Radiation therapy is used to treat many cancers, including those of the breast, cervix, ovaries, uterus, vocal cords and lymph nodes. It is either part of treatment or the only treatment for about half of all cancer patients.
Also called radiotherapy, X-ray therapy or irradiation, this treatment uses X-rays to kill cancer cells. The X-rays react with water and other chemical compounds in the body to create free radicals and peroxides, tiny particles that damage DNA.
Radiation therapy has several uses. It can destroy a tumor, either used alone or together with anticancer drugs. It also can shrink tumors, either to make surgical removal easier or to relieve pain in patients whose tumors can’t be removed.
Although all human cells are damaged by radiation therapy, those that multiply quickly, which cancer cells do, are most affected. In addition, cancer cells are less able to repair the damage done by radiation than are normal cells. Radiation therapy usually is given five days a week over a period of weeks so that the cancer cells have little chance to recover.
To minimize damage to normal cells, radiation treatments are carefully planned. One part of this planning is called simulation. Radiation oncologists (specialists in the treatment of cancer with radiation therapy) use simulation to decide where they want the radiation to enter the body.
The machine used for simulation looks just like the one used for treatment, but regular X-rays are used and films made. The oncologist uses the films to outline the shape of the desired treatment area. A CT scan (a computerized X-ray image) may be used to gather additional information about the shape of the treatment area. When simulation is complete, the patient’s skin is marked with either temporary tattoos or paint to show the radiation therapist where the treatment is to be administered.
Although patients don’t feel anything as they are treated, some experience side effects. Exactly what side effects a patient develops and how troubling they are depends on the type of cancer and the treatment regimen. For example, patients who receive radiation therapy to the gastrointestinal tract, liver or brain are most likely to develop nausea and/or vomiting. Patients who receive treatment to the abdomen, pelvis or rectum may develop radiation enteritis, a malfunction of the bowels. Symptoms include nausea, vomiting, abdominal cramping, the frequent urge to have a bowel movement and watery diarrhea. Patients also may have to cope with irritated or thickened skin, swallowing difficulties, dry mouth and hair loss.
If you or a loved one is facing radiation treatment, talk with your healthcare provider to understand how it will affect you and what steps you can take to make the process easier.