If your dog suffers from metastatic pulmonary cancer, that means his cancer originated somewhere else in his body but spread to the lungs. Primary lung cancer, a tumor originating in the lungs, is relatively rare in canines. It's tough hearing a diagnosis of metastatic pulmonary cancer from your vet, but your dog doesn't know what cancer is. He just needs to know you love him.
Your dog's tumor probably originated in his bones as osteosarcoma, in his mouth as oral melanoma, or in the blood vessels as hemangiosarcoma. In female dogs, mammary cancer also spreads to the lungs. Dogs with metastatic lung cancers generally have several tumors in the lungs, not just a single growth. It's possible that the cancer has spread to other organs besides the lungs.
Symptoms of primary and metastatic lung cancer are similar, although dogs with metastatic disease don't cough as much, according to the Merck Veterinary Manual. When they do cough, they might bring up blood. Other symptoms include exercise intolerance, lethargy and weight loss.
Your dog might already be under treatment or previously treated for cancer when he begins showing signs of metastatic disease. Your vet diagnoses metastatic pulmonary cancer via a lung biopsy, a minimally invasive procedure via thoroscope. This small video-assisted camera allows the vet to take a biopsy without opening up the dog's body. If your dog already has cancer and the vet finds nodules, she will assume they result from metastasis. Your vet might also perform chest X-rays or ultrasound on your pet.
If your dog has fewer than four lung nodules, it's possible for your vet to surgically remove them to increase your dog's life span, according to the Animal Surgical Center of Michigan. Generally, this smaller number of metastases occurs when the primary cancer is an osteosarcoma. Your dog might also receive chemotherapy and radiation.
While the prognosis for a dog isn't very good, treatment might extend his life for up to a year. Give him good supportive care and make his life as comfortable as possible. Your vet should supply you with pain medications for your dog so he can live a somewhat normal life in the time he has remaining, although there will probably be restrictions on his physical activity.
By Jane Meggitt
About the Author
Jane Meggitt has been a writer for more than 20 years. In addition to reporting for a major newspaper chain, she has been published in "Horse News," "Suburban Classic," "Hoof Beats," "Equine Journal" and other publications. She has a Bachelor of Arts in English from New York University and an Associate of Arts from the American Academy of Dramatics Arts, New York City.