Dual Diseases

Treating Cancer in People With Diabetes Poses A Challenge, But Doctors Have Strategies



Battling Cancer and Diabetes

Treating cancer in people who are already managing diabetes poses challenges for doctors and their patients as they struggle to fight the cancer without making diabetes-related issues worse, medical oncologist Dr. Ranjit Goudar says.

“Since eight to nine percent of American adults have diabetes, we’re talking about a sizable number of patients that need to be watched more closely,” says Goudar, who runs the hereditary cancer clinic at Virginia Oncology Associates in Norfolk, part of The US Oncology Network.

One potential problem is that common cancer treatments (cisplatin, oxaliplatin and paclitaxel), can lead to neuropathy—numbness, tingling, burning and pain caused by nerve damage, Goudar says. People with diabetes are more likely to suffer from neuropathy than the general population.

“Patients with diabetes may have some element of neuropathy,” Goudar says. “And even if they don’t have neuropathy, they can be more prone to developing it. So just asking patients whether they already have numbness and tingling is not enough. We know if they’re diabetic, the risk goes way up.”

So, oncologists substitute other treatment regimens that may be less effective but pose a lower risk of neuropathy, he says.

Cisplatin also poses a risk of kidney damage, a risk people with diabetes already face, Goudar says. “So if the patient already has borderline renal function, again that would induce us to switch chemotherapies,” he says.

Dexamethasone, a steroid that oncologists use to combat the nausea and vomiting linked to chemotherapy, and prednisone, a steroid used to treat blood cancers, can cause spikes in blood sugar for patients, which of course is especially problematic for people with diabetes, Goudar says

“For a person without diabetes, the blood sugar will rise for a few days,” he says. “For a patient with diabetes, especially if not well-controlled, the blood sugar rises quite high spiking to the 300s and 400s—and requires quite a bit of coordination between the oncologists, the patient and the doctor treating the diabetes.”

If the diabetic cancer patient is not already on insulin, he or she may need to go on insulin while taking steroids, Goudar says. If the patient is already on insulin, he or she may need to adjust the dose on days he or she is treated with steroids, he says.

Another issue is that patients with diabetes are more prone to infection, he says. Since chemotherapy also increases the risk of infection, oncologists must be cautious about the type of chemotherapy prescribed and may need to prescribe preventative antibiotics as well, Goudar says.

Unfortunately, people with diabetes also have a greater risk of getting certain kinds of cancer, Goudar says. He cited a recent study in The New England Journal of Medicine that says people with diabetes—when matched against other patients with similar weight and medical problems—have a 25 percent greater risk of dying from cancer. Another study showed that people with diabetes also are more likely to have a recurrence of certain types of cancer after treatment, he says. Yet another study showed that the risk of dying—for any reason--was more than twice as high in women with higher blood sugar.

The good news from all of this? Doctors now have another weapon in their arsenal to reduce the risk of cancer coming back.

“Being active, watching diet , watching weight, watching blood sugar is a very important part of cancer treatment that even five years ago wasn’t very high on our list .”

Conventional treatments include surgery, radiation, chemotherapy, anti-hormone pills and antibody treatments. The new weapon is in the hands—and mouth—of the patient. “Being active, watching diet, watching weight, watching blood sugar is a very important part of cancer treatment that even five years ago wasn’t very high on our list,” Goudar says. “We know that in the ongoing battle against cancer, we need to keep an eye on these things.”

He acknowledges that’s it’s a challenge to get patients to change their behavior and lifestyle, but the benefits include lowering the risk of recurring cancer as well as the possibility of reducing medication for high blood pressure and high cholesterol.

That focus on healthy lifestyles will further strengthen the bond between oncologist, primary care doctor and patient and hopefully encourage people to improve their overall health.