When you own a dog, all you want is the best for them. But sometimes, that can include facing challenging problems, including cancer. Lung cancer in dogs is particularly high-risk and can have a poor prognosis — which may be why it can feel so daunting to learn about and understand. That's why we've put together this comprehensive guide on understanding lung cancer in our canine companions, its causes, symptoms, and possible treatments so that every pet owner understands how to help their pup should this disease strike.
What are the different types of lung cancer in dogs?
In the realm of lung cancer in dogs, there are two distinct types: primary and secondary. Primary lung cancer originates within the lung tissue itself and is relatively rare in dogs. Carcinomas are the most common type of primary lung cancer found in dogs. On the other hand, secondary lung cancer in cancer, which is more prevalent, occurs when cancer cells from other parts of the body metastasize, or spread, to the lungs. Understanding the difference between primary and secondary lung cancer is crucial for veterinarians as it impacts the diagnostic process, prognosis, and treatment strategies.
What causes lung cancer in dogs?
When it comes to primary lung tumours, exposure to environmental tobacco smoke is believed to be the main cause in humans. While the link between lung tumours and smoke exposure remains unproven in dogs, one study revealed that dogs with primary lung tumours had higher levels of anthracosis - a dusty black material within pulmonary macrophages, which indicates exposure to air pollutants - compared to control dogs.
In dogs, secondary, metastatic lung cancer is closely related to the factors that contribute to the development of the primary tumour. As such, the cause of secondary lung cancer in dogs will depend on where the primary tumour is located. In cases where the main tumour originates from the spleen due to hemangiosarcoma or from the bone due to osteosarcoma, it is probable that genetic factors are responsible for the cause.
What are the symptoms of lung cancer in dogs?
The signs and symptoms of lung cancer in dogs can vary depending on the type, location, and stage of the disease. It is important to emphasize that the symptoms of lung cancer in dogs can often be vague and easily mistaken for other respiratory or cardiovascular issues. However, recognizing these early signs is essential for prompt diagnosis and treatment.
Some common symptoms to watch for with lung cancer in dogs include:
- Persistent coughing (present in 95% of all cases)
- Lethargy or decreased energy
- Coughing up blood
- Rapid and shallow breathing
- Loss of appetite or weight loss
- Wheezing or excessive panting
How is lung cancer diagnosed in dogs?
During the physical examination, the vet will conduct a thorough examination of the dog's respiratory and overall health, paying attention to the lungs, chest, and the dog's breathing patterns. Based on the examination results, your veterinarian may decide to conduct one or more diagnostic tests, which may include:
- Chest X-rays: X-rays can help detect tumours, nodules or abnormalities in the lungs. This is usually the first test performed to identify any potential issues.
- CT scanning: CT scan gives a more detailed and comprehensive picture of the dog's lungs and even a small tumour. It is most useful in determining the size, location and stage of the cancer.
- Blood testing: Blood testing can provide insights into the dog's overall health and whether any health issues may be present.
- Biopsy: The definitive way to diagnose lung cancer is by taking a biopsy of the affected area of the lung. A biopsy is important to determine if the cancer is benign or malignant.
What are the treatment options for lung cancer in dogs?
Surgery is the best treatment for primary lung tumours in dogs when there's no sign of cancer spreading. In some cases, surgery may also be considered for dogs with cancer that has spread to help reduce the size of the tumours. Dogs that are in good overall health and show few or no symptoms from the tumour are more likely to benefit from surgery.
Radiation therapy can be useful when cancer cells are present, though surgery or chemotherapy may not be an option. It is generally used to control and lessen the growth of cancerous cells, as well as to reduce symptoms or discomfort. The treatment can cause side effects, but these can be managed with the correct medication.
Chemotherapy involves using drugs to kill cancer cells that have spread to different parts of the body. Chemotherapy has been used both on its own and as additional therapy after surgery. However, it also affects healthy cells in the body, which can lead to side effects such as nausea, vomiting, and fatigue.
What is the prognosis for dogs with lung cancer?
There are a variety of prognostic indicators that veterinarians look at when formulating a prognosis for dogs with lung cancer. These include lymph node metastasis, tumour stage, and tumour type and grade. With proper treatment and in favourable conditions (e.g. low tumour grade), dogs can live up to 790 days. Unfortunately, in advanced stages, the median survival time can be as short as 70 days.
Lung cancer in dogs can be a difficult diagnosis to make, as the symptoms are often vague and easily mistaken for other respiratory or cardiovascular issues. However, with an accurate diagnosis through physical examination, chest X-rays, CT scans, blood tests and biopsy analysis, treatment options such as surgery, radiation therapy and chemotherapy may be available to help your pup fight this disease. While prognosis varies depending on tumour type/grade and stage of metastasis at the time of initial diagnosis; early detection is key so that you can work together with your veterinarian to give your pet the best chance possible.