Just like humans, dogs can develop various types of cancers. It is quite worrisome for pet owners when their beloved dog is diagnosed with cancer. So, it’s normal to wonder if dogs can recover from cancer too.
Dogs can recover from cancer, but it depends on various factors, such as the type and stage of cancer, the age and overall health of the dog, and the treatment options available. Early detection and prompt therapy increase the chances of recovery.
Table of Contents
- What Is Cancer, And How Is It Different From Tumors?
- What Is The Difference Between Benign And Malignant Cancer?
- What Are The Types Of Cancer In Dogs?
- What Are The Risk Factors That Predisposes Dogs To Cancer?
- Signs And Symptoms Of Cancer In Dogs
- How To Diagnose Cancer In Dogs
- What Treatment Options Are Available For Curing Cancer In Dogs?
- What Are The Factors That Affect The Recovery Rate Of Cancer In Dogs?
- Conclusion: Can Dogs Recover From Cancer?
What Is Cancer, And How Is It Different From Tumors?
Although cancer and tumors are used interchangeably, there is a difference in how cancer spreads. Both cancer and tumor is a purposeless proliferative growth of a particular cell type. These cell types proliferate to become non-functional. The cells grow uncontrollably with repeated cell divisions. A tumor can be defined as a cluster of abnormal cells that have proliferated but haven’t metastasized.
Cancer, on the other hand, is a tumor (abnormal cell growth) that has metastasized (spread to other organ systems), also called secondary growth. Cancer is, therefore, more dangerous, and in some fatal cases involving vital organs like the brain, can result in death.
What Is The Difference Between Benign And Malignant Cancer?
Malignant or benign tumors can both occur in the body (cancerous). It is typical for benign tumors to grow slowly and not spread. Malignant tumors have the ability to spread throughout the body, grow quickly, infiltrate neighboring normal tissues, and do great damage.
Locally invasive cancer: the tumor can spread “fingers” of malignant cells into the surrounding healthy tissue, invading those areas. The tumor may do this even if those tissues are far from the original tumor.
The “primary tumor” is the original tumor. Its cells can start the growth of new tumors in other organs as they circulate throughout the body. “Secondary tumors” are the name for these novel cancerous growths.
Secondary tumors are created when malignant cells spread through the lymphatic or circulatory systems.
The lymphatic system is made up of a network of tiny channels that transport waste from cells into larger vessels, clearing the lymph from infectious organisms and draining the lymph (fluid) into the bloodstream.
What Are The Types Of Cancer In Dogs?
Dogs may suffer from several types of cancer, from simple melanomas to osteosarcomas and mammary gland tumors. Before going into detail about common types of cancer, let’s first discuss the difference between carcinomas and sarcomas.
A carcinoma is a cancer that develops in skin cells like epidermal cells and in other soft tissue that forms a lining around the various organs like the lungs, liver, kidney, and bladder.
A sarcoma is a proliferative abnormal cell growth that involves the body’s connective tissue, which includes blood cells, nerves, muscles, and bones.
Common Types Of Cancer In Dogs
Let us now discuss the common types of cancers in dogs.
This type of cancer frequently causes several lymph nodes in dogs to grow. These are tiny structures that can be felt along the jaw, in front of the shoulders, in the armpit and groin area, and behind the “knee” area of dogs.
Other locations that may be affected include the spleen, liver, intestinal system, and lymph nodes in the chest or belly, and lymph nodes. Since the lymphocyte, a blood cell, is the cancerous cell, lymphoma can develop in practically any area of the body.
Mast Cell Tumor
The most frequent type of canine skin tumor that vets treat is a mast cell tumor. In dogs, these tumors often develop on or beneath the skin, though they might sporadically develop into the chest or abdominal cavities. A persistent swelling on or beneath the skin is one of the mast cell tumor’s warning signals. Most of the time, these tumors are painless.
Osteosarcoma/Bone Cell Tumor
This type of cancer typically involves bone cells called osteocytes. Large- to giant-breed dogs are the breeds most frequently impacted by bone cancer. Moreover, lameness and swelling at the tumor site are warning indications of this malignancy.
This is a common skin tumor that affects the pigment-producing cells of the body called melanocytes. More specifically, these pigments give black coloration to the skin and can develop anywhere, including lips, gums, mouth, and on eyes.
