Chemotherapy: How cancer drugs impact the body long-term

Chemotherapy is a powerful weapon against cancer, but it can also have lasting effects

First used to treat cancer in the 1950s, chemotherapy drugs use powerful chemicals to kill cancer cells and inhibit them from reproducing and spreading throughout the body.  Most often, these medications are very effective at what they do – but they can also be a little too effective, destroying healthy cells along the way.

This gives rise to many of the common short-term side effects associated with cancer treatments, such as fatigue, nausea and vomiting, constipation and hair loss.  Additionally, health problems can still persist once chemotherapy has ended, as these drugs can sometimes cause permanent changes to the body’s systems.

Because of this, many cancer survivors must remain vigilant and keep an eye out for various health problems that may arise once their treatments are completed.

“All major cancer centers now have informed consent to alert patients to the immediate and long-term consequences of chemo,” Dr. Stan Gerson, director of the UH Seidman Cancer Center in Cleveland, told  “Hardly any of these medicines are benign.  The intensity and complexity of side effects both have to do with the age of the patient, and whether there are sequential treatments.  It’s a complex test to foretell what they’re [going to experience].”

One of the most serious concerns for cancer patients post-chemotherapy is the possibility of a second malignancy. Although the likelihood of this happening is relatively low, both chemotherapy and radiation therapy are particularly toxic to cells in the bone marrow, increasing a patient’s risk for leukemia, a type of blood cancer that originates in the marrow.

The heart and cardiovascular system are also greatly affected by radiation and chemotherapy medications, especially by a class of drugs called anthracycline.  It’s not uncommon for many cancer survivors to experience heart problems, such as swelling of the heart muscle, heart disease and congestive heart failure.  Additionally, chemotherapy can cause long-term lung damage, leading to thickening of the lungs’ lining, inflammation and difficulty breathing.

Perhaps the most common side effect of chemotherapy is suppression of the body’s immune system.  If suppressed for an extended period of time, the lowered immune system can give rise to many secondary infections throughout the course of cancer survivor’s life. In addition, chemotherapy can leave its mark on the nervous system, causing pain or weakness in the nerves of a person’s fingers and toes.

Although most of chemotherapy’s side effects have been well established and are usually very treatable, physicians have recently become concerned with a new concept called “chemo brain.” For many years, patients undergoing treatments have noted changes in their cognitive abilities, experiencing something of a “mental fog” and forgetfulness.

Now, a recent study published in the Journal of Clinical Oncology has revealed that these effects aren’t necessarily all in patients’ heads.  Researchers conducted magnetic resonance imaging (MRI) scans of 18 breast cancer patients undergoing chemotherapy treatments, which showed decreased brain activation during the period the drugs were administered.

“You’re seeing in the MRI study, it’s one of the first times [we’ve seen] there are real changes in the way the memory is recalled and how it functions,” Gerson said. “Somehow [chemo is] affecting the lipids of the brain, so the signals don’t transfer in the way they normally do….Or there is probably the same sort of nerve damage in the fingers and the toes also occurring the nerves of the brain.”

Though not much is known about chemo brain, most health experts believe that cognition returns to normal once chemotherapy has ended and that patients aren't at an increased risk for mental problems as they age.  However, Gerson said more research is needed to establish the long-term effects chemo may have on the brain.

“If you ask patients empirically, it’s not uncommon for folks to say they’ve never gotten back to normal,” Gerson said. “Most physiologic tests say cognitive functions return back to normal within six months.  But the real answer is still out there.”

The list of long-term effects from chemotherapy may seem daunting for some, but Gerson noted that it’s important to remember the alternative to foregoing treatment: living with cancer.  And for many patients, these side effects can be incredibly minor, especially for those who undergo proper rehabilitation – such as exercising regularly and maintaining a good diet.

“There are issues that come up— some patients are debilitated by treatments— but with every treatment we give, that percentage of people is less than 7 percent,” Gerson said.  “Even folks who are left with some residual effects, they usually get by and manage and move on with their lives.”