Eyelid mass in a Labrador Retriever
At our practice, we remove anywhere between 5 – 8 lumps and bumps on an average week. These are submitted for biopsy so that a Board Certified Pathologist can give us information about the lump. Occasionally a pet owner will say “I don’t want a biopsy”. The most common reason is “If it is cancer, I am not going to put my pet through treatment”. Well, perhaps the veterinary profession in the past had made it seem like that was the only reason to evaluate masses or maybe that was the owner’s perception from the information given. I am here to tell you the reasons are more important than just treatment.
First let’s start with Path 101 (more detailed info available on cancer.gov). A ‘mass’ is a growth. They come in different shapes, sizes, and locations. Another common word is ‘tumor’, which can be benign (low risk of spreading and surgical removal is often a cure) or malignant (high risk of spreading to other organs and can grow back at the surgery site). Some people use the terms ‘cancer’ and ‘tumor’ interchangeably, but this is not correct as a cancer is a malignant tumor.
Benign Mammary Tumor (Left); Malignant Mammary Cancer (Right)
You cannot tell just by looking at a growth if it is malignant or not without doing tests. The most common test is cytology, in which the veterinarian introduces a needle into the mass and looks at the cells under a microscope or sends the samples to a pathologist for review. The cytology gives general information about the mass. However, since an aspirate is just a sample of cells, the pathologist cannot always give a definitive answer about the exact type of tumor. Most results give us an idea of what the mass is and help decide a treatment plan. A possible complication of cytology is the potential for spreading the cells and making the tumor to grow faster.
The best way to evaluate a mass is to remove it and send it out for biopsy. The pathologists are able to give information about the type of tumor, how aggressive it is, if it is benign or malignant, if it has been completely removed, and the chances that it will regrow or spread. This information is very important when veterinarians provide care for your pet, as it allows us to give you a prognosis (how good or bad the pet is going to do because of this mass) and treatment recommendations if indicated.
Knowing the behavior of the tumor, we can tell you if it is likely to spread or not. Why is this important? As an example, if a tumor has a high risk of spreading to the lungs and your pet starts coughing, it increases suspicion of cancer in the lungs as opposed to a respiratory infection or other lung problems. Your pet can be better assessed and treated based on this information. It also helps pet owners make difficult decisions, like when it is time for euthanasia based on signs that are consistent with problems secondary to the tumor. Second, some tumor cells spread well beyond what we can see, so there is always a possibility that not all cells are removed during surgery. If a tumor is not completely excised or has a high risk of coming back, the owner can make an informed decision of doing surgery again if possible or pursuing additional treatment options, like chemotherapy.
While some chemotherapy and radiation treatments are very expensive and thus sometimes cost-prohibitive for owners, sometimes there are treatments with less side effects and lower cost that can help improve the pet’s quality of life (which in the end is what really matters). If we remove a mass and do not send it out for biopsy, we are taking away the opportunity for the owner to treat their pet in the future should they change their mind, and believe me that happens often. The emotional distress from worrying about your pet may cause you to say “I don’t want to know if it is cancer” but trust me when I say many people change their mind once the pet starts having problems, and at that time it is sometimes too late. Information doesn’t hurt, yet lack of information can be harmful.
So hopefully, if your pet develops a lump and your veterinarian recommends a cytology or biopsy, now you can better understand the importance of doing these tests. At our practice biopsies are not optional because it is not good practice to not send samples out (and no it is not so we can charge more since our markup on cytologies and biopsies are minimal to help save the pet owner some money). The peace of mind when you receive a good prognosis is a great feeling, and although we never want to hear the bad news of a cancer diagnosis, it helps us prepare for what comes next for our pet’s future. Knowledge is power.
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