Neoplasia

A neoplasia – the medical term for it – stands for abnormal cell growth in the dog’s body, which can result in a tumour. Whether this tumour remains harmless or becomes dangerous depends on whether it is benign (benign) or malignant (malignant). Benign tumours usually remain locally confined and cause few problems as long as they stay small. Malignant ones, however, tend to spread to other body regions – the so-called metastasis – and can cause serious damage. The earlier a diagnosis is made and treatment initiated, the better the chances for the affected dog.

What is neoplasia?

Neoplasia simply means uncontrolled cell proliferation, which eventually results in a tumour. Unlike normal, regulated cell division, this process runs out of control – and this can fundamentally happen in any tissue or organ. A distinction is made between two basic types:

• Benign tumours: Grow slowly, do not invade surrounding tissue and do not metastasise. They only become critical if they grow too large or are unfavourably located – for example in the brain or on vital organs.
• Malignant tumours (cancer): Grow rapidly, infiltrate adjacent tissue and can spread to other parts of the body via blood or lymphatic vessels. Untreated, they are a serious, in the worst case fatal, threat.

Causes of neoplasia in dogs

Rarely can the reason why a tumour develops in one dog and not in another be attributed to a single cause. Usually several factors play together:

1. Genetic predisposition: Some breeds carry a significantly higher risk. Boxers, Golden Retrievers and Rottweilers suffer from lymphomas, mast cell tumours and osteosarcomas at an above-average frequency.
2. Age: With increasing age, genetic mutations in cells accumulate – the risk of tumours increases accordingly.
3. Environmental influences: Chemicals, tobacco smoke, pesticides and other environmental toxins can damage the genetic material of cells and promote neoplasia.
4. Hormonal influences: Unspayed bitches have an increased risk of mammary tumours. Spaying at a young age can significantly reduce this breast cancer risk.
5. Viruses and infections: Certain viruses can trigger neoplasia. Papillomaviruses, for example, are known to cause warts and skin tumours.

Types of neoplasia in dogs

Neoplasias can literally develop anywhere in the body. The most common forms that dog owners and veterinarians encounter:

1. Lymphomas: Cancerous diseases of the lymphatic system – and among the most common malignant tumours in dogs. Enlarged lymph nodes are usually noticed first; the spleen, liver and bone marrow can also be affected.
2. Mast cell tumours: These tumours arise from mast cells, a type of immune cell in the skin. They often appear as skin changes and can be benign or malignant depending on the grade.
3. Osteosarcomas: Malignant bone tumours that occur primarily in large breeds such as Rottweilers and Great Danes. They grow aggressively and frequently metastasise to the lungs.
4. Mammary tumours: Breast tumours in unspayed bitches. Benign variants occur, but malignant ones can metastasise to the lungs and other organs.
5. Hemangiosarcomas: Highly aggressive tumours that preferentially arise in the spleen, liver or heart. Rapid growth and early metastasis are typical.
6. Melanomas: Tumours of the pigment cells (melanocytes), which arise in the skin or mucous membranes. Oral melanomas are considered particularly malignant and often metastasise early to the lungs and other organs.

Symptoms of neoplasia in dogs

Which complaints a tumour causes depends largely on where it is located and how advanced it is. The following signs should alert dog owners:

• Swelling or lumps: Palpable lumps or growths on the skin or elsewhere in the body.
• Weight loss: Unexplained weight loss – particularly with malignant tumours, a frequent warning signal.
• Lethargy and tiredness: Affected dogs often appear noticeably sluggish and lacking in drive.
• Changed appetite: Pain or impaired organs can lead to the dog eating less.
• Breathing difficulties: Tumours in the lungs or chest can make breathing difficult.
• Wounds that do not heal, or persistent bleeding: Both can indicate a malignant neoplasia.
• Limping or lameness: Bone tumours such as osteosarcomas often manifest themselves through lameness and significant pain in the affected area.
• Behavioural changes: Depending on the location of the tumour, the dog’s behaviour and activity level can fluctuate noticeably.

Diagnosis of neoplasia in dogs

Behind the diagnosis is always a thorough veterinary examination. Which methods are used depends on the findings – typical ones are:

1. Clinical examination: The vet palpates and assesses the dog for swelling, nodules and other abnormalities.
2. Biopsy: A tissue sample from the tumour is analysed under a microscope – this is often the most reliable way to distinguish between benign and malignant growths.
3. Imaging techniques: X-rays, ultrasound, MRI or CT scans show how large the tumour is, exactly where it is located and whether it has already metastasised.
4. Blood tests: Blood tests provide indications of organ dysfunction or elevated tumour markers.
5. Fine-needle aspiration: Cells are taken directly from the tumour using a fine needle and then examined.

Treatment of neoplasia in dogs

There is no one-size-fits-all solution: treatment always depends on the type of tumour, stage and the dog’s overall health status. The following options are available:

1. Surgical removal: For many benign and some malignant tumours, surgery can lead to complete remission – especially if there are no metastases and the tumour is easily accessible.
2. Chemotherapy: Chemotherapeutic agents are used for malignant tumours, particularly when metastases are present or complete removal is not possible. They can slow down or stop tumour growth.
3. Radiation therapy: Radiation can shrink tumours or inhibit their growth – useful especially if surgery is difficult or the tumour is located in a critical area.
4. Immunotherapy: For certain types of cancer, such as melanomas, immunotherapy can help by specifically supporting the dog’s own immune system to recognise and fight tumour cells.
5. Palliative treatment: For advanced or inoperable tumours, the main focus is on relieving pain and maintaining quality of life. Painkillers and anti-inflammatory drugs play a central role here.

Prognosis

It is not possible to make general statements about how good the outlook is – this depends on the type of tumour, stage and the dog’s general health status. As a rule, benign tumours have better prognoses than malignant ones. And: early detection combined with prompt treatment makes a significant difference – this is repeatedly demonstrated in veterinary practice.

Regular check-ups

Regular visits to the vet and a watchful eye on changes in behaviour or physical condition are the best protection for detecting tumours early. If you feel a lump, notice an abnormal growth or observe persistent symptoms, you should not wait long – but seek veterinary advice promptly.