Patients with diabetes and cancer need to know that some chemotherapy drugs and adjuvant agents may require modifications in how they manage their diabetes. For example, patients who are receiving steroids might have to further restrict their diet to keep blood sugar levels under control.

“You might have to increase the dose of your insulin. You might have to increase the dose of any oral drug you’re taking for diabetes,” said June McKoy, MD, MPH, JD, MBA, Director of Geriatric Oncology for Robert H. Lurie Comprehensive Cancer Center and Associate Professor of Medicine at Northwestern University Feinberg School of Medicine in Chicago.

Insulin Advice

Patients who are on insulin while receiving chemotherapy should also be advised that if they are not feeling well, eating well, or keeping their food down, they should be cutting their insulin dose, or holding it for a day if they are not eating at all. “There are patients who don’t know that,” Dr. McKoy said, “so they continue to take the medication, and they end up in the hospital almost in a coma because their glucose has dropped to 30 mg/dL.”

Once a patient with diabetes receives a diagnosis of cancer, it is critical that the patient be referred back to a diabetes educator for “a refresher course, but in the context of cancer,” Dr. McKoy said. “The diabetes educator will remind patients that when they are throwing up, they shouldn’t take the medication, or when they are doing well and taking a steroid, they need to check their sugars more often. If they think it is out of control, they can call their doctor and say, ‘You have me on 20 units of insulin; I want to let you know that I have increased my insulin to 22 units because my sugars are running higher since my cancer doctor has me on a steroid.’”

Need for Partnership

Dr. McKoy added, “There needs to be a partnership, and I think diabetes educators are critical to care in these circumstances. They will give directions to patients and tell them that they have to have close contact with their primary care doctor, because many times patients don’t see their primary care doctor once they are diagnosed with cancer. They stick with their oncologist only,” she said.

“To be fair, we want the oncologist to do a lot of things, but it is very difficult,” she continued. “We are trying to get oncologists to start thinking, ‘When I have a patient with diabetes and cancer, I have to give her guidance.’ That guidance may not be specific advice on how to treat the diabetes, but it might be that the patient needs to follow it closely with her primary care doctor.” ■