Chemotherapy Side Effects: to recheck or not?

One of the most important things we perform as veterinary professionals is a TPR. We can tell a lot about a patient by just those three parameters. But the most vital one for patients undergoing chemotherapy is their temperature. For these patients this could mean the difference in life or death in some cases. Febrile neutropenia is a very common occurrence in veterinary oncology.
Rechecks for these patients are crucial to monitoring how well they’re tolerating treatment, whether they need additional support, or whether or not a new treatment course should be considered. Patients are often seen at their primary care providers in between treatments with their oncologist. This is why it is imperative that all members of the patients care team should have clear and open communication.
Information gathered at these rechecks when shared with the specialist providing treatment can help decide on how to proceed with future treatments. This may look like a dose reduction of chemotherapy, prophylactic antibiotics, or supportive medications given before or after chemotherapy administration.
During these recheck visits, a thorough history is key to making sure nothing is missed. All patients being seen for recheck blood work, whether for at home administration or one week post intravenous chemotherapy, should have both a physical exam and TPR. This does not necessarily need to be performed by a veterinarian, but an evaluation needs to be made at every visit. When performing recheck examinations on oncology patients, guidelines are helpful in formulating a plan to support those who are experiencing side effects.
Some oncologic emergencies can be subtle in presentation and may be overlooked, contributing to increased morbidity and mortality. Common occurring emergencies are related to effects of the cancer, ranging from immune dysfunction due to marrow infiltration to brain herniation due to increased intracranial pressure from neoplasia. Often adverse effects secondary to chemotherapy can cause emergency situations such as sepsis. Prompt diagnosis and treatment may result in a favorable outcome.
Depending on the cancer diagnosis, a patient might have a paraneoplastic syndrome associated with it. These can sometimes be more fatal than the cancer diagnosis itself. For example, a patient with multiple mast cell tumors may be experiencing a degranulating event, and has developed systemic anaphylaxis which requires prompt treatment. Patients with lymphoma may have initially presented for care due to malignant hypercalcemia, these patients also needed to be treated immediately.
Cell counts matter! White blood cell counts, especially neutrophil counts are what we most expect to see drop after chemotherapy. Febrile neutropenia is a fairly common occurrence in some patients. Temperature, temperature, temperature. The importance of a temperature cannot be stressed enough. These patients are at risk of sepsis and death.
If a patient is thrombocytopenic, we must then refer to patient history, check for petechiations, and ask the owner if they’ve noticed any epistaxis. Patients who are thrombocytopenic should be monitored at home if there is no bruising present, and just inform the owner that during this time it is necessary that we keep patients from rough play, discourage the use of hard chew toys, bones etc. Client education is our biggest asset. Depending on the levels these patients may require hospitalization.
Anemia is another common side effect of chemotherapy. Most often seen in patients undergoing long term treatment given the life cycle of the red blood cell. This is where history taking is crucial, if patients are anemic, is it due to long term treatment or another cause?
Patients with an Osteosarcoma diagnosis must be monitored for signs of lameness, with or without amputation of affected limb. Long bones should be palpated at all recheck visits. Pathologic fractures are very common in patients with osteolytic lesions and are extremely painful. These need immediate care when presenting for a recheck appointment.
In order to recognize these side effects and act appropriately it often helps to discuss real life case examples. Fitting the history and signalment together like a puzzle in order to achieve the best treatment plan for the patient.
Not all patients presenting for recheck appointments will be in the midst of an emergent event. Some may be experiencing things like nausea, vomiting, hyporexia, or diarrhea. Knowing what to expect and how to act is very important as someone who is a part of the patient care team.