Cancers in dogs and cats

Stomach cancer in dogs

The stomach is a muscular organ that is an extension of the gastrointestinal tract. It serves as a temporary storage place for food and also produces substances that are involved in digestion. Thanks to the stomach, the animal converts the food it receives into energy for the body.

Like other organs, tumors can form in it. They are divided into 2 main groups:

benign tumors;
malignant cancer tumors.

In the first case, the tumor grows slowly, has clear boundaries, does not spread to other organs, and also has no external symptoms for a long time. It can be effectively removed during treatment.

And in the second case, the cells grow in an unpredictable way and very quickly. This type of tumor is called cancerous and is life-threatening. The prognosis for its cure will be unfavorable, regardless of the type of drugs used.

It is not the most common cancer and accounts for only 1% of all malignant tumors. There is no breed predisposition to the disease, but there is a risk group.

It includes:

Dogs that have been given nitrosamines along with their food for a long time. These are dry foods with nitrite salts as a preservative.
German Shepherds. The frequency of the disease in this breed suggests a genetic predisposition, but this has not been proven.

The disease affects pets aged 8–10 years. Statistics have not recorded a difference between the gender of pets with this diagnosis.

Did you know? Not all cancers are painful for your pet. But for a malignant tumor at the initial stage, pain is experienced by 20

–
50% of cases. And in the advanced stage, up to 90% of animals experience pain.

Types of stomach cancer in dogs

There are several main types of stomach cancer in dogs:

adenocarcinomas;
mast cell tumors (mastocytomas);
leiomyosarcoma;
lymphomas.

Adenocarcinomas are most often associated with gastric cancer. They account for 70–80% of this disease. These are tumors of glandular tissue that can spread to the liver, lungs, esophagus, omentum, adrenal glands, pancreas, spleen, duodenum and lymph nodes.

Mast cells are part of the immune system. They are present in the mucous membrane of the digestive tract, lungs, nose and skin. When these cells become abnormal, they form a mastocytoma or mast cell tumor of the stomach.

Leiomyosarcoma are neoplasms that form in the walls of hollow organs. This could be the stomach, bladder, uterus or respiratory tract. The stomach is affected by such tumors more often than other organs. They may also spread (metastasize) to the spleen, kidneys, and lymph nodes.

Lymphoma is a cancer that affects white blood cells called lymphocytes. Although this is not the most common type of tumor, it is also found in the gastrointestinal tract. It accounts for 7–24% of all deaths caused by gastrointestinal cancer. Lymphoma is more often diagnosed in males than in females. The statistical ratio is 2.5:1. People who are predisposed to this type of cancer are:

boxers;
Saint Bernards;
mastiffs;
Airedale Terriers;
bulldogs;
Scottish terriers.

Important! Gastric adenocarcinomas often involve a large area of the stomach wall. Therefore, it is extremely difficult to remove them surgically.

How do symptoms appear?

The most characteristic symptom that the owner may notice is vomiting blood. After some time, sharp weight loss, loss of protein and general weakness of the body will also become noticeable.

Other symptoms of stomach cancer:

pain;
low level of pet activity;
apathy;
growling and whining;
lack of appetite;
unusual reactions, such as squealing and running away in response to touch;
rapid breathing;
urinary and fecal incontinence;
Belly licking.

How is stomach cancer diagnosed?

Standard tests and standard x-rays do not help diagnose cancer. Therefore, veterinarians do x-rays with positive or double contrast and, in addition, ultrasound of the abdominal cavity.

Other types of analyzes and their features:

Fluoroscopy helps identify changes in motility.
To identify large tissue lesions, oncologists perform gastroscopy using a flexible endoscope. The doctor needs to obtain several large tissue samples from the suspicious area in order to confirm or refute the preliminary diagnosis.
Blood may be found in the feces. Its particles are not necessarily visually noticeable, but will be detected when examining a stool sample.
Blood samples will show liver enzymes because the body is experiencing bile duct obstruction (loss of capacity).

It is difficult to assess the stage at which the cancer is without a very thorough internal analysis. This also requires an assessment of the liver and lymph nodes. But it can only be done surgically. Therefore, doctors try to establish a diagnosis in simpler ways.

Important! Radiation therapy can cause inflammation in the mouth.

Methods for treating cancer

Surgical removal of tumors is the most common and useful treatment for stomach cancer in dogs. Malignant tumors are removed before they metastasize. The exception is lymphoma. If such a tumor is preventing food from reaching the stomach, bypass surgery may be helpful, even if the surgery does not cure the cancer itself.

