Sono, congrats on your new beautiful brindle girl....cancer is not always "the end" and dogs can live with cancer for a long time. It really depends very much on many factors. Cancer is a big problem in dogs, and some breeds in particular - the Boxer is one, and my breed, the Rottie.
Cancers related to vaccinations are also a cause for concern, and this is something many traditional vets either will not tell you or don't believe.
My beloved big girl, my older Rottie, developed a mass in her butt cheek about a year after her most recent Rabies vaccine. The tumor was close to the injection site. My holistic vet agreed with me that it -could be- related to the vaccine. Cats in particular are known to develop tumors at vaccination sites.
Boxers are a working breed and have been used for service work and other types of tasks. They have a clownish side to them. Brindles are no more or less aggressive than any other color variant.
Though I refuse to vaccinate yearly for Rabies <and that is no longer recommended, but some vets will not tell you this or will not follow the new veterinary guidelines regarding vaccines> and do the 3 yr. Vaccine for Rabies, it still happened. We felt the mass on a Sunday eve,. called on Monday, had her to our main vet, who did aspiration <to remove some amount and see if the cells were suspicious> and was worried and so we scheduled the procedure for that same week Wed. It was a fibrosarcoma, Grade 1. Vet was confident he got good margins. Pathology report agreed. The whole thing was very shocking and scary for us but she is doing fine. This was in October of '13.
My previous Labrador had several fatty tumors, those are benign.
Kristina, what a scare fir you and your daughter and her dog! And I'm so sorry about the end result.
Konijen, liked your poster.
Most of canine body language is VERY subtle to miniscule, from a person's perspective. It could be as "small" as position of whiskers around the face, an eye movement, or open mouth versus closed mouth.