The Case of the Medication Modification
Doug is a 70-year-old man receiving treatment at the cancer center for metastatic renal cell carcinoma. He was initially treated with sunitinib, a tyrosine kinase inhibitor (TKI). He has been experiencing significant upper back pain and is having trouble with fine motor skills in his fingers.
The oncologist, suspecting spinal cord compression (SCC), ordered a computed tomography scan, which confirmed metastatic lesions in the spine leading to instability and mild SCC. The oncologist refers Doug for surgery and advises him that a new medication, cabozantinib, will be ordered for after his surgery. The oncologist asks you, the oncology nurse, to instruct Doug on surgical preparations and educate him on cabozantinib.
What Would You Do?
TKIs are small molecule inhibitors that target specific cellular proteins. Sunitinib and cabozantinib target vascular epidermal growth factor (VEGF) and prevent new blood vessels from developing to feed the tumor. Just like normal cells, cancer cells need an increased blood supply to nourish the growing mass of cells and remove waste products. Cabozantinib has two additional protein targets (AXL and MET); those additional targets offers cabozantinib a therapeutic advantage, especially when tumor cells have developed a resistance to sunitinib.
You reinforce the oncologist’s instructions that Doug will need to be off the sunitinib for one week prior to having surgery. He will also need to wait until he is fully recovered from the surgery before the oncologist will start him on the cabozantinib.
You ask Doug what side effects he has experienced on the sunitinib and educate him and his wife about the common side effects associated with VEGF-TKIs and how to manage them. Doug reports that he initially had difficulty with diarrhea but has a prescription for diphenoxylate and atropine that is working well. His blood pressure has remained in a normal range with prescribed doses of an antihypertensive. The oncologist also prescribed a steroid to reduce spinal cord inflammation, so you instruct Doug to take the steroid early in the day to reduce sleeplessness.