Primary Lung Cancer in Cats and Dogs
What are primary lung tumors?
The lung is the essential respiration organ whose principal function is to transport oxygen from the atmosphere into the
bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere. Almost all primary cancers of the
lung are carcinomas, the most common being adenocarcinoma, which have a tendency to metastasize (spread) to the
central nervous system.  Adenocarcinomas are further classified based on their location (eg bronchial, bronchoalveolar,
or alveolar carcinoma).

How common are lung tumors in cats and dogs?
Unlike in humans, primary lung cancer is rare in dogs (~1% of all cancers) and even more so in cats. However, the lungs
are a common site to which other types of cancers tend to
metastasize (spread).

What are the symptoms of lung tumors in cats and dogs?
Common symptoms of lung cancer in pets are coughing, exercise intolerance, and other respiratory signs that may be
present from several weeks to months.

How is the diagnosis made?
The first step typically involves a chest X-ray. Recently, advanced imaging (eg CT scan)  has become a helpful tool in
evaluating the extent of the disease prior to surgical treatment.

Does cancer cause in pain pets?
Pain is common in pets with cancer, with some tumors causing more pain than others. In addition to pain caused by the
actual tumors, pets will also experience pain associated with cancer treatments such as surgery, radiation therapy or
chemotherapy. Untreated pain decreases the pet's quality of life, and prolongs recovery from the illness, treatment or
injury. It is, therefore, essential that veterinary teams that are taking care of pets with cancer should also play a vital role
in educating pet owners about recognizing and managing pain in their pets. The best way to manage cancer pain in pets
is to prevent it, a term referred to as preemptive pain management. This strategy anticipates pain ahead of time and
administers pain medication before the pet actually experiences pain, thus ensuring the pet's maximum comfort.

To learn more about which tumors are likely to cause a lot of pain, how to recognize pain in pets with cancer and what
cancer pain management options are available for your pet, please visit the
Cancer Pain Management section.

How important is nutritional support for pets with cancer?
Cancer cachexia (a term referring to progressive severe weight loss) is frequently observed in pets with cancer. Pets with
cancer lose weight partly because of lack of appetite and partly because of cancer-induced altered metabolism. Some of
the causes for decreased appetite are related to the cancer itself (for example, tumors may physically interfere with food
chewing, swallowing, and digestion process) and some may be related to the side effects of cancer treatment (for
example, some chemotherapy drugs cause nausea and vomiting, and radiation therapy can cause mouth inflammation).

Proper nutrition while undergoing cancer treatment is essential to maintain your pet's strength, improve survival times,
quality of life and maximize response to therapy. Adequate nutritional support was shown to decrease the duration of
hospitalization, reduce post-surgery complications and enhance the healing process. Additionally, pets with cancer need
to be fed diets specifically designed to provide maximum benefit and nutritional support for the patient. To learn more,
please visit the
Cancer Nutrition section.

What are the treatment options for lung tumors in cats and dogs?
Once a single mass was identified in the lungs and the pet is in relatively good health to tolerate anesthesia, surgical
removal of the single mass is the treatment of choice. Radiation therapy and chemotherapy have not been largely used
for the treatment of lung cancer.
Metastatic cancer to the lung is rarely treatable and there are several criteria the pet
must satisfy prior to the surgical intervention.

How do I find a qualified veterinary oncologist?
To locate a qualified veterinary oncologist worldwide who can discuss with you appropriate cancer treatment plan for your
pet's cancer condition, please visit the "
Locate a veterinary oncologist" section.  

What is the prognosis for cats and dogs with lung cancer?
The prognosis is generally good for pets with a single, small mass in their lungs that has not spread. In this group, more
than 50% are expected to live 1 year after the surgical removal of the mass. A recent study of 67 dogs diagnosed with
primary lung cancer showed that the prognosis depends on several factors such as the cancer histological type, grade,
how advanced the cancer is and whether the pets had symptoms at the time of diagnosis The overall median survival of
these dogs was 1 year. Dogs with lower grade tumor had a median survival of 22 months whereas dogs with higher grade
tumor had a median survival of 6 months. Dogs who showed symptoms had a median survival of 8 months compared to
18 months in those without symptoms.

Are there any clinical trials for dogs or cats with lung cancer?
Although there are no clinical trials evaluating new treatments specifically for lung cancer, there are several clinical trials
available for cats and dogs with any tumor type for which your pet may qualify. To learn more these trials (which are
partially or fully funded by the institutions), please visit the
Dog Clinical Trials (any tumor type) or Cat Clinical Trials (any
tumor type) section.  

To learn more about veterinary clinical trials in general, please visit the
Pet Clinical Trials section.

Additional online resources

  • Withrow Stephen J, and David M. Vail. Small Animal Clinical Oncology. St Louis: Saunders Elsevier, 2007.
  • Morrison Wallace B. Cancer in Dogs and Cats: Medical and Surgical Management. Baltimore: Williams&Wilkins,
Comprehensive guide to cancer diagnosis and treatment in cats and dogs
© 2007 Pet Cancer Center. ALL RIGHTS RESERVED.
Last updated 2/19/2017