The Top 5 Cancers in Labrador Retrievers

by Anne-Marie Smith
cancer in labs

Cancer in Labrador Retrievers is the most common cause of death in the breed. Dogs, like humans, are susceptible to a variety of cancers, including lymphoma and even breast cancer. The good news is that veterinary oncology treatments are very comparable to those used to treat human cancer. Increasing the survival rate of our beloved dogs. The key to a higher survival rate is to take your dog to the veterinarian as soon as you notice any changes or unknown lumps and bumps. Any cancer in labs could be devastating but these 5 are the most common in labs.

Cancer in Labrador Retrievers and What to Watch for:

Mast Cell Tumor Disease in Labrador Retrievers

Mast cell tumor (MCT) is a cancer of a type of blood cell that normally helps the body fight off allergens and inflammation. MCT is the most common skin tumor in dogs. It can also spread to other parts of the body, such as the spleen, liver, intestines, and bone marrow. MCT cancer in labs is one of the most treatable cancers and they have a high survival rate.

Certain breeds of dogs, like Boston Terriers, Boxers, Pugs, and Bulldogs, as well as Retrievers, are more likely to get MCT than other breeds, but any dog can get it.

MCT can happen anywhere. The biological behavior of these tumors can be very different. Some tumors may be there for a long time and not grow very much, while others can show up quickly and grow very quickly. The most common places where this happens are in the Lymph nodes, the intestine, in bone, the spleen, and the liver.

Signs and symptoms of Mast Cell Tumor Disease in Labs

A few signs and symptoms are Enlarged lymph nodes, Ulcers, Vomiting, Poor appetite, Lethargy, Tarry stools (a sign of intestinal bleeding), Diarrhea, Anaphylactic shock (in severe cases) if your dog is showing any of these symptoms you should contact your vet for an appointment. Mast Cell Tumors can appear anywhere on the body and vary in appearance.

What can cause Mast Cell Tumor Disease in Labs?

It’s not easy to figure out why one dog might get this or any other kind of cancer. Most cancers in labs don’t have a single cause that can be found out for sure. Most seem to be caused by a mix of risk factors, some of which are environmental and some of which are genetic or hereditary. There are several genetic mutations that are thought to play a role in the growth of Mast Cell Tumors. One well-known mutation is to a protein called KIT that helps cells grow and divide.

How are Mast Cell Tumors diagnosed with Disease in Labs?

MCT diagnosing

This type of cancer is usually found with a fine needle aspiration (FNA). FNA is done by taking a small needle with a syringe and sucking a sample of cells right from the tumor and putting them on a microscope slide. A veterinarian then looks at the slide. In cases where the tumor is aggressive a surgical tissue sample (biopsy) can be useful. This is especially true for MCTs.

What is the treatment for Mast Cell Tumor Disease in Labs?

Surgery is likely the best way to treat low-grade tumors that haven’t spread. Most dogs don’t need chemotherapy after surgery for low-grade tumors. However, in high-grade tumors, even if there is no sign that they have spread, surgery and chemotherapy are often recommended. Radiation therapy is another option if the mass is not in a good place for surgery or if the surgery was not complete (with cancerous cells left behind). Talk about how to treat your pet’s cancer with your vet and oncologist.

What is the prognoses for Mast Cell Tumor Disease in Labs?

The prognosis for mast cell tumors in dogs is determined by several factors, including tumor size, location, grade, and symptoms. The most consistent prognostic predictor for mast cell tumors in dogs appears to be tumor grade.

Melanoma Cancer in Labrador Retrievers


Melanomas are cancerous tumors that start with melanocytes. Melanomas in dogs are most often found in the mouth, but they can also be found on the skin, eyes, and digits. A lot of the time, melanomas in dogs look like dark masses that may start to bleed or ulcerate as they get bigger. It may also be amelanotic, which means it doesn’t have dark pigment and looks pink.

Melanoma is a tumor made up of melanocytes, which are cells that are dark in color. As the tumor grows, we also worry about how far it can spread, or spread, to places like the lymph nodes and lungs. Melanoma is the most common type of cancer found in dogs’ mouths.

