Spay It Away
Dogs spayed before their first heat have almost no chance of getting mammary cancer, said Greg Ogilvie, DVM, Diplomate American College of Veterinary Internal Medicine, a professor and veterinary oncologist at Colorado State University. The risk goes up with each succeeding heat the dog experiences until, at 2 years of age, prevention from spaying is minimal.

Look for Warning Signs
It takes less than a minute a month to check for early evidence of cancer. Just run your hands down your dog's chest and belly, then roll it over and look at its nipples. You are looking for:

• A lump on or near the mammary chain. Very early lumps may come and go with the estrus cycle and are more likely to be felt about a month after the bleeding part of your dog's heat cycle has ended. Any lump, even as small as a BB, can be cancerous.
  
  
• A breast that is swollen or hot.
  
  
• A nipple that drips fluid - either clear or bloody.
  
  
• Dimpled or discolored skin around the nipple.
  
  

Ask Your Veterinarian
"The annual veterinary visit is essential," Dr. Ogilvie said. Your veterinarian will double-check your at-home examination and check the deep-lying lymph nodes for signs of trouble. Of course, if you find any warning signs between checkups, see your veterinarian right away. "Early detection means a high probability of cure," Dr. Ogilvie said.