Radiation Therapy Guide: What to Expect During Cancer Treatment

Overview

Radiation therapy (also called radiotherapy) is a common, effective cancer treatment that uses high-energy particles or waves (like X-rays, protons, or gamma rays) to destroy or damage cancer cells so they cannot grow and divide. It works by targeting the DNA inside cancer cells, which stops them from reproducing. Radiation may be used alone, or combined with surgery, chemotherapy, or immunotherapy to treat many types of cancer, including solid tumors (like breast, lung, or prostate cancer) and some blood cancers. Your care team will customize your treatment plan to target your specific cancer while protecting as much healthy tissue as possible.

Common Side Effects of Radiation Therapy

Side effects vary widely depending on the part of your body receiving radiation, the dose, and your overall health. Most side effects are temporary and go away a few weeks after treatment ends, but some long-term effects may appear months or years later.

• Fatigue (tiredness that doesn’t improve with rest)
• Skin irritation, redness, or dryness in the treatment area (similar to a mild sunburn)
• Hair loss in the treatment area only
• Nausea, vomiting, or diarrhea (if the abdomen or pelvis is treated)
• Mouth sores, dry mouth, or difficulty swallowing (if the head or neck is treated)
• Urinary urgency or discomfort (if the pelvic area is treated)

Causes & Risk Factors for Side Effects

Side effects from radiation therapy happen because the high-energy beams can also affect nearby healthy cells, in addition to cancer cells. Factors that increase your risk of more severe side effects include: receiving a high dose of radiation, having radiation to a large area of the body, having pre-existing health conditions (like diabetes or autoimmune disorders), smoking, or having had radiation treatment in the same area before.

Diagnosis & Treatment Planning

Before starting radiation therapy, you will have a consultation with a radiation oncologist (a doctor who specializes in cancer treatment with radiation) to determine if it is the right option for your cancer. You will then have a simulation appointment, where your care team uses imaging tests (like CT, MRI, or PET scans) to map the exact location and shape of your tumor. Small tattoos or marks may be placed on your skin to help guide the radiation beams to the correct spot during each treatment session. Your team will also calculate the exact dose of radiation you need to target the cancer while sparing healthy tissue.

Treatment & Management

The most common type of radiation therapy is external beam radiation, where a machine outside your body delivers targeted radiation to the tumor. Treatments are usually given 5 days a week for 1 to 8 weeks, depending on your cancer type and treatment goals. Each session lasts 10 to 30 minutes, and you will not feel the radiation beams during treatment. Brachytherapy, another common type, involves placing small radioactive seeds or sources directly inside or next to the tumor, so less radiation reaches surrounding healthy tissue. Your care team may also recommend medications, dietary changes, or skin care routines to manage side effects as they arise.

Living With It During and After Treatment

Many people are able to work, care for their families, and participate in light activities during radiation treatment, though you may need to adjust your schedule based on how you feel. It is important to attend all scheduled treatment sessions for the best possible outcome. After treatment ends, you will have regular follow-up appointments with your care team to monitor for cancer recurrence and manage any long-term side effects. Eating a balanced diet, staying hydrated, and avoiding tobacco and excessive alcohol can help support your body’s healing and overall health during and after treatment.