Absolutely! Good point Lisa!

Older animals ingeneral, tend to get, not really tumors rather fatty deposits. Generally its not wise to remove them (stress of surgery and anastetic) unless they grow to severly inhibit the mobility of the dog. Fatty cysts around the breasts occur in both spayed and unspayed females. If you are concerned about cancer, have your vet do a fine needle aspirate and send to a lab for analysis.

If you are concerned that the dog is not well, again, a full case needs to be taken (the deposits may only be one of many symptoms of a greater problem).