Do you have a dog undergoing chemotherapy with an oncologist or are you considering chemotherapy for your dog?
Sometimes it can be a bit scary to drop your dog off for "treatment" and have him disappear "in the back".
In order to help allay your fears I wanted to describe exactly what happens when you drop your dog off for chemotherapy with the oncologist. What is described in this article specifically applies to chemotherapy administered by an oncology service, because they typically adhere to more strict guidelines than other practices may. This is a general rule, but obviously every practice is different.
In most cases, chemotherapy treatments require a morning drop-off with pick up later in the day when treatment is completed. If your dog is receiving oral chemotherapy, such as CCNU (lomustine) or cytoxan (cyclophosphamide), your oncologist may schedule a shorter visit, during which your dog receives treatment in an hour or so.
Your oncologist may recommend that your dog is fasted (no food after 10 PM the night before the visit). One study showed that dogs receiving doxorubicin chemotherapy (Adriamycin) were less likely to experience nausea if they were fasted from 6 PM the evening before chemo until 6 PM the day of chemotherapy.
The second reason your oncologist may recommend fasting is if your dog might require sedation for chemotherapy. Sedation often allows for (1) a more relaxed experience for your dog and (2) safe chemotherapy administration, especially if we are giving an extravasant such as vincristine or doxorubicin (these agents can cause significant tissue damage if leaked outside of the vein during administration and require the patient to lay absolutely still during treatment).
To avoid injectable sedation, your oncologist might recommend giving oral trazodone or trazodone with gabapentin prior to the visit to keep your dog as relaxed as possible.
(2) Intake Questionnaire
When you arrive, you will have to fill out an intake questionnaire. You'll describe how your dog has been feeling since the last visit. This will help the oncologist determine if any adjustments are needed with the chemotherapy protocol, will help determine response to treatment, and overall assess quality of life. You will describe if there has been any nausea, vomiting, or soft stool. You will describe if there has been any lethargy. You will list the medications that your dog is taking, if you need refills, and anything else you think is important for your oncologist to know.
An oncology nurse will then go over your questionnaire briefly and make sure that everything is clear. They'll take your dog to the oncology treatment area and you'll typically go home (to work, etc.). They'll weigh your dog and obtain his temperature, respiratory rate, and pulse.
At that point they'll also obtain the necessary blood samples needed for that day's chemotherapy treatment. A CBC (complete blood count) is needed before giving all chemotherapy agents. This ensures that there are enough neutrophils (the white blood cell we care about) and platelets for chemotherapy (these can fluctuate with treatment); it also ensures that the red blood cell count is stable. Some chemotherapy agents require that liver or kidney values are assessed; this is performed at the same time.
The nurse will begin to fill out your dog's chemotherapy sheet based on (1) the type of chemotherapy he is due for and (2) the previously tolerated dose.
Most oncology teams schedule all drop-offs in the morning before recheck and consult appointments begin. In most cases, drop-off and intake has to be completed in fifteen minutes, before the next patient arrives. Depending on how busy the oncology service is, anywhere from a few to ten (or more) patients might be receiving chemotherapy on a given day.
(4) Oncologist's Assessment
The oncologist will perform a physical exam on your dog. They will assess response to previous chemotherapy treatments. This may involve measuring a skin mass or measuring previously enlarged lymph nodes.
The oncologist will assess your dog's weight and determine if they have gained or lost weight. Chemotherapy is calculated based on the patient's weight, so an accurate weight is very important. If there is a major weight fluctuation, your dog will be re-weighed. If your dog has lost a significant amount of weight, we will question whether they are still responding to chemo or whether their cancer has come back (and if that is causing them to feel sick).
The oncologist then evaluates your dog's blood work and decides if (1) there are enough neutrophils and platelets for treatment, (2) if the remainder of the lab work is adequate (if there is other lab work), (3) or if adjustments in dose of chemotherapy agents are required based on the labs.
The oncologist then calculates the amount of chemotherapy that your dog will receive that day (and double or triple checks their math). They also decide if other medications will be given at the time of chemotherapy (anti-nausea injection, Benadryl injection, steroids, sedation, etc.). They sign the chemotherapy form and "approve" chemo.
One of the oncology nurses/techs then checks the oncologist's math (again) and also signs the chemo form.
(5) Chemotherapy Preparation
Once chemo is approved and the dose of chemo has been decided, the nurses can begin to prep chemo. Safety and accuracy are our top concerns when prepping and administering chemo. We want to ensure that we limit chemotherapy exposure to the oncology nurses, the remainder of the hospital staff, and to hospital surfaces. We also want to make sure that our calculations are as accurate as possible and that every patient receives the correct dose of chemotherapy. This means that we don't want our nurses rushed or distracted while they are handling chemotherapy. It also means that we follow strict protocols while preparing and administering chemotherapy.