Chemotherapy is not considered effective in treating this type of cancer because radiation is harmful to sensitive organs near the stomach. In cases where it is used, it is used:

“Adriamycin” every 2 weeks, 5 procedures in total;
then weekly Cytoxan, daily Doxycycline and monthly Vincristine.

Pain control

It is very important that a pet diagnosed with stomach cancer receive pain medication.

Likely indicators that your dog is in pain include:

Change in activity level - an animal that is in pain refuses to go for a walk.
Reluctance to move. The dog sits or lies for a long time.
Lack of appetite.
Aggression or shyness.
Sad expression of the muzzle, lowered head.
When touched, it tries to run away or growls.
Constantly licks a certain place.

Pain treatment occurs in 2 ways. The first is the elimination of the tumor itself as the source. If this is not done, then the pain itself must be treated.

Here are some medications to reduce pain:

with moderate, weaker opioids are needed, for example, Tramadol, Codeine;
for severe pain - “Morphine”.

Important! Do not use medications without a doctor's prescription, so as not to harm the dog. And be sure to stick to the dosage prescribed by your doctor.

Medications weaker than opioids cannot relieve stomach cancer pain. But analgesics or non-steroidal anti-inflammatory drugs can be supplemented with the main treatment.

Diet for a dog with stomach cancer

A common problem with stomach cancer is weight loss. A low level suppresses the immune system and this leads to the pet being unable to cope with the disease. Therefore, the dog needs a special diet.

A pet with cancer needs food that is high in carbohydrates. Amino acids are also important. Some of them add to your daily diet:

Ancillary drugs

If a dog eats on its own, that’s good. But if she has no appetite, try to warm her food to body temperature (+38–39°C). This makes it more attractive and fragrant. If this fails, contact your veterinarian for an appetite stimulating drug or intravenous feeding.

Medicines used at home:

to stimulate appetite - Cyproheptadine or Megestrol;
to reduce nausea - Metoclopramide.

Did you know? Stomach cancer metastasizes in 75% of cases.

Clinical picture and diagnostic methods

At an early stage of its development, the neoplasm may not have a specific pattern of manifestation. The dog experiences sudden weakness and decreased activity. Appetite worsens, reaction to food is not expressed, and at the same time thirst increases.

In sick animals, chronic dysfunction of the digestive system is noted. The pathology is manifested by vomiting mixed with blood. In the stool, blood is detected when the distal parts of the intestine are affected; disease of the small and upper parts of the large intestine is accompanied by the appearance of a tarry mass.

The dogs are exhausted, general lethargy, weak reaction to stimuli. There is pain during defecation. Due to the loss of protein, swelling of the subcutaneous fat appears. Pain on palpation of the abdomen is rarely detected, usually when the stomach is involved in the pathological process. Very rarely, during palpation, the formations themselves and thickening of the intestinal walls are detected. With adenocarcinoma, rectal prolapse in dogs is often observed due to the localization of this tumor.

During the manifestation of symptoms, the disease becomes acute. Intestinal obstruction is often suspected in dogs due to a similar clinical picture. Intestinal blockage is associated with impaired secretion and damage to the mucous membrane. Intussusception of the intestinal wall often occurs.

Clinical changes are not sufficiently informative, so additional laboratory and instrumental studies are carried out. Hematological changes:

hypochromic anemia;
peripheral leukemia;
leukocytosis with a nuclear shift to the left;
general decrease in protein;
increased activity of liver enzymes.

X-ray of the abdominal cavity may not provide information about the pathological process. In some cases, a stuck bone, obstruction, enlargement of the spleen and liver, and abdominal dropsy are detected. Enlargement of the abdominal organs is most typical for intestinal lymphosarcoma. Chest X-rays are performed to detect metastases in the lungs and pleura, but this procedure is usually performed after a diagnosis of bowel cancer has been made.

Ultrasound examination is a more accurate tool that allows you to exclude other pathologies of the abdominal cavity and gastrointestinal tract. Ultrasound reveals thickening of the intestinal wall and cancerous formations. Under ultrasound guidance, a puncture of the tumor is performed for differential diagnosis.

An alternative method is gastrointestinal endoscopy, which allows you to visually assess the condition of the mucous membrane, as well as perform a biopsy. But this procedure can only be performed for the stomach, duodenum, rectum and colon. It is problematic to examine other departments using this method.

