Pancreatic Cancers In Dogs

Cancer of the pancreas is the second commonest gastrointestinal neoplasm. The pancreas has both functions - exocrine (enzymes of digestion) and endocrine (hormones that affect other parts of the body). Pancreatic cancers are either exocrine (enzyme-producing) or neuroendocrine (hormone-producing) tumors.

Exocrine Tumors: More than 90% of pancreatic cancers are exocrine. They are usually aggressive and spread to nearby tissues as well as to the other organs throughout the dog’s body. The most common type of pancreatic cancer is adenocarcinoma. The exocrine portions of the pancreas are where 95% of malignant neoplasms arise (acinar and ductal cells) and this exhibit features comparable with adenocarcinoma.

Neuroendocrine Tumors: Their incidence is Less than 10% and they often grow slower than exocrine tumors (Islet cell carcinomas).

In spite of its low occurrence when compared to other more common malignancies (lung, colorectal, esophagus, prostate, etc), pancreatic cancer is one of the leading causes of death in dogs.

Similar to other types of cancer, pancreatic cancer usually affects older dogs (> 8 years). There is no gender or breed disposition, but female dogs are found to be at higher risk than others.

• Unconsciousness, or passing out due to low blood sugar.
• Abdominal swelling
• Lack of coordination.
• Yellowing of the skin and the whites of the eyes (jaundice).
• Reduced ability or enthusiasm to exercise.
• Light-colored stools / Dark-colored urine
• Fatigue / Seizures
• Diabetes
• Decrease in the reflex of appendages.
• Muscle Twitching / Degeneration

Discuss the best treatment option with your veterinarian or canine oncologist.

Medical Management:

Prednisolone - Stimulates glycogenolysis and inhibits insulin production (0.5 to 1.0 mg/kg q d).

Other medications that might be used to treat insulinoma include:

• Diazoxide - 5 to 10 mg / kg PO / 12 H.
• Octreotide - Somatostatin Analogue
• Tyrosine Kinase Inhibitors - Toceranib phosphate( 2.75 mg/kg PO/48 H).
• Chemotherapeutic agents, such as streptozocin - nitrosourea alkylating agent.

Every 2 to 3 weeks -500 mg/m².

Chemotherapy:

• Chemotherapeutic agents, such as streptozocin - nitrosourea alkylating agent.

Every 2 to 3 weeks - 500 mg / m².

Surgical removal of tumor: The best chance for relief of clinical signs and the best survival times.

Partial Pancreatectomy - Removal of part of the pancreas.

Exploratory Abdominal Surgery - Dogs with hypoglycemia and inappropriate insulin production.

Check with your veterinarian or Veterinary oncologist for the post-surgical checks, usually once a month to ensure the health of the dog and to check for any infection.

Until the post-operative recovery period is over, do not allow your dogs to play outdoors. This will reduce the risk of infection and injuring the surgical site.

Prevention is not possible for pancreatic cancer as the causes in dogs is varied. Treatment and survival rates vary depending on the grade and stage of cancer.

Good overall health and early detection are the only ways to prevent adenocarcinoma.

Check your dog on a regular basis and consult your veterinarian immediately if you find any odd lumps or lesions.

Large Dog Breeds, Boxer, Irish Setter, Golden Retriever, German Shepherd, Fox Terrier, Middle Age Dogs, Senior Dogs

1. Causes:

As with other forms of cancer, any definitive causation of pancreatic cancers is not yet identified.

It is alleged that there is a genetic component linked to the odds of this cancer occurring, supported by higher incidence in certain breeds.

2. Types:

A. Exocrine Tumors: They represent more than 90% of pancreatic neoplasms.

Pancreatic Adenocarcinoma: Most prevalent exocrine tumor. Also called also known as ductal carcinoma, it typically starts in the ducts where pancreatic enzymes travel to reach the small intestine.