Signs and Symptoms of Melanoma Cancer in Labs

Melanomas are raised lumps that can be ulcerated. They can also be gray or pink lumps that look like they are coming out of the mouth. Nail bed melanomas, on the other hand, have toes that are swollen or even lose their toenails, as well as the bone beneath them. Nail bed and footbed tumors are often misdiagnosed because they often get a secondary infection. Most of the time, these types of tumors move from one place in the body to another, which lowers the chances of having a good outcome.

What can cause Melanoma Cancer in Labs?

Melanoma is a type of cancer that happens when there is too much growth of melanocytes, which are cells that carry pigment in mammalian skin and mucous membranes. Older dogs are more likely to get this cancer, especially in their mouths. Skin cancer can be caused by several factors. Genetics plays a role in determining which dogs are more likely to develop skin cancer. In fact, genetics is thought to be the most important element in a dog’s likelihood of developing skin cancer. Too much sun exposure, toxins in the environment, hormonal disorders, and some types of viruses are all potential causes of skin cancer in labs.

How is Melanoma Cancer in Labs diagnosed?

Cancers in labs can only be definitively diagnosed by taking a sample from the afflicted tissues (biopsy) and analyzing it using histopathology (microscopic analysis of the tissues by a board-certified pathologist). Anesthesia or sedation may or may not be required.

Melanoma is most commonly associated with a black tumor; however, 17 percent of melanomas are non-pigmented (“amelanotic”) and do not seem to be black.

In the course of melanoma diagnosis, the following tests are strongly recommended:

  • Physical examination
  • Complete blood count (CBC)
  • Blood biochemistry panel
  •  Urinalysis
  •  Chest X-rays
  •  Fine needle aspirate of local lymph nodes
  •  Abdominal ultrasound
  •  Fine needle aspirate of the tumor
  •  Biopsy of the tumor

What is the Treatment for Melanoma Cancer in Labs?

Melanoma stages have a very strong correlation with prognosis. With surgery alone, tumors that are less than two centimeters in diameter and have not spread (stage I) can have a survival duration of 15-18 months on average. When tumors are two centimeters or greater, surgery alone has decreased prognosis.

With surgery alone, tumors measuring two to four centimeters (stage II) have a median survival period of about six months, while tumors measuring more than four centimeters or with lymph node metastasis (stage III) have a prognosis of three to four months. This type of Cancer in labs that have already progressed to the lungs has the worst prognosis (stage IV). Patients with stage IV cancer have a one-to-two-month outlook.

What is the prognosis for Melanoma Cancer in Labs?

Malignant melanoma is one of the few tumors in dogs where anatomic location plays a significant predictive role. Regardless of treatment, dogs diagnosed with Stage I melanomas have much longer survival expectancies than dogs diagnosed with Stage II-IV illness.

Lymphoma Cancer in Labrador Retrievers

LymphomaThe number one type of cancer in labs is Lymphoma. Lymphoma is a type of cancer that affects the lymph nodes and lymphatic system. This cancer may be localized to a specific area, or it may spread throughout the body. Lymphoma is a common type of cancer in labs, accounting for about 15% of all new cancer diagnoses. It is more frequent in dogs who are middle-aged or older, and particular breeds are predisposed to it.

Lymphoma appears to be most the common cancer in Labs, Golden Retrievers, Boxer Dogs, Bullmastiffs, Basset Hounds, Saint Bernard’s, Scottish Terriers, Airedale Terriers, and Bulldogs. This shows that lymphoma may have a hereditary component, although this has yet to be verified.

Lymphoma in dogs comes in four different varieties, each with its own severity and prognosis.

  1. Multicentric (systemic) Lymphoma – By far the most prevalent kind of canine lymphoma. Multicentric lymphoma accounts for roughly 80%-85% of lymphoma cases in dogs. Multicentric lymphoma affects lymph nodes throughout the body.
  2. Alimentary Lymphoma – This term refers to lymphoma that affects the gastrointestinal tract. The second most common type of lymphoma is Alimentary lymphoma.
  3. Mediastinal Lymphoma – Lymphoid in the chest (such as lymph nodes or the thymus) are affected. This is a rare type of lymphoma.
  4. Extranodal Lymphoma – This type of lymphoma attacks an organ that is not part of the lymphatic system. Extranodal lymphoma is uncommon, but it can manifest in the skin, eyes, kidney, lung, or nervous system.