Gastroscopy data for adenocarcinoma:

ulcerated formation in the pyloric part;
thickening and changes in the folds of the mucosa;
accumulation of feed and liquid.

When traditional diagnostic methods are unsuccessful, laparotomy is resorted to. In this case, the surgical operation should be planned so that if a neoplasm is detected, it is possible not only to diagnose it, but also to remove it or other treatment.

Treatment of cancer patients is almost the same for both people and animals. It is always complex and consists of the following stages:

Surgical removal of the tumor. The neoplasm must be removed with a part of healthy tissue in order to protect against possible penetration of cancer cells into surrounding tissues and spread of the process.
Irradiation using a special device. This is not possible in all veterinary clinics. The method is not used for all types of cancer tumors and is not applicable for some types of tumor localization.
Chemotherapy. It involves taking toxic drugs that can kill cancer cells, destroy or reduce tumors and metastases, and also prevent their formation and further spread.

You cannot give your dog medications intended for humans, since, despite the general principles of the effect on tumors, the type of medication, dosage and intensity of treatment can only be selected by a veterinarian. This is because the dose is calculated only for the individual dog, taking into account his weight, age, general health and the presence of additional problems.

If the doctor prescribes painkillers, there is also a danger of overdose. Owners should obtain full advice from a specialist on how they should act in certain situations.

Treatment of any form of cancer is extremely complex, lengthy and expensive. However, there are some types of this terrible disease that are easier to treat than others and can be cured completely or give long-term remission. These include skin cancer in the early stages.

Intestinal tumor in dogs

The intestine is the dog's digestive organ, which consists of a small and large intestine. Its task is to organize the absorption of nutrients into the blood and remove the remains of digestion from the body.

The most common intestinal tumor in cats is lymphosarcoma. In dogs these are intestinal:

lymphosarcoma;
adenocarcinoma;
smooth muscle tumors.

All types of cancer occur at approximately the same frequency. Although lymphosarcoma is recorded somewhat more often than other types of tumors. All of them disrupt the normal motility of the gastrointestinal tract and are accompanied by inflammatory processes.

Cancerous tumors cause various pathologies of smooth muscles and mucous membranes. The symptoms of these pathologies will be clearly visible. But their treatment with injections and tablets can blur the signs of cancer. Therefore, it is important that the pet is examined by a specialist, accurately diagnoses the disease, and only then prescribes treatment.

Clinical signs and symptoms of intestinal tumor

Patients with a cancerous tumor in the gastrointestinal tract are characterized by vomiting and sudden weight loss. Melena (dark stool) may be visible in some cases:

the tumor is in the colon;
there is bleeding.

Diarrhea in dogs occurs when the neoplasm is localized in the cecum. In some patients, a hard mass may be palpable in the lower abdomen. Sometimes there is an enlargement of the lymph nodes if the tumor is located next to them.

Additional symptoms:

bloating;
pale mucous membranes.

Important! Caudate patients with intestinal tumors are most often middle-aged or older.

Features of treatment of intestinal cancer

The doctor may recommend removing even a benign tumor. And for malignant ones, this is the main method of treatment. Especially if it is small and has not formed metastases. In the second case, it will be supplemented with chemotherapy or radiation therapy in order to slow down the growth of cancer cells.

Everyone is well aware of the importance of minimizing pain for your pet. But with cancerous tumors in the gastrointestinal tract this is not always possible. Therefore, therapy is aimed at keeping the dog alive until the pain relief stops helping. And then the owner of the animal will be offered euthanasia.

Symptoms

Oncological neoplasms are dangerous because in the first stages the disease occurs without pronounced symptoms. But an experienced and attentive owner can note the following deviations in the behavior or appearance of the animal:

Digestive disorders - vomiting after eating, an unexplained decrease in appetite, strange behavior after eating, allowing one to suspect that the dog is suffering from pain. Constipation and diarrhea may be an indication of the presence of cancer in the gastrointestinal tract.
Problems with urination and bowel movements may be caused by a tumor of the prostate or rectum.
Coughing, bleeding from the mouth, the feeling that the dog is choking on food and water most often occur with damage to the lungs and other respiratory organs, cancer of the larynx, tumors of the jaw, tongue, lip, nose.
Changes in gait, unsteady, uncertain movements, and lameness indicate damage to the skeletal system.
Growths under and on the skin and changes in pigmentation can be symptoms of various types of cancer, including skin cancer.
Pain – the dog may suffer greatly from pain in the affected parts of the body, as well as from general intoxication, which is expressed by severe weakness, exhaustion and apathy.
An unpleasant odor emanating from the animal or from individual areas affected by the tumor. Usually indicates the disintegration of a neoplasm, often accompanies breast cancer, lesions of the mouth, and skin.

