Q: A friend's dog recently died of cancer, and we want to do all we can to keep our own dog cancer-free. What advice can you offer?
A: Cancer is far too common in dogs, particularly large, purebred dogs. You can't change your dog's genetics, but there are things you can do to minimize the risk of cancer.
Overweight dogs develop cancer more often than slim ones. Slim dogs also live two years longer than their overweight counterparts, so keep your dog at a healthy weight.
Environmental toxins can cause cancer in dogs. If you smoke, do so outdoors away from your dog, or better yet, quit. Dogs with long muzzles are particularly susceptible to nasal cancer from secondhand smoke.
Some lawn chemicals increase the risk of cancer, so don't use them, or keep your dog off the grass until the application dries or penetrates into the soil. Paints, solvents and asbestos can also cause cancer, so keep your dog away from them.
While no research has shown that any particular diet prevents cancer, there is some evidence that omega-3 fatty acids may help reduce risk.
Scottish terriers develop transitional cell carcinoma of the urinary tract more often than other breeds. However, some research suggests that feeding them cruciferous vegetables could diminish their risk.
If your dog has a white face or short hair, you can help prevent skin cancer by applying a pet sunscreen and clothing that blocks the transmission of ultraviolet radiation.
A male dog with an undescended testicle should have it removed because it is much more likely to develop cancer than a testicle that has descended into the scrotum normally. An unsterilized female is at greater risk of developing mammary cancer than a spayed female.
Large-breed dogs sterilized before physical maturity are at increased risk of some cancers. So, if you have a large dog, talk with your veterinarian about the timing of spay/neuter surgery.
Regularly check your dog's entire body, including inside the mouth, for any lumps or non-healing sores. Note any loss of energy or appetite, unintended weight loss, increased drinking or urination, persistent stomach upset or cough, trouble breathing, discharge or offensive odor. Have your veterinarian immediately check any abnormalities you find, because early diagnosis and treatment increase the likelihood of a successful outcome.
Q: Moxie, our healthy, indoor, 4-year-old domestic shorthair cat, died suddenly. He was never sick a day in his life, including his last day. His appetite and energy were good. There's no way he could have ingested anything toxic. Why did he die?
A: I am so sorry for your loss. It's especially painful when you don't have the opportunity to prepare for a pet's death or say goodbye.
I don't know the cause of Moxie's death, of course, but if I had to guess, I'd say he may have died of hypertrophic cardiomyopathy, a heart ("cardio-") muscle ("-myo-") disease ("-pathy"). Hypertrophic cardiomyopathy, or HCM, the most common feline heart disease, is characterized by thickening of the heart's muscular walls.
Cats with this condition rarely have heart murmurs or arrhythmias, and they almost never show clinical signs until a catastrophe occurs — sudden death, acute heart failure or sudden onset of pain and paralysis of the hind legs due to a clot that blocks blood flow to the legs. The condition is diagnosed by ultrasound of the heart, called echocardiography.
Studies show that 15%-34% of outwardly healthy cats have this problem. Young to middle-aged cats are most often affected. Over 75% are male, and males develop more severe disease at a younger age than females. Prevalence is highest among domestic shorthairs, which are mixed-breed cats.
The cause is unknown, though genetic mutations have been identified in the Maine coon, ragdoll and sphynx breeds. Hypertrophy is also thought to be inherited in Persian and rex cats, so it might be an inherited tendency in domestic shorthair cats, too.
Lee Pickett, VMD, practices companion animal medicine in North Carolina. Contact her at