Germ Warfare

Mike King

CURE, Summer 2011, Volume 10, Issue 2

Reducing the risk of infection for cancer patients in treatment.

When Chris Prestano learned in 2008 that she had thyroid cancer, she decided to commute between her home in New York City and Baltimore so that experts at Johns Hopkins Hospital could treat her.

Because she also has type 2 diabetes, which can lead to skin infections, Prestano knew that even a relatively simple surgery like removing her thyroid posed a risk. She and her physicians took every precaution necessary, including pre- and postoperative antibiotics, but it didn’t stop her from developing an infection. Now, more than two years later, she is battling a surgical wound infection that aggravates her recovery from cancer as well as her diabetes.

“My team of doctors is the best team I think I could assemble,” Prestano says. “We were very careful, very cautious going into this, and it still happened.”

Most cancer patients are aware of the tradeoff: Targeting cancer cells with chemotherapy agents and radiation or removing damaged organs and tissue through surgery greatly increases the chance of infection by germs that attack weakened immune systems.

The risk-versus-benefit equation is a standard topic whenever options are discussed. And both patients and their healthcare teams are getting savvier about what they can do to control infection risks before, during and after treatment.

Still, since that first thyroid operation, Prestano has been in and out of the hospital several times to treat the surgical-site infections. Among other procedures, she’s received five rounds of steroids, pulsed-dye laser treatments and surgical alterations to the scar. The loss of her thyroid and the recurrent infections has exacerbated her diabetes. Before surgery it was controlled without drugs, but now she is insulin-dependent.

“I had no idea it would take this long to heal,” says Prestano, 30, who moved to Frederick, Md., last year and now makes a much more manageable 50-mile drive to Johns Hopkins every three to five weeks so that doctors can monitor her progress. “I was more concerned about the infection and recovery from the surgery than the cancer itself.”

Prestano says she usually avoids large groups, rarely socializes with anyone who seems to be fighting a respiratory infection and has become vigilant about using hand sanitizers. “That’s the price we pay as cancer patients, I guess,” she says. While most patients won’t have the difficulties that Prestano has, it’s important to know Prestano is not alone.

I was more concerned about the infection and recovery from the surgery than the cancer itself.

Since the skin is the body’s first line of defense against infection, any break in it—through a surgical site or where a central line catheter is inserted into a vein to facilitate chemotherapy infusions—becomes a potential source for infection. Even subcutaneous central venous access devices, in which medicine is released through chest ports implanted under the skin’s surface, get infected about 5 percent of the time.

One of the most risky complications for any cancer patient is neutropenia, a hematologic disorder characterized by a lack of neutrophils—the granular white blood cells that fight micro-organisms, particularly bacteria.

Even though these treatments carry certain risks, cancer patients and care-givers can take some simple precautions to prevent infection. Wash your hands with warm, soapy water before eating or touching your face, and wash them again after blowing your nose or sneezing. Also, use hand sanitizers or disinfecting wipes after contact with items frequently touched by others, such as ATMs or grocery carts. Patients, caregivers and other family members should get annual influenza vaccines to prevent the virus’ spread. Finally, be aware of the symptoms of infection, such as fatigue, fever, redness and swelling, and contact your healthcare provider if those symptoms persist.

Healthcare providers in most states have voluntarily started using an infection-control checklist when inserting and working with infusion ports in patients, says Peter Pronovost, MD, professor of anesthesiology and critical care at Johns Hopkins, who has spearheaded the checklist effort. Patients and family members, he adds, should be aware of them too and insist that they be followed. For example, patients should confirm that medical personnel have washed their hands with soap and water or alcohol gel before and after examining the patient, as well as when inserting, replacing, repairing or dressing a catheter; disinfected the patient’s skin before inserting a catheter and during dressing changes; maintained aseptic technique by wearing a mask, sterile gown and sterile gloves—as well as draping the patient with a sterile sheet—when inserting a catheter.

Each year, an estimated 60,000 cancer patients are hospitalized for chemotherapy-induced neutropenia. A patient dies every two hours from the complication, according to the CDC Foundation, an independent nonprofit organization. The overall mortality of cancer patients hospitalized due to febrile neutropenia, or neutropenia with fever, is estimated between 9.5 and 11 percent, the foundation reports.

