Radiotherapy: Practical Guide for Patients

Radiotherapy uses high-energy beams to shrink or destroy tumors. Nearly half of people with cancer get radiation at some point, either alone or with surgery and drugs. If you or a loved one is starting treatment, this page gives clear, useful steps to make care less stressful and more effective.

What to expect during treatment

First you’ll meet the radiation team—radiation oncologist, therapist, and nurse. They’ll plan treatment with a CT scan and may mark small skin dots or use temporary tattoos to line up machines the same way each day. Most external beam sessions take 10–30 minutes, but the planning visit may last an hour or more.

Treatment schedules vary. A common plan is short daily sessions, five days a week for several weeks. Some cases use fewer, higher-dose sessions (stereotactic) or internal radiation (brachytherapy). Ask your team which type fits your situation and how many visits to expect.

Common side effects and simple ways to manage them

Side effects depend on the area being treated. They usually start after a week or two and often get better several weeks after finishing radiation. Fatigue is the most common; plan low-energy days and short rest breaks. Light exercise, like short walks, can actually reduce fatigue for many people.

Skin in the treated area can get red, dry, or tender. Use mild soap, pat dry, and apply the moisturizer your clinic recommends. Don’t use strong perfumes, exfoliants, or heat on that skin. Protect treated skin from sun for at least a year.

If radiation hits the head or neck, expect sore mouth, dry throat, and taste changes. Rinse with a gentle salt-and-baking-soda mouthwash (ask your nurse for a recipe) and choose soft, moist foods. For chest or lung radiation, you might cough or feel short of breath—tell your team if breathing gets worse.

Pelvic radiation can cause diarrhea, bladder irritation, or sexual side effects. Drink enough water, eat low-fiber foods when symptoms flare, and ask about meds that reduce diarrhea. For sexual or fertility concerns, talk to your team before treatment starts—preservation options may be available.

If you’re taking cancer drugs (for example targeted drugs like ribociclib), always tell the radiation team. Some medicines change side effects or timing. Your team will coordinate care so treatments don’t overlap harmfully.

Keep a simple checklist: bring meds list, wear comfortable clothes, arrange rides for tired days, and note any skin or bowel changes. Ask how to handle missed sessions and who to call after hours.

Red flags to report right away: high fever, sudden severe pain, new or worsening shortness of breath, heavy bleeding, or signs of infection at the treatment site. If anything feels very wrong, reach out—don’t wait for the next appointment.

Radiation teams expect questions, so bring them. Ask about goals of treatment, expected side effects, daily practical tips, and when you can resume work or driving. Small planning steps make a big difference in comfort and recovery.

Want targeted advice for your area of treatment? Bring this guide to your appointment and ask for written instructions specific to your plan and medicines.