Pets’ cancer prevalence is increasing at an alarming rate. As many as one in every five adult pets and half of pets older than 10 years of age will be diagnosed with cancer during their lifetime. Although treatment modalities continue to improve cancer diagnosis outcomes, early detection remains their best opportunity to fight against this devastating disease. In addition to scheduling your pet’s annual or biannual exams, our Creature Comforts Veterinary Services team recommends you stay vigilant to recognizing these 10 common cancer warning signs. 

10 Cancer signs in pets

Observing your pet’s daily habits—including food and water intake, urination, and bowel movements—is a pet owner’s responsibility. Because cancer can take many forms and develop anywhere on your pet’s body—such as their skin, organs, bone marrow, or blood—this disease can present with a wide range of signs, some of which may seem vague or generic. 

Many clinical signs are commonly linked to pets’ cancer. However, these signs are also associated with unrelated—often benign—illnesses. While only your veterinarian can make a definitive diagnosis regarding your pet’s condition, no one knows your pet better than you. If you have any concerns about your beloved companion’s health—especially the 10 cancer signs presented here—schedule a veterinary assessment as soon as possible. 

#1: Lumps and bumps on your pet’s skin  

Unusual swellings, palpable tumors, or skin lumps and bumps are perhaps the most recognizable cancer signs. However, keep in mind that not all tumors and warts are cancerous. Your veterinarian may perform a needle aspirate to detect cancer cells, but a larger biopsy or surgical removal may be necessary for a definitive diagnosis. Lumps along your pet’s neck, chest, armpits, or groin may be lymph nodes, which can enlarge in response to infection or blood cancer such as lymphoma. 

#2: Sores that do not heal on your pet 

Non-healing wounds, sores, or ulcerated areas can indicate your pet’s immune system is impaired or may signal skin cancer such as melanoma, mast cell tumors, or carcinomas. If your pet has a persistent skin issue that does not resolve after treatment, your veterinarian may recommend a skin biopsy to screen for cancer.

#3: Bleeding from a pet’s body opening  

Bleeding is always concerning, especially when the blood originates from your pet’s mouth, nose, rectum, or urinary tract. Although your pet’s unexplained bleeding can be alarming, stay calm so your four-legged pal’s emotions remain neutral. Avoid increasing your pet’s stress level, which can raise their blood pressure and worsen the bleeding.

#4: Pet weight loss  

Cancer alters your pet’s metabolism, causing fat and muscle loss (i.e., cancer cachexia). This condition can occur despite your pet eating normally. You can assess your pet’s weight by routinely feeling their ribs and spine. Healthy pets have a small amount of fat covering these areas, while thin pets have prominent—sometimes visible—ribs and vertebrae.

#5: Pet appetite loss  

Oral cancers or those affecting the upper airway and esophagus can affect your pet’s ability to pick up, chew, or swallow their food. In addition to these mechanical challenges, all cancers can result in your pet exhibiting a general flu-like malaise, which can cause them to lose their appetite. Schedule a veterinary examination if your pet is suddenly dropping or refusing food.

#6: Abnormal pet odor  

Unusual odors from your pet’s mouth, nose, or rectum can indicate cancerous growths. Tumors may become ulcerated or infected, resulting in draining tracts or dying tissue that causes a noticeable odor. Routinely look in your pet’s mouth and under their tail for tissue changes, swelling, or unusual discharge.

#7: Loss of stamina in pets 

Cancer can cause your pet to tire more quickly. An affected pet may lay down during a walk, lose interest in their favorite game, or refrain from joining in family activities. A pet who pants heavily or experiences labored breathing after only mild exertion may have lung or heart cancer. 

#8: Changes in your pet’s urinary or defecation habits  

Cancerous masses along your pet’s intestinal tract, rectum, bladder wall, or urethra can cause uncomfortable elimination, straining, bloody urine or stool, and diarrhea. If your pet has any of these intestinal or urinary cancer signs, schedule an appointment with your veterinarian. 

#9: Unusual breathing or respiratory distress in pets 

Primary lung or heart tumors, metastatic cancer in the lungs, or cancer-related complications, such as fluid accumulation in the abdomen (i.e., ascites), can cause labored breathing, at-rest panting, and coughing. Your pet’s respiratory distress is a painful and anxiety-inducing condition that warrants immediate veterinary attention. 

#10: Persistent pet lameness  

Osteosarcoma is a bone cancer that most frequently affects large-breed dogs. Dogs with osteosarcoma experience progressive lameness (i.e., limping), limb swelling, and severe pain. Because the tumor weakens bone, fracture is possible during late-stage disease. Limb amputation and chemotherapy are the best treatments for pets with osteosarcoma. However, bone cancer commonly recurs.

Our Creature Comforts Veterinary Service team understands that you feel concern regarding the possibility of your pet developing cancer. However, early detection, current treatments, and palliative care can extend and enhance your pet’s quality of life. If your pet exhibits any concerning health changes, do not delay—schedule an appointment with our Creature Comforts Veterinary Service team.