Canine Parotid Salivary Gland Cancer

Last Modified: September 14, 2008

Dear OncoLink "Ask The Experts,"

I have been told my dog has parotid salivary gland cancer. He is a mini American Eskimo. His chest x-ray was clean for metastasis and his blood work was excellent. I have been recommended to get the gland removed and do radiation. I am not going to do radiation and am nervous about the surgery. I would do the surgery if I could be made to feel comfortable that complete resection was likely. I don't have a CT scan of the mass yet, but if it spread to the lymph nodes [they] won't do the operation. Under the assumption that it didn't spread, what is the likelihood that complete resection of this gland could occur? Also, can you recommend a board- certified oncology surgeon in the Midwest - Chicago area I could go to for another opinion?

Lili Duda, VMD, Section Editor of the OncoLink Veterinary Oncology Menu, responds:

The American College of Veterinary Surgeons has a searchable directory that can be found at: www.acvs.org/VeterinaryProfessionals/FindaSurgeon/

In general, the best way to determine whether or not a mass has a reasonable chance of being completely removed (i.e. with "clean" margins) is using imaging such as an MRI or CT scan of the region. These imaging modalities are fairly reliable in determining which masses are not amenable to surgery. On the other hand, even masses that appear to be removable on imaging scans might not be once they are directly visualized at the time of surgery. Similarly, even masses that the surgeon is comfortable were removed with good surgical margins might still have evidence of residual cancer cells being left behind (i.e. "dirty" margins) upon microscopic evaluation (histopathology) of the biopsy specimen. The likelihood of success should be discussed with a board-certified surgeon who has evaluated the dog's history (is the tumor slow or fast-growing?), the histopathology report (does it appear to be a less aggressive, well-differentiated tumor or a more aggressive, poorly differentiated tumor?), the physical examination (is the tumor freely moveable or is it fixed to the underlying tissues?), and the imaging results (is the tumor well-defined or intertwined with surrounding structures, is there evidence of lymph node involvement?).