There are two types of oral tumors: benign (likely to remain within the mouth) and malignant (likely to spread to other parts of the body). Melanoma, squamous cell carcinoma, and fibrosarcoma are the three most prevalent types of cancerous oral tumors in dogs.
Worsening breath, drooling, losing food or having trouble eating, blood or bloody discharge in the water bowl, and/or facial deformity are all signs of an oral cavity tumor.
This type of cancer typically affects the nasal cavity of the dog and may involve the sinuses. Blood dripping from one side of the nose, sneezing, facial deformity, or protrusion of an eyeball are all warning indications of nasal cancer as well.
Mammary Cell Tumor
Breast cancer is quite common in female dogs. This involves abnormal enlargement of mammary gland cells called alveoli and surrounding tissue. Moreover, intact females that have their reproductive organs intact have an increased risk of developing cancer in the latter half of their life.
The most prevalent blood cancer found in dogs is leukemia, an immune system disease. Leukemia in dogs is literally a lymphoma of the blood cells. Moreover, the common site for neoplastic lymphocyte proliferation is bone marrow cells (the production house of all types of blood cells).
However, lymphoid leukemia is the most prevalent type of disease. The aberrant increase of the lymphocyte population in the blood is known as lymphoid leukemia.
What Are The Risk Factors That Predisposes Dogs To Cancer?
There are certain intrinsic and extrinsic factors that can predispose a dog to develop cancer.
These factors are natural and cannot be controlled. They include age, sex, hereditary factors, and breed.
Old-age dogs are more prone to cancer. With age, the body’s defense cells get weak and cannot control the mutated cells that grow into cancer.
The sex of the dog is another factor. Almost 60 percent of mammary cancer is seen in female intact dogs that are not spayed. Similarly, there is a high incidence of testicular and prostate cancer in male unneutered dogs.
Genetic mutation is a common cause of most cancers, and the hereditary transfer of defective genes can predispose the progeny of dogs to develop cancer.
Some breeds are more prone to develop cancer.
For example, has been observed that Labrador Retrievers, Rottweilers, German Shepherds, and Bernese Mountain dogs are more prone to develop specific types of tumors like melanoma, hemangiosarcoma, etc.
Some long-bone breeds, like Great Danes and Irish Wolfhounds, can develop osteosarcomas. Also, you can learn more about these factors in this study.
This includes the environmental factors that can be controlled to some degree. These include, for instance, exposure to cigarette smoke and air pollutants.
Moreover, chemicals like herbicides and some insecticides are known carcinogens. Lastly, exposure to ultraviolet and electromagnetic radiation can cause cancer in dogs as well.
Signs And Symptoms Of Cancer In Dogs
Some signs are more apparent, while in some cases, subtle signs of cancer may be overlooked.
Following is a list of signs and symptoms that may indicate different kinds of cancer:
- Lumps of swelling on the skin
- Wounds or sores that won’t heal
- Lethargy or lack of stamina
- Unexplained weight loss and loss of body condition
- Dyspnea (difficulty breathing) and coughing
- Abdominal pain and swelling in case of tumors of the abdominal cavity, stomach, or liver cancer
- Persistent diarrhea and vomiting
- Anorexia and depression
- Abnormal discharge from nose, eyes, or mouth
- Increased drinking or urination
How To Diagnose Cancer In Dogs
A veterinarian may take a fine needle aspirate of a visible tumor and send the sample to an oncologist, who can then diagnose the specific type of cancer by performing histopathology (examining cells and tissues under the microscope).
Moreover, blood tests like cbc (complete blood count) can help detect cancer as cell counts may get disturbed in cancer, like changes in the number of white blood cells (wbc), red blood cells (rbc, and platelet counts. For instance, higher than normal wbc can indicate leukemia. X-rays and ultrasonography may help detect abdominal tumors.
Advanced techniques like MRI (magnetic resonance imaging) can be used to diagnose brain tumors in dogs as well.
What Treatment Options Are Available For Curing Cancer In Dogs?
There are three treatment options available for curing neoplasia/cancer in dogs. These options are chemotherapy, radiotherapy, and surgery. These can be used alone or in combination, depending on the location, type, and severity of cancer.
Chemotherapy refers to the use of drugs to cure cancer by inhibiting the growth of cancerous cells. Many drugs that are used in humans are often used in pets as off labels to treat cancer.