Signs and Symptoms of Lymphoma Cancer in Labs

  1. Multicentric Lymphoma – Dogs with multicentric lymphoma frequently present with only enlarged peripheral lymph nodes; however, they may present with a variety of nonspecific clinical signs such as lethargy, weight loss, anorexia, or polyuria/polydipsia.
  2. Alimentary Lymphoma – The stomach, small intestine, large intestine, and/or rectum are all possible sites for alimentary lymphoma to occur. Vomiting, diarrhea, weight loss, fatigue, loss of appetite are symptoms of gastrointestinal lymphoma. Lymphoma rarely causes discomfort unless the lymph nodes are swollen severely, or the malignancy has spread to the bones.
  3. Mediastinal Lymphoma – Breathing problems are common in dogs with mediastinal lymphoma. This could be caused by the presence of a large mass in the chest or the buildup of fluid in the chest (pleural effusion). Swelling of the face or front legs, as well as increased thirst and urination, may be seen in affected dogs.
  4. Extranodal Lymphoma – Symptoms of respiratory distress are prevalent if the Extranodal Lymphoma is in the lungs. Similarly, Extranodal Lymphoma in the kidneys can result in renal failure, lymphoma in the eyes can result in blindness, lymphoma in the central nervous system can result in seizures, and lymphoma in the bones can result in discomfort or fractures.

What can cause Lymphoma Cancer in Labs?

Unfortunately, there is no recognized cause of lymphoma in dogs. Although various possible causes have been studied, including viruses, bacteria, chemical exposure, and physical elements such as powerful magnetic fields, the cause of this malignancy remains unknown.

How is Lymphoma Cancer in Labs Diagnosed?

A fine needle aspirate is the most commonly used test in the diagnosis of lymphoma. A veterinarian performs this test by inserting a needle into an enlarged lymph node (or other organs) and extracting a small number of cells. These cells are then examined under a microscope for evidence of cancerous cells, which would indicate lymphoma. Keep in mind that just because your dog has an enlarged lymph node that does not mean they have Lymphoma. If you notice anything unusual you should contact your veterinarian immediately.

What is the Treatment for Lymphoma Cancer in Labs?

Lymphoma is a disease that responds well to treatment, although it is not curable in canines. Chemotherapy is the most common treatment option.

What is the prognosis for Lymphoma Cancer in Labs?

A dog with lymphoma has a very limited lifespan without treatment, usually 1-2 months. However, after therapy, roughly 85% of dogs with lymph node involvement will go into remission, meaning lymphoma in the lymph nodes will no longer be detectable.

Bone Cancer in Labrador Retrievers (Osteosarcoma) (OSA)


Osteosarcoma (osteo = bone, sarcoma = cancer) account for about 85% of canine bone tumors. Osteosarcomas are aggressive tumors that cause painful bone deterioration in the area where they grow. Osteosarcoma is cancer that most usually affects dogs’ limbs, although it can also affect other regions of the body (skull, ribs, vertebrae, pelvis).  OSA is one of the worst and hardest cancers in labs to treat and they have a lower survival rate.

This cancer will progress to the lungs in roughly 80% of canines. Bone cancers’ biological behavior, prognosis, and treatment are all influenced by the type of tumor, initial location, and extent of disease dissemination. To determine the most appropriate treatment, various diagnostic tests such as X-rays, blood tests, and sometimes a biopsy are required.

Signs and Symptoms of Osteosarcoma Cancer in Labs

The symptoms of a bone tumor may be nonspecific. A bulge, either soft or hard tissue, that expands over time might be connected with a bone tumor anywhere on the body. Typically, these tumors are painful, as the cancer is killing the healthy bone. Limb tumors typically result in varying degrees of lameness, which may be sporadic at first and may improve temporarily with pain medication given by your veterinarian.

As the level of discomfort grows, other symptoms such as irritation, aggression, loss of appetite, weight loss, insomnia, or aversion to exercise may occur. Certain dogs may present to the veterinarian with a fracture caused by the damaged bone becoming weakened. Other clinical indications may differ according to the main site and the extent to which underlying structures are involved.

What can cause Osteosarcoma Cancer in Labs?

As is the case with the majority of canine cancers, the cause is unclear. There has been no evidence of a gender propensity. There does appear to be a genetic component, as OSA is more prevalent in breeds with long limbs. Due to their height and weight, large and giant breeds are predisposed to OSA. OSA can occur in small dogs as well, but it is significantly less prevalent. OSA is a common cancer in labs due to the fact that they are considered a large breed dog.

