Side Effects of Cancer Treatment

What are side effects of cancer treatment?

Because cancer treatment may damage healthy cells and tissues, unwanted side effects sometimes occur. These side effects depend on many factors, including the type and extent of the treatment. Side effects may not be the same for each person, and they may even change from one treatment session to the next. Before treatment starts, the health care team will explain possible side effects and suggest ways to help the patient manage them.

The NCI provides helpful booklets about cancer treatments and coping with side effects, such as Radiation Therapy and You, Chemotherapy and You, and Eating Hints for Cancer Patients. See the sections "National Cancer Institute Information Resources" and "National Cancer Institute Booklets" for other sources of information about side effects.

Surgery

Patients are often uncomfortable for the first few days after surgery. However, medicine can usually control their pain. Patients should feel free to discuss pain relief with the doctor or nurse. It is also common for patients to feel tired or weak. The length of time it takes to recover from an operation varies for each patient.

After surgery to remove the thyroid and nearby tissues or organs, such as the parathyroid glands, patients may need to take medicine (thyroid hormone) or vitamin and mineral supplements (vitamin D and calcium) to replace the lost functions of these organs. In a few cases, certain nerves or muscles may be damaged or removed during surgery. If this happens, the patient may have voice problems or one shoulder may be lower than the other.

Radioactive iodine (I-131) therapy

Some patients have nausea and vomiting on the first day of I-131 therapy. Thyroid tissue remaining in the neck after surgery may become swollen and painful. If the thyroid cancer has spread to other parts of the body, the I-131 that collects there may cause pain and swelling.

Patients also may have a dry mouth or lose their sense of taste or smell for a short time after I-131 therapy. Chewing sugar-free gum or sucking on sugar-free hard candy may help.

During treatment, patients are encouraged to drink lots of water and other fluids. Because fluids help I-131 pass out of the body more quickly, the bladder's exposure to I-131 is reduced.

Because radioactive iodine therapy destroys the cells that make thyroid hormone, patients may need to take thyroid hormone pills to replace the natural hormone.

A rare side effect in men who received large doses of I-131 is loss of fertility. In women, I-131 may not cause loss of fertility, but some doctors suggest that women avoid pregnancy for one year after I-131 therapy.

Researchers have reported that a very small number of patients may developleukemia years after treatment with high doses of I-131.

Hormone treatment

Thyroid hormone pills seldom cause side effects. However, a few patients may get a rash or lose some of their hair during the first months of treatment.

The doctor will closely monitor the level of thyroid hormone in the blood during followup visits. Too much thyroid hormone may cause patients to lose weight and to feel hot and sweaty. It also may cause chest pain, cramps, and diarrhea. (The doctor may call this condition "hyperthyroidism.") If the thyroid hormone level is too low, the patient may gain weight, feel cold, and have dry skin and hair. (The doctor may call this condition "hypothyroidism.") If necessary, the doctor will adjust the dose so that the patient takes the right amount.

External radiation therapy

External radiation therapy may cause patients to become very tired as treatment continues. Resting is important, but doctors usually advise patients to try to stay as active as they can. In addition, when patients receive external radiation therapy, it is common for their skin to become red, dry, and tender in the treated area. When the neck is treated with external radiation therapy, patients may feel hoarse or have trouble swallowing. Other side effects depend on the area of the body that is treated. If chemotherapy is given at the same time, the side effects may worsen. The doctor can suggest ways to ease these problems.

Chemotherapy

The side effects of chemotherapy depend mainly on the specific drugs that are used. The most common side effects include nausea and vomiting, mouth sores,loss of appetite, and hair loss. Some side effects may be relieved with medicine.