What to Do When the Kidney Does Not Function Well

We need to monitor not only for liver function but also for kidney function. However kidney problems are much less frequent.

Patients who undergo chemotherapy know that every time they receive chemotherapy, oncologists take blood to test for blood counts and also for liver and kidney function.

There are many drugs which need their doses reduced or treatment held held if the kidney function changes. One of the common mistakes is that Xeloda, the oral 5-FU drug used for colon cancer, does need to have its dose reduced for kidney dysfunctions. However 5-FU and oxaliplatin don’t have to be dose reduced, which is astonishing since cisplatin has tremendous kidney toxicities which oxaliplatin does not.

Avastin needs to closely monitored for kidney toxicities. Rarely patients can develop proteinuria, which means the kidney loses too much protein. In this situation Avastin needs to be stopped. This is usually reversible within weeks. Proteinuria has been well described, particularly in patients with renal cancer. We have seen proteinuria in patients with colorectal cancer treated with Avastin, which is the reason we check a urinanalysis every 4 weeks to make sure there is no significant protein in the urine.

Patients can monitor proteinuria at home. Whenever there is a lot of protein in the urine, urine foams and makes a lot of bubbles in the toilet. Let your doctor know if this is happening.

Erbitux has also some toxicity to the kidney. It is very rare but needs to be monitored too. It can make the kidney loose magnesium. Your oncologist should test magnesium levels in the blood at every visit. Clinically patients can experience cramping in their legs and hands or can feel lethargic. Make sure magnesium levels are within normal range. This is particular important for patients who have diarrhea who may lose additional magnesium in the stool. If any of these symptoms occur you need to contact your oncologist to work you up.

In my own practice we have a number of patients who are on dialysis and treated effectively with chemotherapy. This is possible depending on the amount of the drugs being eliminated by the dialysis. Usually we treat these patients after their dialysis to allow optimal exposure of drugs to the tumor. Please discuss this with your oncologist if you have a chronic renal failure.

One of the problems for patients who have some increased creatinine levels is using contrast agents when they undergo CT scans. With any decreased kidney function you need to be very careful using IV contrast which can be harmful to your kidney. Discuss this with your oncologist.

Again for patients with kidney dysfunction, we offer very specific clinical trials which should consider if you do not qualify for other clinical trials.