How is Osteosarcoma Cancer in Labs Diagnosed?

A comprehensive physical examination, blood tests, X-rays (of both the afflicted site and the lungs), a bone scan to rule out further areas of bone involvement, and occasionally a small needle aspirate or biopsy are often performed during the initial evaluation of a dog with a suspected bone tumor. A PET-CT scan of the complete body may be recommended to determine the presence of spread.

Without a prior biopsy, definitive surgery, such as amputation in the case of a limb tumor, may be undertaken if the age, breed, location, and look of the tumor all strongly imply Osteosarcoma. Preparation and staging are critical for two reasons. To begin, it is vital to determine the cancer’s type and extent. Additionally, diagnostic testing offers information about the dog’s overall health and may reveal concurrent medical, bone/joint, or nerve/spinal disorders, all of which may impact the oncologist’s treatment recommendations.

The “TNMG” (tumor, node, metastasis, grade) staging approach is used. Stage I refers to dogs with low-grade tumors (G1) that have not metastasized; stage II refers to dogs with high-grade tumors (G2) that have not metastasized, and Stage III refers to dogs with metastatic disease. The substages “a” and “b” correspond to intramedullary lesions (T1) and extramedullary spread (T2). The majority of canines diagnosed with osteosarcoma are in Stage IIb.

What is the Treatment for Osteosarcoma Cancer in Labs?

The typical initial therapy for canine appendicular OSA is wide-margin surgery, which may involve limb amputation or limb-sparing surgery. While biopsies are normally indicated prior to surgery for the majority of cancers, they are not required in the case of OSA when other diagnostic signs exist.

Amputation – Removing the limb quickly eliminates the local malignancy and is the quickest and most efficient technique to alleviate discomfort and the majority of the damaging processes associated with OSA. Additionally, it eliminates the possibility of developing a painful pathological fracture, which frequently develops as the disease advances.

Amputation is considered a quality-of-life choice since pain impairs quality of life. The majority of dogs soon recover and return to their usual lives on three legs. Amputation removes the original tumor completely, is a less complicated surgery with a shorter anesthesia duration, has a lower risk of postoperative problems, and is less expensive than limb-sparing surgery (discussed next).

Limb-Sparing Surgery – For dogs with severe orthopedic or neurological illnesses, limb-sparing surgery may be preferred to amputation. Candidates for limb-sparing surgery should be in otherwise good health and have a primary tumor limited to the bone. To reconstruct a functioning limb, this surgical treatment substitutes the damaged bone with a metal implant, bone graft, or a mix of the two.

Stereotactic Radiosurgery (aka SRS, Stereotactic Radiotherapy/SRT, Cyberknife) – Stereotactic radiosurgery can be used as an alternative to amputation or limb-sparing surgery, or as a follow-up treatment after amputation. It is a non-invasive method that delivers radiation straight to the tumor spot (but it does require anesthesia). Radiation works by preventing cancer cells from reproducing.

Chemotherapy – To date, the best outcomes for dogs with OSA have been achieved through amputation followed by chemotherapy. Due to the fact that surgical removal of the tumor does not address metastases, systemic treatment via chemotherapy may be necessary as part of a treatment plan. Numerous studies have demonstrated increased survival rates when cytostatic medication treatments were utilized, the most frequently used being carboplatin, cisplatin, and doxorubicin.

What is the Prognosis for Osteosarcoma Cancer in Labs?

The heartbreaking reality is that the vast majority of dogs affected by OSA will succumb to the disease or be released through euthanasia due to disease progression. Dogs who do not receive any form of cancer-specific treatment are usually euthanized within one to two months of diagnosis due to uncontrolled pain.

Age, weight, and the location of the tumor all have an effect on your dog’s prognosis. Only your veterinarian is qualified to provide an accurate prognosis for your pet. Your veterinarian or veterinary oncologist will create a customized treatment plan to ensure the best possible outcome for your dog.

Dogs diagnosed with and treated for bone cancer typically live another 1 – 6 years. Unfortunately, bone cancer is extremely aggressive and frequently proves fatal even when surgical and therapeutic measures are taken.

