When cancer is diagnosed in a pet – finding orientation

When cancer is diagnosed in a pet – finding orientation 

Understanding, assessing and moving forward together 

Even the thought of cancer causes stress for many people. Emotions such as fear (Is my pet in pain? What happens next? How much will treatment cost?), grief (Why is this happening to us? He is only 10 …) and guilt (Could I or should I have noticed it earlier? Did I do something wrong?) can overwhelm pet owners within a very short time – and are often passed on to veterinarians unfiltered. 

Yet it is often precisely in these first few minutes that the course for the further diagnostic and therapeutic pathway is set. 

In the age of ChatGPT, Google and Facebook groups, it is not difficult for pet owners to access information. The real challenge lies in correctly assessing and filtering this information – something that is naturally difficult without the necessary professional knowledge. 

The result is often an uncertain attempt to navigate through a sea of possibilities, half-knowledge and individual opinions. In the worst case, this can lead either to panic or to procrastination. 

At the same time, oncology in veterinary medicine has made enormous progress in recent years. Both in diagnostics and in therapy, there are now far more options available than only a few years ago. This makes it all the more important not to classify tumour diseases too quickly, but to proceed in a structured and medically sound way. 

What is currently changing in small animal oncology 

Oncology in dogs and cats is increasingly moving away from the simple question of “tumour: yes or no?” towards a more differentiated assessment. What matters is not only recognising a mass, but assessing it diagnostically, biologically and prognostically. 

The AAHA Oncology Guidelines for Dogs and Cats published in 2026 emphasise exactly this structured approach: diagnosis, staging, treatment planning and supportive care belong together and should also be considered in general practice settings. 

Five developments are particularly relevant for practice: 

1. Staging and diagnosis belong together 

   A tumour diagnosis does not end with identifying a mass. Depending on the case, further planning requires clinical examination, laboratory tests, diagnostic imaging, cytology or histopathology, as well as assessment of general condition, metastatic risk and quality of life. The current AAHA guideline explicitly describes oncology as a structured process involving diagnosis, staging, treatment and supportive care. 

2. Histology and tumour biology are becoming more important 

   The question is increasingly not only: “Is it malignant?” What matters more and more is: What type of tumour is it, how aggressive is it, how advanced is it, and what prognosis can be derived from this? Tumour type, grade and stage are central factors in treatment planning and counselling. PubMed also summarises the AAHA Guidelines by stating that treatment decisions should be based on tumour type, grade and stage – supported by cytological or histological evaluation and staging. 

3. New diagnostics are emerging – but they do not replace the basics 

   Liquid biopsy, genomic testing and molecular markers are increasingly being discussed. A review on “Next-Generation Diagnostics” describes liquid biopsy as a promising approach for earlier detection and monitoring in pets. At the same time, it remains important to remember that these methods are additions, not replacements for thorough clinical examination, diagnostic imaging and tissue evaluation. 

4. Genomic diagnostics are moving closer to practice 

   A recent review from April 2026 describes the current status of genomic testing in veterinary oncology and shows that tumours may increasingly be classified according to molecular characteristics in the future. For practicing veterinarians, this does not mean that every practice must immediately implement genetic tumour diagnostics. It does show, however, where oncology is heading: away from generalised decisions and towards more individualised strategies. 

5. New therapeutic approaches are exciting – but must be assessed realistically 

   Targeted therapies, immunotherapies, electrochemotherapy and other approaches are being intensively investigated. The AAHA describes electrochemotherapy as a growing field of research and application in local tumour treatment. At the same time, not every new option immediately becomes standard practice. This is precisely why it is important to know about new developments, while assessing them critically and in relation to the individual patient. 

What this means for practice 

For veterinarians, the challenge today is not only to recognise a tumour disease. What matters is guiding pet owners through the initial uncertainty while proceeding in a medically structured way. 

This includes clarifying early on: 

• What do we already know?
• What still needs to be confirmed diagnostically?
• Is staging useful or necessary?
• What prognosis is realistic?
• Which treatment goals are most important – cure, control, gaining time or quality of life?
• When is referral to specialised colleagues appropriate? 

Especially in the first phase after a suspected tumour, pet owners do not need an unfiltered flood of information, but orientation. They need someone who explains what is known, what remains unclear and which next step makes medical sense. 

In small animal medicine, cancer has long since ceased to be an automatic endpoint. Uncertainty, lack of assessment and procrastination, however, can become very dangerous.