There are other types of exocrine tumors that are rare and account for < 4 percent of exocrine tumors:

• Adenosquamous Carcinoma of the pancreas: Clinical presentation similar to that of pancreatic adenocarcinoma, but have a worse overall prognosis. Squamous and glandular elements are histologically malignant in Adenosquamous Carcinoma.
• Acinar Cell Carcinoma: 1-2%; develops in the acinar cells that synthesize, store, and secrete digestive enzymes.
• Ampullary Cancer: Rare cancer in the ampulla of Vater of the duodenum (a region in which pancreas ducts combine with the bile duct and drain into the small intestine).
• Pancreatic Squamous Cell Carcinoma: Rare pancreatic cancer (of ductal origin) as they lack squamous cells and the possibility is skin neoplastic cells may metastasize to the pancreas.
• Signet Ring Cell Carcinoma: Rare type of pancreatic adenocarcinoma that most often begins in the abdomen but can also appear in the gallbladder and colon.
• Undifferentiated Carcinoma: Heterogeneous group of neoplasms with no glandular differentiation and little or no evidence of expression of neuroendocrine markers.

1. Neuroendocrine Tumors:

Pancreatic Neuroendocrine Tumors (pNETs): NETs originate from the endocrine portion of the pancreas. They are less prevalent than exocrine tumors. The gland secretes cells that help your body regulate blood sugar levels.

Types of NETs:

• Functional NETs: Functioning pNETs (30 - 40%) cause the pancreas to produce surplus digestive hormones - insulin, glucagon, and gastrin ( insulinoma, gastrinoma, VIPoma, glucagonoma, etc).
• Nonfunctional NETs: They are the largest group of pNETs (60%) and they do not produce excess enough hormones to cause symptoms; rather, they cause mortality and morbidity by metastasizing.
• Carcinoid Tumors: They are called cancer in slow motion as the dogs may have it for a long time without any symptoms. They arise from enterochromaffin cells dispersed throughout the bronchopulmonary and gastrointestinal systems.

3. Morbidity:

TNM System:

Tumour:

T1 - 2cm or less in any direction.

This stage is split into 3 stages:

• T1a - ≤ 0.5cm
• T1b - > 0.5cm but < 1cm
• T1c - tumor is between 1cm and 2cm

T2 - Tumor is between 2cm and 4cm in any direction.

T3 - Still within the pancreas and cancer is > 4cm.

T4 - Cancer has crept outside the pancreas.

N0 - Nearby lymph nodes are free of cancer cells.

N1 - Very few lymph nodes contain cancer cells.

N2 - Cancer spread in several lymph nodes.

M0 - No metastasis or spread to other areas of the body.

M1 - Cancer has spread to other areas of the body such as the liver or lungs.

Grading:

Grade 1 - They look normal, well-differentiated, low grade, and slow-growing.

Grade 2 - They look more abnormal, moderately differentiated, or intermediate grade.

Grade 3 - They look very abnormal, poorly differentiated, high grade, and grow or spread more quickly.

4. Mortality:

For dogs undergoing surgery:

• In stage 1: 785 days (MST - Median Survival Time)
• In stage 2: 380 MST
• In Stage 3: 217 MST

For medical management:

• 2½ months (Tobin et al 1999)
• 196 days (Polton et al)

5. Diagnosis:

• Routine Hematology, Urinalysis
• Glucose Level Exams
• Test for Hypoglycemia
• Tissue Biopsy
• Abdominal Radiographs, Ultrasound, or CT Scan

6. Prognosis:

Following a diagnosis of pancreatic cancer in dogs, life expectancy is related to the development of postoperative complications.

Life expectancy is greatly reduced for dogs that are not good surgical candidates or for owners who are not interested in surgery and opt for medical management.

Time to visit the vet clinic for an examination, if you notice any of the following:

• When you see your dog has extreme fatigue after exercise and higher collapsing episodes.
• When your dog has prolonged seizure activities.
• Muscle Degeneration

• Diet high in protein, fat, and complex carbs.
• Protein: High protein diet comprising 40% of the dog's calories.
• Fats: Omega-3 and other healthy fats.
• Complex Carbohydrates: Fibers and starches (Whole Grains, Oatmeal, Brown Rice, Potatoes & Sweet Potatoes).
• Overweight Dogs - Lower calorie diets, for underweight dogs- Higher calorie diets.
• Feed foods have a lower (or moderate) Glycemic Index and Glycemic Load than others.

The prognosis is guarded at best due to this malignant neoplasia’s high frequency of metastasis. Metastatic pets survive up to 10 months with a combination of surgery and medical therapy.

However, for dogs in the initial stages, Surgery is recommended as it provides the best-reported survival times (up to 2 years and more).

Medical management of dogs does not make them survive longer than 6 months from the onset of clinical signs.