Hemangiosarcoma Tumor in Labrador Retrievers

hemangiosarcoma is a cancer in labs

Hemangiosarcoma can grow anywhere there are blood vessels in the body. These tumors are most frequently found in the spleen, liver, skin, or heart of dogs, but they can arise anywhere in the body. These tumors are so lethal because of their proclivity for growing in blood-rich locations. Hemangiosarcoma can rupture unexpectedly, resulting in massive blood loss and forcing owners and veterinarians to make difficult decisions within minutes of diagnosis. This cancer in labs could be life-threatening.

Signs and Symptoms of Hemangiosarcoma Tumors in Labs

Symptoms vary according to the organ involved. Due to the fact that the arteries in hemangiosarcoma tumors lack regular connections, they are more prone to rupture and hemorrhage. This is why the first sign of this type of cancer may manifest as bleeding from a tumor in the liver or spleen. A bleeding episode might result in fatigue, weakness, pale gums, decreased appetite, and abdominal pain.

If this happens your canine needs to be examined by a veterinarian immediately.

Hemangiosarcoma is a cancer in labs that is the hardest to detect.

If bleeding occurs surgery will need to be performed to remove the mass and stop the bleeding.

Except for sudden, severe internal bleeding, no clinical signs (symptoms) are typical of hemangiosarcoma. Other clinical signs that owners have reported include:

  • Intermittent lethargy or fatigue
  • Anorexia
  • Panting
  • Sudden collapse
  • Sudden death

What causes Hemangiosarcoma Tumor in Labs?

Though the actual origin of this malignancy is unknown, a combination of genetic and environmental factors is assumed. Exposure to sunlight is a big risk factor for pets who have the skin (cutaneous) version. Unfortunately, the majority of dogs with hemangiosarcoma have a poor prognosis.

How is Hemangiosarcoma Tumor in Labs Diagnosed?

Hemangiosarcoma is a diagnosis made when a tumor has been completely removed by a pathologist. Certain lumps in the liver or spleen may appear to be hemangiosarcoma on ultrasonography but may in fact be another sort of tumor or even a hematoma (blood clot) that a pathologist can differentiate.

What is the Treatment for Hemangiosarcoma Tumor in Labs?

At this time, surgery to remove the tumor followed by adjuvant chemotherapy, typically with doxorubicin, is the standard of care for this tumor. In most cases, this cancer in labs will spread to other parts of the body 1-3 months after surgery.

What is the Prognoses for Hemangiosarcoma Tumor in Labs?

Unfortunately, the prognosis for this disease isn’t good at all. Dogs often keep bleeding around their heart, which means they need to be tapped repeatedly to get the fluid out. Dogs who have this disease are often euthanized soon after they’re diagnosed because they expect to have a poor quality of life. Most dogs die within a few days to a few months if they aren’t treated.


Life is finally getting better for dogs suffering from cancer, the leading cause of death in our beloved pets. One in every three canines is estimated to get the disease. Some purebreds, such as Labrador retrievers and boxers, are particularly susceptible. For decades, however, there was little research into canine cancer, and as a result, veterinarians had little to offer sick pets and their distraught owners. These are the top 5 cancers in labs and you should be aware of the warning signs in order to detect them early.

Each type of canine cancer in labs requires personalized treatment, which may include a combination of therapies such as surgery, chemotherapy, radiation, or immunotherapy. Your veterinarian may also advise you to make dietary changes or other things to help your pet respond to treatment. Some types of canine cancer can be cured, while others can only be managed to extend your pet’s life and make them more comfortable.

Canines now have a better chance of surviving cancer treatment than ever before, thanks to advancements in diagnostic and treatment methods. Current research will help to improve the odds even further.

The best way to detect cancer in labs is to take them to their vet for an annual check-up.

If you suspect cancer in your lab, whether you find a bump or notice behavioral changes, please contact your veterinarian to schedule an appointment.

This is Dedicated to Tango

Mocha and Tango

Tango is a black lab that has been coming to Doggie Daycare at DogTown East Powell since he was about a year old, along with his brother Mocha. Tango has been diagnosed with Osteosarcoma. He has had his back left leg amputated to remove the cancer. His owners (Michael and Holly Seiwald) have just found out that the cancer has returned to his front left leg. Thank you Michael and Holly for sharing your beautiful boys with us here at DogTown East Powell.

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