The Veterinary Surgeon's Dilemma: To Biopsy or Not Biopsy?

Veterinary surgeon experts give their advice.

Let’s discuss two common dilemmas that are commonly encountered in everyday veterinary surgery. What is your philosophy when it comes to biopsies?

Dilemma No. 1 

Let’s pretend you need to perform a cystotomy on a patient. While tying the patient to the surgery table, your technician notices a firm, not-so-mobile 1-inch-diameter mass on the hock. While you are in surgery, a receptionist calls the owner to see if he wants you to excise the mass. He approves the extra surgery fee but declines the fee for histopathology despite your impression that the mass is malignant.

What would you do?

Clearly, some colleagues will remove the mass with no second thought. Others firmly believe that “if it’s worth taking out, it’s worth sending out.” What is the right thing to do? Being lenient? Being dogmatic?

We asked a few specialists to share their thoughts.

Veterinary pathologist Jim Walberg, DVM, Dipl. ACVP, of VetPath Services in Stone Ridge, N.Y., reminds us that in human medicine, where lawsuits are so prevalent, all excised tissues are sent to pathology.

“Similarly, we should insist that any mass excised be evaluated histologically,” Dr. Walberg said. “In reality, cost is often the main deciding factor in veterinary medicine when pet owners don’t have pet insurance.

“When a client declines histopathology, the least you should do is to save all masses in formalin in a well-labeled container. Then archive the mass so that it can be sent to the lab at some future time if there is recurrence of the mass or if the clients change their minds.”

He concluded: “The tumor should be removed for the sake of the patient, even if there is no histopath. Then save the tissue, and make the client sign a document stating that they declined biopsy.”

Veterinary oncologist Alice Villalobos, DVM, of Pawspice in Hermosa Beach, Calif., said, “Remember the old saying, ‘Let the customer win so you win’? The only reason you have a dilemma here is because veterinarians are so accustomed to giving clients an either/or option.

“Instead, we can find a compromise to get things done as well as possible under the circumstances.”

She continued: “My compromise would have been at least to perform cytology prior to the excision of the mass. I would tell the pet owner that pre-surgical cytology is in their pet’s best interest.

“I would inform them that it is standard medicine to have a good idea of tumor type before surgery and that my ethics would be compromised if I did not know the tumor type before surgery," she continued.

“If you have New Methylene Blue, the staining procedure goes very fast and you just need to look under high power for intra-cytoplasmic granules inside fried egg-shaped cells to determine if you have a mast cell tumor.

“Finding a compromise, rather than sticking to dogma or the either/or option, would be easy for me to live with.”

Dr. Villalobos insisted that your compromise offer, the cytology findings and the lack of post-op histopath should be documented in the medical record in case the mass recurs.

California veterinary pathologist Ken Mero, DVM, MS, Ph.D., agreed that “histopath on any mass is ideal whenever possible.”

“We are sometimes caught between the ideal scenario and the client’s wishes,” he said. “The bottom line is that we are the client’s servants unless, perhaps, an issue is unethical.

“This scenario might cause future problems if we refused to remove a mass as requested and eventual complications with this lesion developed, such as a malignancy with subsequent metastasis or progressive enlargement to the degree that it becomes inoperable or requires radiation or amputation.

“Knowing how litigious the public is, I suppose a client could sue you over your refusal to remove a mass that eventually developed secondary complications, even though their ability to prove anything may be difficult.

“The client could also go to a different clinic for the mass removal—with or without histopath—and you may lose that patient,” he added.

“Ultimately, an option in such a situation might be removal of the mass as requested and saving it in formalin indefinitely in case the clients change their minds. It can also be sent for histopath if a lawyer enters the picture.”

Dilemma No. 2 

What is the best course of action? Excising a mass without the benefit of a biopsy? Or should every mass be biopsied first?

Option 1: biopsy first, excise second. 

Depending on the location of the mass, it may be challenging to safely excise it entirely, with clean margins, and close the defect.

If the biopsy reveals that the mass is malignant, your goal will be not only to remove the mass, but also to obtain clean margins. This can be difficult at best and impossible at worst, especially in areas with little extra skin, such as the foot or leg.

However, if the biopsy reveals that the mass is benign, that knowledge will change what you do, since you won’t have to be as invasive during surgery.

Option 2: excise first, biopsy second. 

When a mass is small, a complete excision (“excisional biopsy”) is likely not much more invasive or costly than performing an incisional biopsy first. In such a case, skipping the biopsy and going straight to surgery makes sense.

Delaying treatment by performing a biopsy first is not always ideal either. Even if a mass is benign, if it’s causing a blockage, mobility issues or bleeding, it may have to be removed right away. In these cases, since a biopsy would not change the treatment plan, it is reasonable, if not advisable, to go straight to surgery.

For very aggressive or fast-growing masses, actively bleeding masses or rapidly declining patients, delaying treatment also is not recommended. Waiting about a week for biopsy results could make the difference between life and death, or it could cause additional suffering. This scenario also avoids the need for two anesthesia episodes in a sick patient and decreases the associated cost.

In other words, if performing a biopsy before mass excision will not change your treatment plan or your surgery, then it makes sense to skip the biopsy pre-op.

Originally published in the February 2016 issue of Veterinary Practice News. Did you enjoy this article? Then subscribe today! 

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