Lung cancer, a rather rare cancer in dogs
Lung cancer is defined as a disorganized and uncontrolled proliferation of certain cells present in the lungs.
Primary lung tumors are fairly rare in dogs but can still occur. The most common type of lung tumor in dogs is lung carcinoma, although other tumor types such as lymphomas, malignant histiocytosis or even sarcomas can also be found.
Most often, tumors that develop in a dog's lungs are metastases. These are tumors resulting from the spread of a tumor that originally developed elsewhere in the animal's body.
Zoom in on lung carcinoma, the most common in dogs
Lung carcinoma is defined as a malignant tumor of the epithelial cells of the lung.
There are 4 subtypes: bronchioloalveolar carcinoma, squamous cell carcinoma, pulmonary adenocarcinoma, and adenosquamous carcinoma.
Bronchioloalveolar carcinoma is by far the most common in dogs.
We know that certain dog breeds are particularly prone to developing lung carcinomas, including Boxers, Dobermans, Australian Shepherds, Bernese Mountain Dogs and Irish Setters. Most often, the tumor occurs in an older animal.
But, however, the breed is not everything and does not yet know precisely the reasons why a dog can develop this type of cancer. It appears that this type of condition is caused by a complex mix of environmental, genetic and/or hereditary risk factors.Among the environmental factors involved, the dog's exposure to cigarette smoke could play a role in the appearance of this type of cancer.
What are the clinical signs of lung cancer in dogs?
Symptoms of lung cancer in dogs can vary from animal to animal. However, the most common clinical signs are cough, difficulty breathing (labored or rapid breathing, even at rest) and exercise intolerance.
General and non-specific symptoms may also present as depression, anorexia and weight loss.
We can also observe lameness caused by bone disorders and more specifically by swelling at the end of the long bones (Cadiot Ball syndrome).
In the event of metastases in the central nervous system, the animal may present neurological disorders.
How is lung cancer diagnosed?
This type of tumor is often diagnosed incidentally during chest X-rays.
The diagnosis is then confirmed by cytopuncture (ultrasound-guided fine needle aspiration) and/or biopsy (surgical excision of a piece of the tumour). These techniques make it possible to remove cells from the tumor or pieces of the tumor for histological analysis.
Since lung tumors have indeed a strong potential to spread to other parts of the body, your veterinarian may recommend that you carry out a spread assessment in order to highlight any metastases. This workup may include blood tests, urine tests, other x-rays, abdominal ultrasound and/or CT scan.
In some cases, a pleural effusion may develop.This is the collection of fluid around the lungs. The veterinarian can then perform a thoracocentesis, that is to say a puncture of liquid using a needle. It is sometimes possible to visualize tumor cells bathed in this liquid.
What are the treatments for dog lung cancer?
In case of lung cancer in your dog, surgery is often the treatment of choice. However, it is only possible if the tumor is unique, no metastasis is present and the general condition of the animal is satisfactory and allows it to withstand the operation well. More than half of the operated dogs can expect a life expectancy of one year after the intervention.
In other cases, radiotherapy or chemotherapy may be recommended, but unfortunately these treatments offer little effectiveness on this type of cancer. In the absence of metastases, the life expectancy of a dog with this type of cancer is about 11 months and only 2 months in the presence of metastases.