These anticancer drugs are most effective when used in combination with surgery or radiotherapy and when treating cancers that can spread to the whole body, like lymphomas.
Antineoplastic drugs are given intravenously or orally to target the cancerous cells in the body and suppress their cell multiplication. Those drugs that specifically inhibit mitosis (the process of cell division) are called antimitotic drugs. Drugs that cross links with DNA are active in the cell cycle phase called alkylating agents like chlorambucil and cyclophosphamide. Other types of drugs include antimetabolites and Plant alkaloids.
Although these drugs are effective to some extent, they can have side effects on dog health, like nausea, vomiting, diarrhea, kidney damage, etc. However, research is being carried out to develop drugs that have a high affinity to target cancerous cells and have minimal to no effect on healthy cell division.
Examples of chemotherapy drugs are doxorubicin, chlorambucil, vinca alkaloids like vincristine sulfate, etc. Also, you can learn more about anti-neoplastic drugs in this research.
Vinca alkaloids are commonly used in veterinary medicine to treat tumors like TVT (a trans-venereal tumor that has a viral cause and develops due to coitus between infected male or female dogs).
This drug has promising results in treating cancer. However, long-term use can cause myelosuppression (reduction in blood cell types due to decrease bone marrow activity). This, in turn, causes low wbc, rbc, and platelet counts.
Radiotherapy, also called radiation therapy, refers to the use of high-energy x-rays exposing cancerous cells to electromagnetic radiation, which damages those cells.
This procedure uses high-energy x-rays for a longer time of exposure. Radiation therapists use enough radiation to kill the infected cells while minimizing the damage to normal cells.
This can be done using an x-ray machine with a medical linear accelerator that produces high-energy beams of x-rays or an internal implant (a radioactive implant that oncologists put inside the body near tumors).
Compared to normal cells, cancer cells divide more often. Another flaw of cancer cells is that they do not repair radiation damage as rapidly or fully as healthy cells do. Radiation therapy for cancer is effective because it destroys rapidly dividing cells and, in some situations, renders cancer cells incapable of proliferating.
In addition to treatments like surgery, chemotherapy, or both, radiation therapy is frequently employed.
Moreover, radiation therapy may be the best option for treating head and neck malignancies, including brain, nasal, and other tumors. It can be the only effective course of treatment for malignancies of the spine or pelvis.
One of the oldest anti-tumor therapies is the surgical excision of cancerous cells. The goal is to remove all the cancerous cells. Otherwise, a relapse is likely. In cases where vets diagnose cancer earlier, a complete recovery is more likely.
However, a surgical procedure is not very effective in cancers that have metastasized into deeper tissues in the body, as this may involve removing a part of an organ that affects the physiology of that particular organ. Therefore, in such cases, vets use surgery in combination with chemotherapy or radiotherapy.
Another procedure that can comfort a dog is called debulking, which involves removing a part of the tumor that reduces the signs of cancer, like pain, and can improve the dog’s mobility.
What Are The Factors That Affect The Recovery Rate Of Cancer In Dogs?
The rate of recovery depends on the severity, location, early detection, type of cancer, and presence or absence of metastasis. Moreover, the age of the dog and the overall health status and condition of vital organs like the liver and kidney are also important factors.
Also, dogs with a compromised immune system and other complications like viral or bacterial infections are at high risk of mortality as well. Cancers involving vital organs like the lungs, heart, or brain can have a relapse and can prove to be fatal too.
Some cancers have a high survival rate though. Chemotherapy has shown to be quite effective as a treatment for lymphoma, and almost 95% of dogs go into remission.
However, in cases of hemangiosarcomas, only 10% of dogs treated with surgery and chemo can survive longer than a year.
Conclusion: Can Dogs Recover From Cancer?
In conclusion, dogs can recover from cancer, given that cancer is diagnosed in early stages and hasn’t metastasized. Moreover, the treatment plan must be considered in terms of the type and location of the cancer.
Most dogs can recover from cancer if no complications arise during the course of treatment. However, in some severe types of cancer, like hemangiomas and brain tumors, the survival rate is low.
Thanks to the advances in medicine though, cancer is more curable in dogs than ever before, and research is ongoing in the field of oncology to develop more effective and safer treatment options to fight cancer in dogs.
So, do you feel better knowing about how dogs can recover from cancer? Are you currently helping your dog through cancer? Let us know what’s going on in the comments below. And we wish you and your dog all the best.