Most symptoms relate to the gastrointestinal tract. Among them:

weight loss;
blood in feces (hematochezia);
accumulation of gases in the stomach and intestines (flatulence);
rumbling in the stomach;
false painful urge to defecate.

Rectal cancer

The rectum ends the dog's digestive system. Its task is to remove digestive waste out through the anus.

Tumors develop in:

colon;
in the middle or at the end of the rectum at the anus.

Benign tumors, or polyps, occur at the end of the rectum. Most rectal tumors are internal and not visible. But if the tumor is located at the anus itself, then it may be noticeable.

Some breeds are thought to be predisposed to colorectal cancer. Among them:

German Shepherds;
springer and cocker spaniels;
malamutes;
dachshunds.

We recommend reading the symptoms and treatment of spleen cancer in dogs.

Symptoms of colorectal cancer

The main symptom for a pet with colon cancer is difficulty defecating. Owners may also detect blood in his stool. The pet has to push and this causes additional pain, which is accompanied by:

whining;
yapping;
mucus in stool;
diarrhea.

Tumor diagnosis

A tumor can be diagnosed by palpation, as well as blood tests and endoscopy. A tissue biopsy will also be required to identify the type of tumor and stage of development.

Treatment of rectal cancer

Usually, by the time most intestinal tumors are discovered, it is too late to remove them, as they have metastasized. But in the case of rectal tumors, the situation is somewhat different. Not all of them are malignant. About half are benign. Therefore, the veterinarian may recommend surgery + chemotherapy as treatment. The average survival time depends on the type of tumor diagnosed and is about 32 months, which is quite long.

Postoperative care

Most animals are discharged 1–2 days after surgery. Your doctor will tell you a schedule for checking stitches and changing bandages.

The owner will also need:

Restrict the dog's freedom of movement for 2 weeks. To prevent the pet from being active, it must be placed in a cage and put on an Elizabethan collar. This will prevent him from licking the seams.
Do not bathe your pet or allow the incision to get wet.
Do not allow running and playing with other animals.
Check the incision daily for signs of redness, swelling, or discharge. It will be slightly swollen for the first 2 days as the healing process occurs. But if this condition continues or you notice that the inflammation is intensifying, then you need to inform your doctor about it.
Do not take any action regarding the incision that has not been approved by your veterinarian.

Important! It is believed that various viruses lead to the appearance of 25% of cancerous tumors in animals.

In the postoperative period, you will definitely need painkillers. This may be Ketamine 10 mcg/kg every 6 hours, but the surgeon who performed the operation may also indicate another drug. The choice depends on the degree of pain the dog is experiencing.

Postoperative complications may include:

infection;
divergence of the edges of the wound.

To minimize risks, you will be given a schedule of seam control checks. It is designed to help your doctor notice signs of inflammation or other complications. This will allow you to take action in time.

The owner needs to know that after removal of a tumor in the rectum, 33% of dogs experience fecal incontinence. This is usually temporary, but the doctor should warn you about this and other possible complications, and also explain what and how you should do so as not to harm your pet.

Forms, types of intestinal cancer

Intestinal cancer in dogs can be either malignant or benign. Animals of different ages are equally susceptible to cancer, but neoplasia in most cases appears after five to seven years.

The following types of intestinal tumors are diagnosed in dogs:

Adenocarcinomas.
The most common type of cancer that develops in the duodenum and colon. Characterized by intensive development and aggressive growth. Often metastasize.
Lymphomas.
A very rapidly developing neoplasm that metastasizes to all organs of the digestive tract.
Adenomas.
They are benign polypoid formations. The tumor is localized mainly in the colon.
Leiomyomas, leiomyosarcoma.
Tumors affect the muscle structures of various parts of the intestine. They can provoke partial or complete atony, local peritonitis if they rupture.
Mastocytomas.
Manifest in the form of erosive lesions of the small and large intestines. Most often diagnosed in miniature, dwarf breeds of dogs. Give metastases to regional lymph nodes.

The clinical picture and the intensity of development of the oncological process depend on the form, stage, localization of the oncological disease, the presence of metastases,

Esophageal tumor in dogs

The esophagus is a small tube connecting the mouth to the stomach. Its walls are made of muscles that contract in waves and push food into the stomach. Thus, the only function of this organ is to deliver food from the mouth to the stomach.

