The Most Critical Tool in a Veterinary Oncologist’s Bag

Joanne Lynn Intile, DVM, MS, DACVIM
Published: November 18, 2015
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What tool is most critical for you to complete your job to your best and most efficient capability?

If you’re a graphic designer, is it a lightning fast computer processor equipped with the latest software? If you’re a pilot, is it a state of the art turbine engine propelling a multi-million dollar aircraft? If you’re a professional tennis player, do you require the most technologically designed tennis racket to play your best?

One could argue that a talented artist would be equally as creative with a piece of paper and a pencil as with a fancy computer, or that a pilot could fly a propeller plane with just as much expertise as a Boeing 787 Dreamliner, or that Serena Williams would still be a phenomenal tennis player using a wooden racket strung with yarn. But when those individuals are equipped with advanced tools designed specifically for their respective crafts, they are able to produce extraordinary outcomes.

As a veterinary oncologist, the equivalent of my high-tech-Dreamliner-graphite-tungsten tennis racket is an impeccably written, thorough, and all-inclusive biopsy report.

Biopsy reports are essential to my ability to make diagnostic and treatment decisions for my patients. Biopsy reports provide me not only with a diagnosis, but also an interpretation of how likely the cancer will be to spread and what that animal’s needs for further local and/or systemic treatment might be.

The pathologist interpreting the submitted sample is responsible for writing the biopsy report. Unfortunately, standardization is lacking regarding what information should be included, and vast variations exist in the quality of reported information.

At minimum, a biopsy report should include a portion (if not all) of the history provided by the submitting veterinarian, a morphologic description of what was observed under the microscope, and a finalized histological diagnosis.

Ideally, biopsy reports include so much more.

A report should break down the morphologic description into two parts: the gross description and the microscopic description.

The gross description would include information related to the tissue sample as visualized with the naked eye. This would include information about the color, weight, size, and consistency of the submitted sample. This is not a typical feature of most biopsy reports because instead of receiving the actual tissue sample, the pathologist receives a set of pre-processed slides.

The microscopic description should include descriptions of the cells, including whether they are consistent with a cancerous process or not. If they are cancerous, the report should indicate how different they appear from healthy cells. The size, shape, and staining characteristics of the cells should be indicated.

The pathologist should use this information to assign a grade to the tumor. When the cells are similar in appearance to healthy cells, this is consistent with a low-grade or well-differentiated tumor. High-grade, poorly differentiated, and/or undifferentiated tumors are comprised of cells that vary drastically in appearance from healthy cells.

A biopsy report should also include a numerical quantification of mitotic rate, which is a parameter that is thought to correlate with the rate of division of cancer cells. Tumors with a lower mitotic rate are usually low grade and correspond to a better prognosis, whereas high mitotic rates often correlate to a higher grade and more aggressive biologic behavior.

Reports should include a description of whether tumor cells can be found at the margins (edges) of the biopsy, and if not, there should be quantification of the distance between the last tumor cell observed and the cut edge of the specimen. If tumor cells are present at the edge, this indicates that the tumor was not entirely excised and that there is a potential for regrowth and/or spread.

The pathologist should also record whether they observe any cancer cells within blood or lymphatic vessels. The presence of cancer cells within either vessel raises concern for the possibility of the spread of disease to distant sites in the body.

Pathologists should also indicate if further testing to identify specific genes, proteins, or other factors could help better characterize the tumor. Many times I use the results from such tests to tailor a treatment plan specifically for the patient attached to the report.

Far too frequently I am asked to consult on cases where the biopsy reports lack one (or several) of the aforementioned aspects. This limits my understanding of a pet’s diagnosis and restricts my ability to fully treat its cancer. Not only does this render me unable to answer an owner’s questions about their pet’s disease, but also I am unable to determine the best plan of action for that patient.

I require a high-quality biopsy report to perform my job to the best of my abilities. Without this tool, I’m unhappy with the product of my efforts. It doesn’t take much for us to ensure that the outcome for our patients moves from subpar to superb.

So pathologists—I challenge you to let me release my inner Serena and send me the Dreamliner of biopsy reports! 

Dr. Joanne Intile