Abdominal cancer can be a silent killer because dogs don’t usually show any signs of illness by the time it might be too late. Even though abdominal cancer is usually thought of as stomach cancer, the truth is that this disease can affect multiple organs within the abdominal cavity – from the liver to the spleen.
In this article, we will look at some of the types of tumors that affect abdominal organs, their clinical signs, and the treatment and prognosis for some of the most common ones.
Intestinal cancer mostly takes the form of a malignant tumor called adenocarcinoma, which originates in the epithelial and glandular tissue. This type of neoplasm can invade a variety of parts of the gastrointestinal system, including the rectum. It commonly affects dogs that are older than six years of age. There isn’t a particular predisposition with regard to the breed, but there is one with regard to the gender as male dogs are more predisposed to this type of cancer than females.
Some of the symptoms of intestinal cancer range from vomiting and weight loss to abdominal pain, melena (black feces due to the presence of hemorrhages in the gastrointestinal tract), and vomiting of blood (hematemesis). The causes of intestinal cancers aren’t known yet, but there is a suspicion according to which Belgian shepherds are genetically predisposed to developing it.
The diagnosis is complex, and it calls for several types of investigation methods from a physical examination, blood tests, and contrast X-rays to endoscopy and biopsy.
Intestinal cancer is mostly treated through surgery. Radiation therapy has a host of side effects on abdominal organs, and it is not recommended in this type of neoplasia. Chemotherapy and surgery work well together, but the first of the two rarely is successful on its own.
Gastric cancers are usually malignant and have a tendency to metastasize. In case the disease does spread to other organs, it typically affects the liver, as well as the lymph nodes present inside the abdominal cavity. Three of the malignant gastric cancers that can be found in dogs are adenocarcinoma, leiomyosarcoma, and lymphoma. Benign leiomyomas can also affect the stomach, but they can be treated thanks to surgery and have a fairly good prognosis.
The breeds that are predisposed to developing stomach cancer are Belgian shepherds, Chow Chow, Rough Collie, and Staffordshire Bull Terrier. Some of the symptoms of this illness are vomiting, decreased appetite, the same black stools we mentioned in the section about intestinal cancer, abdominal pain, as well as weight loss.
The diagnosis is made with the help of endoscopy, contrast X-rays, and biopsy. These methods are not conclusive when it comes to telling whether the tumor has spread to other organs. Staging the cancer via cytology can be useful.
Surgery and chemotherapy are used to treat gastric cancers. In most cases, this type of tumor can be found in the lower part of the stomach, so it is removed along with a portion of the small intestine after which the remaining parts are surgically re-connected.
The issue with gastric cancers is that most adenocarcinomas that affect this organ are diagnosed when the dog has already developed metastasis to other organs. In some of these cases, the life expectancy can range from 2 to 9 months.
There are several types of liver cancer, but the most common one diagnosed in dogs is hepatocellular carcinoma (HCC). This is the primary liver cancer that originates from this organ. Other types that affect the liver are neuroendocrine tumors, bile duct carcinomas, as well as sarcomas (mesenchymal tumors).
HCC evolves in three different ways. One of them involves the development of a single massive tumor and the second is a nodular form, with several masses spread throughout the organ. The last (and most severe) manifestation is diffuse, so it basically affects the entire liver. Fortunately, in most cases, the single tumor development is the one that is diagnosed and compared to the other two, this one has a significantly lower chance of metastasizing to other organs.
Liver cancer is dangerous because it can spread to virtually any organ. Metastatic neoplasms are typically associated with intestinal and pancreatic cancers, but also mammary carcinomas and even lung cancers.
No dog breed is more predisposed to developing liver cancer than the other. When it comes to the signs that can be discerned, most dogs will show symptoms ranging from diarrhea and polydipsia to weight loss, fever, weakness, and lethargy. Vomiting and seizures can be seen in cases where the dog is suffering from an abdominal hemorrhage due to a necrotic tumor core.
The diagnosis is made through imaging tests like ultrasounds and X-rays, and needle aspirations and biopsies always prove their worth when it comes to staging the neoplasm. However, depending on the severity of the illness, the size of the tumor, as well as any blood-clotting issues, needle aspirates and biopsies have to be performed with the utmost care.
When it comes to the treatment and prognosis, the positive aspect of a large and single primary liver cancer is that it can be removed surgically and the prognosis is good. Most canine patients that go through surgery for this type of tumor survive for many years following the procedure.
Unfortunately, most of the malignant tumors cannot be removed, especially when they have metastasized. In these cases, the prognosis is poor, and the life expectancy ranges from three to six months. Chemotherapy doesn’t cure cancer in this situation, but it can delay its progression.
While it is less frequent compared to liver cancer, for example, spleen cancer can be seen in a number of cases. The types of spleen neoplasia commonly diagnosed are hemangiosarcoma and lymphosarcoma. Internal lymphoma can have severe signs from vomiting and diarrhea to abdominal pain and difficult breathing. If it is left untreated, it can quickly become fatal.
When it comes to the dog breed predisposition, hemangiosarcoma has an increased frequency in German Shepherds and Golden Retrievers. It is not characterized by any particular signs, unfortunately, because the symptoms can’t be noticed until late in the disease. The tumor can rupture, and as such, dogs can suffer potentially lethal internal bleeding.
Hemangiosarcoma can metastasize to other organs – the liver and the heart being two of the common metastasis sites. Because it is diagnosed so late in its development, most dogs that have hemangiosarcoma rarely live for more than seven to eight months even with surgery and chemotherapy combined.
Almost all organs, be they inside the abdominal cavity or anywhere else in a dog’s body can be affected by cancer. Because the incidence is higher with pets that are over the age of eight, we would advise you to take your canine friend to the vet for regular checkups as he or she ages.
We have already noted that most of these types of neoplasms rarely have any discernible symptoms, whether they are malignant or benign. In both of these cases, they take time to grow and many times, only their size and the metastasis to other organs will make your dog show any symptoms. When the clinical signs become noticeable, it might already be too late.