Esophageal cancer is very rare in dogs. It accounts for even less than 0.5% of all cancer cases in pets.

The most common primary esophageal tumors include:

sarcomas (fibrosarcoma and osteosarcoma);
squamous cell carcinoma;
leiomyosarcoma.

Important! Surgeries on the esophagus are always difficult due to its location in the chest and the slow healing rate.

Infection with the nematode spirocerca lupi causes the disease spirocercosis and can cause osteosarcoma of the esophagus. If the growth becomes massive and malignant, the dog will typically develop spondylitis (changes in compounds).

Sometimes there are benign tumors in the esophagus. Such as leiomyoma and plasmacytoma. The decision about whether they need to be removed is made by the oncologist after examining the dog.

The esophagus is also affected by metastases from other organs. and this happens 3 times more often than primary tumors develop in it. Typically, metastases appear from the thymus, thyroid or breast adenocarcinoma.

How does esophageal cancer manifest in dogs?

The most common symptom of esophageal cancer is trouble swallowing. Other symptoms of the disease usually include:

weakness;
weight loss;
pain when swallowing;
burning;
regurgitation of undigested food (reverse movement of masses along the esophagus);
weight loss;
vomiting

Pneumonia may develop as a secondary disease. If spondelitis develops, then signs of joint damage will be observed: lameness, pain, inflammation.

Important! Traditionally, chemotherapy is given intravenously, but there are drugs that are given by injection and even those that are taken orally.

Diagnosis and treatment of esophageal tumors

Since the upper gastrointestinal tract is partially blocked by the tumor, x-rays can reveal:

gas retention in the lumen of the esophagus;
expansion in some part of it.

And this makes it easy to establish the presence of a tumor. A tissue biopsy will determine the type and stage of its development.

If the neoplasm is a leiomyoma (mucous tumor), then its biopsy is of little use. Therefore, the doctor will prescribe an MRI or computed tomography scan of the organ. They allow you to obtain a 3D model and very accurately determine all the features of the tumor.

Treatment for esophageal cancer depends on two main factors:

degree of tumor development;
the general health of the dog.

At an early stage of pathology development, only surgery is indicated. And only leiomyoma can be treated with endoscopic resection. But if we are talking about the late stages of development of a malignant neoplasm, chemotherapy or radiation therapy will be offered. Both types are important in advanced cancer.

Radiation therapy uses X-rays to kill cancer cells. Normal cells in the body are able to recover from radiation much faster than cancer cells. Therefore, radiation therapy is often quite effective. Irradiation is carried out several times a week (up to 5) for 5-7 weeks. The exact number of treatments will be determined by your veterinarian. The procedure may have side effects:

a sore throat;
skin irritation.

Chemotherapy is a medicine that is given intravenously. It spreads throughout the body and reaches cells that have metastasized. The goal of this type of therapy is to stop cell growth. In some cases, chemotherapy is combined with radiation therapy. This allows you to stop the development of the tumor and helps to reduce it.

Did you know? Dogs can detect the scent that comes from cancer cells. Therefore, they are used to detect cancer in humans.

Diagnosis of the disease

In order to notice and defeat the disease in time, it is not enough to simply observe your pet. Any change in behavior or physical signs should prompt immediate veterinary attention. How can the doctor help? He carefully examines the animal and, perhaps, notices signs that have escaped even the owner’s attentive gaze.

Secondly, he will prescribe the necessary tests. First, the standard ones - general and biochemical, and then, if changes in certain indicators are noticed, special ones - to identify tumor markers confirming the presence of cancer cells.

Diagnosing cancer is a rather complex process, therefore, in addition to tests, the doctor will conduct many different examinations - from ultrasound and fluorography to gastroscopy and MRI. If you suspect breast cancer, your doctor will suggest you undergo a mammogram, a special X-ray of the breast that shows the presence of a cancerous tumor at an early stage.

When a tumor is detected, the doctor will take a small piece of tissue (puncture) and send it for cell analysis. This will help determine whether a neoplasm is benign or malignant, as well as the stage of development of the disease.

Recovery forecasts

The prognosis for a diagnosis of stomach cancer is not optimistic. Most pets will live no more than 6 months after diagnosis. This is because the cancer recurs and spreads to other organs.

Despite this, each situation is unique. Some animals will have a little more time, others a little less. The most important thing you can do is try to make your pet as comfortable as possible and show how much you love him.