is its tendency to come back locally that makes it essential to act early and widely. Spotted and operated on quickly, it is far better controlled — at the slightest suspicious nodule, let’s talk.