While infections in healthcare settings correctly get the most attention, the risk of neutropenia also extends to other widely prescribed anticancer treatments given in a variety of settings.

In February, researchers examining 16 randomized control trials of Avastin (bevacizumab) found that patients prescribed the drug in combination with chemotherapy or biological therapy were at increased risk of death from neutropenia compared with patients who were getting conventional chemotherapy or other biologic treatments. While some cancer patients may still benefit from taking Avastin, they and their oncologists should be aware of the risk of neutropenia and other life-threatening effects, says Daniel F. Hayes, MD, a professor of internal medicine at the University of Michigan Comprehensive Cancer Center in Ann Arbor, who also serves as co-director of the Breast Care Center and clinical director of the breast cancer program.

The CDC Foundation and Amgen, a maker of anti-infective prophylactic drugs, are collaborating on a three-year effort to raise awareness of preventing infections in cancer patients. An Amgen-sponsored survey of cancer patients in 2009 showed that nearly one-fourth experienced an infection within the first year of chemotherapy. Sixty-one percent of those had more than one infection, and all of them took at least a week to recover, often interrupting their chemotherapy regimens.

Experts say cancer patients must know their infection risks as well as preventive steps they can take depending on their cancer type and treatment regimen.

Surgery > The body’s immune function often decreases in the hours immediately following surgery and may take many months to fully recover. Using antibiotics prior to surgery is sometimes recommended for those most prone to infection.

According to the American Cancer Society (ACS), the risks for patients include how long the patient is in the hospital, the extent of the surgery, the length of the operation and the amount of bleeding. Patients who have had previous treatments for cancer, including chemotherapy and radiation, and those who are diabetic or poorly nourished going into the surgery are also at greater risk.

The surgical site itself is the most common place for infection to take hold. In addition to the complications caused by infection, including treatment delays, it can also increase medical costs. A 2008 study of women undergoing breast surgery showed that surgical-site infections raised the cost of care by more than $4,000 compared with women who came out of surgery free of infection, especially women undergoing mastectomies.

Chemotherapy > Patients’ immune systems could be impacted by the types and dosages of chemotherapy, frequency of treatment and the cancer type and stage. Age, nutritional status and prior treatments also impact how the body’s infection-fighting ability is affected by chemotherapy.

Patients with central venous access devices should be especially vigilant. Central lines deliver chemo agents and other medications directly into the bloodstream, usually via a catheter placed in the chest, neck or groin. Because the lines stay in for days, sometimes weeks, they must be routinely handled and can become the site for infections. Even medication ports placed under the skin, usually in patients needing long-term infusion, can become infected below the surface. Patients should watch for redness, swelling and drainage from skin around the catheter or above the port site, as well as other symptoms, such as sudden fever or chills.

Radiation > Radiation’s effect on the immune system, much like that of chemo, is exerted through changes to the bone marrow. Unlike chemo, it affects bone marrow only within the treatment field (“inside the beam”), so it has little impact when the fields are small. However, depending on the part of the body radiated and the dosage, it can also increase the risk of skin damage and infection. Patients who undergo total body irradiation should know that it is much more likely to trigger very low white blood cell counts, which can be risky. The ACS recommends patients be aware of their radiation dose, how often it is given and what parts of the body are getting the most radiation when discussing treatment options with their physicians.

Immunotherapy > Immunotherapy boosts the immune system to recognize and attack specific cancer cells but sometimes can change the way the immune system works. Some forms of immunotherapy cause the level of all white blood cells to drop, not just neutrophils. When lymphocyte levels become too low, the risk of certain viral and fungal infections increases. But most often the neutrophil counts return to normal soon after treatment is stopped, even though lymphocyte counts stay low for months.

Bone Marrow Transplant > Bone marrow transplants pose the most significant risk because they often involve very high doses of chemo and total body irradiation, which severely weakens the immune system. That’s why stem cells are removed from the body before treatment or taken from a donor and re-infused after the procedure so that the immune system can be rebuilt. Precautions include keeping patients in an access-controlled environment of the hospital until white blood cell counts reach normal levels—a wait that can often take weeks. During this time, exposure to people outside of the medical team is severely limited, and patients must be monitored for fever and other signs of infection.