Before preparing chemotherapy, an oncology nurse must don the appropriate PPE (personal protective equipment). Recommended PPE includes a face mask or shield, goggles, disposable gloves (double gloving is recommended), a chemo gown that is impermeable to liquid, and disposable booties.
PPE protects them from chemotherapy during chemotherapy handling - our goal is to reduce exposure as much as possible.
Chemotherapy is only removed from its individual glass vials while working in a chemotherapy hood. The hood needs to meet certain specifications to allow for chemotherapy handling; it also needs to be vented to the outside. This ensures that if there is a chemotherapy spill inside the hood while removing chemotherapy, there is minimal exposure.
See the image below for an example of an oncology nurse drawing up chemotherapy from a vial inside of a chemotherapy hood:
An oncology service will also find it essential to handle chemotherapy using a closed system drug transfer device such as PhaSeal. PhaSeal is an airtight leak-proof system that we use to transfer chemotherapy from its commercial vial to an administration syringe and then to the patient. It significantly minimizes individual and environmental exposure and contamination with chemotherapy.
Why is using a closed system drug transfer device like PhaSeal so important? Well, healthcare workers that work with chemotherapy drugs have an increased risk of leukemia and other cancers. This increase exists because of routine chemotherapy use (treating patients), not because of spills. PhaSeal significantly minimizes exposure and helps to keep us safe.
(6) Chemotherapy Administration
In some cases we will need to pre-med patients with Benadryl, steroids, Cerenia (anti-nausea), or sedation prior to chemotherapy administration.
Once all pre-meds are given and chemo is prepped, we're ready to administer.
Two oncology nurses (techs) are involved in chemotherapy administration for each patient. They wear all of the PPE that we discussed in the last section. Small and medium sized dogs are treated while laying on an elevated table and large dogs are treated on the floor. One nurse is responsible for administration and the other is responsible for petting/calming/holding/keeping the patient still.
Sometimes an IV catheter is placed and taped in and for other types of chemotherapy a butterfly catheter is held in place (this is for quick chemo injections involving a very small volume of chemo).
Most dogs will just lay still for treatment and are excellent patients (we love those!). In some cases, some form of sedation is required to decrease anxiety and ensure that chemo administration is as safe as possible. As mentioned earlier, this may be oral sedation (trazodone/gabapentin) you give at home, or injectable sedation given at the clinic.
Thankfully, oncology nurses are excellent at their job and very good at perfect catheter placement, even in patients with very difficult veins.
Safety is the utmost priority. We have to be certain that catheter placement is absolutely perfect - this avoids chemotherapy leakage outside of the vein, which can cause significant irritation and even necrosis (dying skin) with certain types of chemotherapeutics.
Many types of chemotherapy are given as a quick IV bolus injection (vincristine, vinblastine). Others are given as a slow IV push (carboplatin), while still others are given over 30 minutes (doxorubicin). In veterinary medicine, it's less common to give a chemotherapy infusion over 6 or 8 hours.
Your dog may also receive oral chemotherapy (cytoxan, CCNU). Nurses still don PPE for oral chemotherapy and take the same necessary precautions as for injectable chemotherapy.
Sometimes monitoring is necessary post chemotherapy (Lspar); in most cases, once a patient is treated, they can go home.
Your oncologist will often call you with an update or speak to you when your dog is ready to be picked up. If your dog is being treated at a very busy practice, you may speak with an oncology nurse at release, unless you have specific questions for the oncologist.
You will usually be given paper work describing what treatment was given and what signs to watch for. Typically this is thoroughly discussed at the first treatment; signs to monitor for are the same for most chemotherapy treatments (I will discuss these in detail in a future article).
You will then schedule your next appointment.
Before you leave, make sure you have a good understanding of who to call if you're worried about your dog, when they're available, and what signs you are monitoring for.
Your oncologist's goal is to help your dog live longer and feel better. If your dog isn't feeling well, they want to know about it. Make sure you ALWAYS have anti-nausea and anti-diarrhea medication on hand. Try to contact your oncologist sooner rather than later if your dog isn't feeling well - this allows them to help troubleshoot before he feels bad (or before a weekend or holiday interfere with you being able to get in touch with them).
Remember that you and your oncologist are the BEST people to help your dog - you both know the most about your dog's disease, his meds and how he is feeling. Reach out to your oncologist before friends/family/neighbor's and Facebook groups.
Dr. Lori Cesario
Board Certified Veterinary Oncologist
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