Lung Cancer (Adenocarcinoma) in Dogs

PetMD Editorial
By PetMD Editorial
Published: July 15, 2009
Lung Cancer (Adenocarcinoma) in Dogs

Adenocarcinoma of the Lung in Dogs

Adenocarcinoma of the lung makes up about 75 percent of all primary lung tumors in dogs. This is a malignant neoplasm, with the ability to grow rapidly and metastasize to distant parts of the body, including the organs, lymph nodes, bones, brain and eyes. Like other types of malignant tumors, adenocarcinoma of the lungs is usually seen in older dogs, over ten years of age, and is more common in dogs than cats. Any breed can be affected by this type of cancer, but boxers have been found to be more more at risk of developing adenocarcinoma of the lungs than other breeds.

Symptoms and Type

Most symptoms are related to the respiratory system, but in cases of metastasis the symptoms may vary depending upon the location of the metastasis in the body. Following are some of the symptoms seen in patients with adenocarcinoma of the lung:

  • Pain
  • Dyspnea (difficult breathing)
  • Tachypnea (rapid breathing)
  • Low energy level and lethargy
  • Poor appetite
  • Gradual weight loss
  • Hemoptysis (coughing up blood)
  • Lameness, in cases with metastasis to bones
  • Muscle wasting
  • Fever in some patients
  • Ascites (an accumulation of fluid in the peritoneal cavity of the abdomen)


  • Exact cause is still unknown (idiopathic)
  • Risk factors include residing in an urban environment and passive inhalation of cigarette smoke, but both are unproven


You will need to give a thorough history of your dog's health, including a background history of symptoms. After taking a detailed history and performing a thorough physical examination, your veterinarian will order various laboratory tests, including a complete blood profile, a chemical blood profile, a complete blood count, and X-ray studies.

Thoracic (chest) radiographs are the most important tool in diagnosing this condition in pets. An ultrasonography, computed tomography (CT) scan, and magnetic resonance imaging (MRI) may also be used in some patients to confirm the diagnosis. The CT scan and MRI may also help in determining the possibility of metastasis of the tumor into other parts of the body.


After diagnosis your dog may be referred to a veterinary oncologist for treatment. There are three major procedures for treating carcinoma, including surgery, radiotherapy, and chemotherapy. The protocol, or combination of protocols, that is selected will based upon the nature, size, location, or presence of metastasis (the single most important prognostic factor). Your dog's age and other such factors are also significant in determining the course of treatment. No single treatment works for all patients. Surgery will usually be chosen for removing a well localized tumor in the lungs and resection of the affected lung lobe. Chemotherapy and radiotherapy are often used in combination to improve the prognosis and to increase the survival period. In addition to the chemotherapeutic agents, your veterinarian will also recommend biochemical and serial blood tests, along with chest x-rays, during the treatment period.

Living and Management

Dogs with metastasis are usually given less than one year to live, but treatment may increase the survival time. During this period you can improve your dog's quality of life by providing extra comfort and affection. As best as you can, be attentive to your dog's breathing patterns, and protect it from exposure to second hand smoke. For ongoing treatment, you may need to visit your veterinary oncologist on a regular basis. Follow your veterinarian's guidelines, especially in giving chemotherapeutic agents at home. Many chemotherapeutic agents can be hazardous to your health if not handled properly, consult with your veterinarian regarding the best handling practices.

Help us make PetMD better

Was this article helpful?