Clinical Signs of Esophageal Cancer in Dogs and Cats

執筆者 TCMVET | 2024年9月8日 | 犬の癌と腫瘍

Esophageal cancer, while rare in dogs and cats, is a serious and life-threatening condition. The esophagus, responsible for transporting food from the mouth to the stomach, can be affected by various tumor types, including 扁平上皮癌, 腺癌, and, more rarely, 平滑筋肉腫. Early detection is crucial for improving the prognosis, but due to the subtle nature of the initial symptoms, esophageal cancer is often diagnosed late. This article outlines the clinical signs of esophageal cancer in pets, helping pet owners recognize early warning signals and seek timely veterinary care.

Common Clinical Signs of Esophageal Cancer in Dogs and Cats

The symptoms of esophageal cancer in dogs and cats can often be mistaken for other gastrointestinal or respiratory conditions. Here are some of the most common signs that could indicate an esophageal tumor:

1. Regurgitation

Regurgitation is the most frequently observed symptom of esophageal cancer in pets. It differs from vomiting in that it involves the passive expulsion of undigested food or liquids shortly after eating, without any abdominal effort. As tumors grow and obstruct the esophagus, they prevent food from passing into the stomach, leading to regurgitation.

• Key Observation: Unlike vomiting, regurgitated material looks undigested, as it has not yet reached the stomach. If you notice your pet frequently regurgitating after meals, it’s important to consult a veterinarian.

2. Difficulty Swallowing (Dysphagia)

As the tumor progresses, pets may experience dysphagia, or difficulty swallowing. This can occur due to the tumor physically blocking or narrowing the esophagus, making it hard for food or water to pass through. Pets may gag, cough, or display signs of distress when attempting to swallow.

• Key Observation: Look for signs such as drooling, excessive salivation, or repeated attempts to swallow, especially after eating or drinking. Some pets may even refuse food due to the discomfort associated with swallowing.

3. Painful Swallowing (Odynophagia)

In addition to dysphagia, pets with esophageal cancer may experience odynophagia, which refers to pain when swallowing. The tumor’s invasion into surrounding tissues and nerves can cause significant discomfort during the swallowing process. Pets may show signs of pain by whining, pawing at their mouth, or refusing to eat.

• Key Observation: Watch for signs of discomfort during or after meals, such as sudden refusal to eat, head shaking, or crying when swallowing. Painful swallowing can lead to weight loss and malnutrition.

4. 減量

As the tumor grows, it becomes harder for pets to consume and digest food properly, leading to weight loss. In some cases, pets may develop a reduced appetite due to discomfort when eating, while in others, they may try to eat but fail to keep food down due to regurgitation.

• Key Observation: If you notice unexplained weight loss in your pet, particularly when accompanied by regurgitation or difficulty swallowing, this could indicate an underlying esophageal condition.

5. Coughing and Respiratory Issues

Esophageal tumors can sometimes lead to coughing and respiratory issues. This occurs when food or liquids enter the airways (a condition known as 誤嚥性肺炎) because the esophagus is obstructed, and material intended for the stomach is mistakenly inhaled into the lungs.

• Key Observation: If your pet starts coughing frequently, especially after meals, or shows signs of respiratory distress like labored breathing or wheezing, it could be related to esophageal dysfunction.

6. Lethargy and Weakness

As esophageal cancer progresses, pets may become increasingly lethargic. The inability to properly digest food and the development of secondary infections like aspiration pneumonia can drain their energy, leading to fatigue and weakness.

• Key Observation: Monitor your pet for signs of reduced activity, tiredness, or reluctance to engage in their usual activities. Lethargy in combination with other symptoms such as regurgitation or weight loss should be evaluated by a veterinarian.

Diagnosis of Esophageal Cancer in Dogs and Cats

Recognizing these clinical signs early can lead to quicker diagnosis and potentially better outcomes. Veterinarians use a combination of techniques to diagnose esophageal cancer:

• 内視鏡検査: This procedure involves using a flexible camera to view the inside of the esophagus and take biopsy samples of any abnormal growths.
• イメージング: X線検査, ultrasoundそして CT scans can help visualize tumors and assess whether the cancer has spread to other parts of the body.
• 生検: A tissue biopsy is the definitive way to diagnose the type of esophageal tumor and determine whether it is benign or malignant.

Treatment Options for Esophageal Cancer

Once esophageal cancer is diagnosed, treatment options will depend on the type, location, and stage of the tumor. Common treatments include:

• 手術: If the tumor is localized and surgically accessible, removing the tumor may provide the best chance of survival.
• 化学療法: This treatment may be used in conjunction with surgery or when surgery isn’t possible. It helps slow tumor growth and manage metastasis.
• 放射線治療: Although not always highly effective for esophageal cancer, radiation may be used to shrink the tumor or relieve symptoms in some cases.
• 緩和ケア: In advanced cases where curative treatment is not possible, palliative care focuses on managing symptoms like pain, regurgitation, and malnutrition to improve the pet’s quality of life.

Esophageal cancer in dogs and cats is a serious condition with subtle initial symptoms, making early diagnosis challenging. Clinical signs such as regurgitation, difficulty swallowing, weight loss, and respiratory issues can indicate the presence of a tumor. If these symptoms appear, pet owners should seek veterinary attention as soon as possible. Early diagnosis and treatment are critical for improving the prognosis and quality of life for pets suffering from esophageal cancer.