Lung Adenocarcinoma in Cats
Adenocarcinoma is a malignant neoplasm, making up about 75 percent of all primary lung tumors in cats. Adenocarcinoma grows rapidly and metastasizes to distant parts of the body and organs, including the brain, eyes, bones, and lymph nodes. Like other malignant tumors, adenocarcinoma of the lungs is usually seen in older animals (more than ten years). This type of carcinoma is relatively rare in cats, with no known breed disposition.
Symptoms and Types
Most symptoms are related to the respiratory system, but in cases of metastasis the symptoms vary depending upon the location of the metastasis in the body. Following are some of the symptoms seen in patients with lung adenocarcinoma:
- Dyspnea (difficult breathing)
- Tachypnea (rapid breathing)
- Low energy level and lethargy
- Poor appetite
- Gradual weight loss
- Hemoptysis (coughing up blood)
- Lameness in cases of metastasis to bones
- Muscle wasting
- Fever in some patients
- Ascites (an accumulation of fluid in the peritoneal cavity of the abdomen)
- Idiopathic - exact cause is still unknown
- Suspected risk factors include living in an urban environment and passive cigarette smoking, but not proven
You will need to give a thorough history of your cat'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 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 cat 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 cat'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
Cats with metastasis usually have less than one year to live, but treatment may increase the survival time. During this period you can improve your cat's quality of life by providing extra care and affection. As best as you can, be attentive to your cat'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 on the best handling practices.